From: krnet-bounces@mylist.net on behalf of krnet-request@mylist.net Sent: Wednesday, October 22, 2003 7:02 PM To: krnet@mylist.net Subject: KRnet Digest, Vol 196, Issue 2 Send KRnet mailing list submissions to krnet@mylist.net To subscribe or unsubscribe via the World Wide Web, visit http://mylist.net/listinfo/krnet or, via email, send a message with subject or body 'help' to krnet-request@mylist.net You can reach the person managing the list at krnet-owner@mylist.net When replying, please edit your Subject line so it is more specific than "Re: Contents of KRnet digest..." Today's Topics: 1. Re: VW Engine Rockers (Mark Langford) 2. Re: VW Engine Rockers 3. Re: VW Engine Rockers (Wayne Israelsen) 4. Re: finishing composites (pole shed) 5. Re: Painting tips (William Clapp) 6. Filling Pin Holes (Mark Jones) 7. Ordering plans - kit (Steve and Lori McGee) 8. Re: Ordering plans - kit (Mark Jones) 9. Re: Ordering plans - kit (Steve and Lori McGee) 10. Re: Ordering plans - kit (Mark Langford) 11. Re: VW Engine Rockers 12. Re: VW Engine Rockers 13. Re: VW Engine Rockers (Ross Youngblood) 14. Re: Filling Pin Holes (Dan Heath) ---------------------------------------------------------------------- Date: Wed, 22 Oct 2003 14:14:05 -0500 From: "Mark Langford" To: "KR builders and pilots" Subject: Re: KR>VW Engine Rockers Message-ID: <00c401c398d0$aa612aa0$5e0ca58c@tbe.com> References: <1093.66.196.7.14.1066835478.squirrel@www.vvm.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 1 Brian Douglas wrote: > I'm doing a top averhaul on my Revmastr 2100. I ordered new head > and pistons etc... My question, when I took the thing apart there > were shims under the rockers. What is the proper way to shim the > rockers? Are they there just so you can get the proper valve > adjustment screw engagement? or should I just put it togeather and > see how the valves adjust, then shim if I have a problem? The shims are there to get the valve train geometry right. The "right" way to do it is to make custom pushrods the right length, but shims under the rocker stands will work within limits. The fact that they are there at all is a sign that somebody knew at least something about it when they assembled the engine. Although the Corvair is somewhat different, the principle is the same, and shown in excruciating detail on my Corvair valve train geometry page at http://home.hiwaay.net/~langford/corvair/valve_geometry.html . Proper valve train geometry is vital to long valve guide life. Improper geometry is responsible for a lot of (most) valve guide wear problems. The bottom line is that you want to shim the stand out so that the rocker tip is in the middle of its sweep across the end of the stem at half lift. So check it at full and no lift and the tip should be equidistant from the center of the stem (vertically). Mark Langford, Huntsville, AL N56ML at hiwaay.net see KR2S project N56ML at http://home.hiwaay.net/~langford ------------------------------ Date: Wed, 22 Oct 2003 16:04:06 EDT From: Veeduber@aol.com To: krnet@mylist.net Subject: Re: KR>VW Engine Rockers Message-ID: <3c.368c19ba.2cc83cb6@aol.com> Content-Type: text/plain; charset="US-ASCII" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 2 In a message dated 10/22/03 12:12:01 PM Pacific Daylight Time, n56ml@hiwaay.net writes: > The shims are there to get the valve train geometry right. The > "right" way to do it is to make custom pushrods the right length, but > shims under the rocker stands will work within limits. ------------------------------------------------------------------ On the VW engine the valves are at an angle of 9.5 degrees. Depending on the ratio of the rocker and the lift of the cam, to achieve proper valve train geometry on a VW you may have to adjust both the tower height, the rocker arm position (vertically) and the push-rod length, which provides maximum transmission of lift 'around the corner' at only ONE particular length. This is easy to illustrate in a classroom... or with lots of charts -- but difficult to get across via email without getting into trig The shims you found on the old heads are going to be relative to the length of the valves and the wear (if any) of your rockers, plus the assumption that you're using the same type of adjusters. The length of the push-rods is going to be relative to all of the ABOVE plus the width of the engine (actually, the distance from the centerline of the camshaft to the centerline of EACH rocker-shaft [so don't get the banks mixed up; they could be of different length]. All of which assumes your new heads are identical to your old heads, right down to the freckles on their fanny. If not, you gotta start over again, set up the valve train geometry from scratch. Or do like most engine builders and simply ignore it. No big deal. Get your valve train geometry wrong you only give away up to 20% of your power. :-) (Chorus: 'THAT CAN'T BE RIGHT! THAT CAN'T BE RIGHT!' ) (From the Conventional Wisdom Opera, Act II) -R.S.Hoover PS - Actually, a 20% hit would be the Worse-Case. But the typical dune buggy engine gives away a solid 10% of its potential output. There's even room for improvement in a crate engine from the Puebla plant, thanks to the normal manufacturing tolerances. Find a Formula V race-engine builder, rattle his cage, get ready to be impressed with some serious attention to detail. ------------------------------ Date: Wed, 22 Oct 2003 15:08:30 -0700 From: "Wayne Israelsen" To: "KR builders and pilots" Subject: Re: KR>VW Engine Rockers Message-ID: <00cf01c398e9$077adc00$6701a8c0@HISPEEDWIRELESS.COM> References: <3c.368c19ba.2cc83cb6@aol.