Just a couple of questions. I am thinking about throwing in a high comp piston std. bore in the Raptor. First question is why are all of the pistons available only 11:1 compression and not higher like 12 OR 12.5:1? Is this going to help out very much staying with the std. bore? And finally how well do the advance keys(Sparks) work? I know that timing can make a huge gain in most motors, how about the Raptor?

 

Do some advanced searches and you should find the info you seek. Specifically, do a search on Raptor720 and read through his posts.

/NotuRaptor

 

I've seen 12:1 pistons around... But I wouldn't really want one, every point in compression you go up the higher the chance of detonation you run... IE: KABLAM!

 

I agree, but then again that's what race gas is for. I just don't understand why no one is offering a higher comp piston, especially for the racers?

 

ct racing offers a 12:1 piston in 100mm, 102mm, and 105mm sizes, you can also check with LA.Sleeve. a high comp piston is most effective if you add a cam at the same time. as for the timing advance key, I tried the sparks 7degree advance woodruff key (a pain to install) it was not worth the trouble

 

Thanks vraptor! Let me get this straight, 102mm is the 686 with standard stroke and you don't have to put in a new sleeve, just bore?

 

that is correct if you go to the 105mm you will have to sleeve, apparently this is a problem with some engine builders who are reporting engine oil getting into the coolant. If you go that route make sure you or whomever builds your motor is familiar with the problem

 

Sounds good, I just ordered the 102mm direct from JE. I thought that it seemed pretty cheap so I bought it. I think Trinity want's $240 for their kits and I got the whole kit from JE for $180. The only shortfall is that its the 11:1 piston(Actually 10.75:1). But for the money it seemed like a good option, what cam and springs would you recommend. Thanks.