is .060" overbore to much for a stock block?

[jackchan]

I've found a set of .060" overbore ross pistons for my FS engine I'm building but several people have told me that .060" is to much, that i should stick with .030 or .040" overbore max.......something about that much overbore causing the block to crack? Also they stated I need to have the block sonic checked for cracks?

I want to build this engine once, build it right and have it stay together!
Ben

 

[Mike92GT]

Probably depends on who you ask, but .060 on a stock block is too much in my opinion. Stock blocks are weak enough as it is, and the more material you remove the weaker they get. I have a 308 (.040), and I wish I had a 302 or 306.

 

[Daggar]

The power you gain from an overbore in a 302 block is negligible. If you want more cubes... stroke it.

 

[jackchan]

The power you gain from an overbore in a 302 block is negligible. If you want more cubes... stroke it.

I wished I could. Our class rules won't allow it! dagger, I'm gonna try and let Rick do my engine. Man, it aint gonna be cheap, but spend the money the first time, and you have the game won! I'll keep you guys posted on progress etc....still in my building year!
Ben

 

[N8Miller]

too much

 

[1SLO306]

if u want to bore and not stroke it i say go 306. not much if a power difference

 

[jackchan]

unshrouding the combustion chambers is definetly a plus in the class i run in. Therefore the bigger the bore the more unshrouding you do. I'd love to just go 347 stroker with it lol
Ben

 

[dastang2]

i had a .060 302 and it ran fine but needs the extra cooling capacity to cool it. i ruan 250 and above with a truck heavy duty 3 row. then i got an aluminum and never used it because the bearings went down. all in all, it is not worth the hassle. if you scar the cylinder there goes the whole block because you won't be able to rebore it again.

 

[PoopDawg]

I don't think he's looking for more power... he's looking to see if he could use these pistons... and no... That's too much material to take off... One, it will weaken the already thin cylinder bores, and two... cooling will be an issue.

Nick

 

[Realmongo]

Some blocks will, some blocks won't. Some blocks can't be overbored at all. It all depends on how much core shift it suffered during casting. The only way to tell is take it to a shop that has a working sonic tester.

 

[Rick 91GT]

Sonic Test is really the only way to tell, most factory blocks will go out .060 but your taking a chance with the integrity of the cylinders, and to keep them round most of the time we atleast half fill the block HARDBLOK, not the most weight freindly thing to do for your class...

 

[jackchan]

Rick 91GT,

I worked a lot of long days this past week.......trying to get all my funds together for my engine. I want to thank you for all the information you've given. I know I can ask a million questions.....but I have to be sure of what I'm doing....I want to buy an engine I can run for awhile. With only a freshing every year and a half or so. The best part about your engine's is this....you blueprint, and if ever I needed something (i.e. rings, single piston, )then you'd be able to tell me exactly what I needed or could order it and have it sent to me. That is a definate plus.......!

With that, let me ask a few more questions !

how close can we set piston to valve clearance on this engine? How would this be affected if I missed a shift? not that I will but we have to always cover what ifs!

what year crank would this engine use? And do I need to be getting one to send you or will you provide that? I have access to a couple....hell I probably have 4-5 laying around my shop lol

which is the better rod and main bearings? federal mogul? clevite 77?

I'll call you sometime this week to better discuss this engine.

thanks for all your help Rick!!
Ben

 

[Rick 91GT]

Ben, lets keep our discussions off the board Please give me a call later tonight if you can or shoot me an e-mail...

 

[jackchan]

sounds good!
Ben