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 3 Hey all this is why I used to rebuild my VW in my sandrail every year and now since being converted to the R.S Hoover way of Do it right and maintain it. I have not needed an overhaul since 97. Thanks Wayne ----- Original Message ----- From: To: Sent: Wednesday, October 22, 2003 1:04 PM Subject: Re: KR>VW Engine Rockers > In a message dated 10/22/03 12:12:01 PM Pacific Daylight Time, > n56ml@hiwaay.net writes: > > > The shims are there to get the valve train geometry right. The > > "right" way > > to do it is to make custom pushrods the right length, but shims > > under the > > rocker stands will work within limits. > > ------------------------------------------------------------------ > > On the VW engine the valves are at an angle of 9.5 degrees. Depending > on the > ratio of the rocker and the lift of the cam, to achieve proper valve > train geometry on a VW you may have to adjust both the tower height, > the rocker arm > position (vertically) and the push-rod length, which provides maximum > transmission of lift 'around the corner' at only ONE particular > length. This is easy to > illustrate in a classroom... or with lots of charts -- but difficult > to get > across via email without getting into trig The shims you found on the > old heads are going to be relative to the length of the valves and the > wear (if any) > of your rockers, plus the assumption that you're using the same type > of adjusters. The length of the push-rods is going to be relative to > all of the ABOVE > plus the width of the engine (actually, the distance from the > centerline of the > camshaft to the centerline of EACH rocker-shaft [so don't get the > banks mixed > up; they could be of different length]. > > All of which assumes your new heads are identical to your old heads, > right down to the freckles on their fanny. If not, you gotta start > over again, set up > the valve train geometry from scratch. Or do like most engine > builders and > simply ignore it. > > No big deal. Get your valve train geometry wrong you only give away up to > 20% of your power. :-) > > (Chorus: 'THAT CAN'T BE RIGHT! THAT CAN'T BE RIGHT!' ) > > (From the Conventional Wisdom Opera, Act II) > > -R.S.Hoover > > PS - Actually, a 20% hit would be the Worse-Case. But the typical > dune buggy > engine gives away a solid 10% of its potential output. There's even > room for > improvement in a crate engine from the Puebla plant, thanks to the > normal manufacturing tolerances. Find a Formula V race-engine > builder, rattle his cage, > get ready to be impressed with some serious attention to detail. > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html > ------------------------------ Date: Wed, 22 Oct 2003 15:13:39 -0700 (PDT) From: pole shed To: KR builders and pilots Subject: Re: KR>finishing composites Message-ID: <20031022221339.9450.qmail@web11004.mail.yahoo.com> In-Reply-To: <000d01c3989a$746f90c0$8d00a8c0@dad> Content-Type: text/plain; charset=us-ascii MIME-Version: 1.0 Precedence: list Message: 4 Thanks Ed. Still in the drooling stage, but learning. Greatly appreciate you sharing this. Larry Lipe, Carbondale,IL __________________________________ Do you Yahoo!? The New Yahoo! Shopping - with improved product search http://shopping.yahoo.com ------------------------------ Date: Wed, 22 Oct 2003 19:20:38 -0400 From: "William Clapp" To: "KR builders and pilots" Subject: Re: KR>Painting tips Message-ID: <000d01c398f3$1b578020$05fcd241@clapp> References: <002501c3978f$813bc000$09fcd241@clapp> <3F9506F6.000055.02224@Computer> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 5 Dan - "orange peel" comes from a couple problems. Most times if I get an orange peel effect it is because I dont have the paint thinned out enough and it does not get on the surface smoothly. If you have sanded the surface "baby butt smooth" and then apply several coats of propperly thinned paint it will be smooth. Paint applied too dryly begins the orange peel effect. It is critical to get the viscosity right - too thin and the paint will run. Always use appropriate thinner. Sometimes it can be the fact the gun size may be too small or too low in pressure and not make the paint flow properly. Hope this helps. Bill ----- Original Message ----- From: Dan Heath To: Sent: Tuesday, October 21, 2003 6:14 AM Subject: Re: KR>Painting tips Bill, What is the best way to avoid "orange peel"? N64KR Daniel R. Heath - Columbia, SC DanRH@KR-Builder.org See you in Mt. Vernon - 2004 - KR Gathering See our KR at http://KR-Builder.org - Click on the pic See our EAA Chapter 242 at http://EAA242.org _______________________________________________ see KRnet list details at http://www.krnet.org/instructions.html ------------------------------ Date: Wed, 22 Oct 2003 18:38:00 -0500 From: "Mark Jones" To: "KR Net" Subject: KR>Filling Pin Holes Message-ID: <004a01c398f5$87f07c80$6401a8c0@wi.rr.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 6 Has anyone tried the following method? What are the methods you use to = fill pin holes??? Pinholes=20 These are tiny voids, bubbles and pits caused by air mixed into the = filler. They are invisible until the minute you start spraying the first = coat of primer. They can give you a big headache if you attack them the = wrong way. You might have heard horror stories of builders spraying coat = after coat of primer trying to get rid of them. The bottom line is, you = cannot fill the pinholes by spraying. Yes, if you keep spraying long = enough, eventually they will disappear, but they will not be filled, = they will be bridged. Bridged pinholes can cause the painted surface to = develop little pimple like bumps on the sun when the paint softens some = and the trapped air expands with the heat.