Did not think to ever hear anything like that from Langford, the head has to be measured to get the correct ratio because if one just does the cylinder you don't get the correct ratio. And, this is how you do it, place a 1/8" acrylic plate on the seat where the top of the cylinder sits with a small hole in the acrylic and start to fill the combustion chamber with oil with a cc syringe. This is cc-ing the head and this volume has to be added to the cylinder volume. To get the proper volume of the combustion chamber by shimming up the barrels, sometimes if it requires more volume without any shims the lip on the bottom of the barrel had to be machined down to enable proper volume. Mine were set at 8.1:1, it can mean a lot of fiddling around. Also, make absolutely sure you balance the pistons, rods and crankshaft. An unbalance crank is what leads to a broken crank and then the blame it placed on a perfectly good unbalanced crank.
Mark Langford wrote: >Ryan wrote: > > > >>What is the piston to head deck height for an 1835 ? >> >> > >"Deck height" on VW's is usually considered to be the distance from the top >of the piston to the top of the cylinder, not to the head (although I guess >they are actually the same thing, since the head is pulled up against the >cylinder). Since the head is the combustion chamber, and you can't measure >it anyway, the deck height is the distance that the piston sits down in the >cylinder (or sticks out). Basically, it's whatever you set it to be by >using shims between the cylinders and the the engine case. It's not just a >number that is set in stone, but a number that you determine you want it to >be based on what compression ratio you want the engine to have. Then you >put the shim that gets you closest to that number under the cylinder to set >it. I did a web page on how to check it at >http://home.hiwaay.net/~langford/corvair/trial_assy.html , but you'll also >need to know the combustion chamber volume to calculate compression ratio, >and that was shown at http://home.hiwaay.net/~langford/corvair/valvejob.html >. If you take a stock engine and bore it out to 1835, your compression >ratio will almost certainly be higher than it should be for aircraft use, >but I guess that's a matter of opinion. I feel strongly that everybody >should cc their chambers and KNOW for a fact what their compression ratio is >on all four cylinders. Otherwise you're just guessing what's going on in >your engine... > >Mark Langford, Huntsville, AL >N56ML "at" hiwaay.net >see KR2S project at http://home.hiwaay.net/~langford > > > >_______________________________________ >to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >please see other KRnet info at http://www.krnet.org/info.html > > > -- Adrian VE6AFY Mailto:cart...@cuug.ab.ca http://www.cuug.ab.ca/~cartera
