Piston/rod combination questions and cam

[SilverXJ]

Right now I am planning on going with dished Silvolite 2229 (28cc-30cc by oleshot hopefully) and the 258 rods. However there are a few more options I am considering. I'm using my P&P head and most likely a Comp Cam 68-231-4 cam on this.

One is the 505 Performance kit with the Ross pistons and the eagle rods. Its $1200. I don't plan on any forced induction in the future, so would the extra strength of this combo be necessary?

The KB stroker pistons... .030 is $400 some .. however my block is already bored over .040... even if I can just clean up the bores and keep .040 over the price is $600 some (which is a ridiculous price jump IMHO). Is the gain worth it? The $400 may have been feasible, but $600 is pushing it. What would I gain by running these over the 2229s?

I'm going to go for a better than stock quench (using the .051 gasket as the .043 could be scarce real soon) and I would like to keep my compression ratio inline for premium fuel. I thought about dishing the pistons out for regular, but I would rather have the extra 25 hp afforded by the higher compression. Is there a hard and true number for quench vs compression vs octane rating? What is the most amount of decking/ deck clearance I can use with the 2229 pistons/4.0L block?

The last question, the cam. I have used the comp cam 68-231-4 in the past and I like the way it behaves. However I am concerned about comp cam's quality and longevity of the cam. Is there any recommendation for a cam that performs better with my combo or that is built of better materials? If not then I will probably go with a nitride'd 231.

Any other opinions are welcome.

-Chris

[seanyb505]

I would say dont waste the money on the 505 stuff. You already said you didnt plan on forced induction, and even if you dont get it now you could do it later if you decide on FI.

I dont know the magic numbers for quench+CR+octane= I know Dinos running .088 quench with 9.2CR, and he does just fine. I run 8.98 with .0565 on 87. If you dish the pistons to around 28-30cc youll be looking at regular like me. Looking back on my build I wish I would have shot for higher CR (~9.5ish) via less piston dish because I have good enough quench to not ping. If you know you want to stick with premium look for upper 9.xCR with .040-.050 quench.

I would skip the KB pistons. Im assuming yours already has 258 rods, you would have to buy 4.0 rods with the KBs (unless you already have some sitting around, but it will still be a huge $ difference.)

According to my machine shop and my calculations, my 2229s are sitting .0045 down in the block at TDC. I decked the block .045 and the head .015 so I could use .060 shims on the rocker arms. (.045+.015=.060)

Since youre shooting for relatively high compression and premium look for a cam that doesnt bleed too much off. I cant remember the relationship between LSA and bleeding compression, but you could look into it. The only cams Ive read about going bad are the Cranes around 25+K. Make sure you break it in correctly, use the right oil, and I dont know how effective they are, but you could go with the Crower cam saver lifters again. I can vouch that they have held up for 1200 miles.