=20 Luckily, we have a simple effective way how to deal with pinholes before = we even see any. Vacuum the surface real well to remove any dust and = then squeegee pure epoxy resin over the surface. The coat is very thin = and the amount of resin is mall, you are basically just wetting the = surface, give it some time to soak in and squeegee off all the excess. = The resin has very low surface tension so it flows into all those small = voids and because unlike primers it doesn't contain any volatiles it = doesn't shrink as it cures so the fill is complete. The second benefit = of this step is that the resins hardens the top shell of the micro, = making it more durable.=20 A word of caution, many epoxy resins do not cure well and stay gummy at = very thin coat, especially in humid condition. If yours is one of those = or you are not sure, use the West system epoxy for this.=20 When this top coat is cured sand it lightly with 100 just to break the = gloss, and you are ready for the primer.=20 Mark Jones (N886MJ) Wales, WI USA=20 E-mail me at flykr2s@wi.rr.com Visit my KR-2S CorvAIRCRAFT web site at =20 http://mywebpage.netscape.com/n886mj/homepage.html ------------------------------ Date: Wed, 22 Oct 2003 18:59:37 -0500 From: "Steve and Lori McGee" To: Subject: KR>Ordering plans - kit Message-ID: <004b01c398f8$8c8b0be0$0302a8c0@lori8v5h2xi9m3> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 7 Can someone point me to a website or phone # to get the current list and = prices for plans, etc.. I have tried the URL in some web pages and they = keep coming up "not found". I am ready to grow my wings and am about = 100% set on the KR2S. I would also like to see some KR2s if there are = any in my area. (Central Wisc.) Any help would be appreciated. Thanks! Steve McGee ------------------------------ Date: Wed, 22 Oct 2003 19:07:33 -0500 From: "Mark Jones" To: "KR builders and pilots" Subject: Re: KR>Ordering plans - kit Message-ID: <005a01c398f9$a8ca1340$6401a8c0@wi.rr.com> References: <004b01c398f8$8c8b0be0$0302a8c0@lori8v5h2xi9m3> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 8 Hi Steve, I am 25 miles west of Milwaukee off I-94. The Rand website is www.fly-kr.com however I too noticed earlier today this site was not working. Mark Jones (N886MJ) Wales, WI USA E-mail me at flykr2s@wi.rr.com Visit my KR-2S CorvAIRCRAFT web site at http://mywebpage.netscape.com/n886mj/homepage.html ----- Original Message ----- From: "Steve and Lori McGee" To: Sent: Wednesday, October 22, 2003 6:59 PM Subject: KR>Ordering plans - kit Can someone point me to a website or phone # to get the current list and prices for plans, etc.. I have tried the URL in some web pages and they keep coming up "not found". I am ready to grow my wings and am about 100% set on the KR2S. I would also like to see some KR2s if there are any in my area. (Central Wisc.) Any help would be appreciated. Thanks! Steve McGee _______________________________________________ see KRnet list details at http://www.krnet.org/instructions.html ------------------------------ Date: Wed, 22 Oct 2003 19:36:38 -0500 From: "Steve and Lori McGee" To: "KR builders and pilots" Subject: Re: KR>Ordering plans - kit Message-ID: <005501c398fd$b8db1820$0302a8c0@lori8v5h2xi9m3> References: <004b01c398f8$8c8b0be0$0302a8c0@lori8v5h2xi9m3> <005a01c398f9$a8ca1340$6401a8c0@wi.rr.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 9 Thank you - guess I will have to wait or get a phone number. Can we set up a time when I can see your plane? Steve ----- Original Message ----- From: "Mark Jones" To: "KR builders and pilots" Sent: Wednesday, October 22, 2003 7:07 PM Subject: Re: KR>Ordering plans - kit > Hi Steve, > I am 25 miles west of Milwaukee off I-94. The Rand website is > www.fly-kr.com however I too noticed earlier today this site was not > working. > > Mark Jones (N886MJ) > Wales, WI USA > E-mail me at flykr2s@wi.rr.com > Visit my KR-2S CorvAIRCRAFT web site at > http://mywebpage.netscape.com/n886mj/homepage.html > > > ----- Original Message ----- > From: "Steve and Lori McGee" > To: > Sent: Wednesday, October 22, 2003 6:59 PM > Subject: KR>Ordering plans - kit > > > Can someone point me to a website or phone # to get the current list > and prices for plans, etc.. I have tried the URL in some web pages and they > keep coming up "not found". I am ready to grow my wings and am about 100% > set on the KR2S. I would also like to see some KR2s if there are any > in my > area. (Central Wisc.) Any help would be appreciated. Thanks! > > Steve McGee > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html > > > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html > > ------------------------------ Date: Wed, 22 Oct 2003 19:40:28 -0500 From: "Mark Langford" To: "KR builders and pilots" Subject: Re: KR>Ordering plans - kit Message-ID: <20f301c398fe$41d61490$1202a8c0@basement> References: <004b01c398f8$8c8b0be0$0302a8c0@lori8v5h2xi9m3> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 10 Steve McGee wrote: > Can someone point me to a website or phone # to get the current list > and prices for plans, etc.. I have tried the URL in some web pages and they keep coming up "not found". < I'll try to figure out what's going on, but in the meantime, try http://66.70.235.96 . Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ------------------------------ Date: Wed, 22 Oct 2003 20:48:54 EDT From: Veeduber@aol.com To: krnet@mylist.net Subject: Re: KR>VW Engine Rockers Message-ID: <25.3fc8810c.2cc87f76@aol.com> Content-Type: text/plain; charset="US-ASCII" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 11 In a message dated 10/22/03 3:12:57 PM Pacific Daylight Time, wayne@hispeedwireless.com writes: > Hey all this is why I used to rebuild my VW in my sandrail every year > and now since being converted to the R.S Hoover way of Do it right and > maintain it. I have not needed an overhaul since 97. > ------------------------------------------------------------ Now my hat don't fit :-) ------------------------------------ Actually, it isn't too difficult to get the VW valve train geometry dead-on, it just takes a bit of time. I'm told Santa is bringing me a digital camera this Christmas so I'll be able to post some pictures of the tools I've made for setting up valve train geometry. 'VW Trends' published a rather lengthy article titled 'Dialing in Your Cam' which describes the first stage of the process. Once you've got the cam dialed in and have measured the actual lift at the cam the remaining pieces of the puzzle fall into place. (If you're into engines there's a lot more poop about PORSCHE valve train geometry than you'll ever find for the VW. You CAN set-up a VW properly... but the factory never did. Close enough was good enough.) The whole idea behind setting up the valve train geometry is to find the point of minimum loss in the process of turning an upward push, delivered at an angle of about three degrees, into a downward shove, delivered at an angle of about nine and a half. The two basic principles involved are the fact that the push-rod and valve can only move in a linear fashion (or nearly so) while the rocker arm can only move through an arc, with the input arc typically having a shorter radius than the output (that is, the rocker ratio is 1.1 to 1, 1.25 to 1 and so forth. Stock is 1.1, after-market rockers go up to 1.45 and just to make things interesting, sometimes the rockers actually come pretty close to those numbers :-) (Nowadays, you gotta check EVERYTHING.) The tricky bit is HOW you go about matching the mid-point of the linear push (or shove) to the tangental mid-point of the arc. Think about it for a minute. Push the DOOR open with a broom stick... Broom stick travels pretty much in a straight line but the door has to swing thru an arc. No matter WHAT YOU DO the path traveled by the broomstick will always be LESS than the arc traveled by the door. That is, the broom stick travels on the chord of the arc whereas the door follows the radius of the arc. Bottom line, there's always some loss. Your job is to arrange things so as to give the LEAST loss, which also translates as the MOST motion at the valve. So you find out how much the cam pushes the follower and the follower pushes the push-rod and the rocker swings through an arc... and you raise the rocker up or lower it down so that the mid-point of its arc perfectly matches the mid-point of the linear travel of the valve and you adjust the length of your valve stems (if needed) and the length of your push-rod (ALWAYS needed) and then you run the engine on the test stand for five or six hours and discover everything has changed anyway... :-) Actually, you crank in a bit of Texas Windage when you do the set-up, so that as the engine wears in and you come back and re-torque the heads and tweak the valves, the anticipated amount of wear will have caused the tangental point to be within a gnat's ass of dead on, or so close that it's well within the range of your adjusting screw. (Gnat's ass is a technical term meaning five-tenthousandths of an inch if the wind is from a south and its a Tuesday. Work with me here; you'll pick it up as we go along.) I suppose that's really the tricky part, knowing the amount you have to stay on the high side of spec so that as the engine wears in it runs sweet instead of sour. A lot of that part of valve train geometry won't make a lot of sense because nowadays, with "Volkswagen" parts coming from all over the world, from factories Volkswagen never heard of and without any quality control to speak of, the initial wear-in coefficient is based on guesses and good intentions. But ANY attention you pay to your valve train geometry will usually be rewarded with SOME improvement in your volumetric efficiency. On the other hand, I've seen lots of engines that gave away as much as 25% of their lift at the valve from being thrown together right out of the box. The engine will tell you. Trouble is, most folks don't understand what it sez. --------------------------------------------------------------- Didja see how Mike did the set-up on his Corvair? That photo of the roller-rocker just kissing the valve stem? For VW's I made a jig so I can set a valve at its computed half-height. Then I paint the stem with Dykem and have a scriber on the rocker arm so that when it's set at the proper height it draws a line across across the face of the valve stem. An optical comparitor shows me how close I've come to the center of the valve stem for that particular setting. That probably sounds sorta gim-crack but I haven't found any better way of doing it. Actually, it's not too bad of a method for a guys like me with greasy fingernails instead of engineering degrees because I'm not actually MEASURING anything in quantified terms, I'm simply COMPARING things, peering through a glass to see if the line is too high, too low or just right. Raising the pivot point of the rocker will cause the line to fall a little lower, lowering the tower will raise it. Once you get it dead on you go back and re-run the numbers to see if the input is close enough to tangental. If not, you can use a different valve or a different tower. The height of the tower and the length of the valve stem don't really matter (within reason) so long as the mid-points of the linear travel exactly match the tangental points on the arcs. And keep in mind, you've got four rockers on the same shaft; you're seeking HARMONY rather than an identical numerical value. Then it hums. 'Free' horsepower. More power for the same fuel. Wears at a slower rate. Runs a lot smoother becuase the valve train stresses are more evenly distributed... or something. It also causes you to grow long, blond Surfer God hair allll over your bod-dee. Actually, I was just kidding about that last part. (As he tosses his long, blond, Surfer God hair back from his noble sunburnt brow. Being a native Californian isn't as easy as it looks.) Engineering types get off on what happens when you DON'T pay attention to the valve train geometry, as in calculating how fast the engine will trash itself, or how low the efficiency can fall before EPA will sue your ass back into the Stone Age. The Stone Age is where you'll find all those VW 'experts' who never mention valves at all, telling the Yuppies, "This engine will RUST OUT before it WEARS OUT." Uh, right, John. -R.S.Hoover ------------------------------ Date: Wed, 22 Oct 2003 20:53:35 EDT From: Veeduber@aol.com To: krnet@mylist.net Subject: Re: KR>VW Engine Rockers Message-ID: <2b.4a14c4f1.2cc8808f@aol.com> Content-Type: text/plain; charset="US-ASCII" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 12 In a message dated 10/22/03 3:12:57 PM Pacific Daylight Time, wayne@hispeedwireless.com writes: > Hey all this is why I used to rebuild my VW in my sandrail every year > and now since being converted to the R.S Hoover way of Do it right and > maintain it. I have not needed an overhaul since 97. > ------------------------------------------------------------ Now my hat don't fit :-) ------------------------------------ Actually, it isn't too difficult to get the VW valve train geometry dead-on, it just takes a bit of time. I'm told Santa is bringing me a digital camera this Christmas so I'll be able to post some pictures of the tools I've made for setting up valve train geometry. 'VW Trends' published a rather lengthy article titled 'Dialing in Your Cam' which describes the first stage of the process. Once you've got the cam dialed in and have measured the actual lift at the cam the remaining pieces of the puzzle fall into place. (If you're into engines there's a lot more poop about PORSCHE valve train geometry than you'll ever find for the VW. You CAN set-up a VW properly... but the factory never did. Close enough was good enough.) The whole idea behind setting up the valve train geometry is to find the point of minimum loss in the process of turning an upward push, delivered at an angle of about three degrees, into a downward shove, delivered at an angle of about nine and a half. The two basic principles involved are the fact that the push-rod and valve can only move in a linear fashion (or nearly so) while the rocker arm can only move through an arc, with the input arc typically having a shorter radius than the output (that is, the rocker ratio is 1.1 to 1, 1.25 to 1 and so forth. Stock is 1.1, after-market rockers go up to 1.45 and just to make things interesting, sometimes the rockers actually come pretty close to those numbers :-) (Nowadays, you gotta check EVERYTHING.) The tricky bit is HOW you go about matching the mid-point of the linear push (or shove) to the tangental mid-point of the arc. Think about it for a minute. Push the DOOR open with a broom stick... Broom stick travels pretty much in a straight line but the door has to swing thru an arc. No matter WHAT YOU DO the path traveled by the broomstick will always be LESS than the arc traveled by the door. That is, the broom stick travels on the chord of the arc whereas the door follows the radius of the arc. Bottom line, there's always some loss. Your job is to arrange things so as to give the LEAST loss, which also translates as the MOST motion at the valve. So you find out how much the cam pushes the follower and the follower pushes the push-rod and the rocker swings through an arc... and you raise the rocker up or lower it down so that the mid-point of its arc perfectly matches the mid-point of the linear travel of the valve and you adjust the length of your valve stems (if needed) and the length of your push-rod (ALWAYS needed) and then you run the engine on the test stand for five or six hours and discover everything has changed anyway... :-) Actually, you crank in a bit of Texas Windage when you do the set-up, so that as the engine wears in and you come back and re-torque the heads and tweak the valves, the anticipated amount of wear will have caused the tangental point to be within a gnat's ass of dead on, or so close that it's well within the range of your adjusting screw. (Gnat's ass is a technical term meaning five-tenthousandths of an inch if the wind is from a south and its a Tuesday. Work with me here; you'll pick it up as we go along.) I suppose that's really the tricky part, knowing the amount you have to stay on the high side of spec so that as the engine wears in it runs sweet instead of sour. A lot of that part of valve train geometry won't make a lot of sense because nowadays, with "Volkswagen" parts coming from all over the world, from factories Volkswagen never heard of and without any quality control to speak of, the initial wear-in coefficient is based on guesses and good intentions. But ANY attention you pay to your valve train geometry will usually be rewarded with SOME improvement in your volumetric efficiency. On the other hand, I've seen lots of engines that gave away as much as 25% of their lift at the valve from being thrown together right out of the box. The engine will tell you. Trouble is, most folks don't understand what it sez. --------------------------------------------------------------- Didja see how Mike did the set-up on his Corvair? That photo of the roller-rocker just kissing the valve stem? For VW's I made a jig so I can set a valve at its computed half-height. Then I paint the stem with Dykem and have a scriber on the rocker arm so that when it's set at the proper height it draws a line across across the face of the valve stem. An optical comparitor shows me how close I've come to the center of the valve stem for that particular setting. That probably sounds sorta gim-crack but I haven't found any better way of doing it. Actually, it's not too bad of a method for a guys like me with greasy fingernails instead of engineering degrees because I'm not actually MEASURING anything in quantified terms, I'm simply COMPARING things, peering through a glass to see if the line is too high, too low or just right. Raising the pivot point of the rocker will cause the line to fall a little lower, lowering the tower will raise it. Once you get it dead on you go back and re-run the numbers to see if the input is close enough to tangental. If not, you can use a different valve or a different tower. The height of the tower and the length of the valve stem don't really matter (within reason) so long as the mid-points of the linear travel exactly match the tangental points on the arcs. And keep in mind, you've got four rockers on the same shaft; you're seeking HARMONY rather than an identical numerical value. Then it hums. 'Free' horsepower. More power for the same fuel. Wears at a slower rate. Runs a lot smoother becuase the valve train stresses are more evenly distributed... or something. It also causes you to grow long, blond Surfer God hair allll over your bod-dee. Actually, I was just kidding about that last part. (As he tosses his long, blond, Surfer God hair back from his noble sunburnt brow. Being a native Californian isn't as easy as it looks.) Engineering types get off on what happens when you DON'T pay attention to the valve train geometry, as in calculating how fast the engine will trash itself, or how low the efficiency can fall before EPA will sue your ass back into the Stone Age. The Stone Age is where you'll find all those VW 'experts' who never mention valves at all, telling the Yuppies, "This engine will RUST OUT before it WEARS OUT." Uh, right, John. -R.S.Hoover ------------------------------ Date: Thu, 23 Oct 2003 02:27:49 +0100 From: "Ross Youngblood" To: "KR builders and pilots" Subject: Re: KR>VW Engine Rockers Message-ID: <20031023012750.32032.qmail@operamail.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 13 This is the type of stuff that we all pay good $$ to read about on KR-net! Thanks! This was well worth my hefty annual subscription fee! -- Ross More of this, and less of the other stuff please! ----- Original Message ----- From: Veeduber@aol.com Date: Wed, 22 Oct 2003 20:53:35 EDT To: krnet@mylist.net Subject: Re: KR>VW Engine Rockers > In a message dated 10/22/03 3:12:57 PM Pacific Daylight Time, > wayne@hispeedwireless.com writes: > > > Hey all this is why I used to rebuild my VW in my sandrail every > > year and now since being converted to the R.S Hoover way of Do it > > right and maintain it. I have not needed an overhaul since 97. > > > > ------------------------------------------------------------ > > Now my hat don't fit :-) > > ------------------------------------ > > Actually, it isn't too difficult to get the VW valve train geometry > dead-on, > it just takes a bit of time. I'm told Santa is bringing me a digital camera > this Christmas so I'll be able to post some pictures of the tools I've made for > setting up valve train geometry. 'VW Trends' published a rather lengthy > article titled 'Dialing in Your Cam' which describes the first stage of the > process. Once you've got the cam dialed in and have measured the actual lift at the > cam the remaining pieces of the puzzle fall into place. > > (If you're into engines there's a lot more poop about PORSCHE valve > train > geometry than you'll ever find for the VW. You CAN set-up a VW properly... but > the factory never did. Close enough was good enough.) > > The whole idea behind setting up the valve train geometry is to find > the > point of minimum loss in the process of turning an upward push, delivered at an > angle of about three degrees, into a downward shove, delivered at an angle of > about nine and a half. The two basic principles involved are the fact that the > push-rod and valve can only move in a linear fashion (or nearly so) while the > rocker arm can only move through an arc, with the input arc typically having a > shorter radius than the output (that is, the rocker ratio is 1.1 to 1, 1.25 > to 1 and so forth. Stock is 1.1, after-market rockers go up to 1.45 and just > to make things interesting, sometimes the rockers actually come pretty close to > those numbers :-) (Nowadays, you gotta check EVERYTHING.) > > The tricky bit is HOW you go about matching the mid-point of the > linear push > (or shove) to the tangental mid-point of the arc. > > Think about it for a minute. Push the DOOR open with a broom stick... > Broom > stick travels pretty much in a straight line but the door has to swing thru > an arc. No matter WHAT YOU DO the path traveled by the broomstick will always > be LESS than the arc traveled by the door. That is, the broom stick travels > on the chord of the arc whereas the door follows the radius of the arc. > > Bottom line, there's always some loss. Your job is to arrange things > so as > to give the LEAST loss, which also translates as the MOST motion at the valve. > So you find out how much the cam pushes the follower and the follower pushes > the push-rod and the rocker swings through an arc... and you raise the rocker > up or lower it down so that the mid-point of its arc perfectly matches the > mid-point of the linear travel of the valve and you adjust the length of your > valve stems (if needed) and the length of your push-rod (ALWAYS needed) and then > you run the engine on the test stand for five or six hours and discover > everything has changed anyway... :-) > > Actually, you crank in a bit of Texas Windage when you do the set-up, > so that > as the engine wears in and you come back and re-torque the heads and tweak > the valves, the anticipated amount of wear will have caused the tangental point > to be within a gnat's ass of dead on, or so close that it's well within the > range of your adjusting screw. (Gnat's ass is a technical term meaning > five-tenthousandths of an inch if the wind is from a south and its a Tuesday. Work > with me here; you'll pick it up as we go along.) > > I suppose that's really the tricky part, knowing the amount you have > to stay > on the high side of spec so that as the engine wears in it runs sweet instead > of sour. A lot of that part of valve train geometry won't make a lot of sense > because nowadays, with "Volkswagen" parts coming from all over the world, > from factories Volkswagen never heard of and without any quality control to speak > of, the initial wear-in coefficient is based on guesses and good intentions. > > But ANY attention you pay to your valve train geometry will usually be > rewarded with SOME improvement in your volumetric efficiency. On the other hand, > I've seen lots of engines that gave away as much as 25% of their lift at the > valve from being thrown together right out of the box. > > The engine will tell you. Trouble is, most folks don't understand > what it > sez. > > --------------------------------------------------------------- > > Didja see how Mike did the set-up on his Corvair? That photo of the > roller-rocker just kissing the valve stem? For VW's I made a jig so I can set a valve > at its computed half-height. Then I paint the stem with Dykem and have a > scriber on the rocker arm so that when it's set at the proper height it draws a > line across across the face of the valve stem. An optical comparitor shows me > how close I've come to the center of the valve stem for that particular > setting. > > That probably sounds sorta gim-crack but I haven't found any better > way of > doing it. Actually, it's not too bad of a method for a guys like me with greasy > fingernails instead of engineering degrees because I'm not actually MEASURING > anything in quantified terms, I'm simply COMPARING things, peering through a > glass to see if the line is too high, too low or just right. > > Raising the pivot point of the rocker will cause the line to fall a > little > lower, lowering the tower will raise it. Once you get it dead on you go back > and re-run the numbers to see if the input is close enough to tangental. If > not, you can use a different valve or a different tower. The height of the tower > and the length of the valve stem don't really matter (within reason) so long > as the mid-points of the linear travel exactly match the tangental points on > the arcs. And keep in mind, you've got four rockers on the same shaft; you're > seeking HARMONY rather than an identical numerical value. > > Then it hums. 'Free' horsepower. More power for the same fuel. > Wears at a > slower rate. Runs a lot smoother becuase the valve train stresses are more > evenly distributed... or something. It also causes you to grow long, blond > Surfer God hair allll over your bod-dee. > > Actually, I was just kidding about that last part. (As he tosses his > long, > blond, Surfer God hair back from his noble sunburnt brow. Being a native > Californian isn't as easy as it looks.) > > Engineering types get off on what happens when you DON'T pay attention > to the > valve train geometry, as in calculating how fast the engine will trash > itself, or how low the efficiency can fall before EPA will sue your ass back into > the Stone Age. The Stone Age is where you'll find all those VW 'experts' who > never mention valves at all, telling the Yuppies, "This engine will RUST OUT > before it WEARS OUT." > > Uh, right, John. > > -R.S.Hoover > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html -- ___________________________________________________ OperaMail free e-mail - http://www.operamail.com OperaMail Premium - 28MB, POP3, more! US$29.99/year Powered by Outblaze ------------------------------ Date: Wed, 22 Oct 2003 21:45:30 -0400 (Eastern Standard Time) From: "Dan Heath" To: Subject: Re: KR>Filling Pin Holes Message-ID: <3F9732BA.000025.02772@Computer> References: <004a01c398f5$87f07c80$6401a8c0@wi.rr.com> Content-Type: Text/Plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 14 Mark J.,=0D =0D Where have you been all of my SANDING life?=0D =0D Thank you. =0D =0D N64KR=0D =0D Daniel R. Heath - Columbia, SC=0D =0D DanRH@KR-Builder.org=0D =0D See you in Mt. Vernon - 2004 - KR Gathering=0D =0D See our KR at http://KR-Builder.org - Click on the pic=0D See our EAA Chapter 242 at http://EAA242.org=0D =0D -------Original Message-------=0D =0D From: KR builders and pilots=0D Date: Wednesday, October 22, 2003 7:37:25 PM=0D To: KR Net=0D Subject: KR>Filling Pin Holes=0D =0D Has anyone tried the following method? What are the methods you use to fi= ll pin holes???=0D =0D Pinholes=0D These are tiny voids, bubbles and pits caused by air mixed into the fille= r. They are invisible until the minute you start spraying the first coat of primer. They can give you a big headache if you attack them the wrong way= =2E You might have heard horror stories of builders spraying coat after coat = of primer trying to get rid of them. The bottom line is, you cannot fill the pinholes by spraying. Yes, if you keep spraying long enough, eventually t= hey will disappear, but they will not be filled, they will be bridged. Bridge= d pinholes can cause the painted surface to develop little pimple like bump= s on the sun when the paint softens some and the trapped air expands with t= he heat.=0D Luckily, we have a simple effective way how to deal with pinholes before = we even see any. Vacuum the surface real well to remove any dust and then squeegee pure epoxy resin over the surface. The coat is very thin and the amount of resin is mall, you are basically just wetting the surface, give= it some time to soak in and squeegee off all the excess. The resin has very = low surface tension so it flows into all those small voids and because unlike primers it doesn't contain any volatiles it doesn't shrink as it cures so the fill is complete. The second benefit of this step is that the resins hardens the top shell of the micro, making it more durable.=0D A word of caution, many epoxy resins do not cure well and stay gummy at v= ery thin coat, especially in humid condition. If yours is one of those or you are not sure, use the West system epoxy for this.=0D When this top coat is cured sand it lightly with 100 just to break the gl= oss and you are ready for the primer.=0D =0D =0D Mark Jones (N886MJ)=0D Wales, WI USA=0D E-mail me at flykr2s@wi.rr.com=0D Visit my KR-2S CorvAIRCRAFT web site at=0D http://mywebpage.netscape.com/n886mj/homepage.html=0D =0D _______________________________________________=0D see KRnet list details at http://www.krnet.org/instructions.html=0D =2EFrom DanRH@alltel.net Wed Oct 22 18:53:08 2003 Received: from mta02.alltel.net ([166.102.165.144] helo=mta02-srv.alltel.net) by lizard.esosoft.net with esmtp (Exim 3.36 #1) id 1ACUex-000KiN-00 for krnet@mylist.net; Wed, 22 Oct 2003 18:53:07 -0700 Received: from Computer ([151.213.92.252]) by mta02-srv.alltel.net with SMTP id <20031023015716.OOBF527.mta02-srv.alltel.net@Computer> for ; Wed, 22 Oct 2003 20:57:16 -0500 MIME-Version: 1.0 Message-Id: <3F973580.000029.02772@Computer> Date: Wed, 22 Oct 2003 21:57:20 -0400 (Eastern Standard Time) X-Mailer: IncrediMail 2001 (2001155.2001155) From: "Dan Heath" References: <20031021041525.91686.qmail@web9407.mail.yahoo.com> X-FID: FLAVOR00-NONE-0000-0000-000000000000 X-FVER: X-CNT: ; X-Priority: 3 To: Subject: Re: KR>Newbie Questions Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1b3 X-BeenThere: krnet@mylist.net X-Mailman-Version: 2.1b3 Precedence: list Reply-To: KR builders and pilots List-Id: KR builders and pilots List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Help: Rick,=0D =0D I have not seen an answer to your questions, so I will give it a whack. = I am on my second KR and flew my first one for 6 years, 185 hours approximately. =0D =0D 1. I weight 145, and as a low-time pilot would want to=0D fly with someone experience any time I went up. I know=0D everyone asks this, but is it really a two-place=0D aircraft?=0D =0D If built properly, with the appropriate power plant and the CG in the rig= ht, absolutely. I also was a low time pilot, and my first KR did not have enough power nor was the CG in the right place for 2.=0D =0D 2. The plane I=92m looking at is in the boat stage, the=0D workmanship looks terrific, but the work was done 20=0D years ago and the fuse was widened 4 inches. Is the=0D extra width an issue in terms of flying=0D characteristics?=0D =0D I don't think the width will be a problem. Put on a nice Corvair or 0200 and you should be good to go. The plane I am working on now was started almost that long ago. If properly kept, it should not be a problem, but = you should be able to tell if it has been properly housed.=0D =0D 3. Given the widened fuse, how difficult would it be=0D to fit a preformed canopy and cowling (not included in=0D the package).=0D =0D I think the KR2S guys can give you a better answer here, but since it is = not in your package, you have a lot of options.=0D =0D N64KR=0D =0D Daniel R. Heath - Columbia, SC=0D =0D DanRH@KR-Builder.org=0D =0D See you in Mt. Vernon - 2004 - KR Gathering=0D =0D See our KR at http://KR-Builder.org - Click on the pic=0D See our EAA Chapter 242 at http://EAA242.org=0D =20From n56ml@hiwaay.net Wed Oct 22 19:00:41 2003 Received: from smtp1.knology.net ([24.214.63.226]) by lizard.esosoft.net with smtp (Exim 3.36 #1) id 1ACUmG-000KnT-00 for krnet@mylist.net; Wed, 22 Oct 2003 19:00:40 -0700 Received: (qmail 22089 invoked from network); 23 Oct 2003 02:04:49 -0000 Received: from unknown (HELO basement) (24.214.88.148) by smtp1.knology.net with SMTP; 23 Oct 2003 02:04:49 -0000 Message-ID: <49d101c3990a$55dfd140$1202a8c0@basement> From: "Mark Langford" To: "KR builders and pilots" References: <20031021041525.91686.qmail@web9407.mail.yahoo.com> <3F973580.000029.02772@Computer> Subject: Re: KR>Newbie Questions Date: Wed, 22 Oct 2003 21:06:56 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-BeenThere: krnet@mylist.net X-Mailman-Version: 2.1b3 Precedence: list Reply-To: KR builders and pilots List-Id: KR builders and pilots List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Help: > 3. Given the widened fuse, how difficult would it be > to fit a preformed canopy and cowling (not included in > the package). RR will be quick to tell you that their canopy will not fit a KR2 or S that's been widened more than 1.5". I doubt that the firewall is widened 4", but if it is, their cowling certainly won't fit either. The Dragonfly will fit perfectly though, as detailed at http://home.hiwaay.net/~langford/kcf.html . Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 196, Issue 2 *************************************