Originally Posted by Lucky161:
Since Tim brought up pistons in my valve spring thread, I they would be a good topic to go to next. Some of this stuff I've found online somewhere and some of it I haven't. But so everyone knows, I am not looking for arguments with anyone, just information, which may naturally include some differences of opinion.
For instance Tim suggested that stock pistons would be a bad choice and forged pistons would be the best choice, with hypereutectic being a possible compromise. I don't think anyone would argue with that logic all things being equal. But I wonder if Tim was considering the point of Racesaver engine rules is to keep costs down as low as possible? It wouldn't serve much purpose to have an expensive 305 engine in my opinion.
So my questions are
If forged pistons are ruled out due to cost, then which of the other two would be the best compromise? My thinking here is that forged pistons provide a strength factor not needed for this type of engine. Another question I have concerns ceramic coatings for pistons. Is this something that would be desirable and if so what kind of cost are we looking at?
I agree the point of the RaceSaver series is to keep the motor cost down, but I look at it in the long run. Forged pistons should last longer than cast both from a longevity standpoint as well as taking more abuse due to mis-tuning, etc. This should allow pistons to last several seasons before needing replacement, which saves money in the long run. Hypereutectic are the way to go if forged are too expensive but, as I look at the Speedway Motors catalog, the difference in forged vs. hypereutectic is around $200. Cheap insurance to me. I can't comment intelligently on the ceramic coatings except to say it would surprise me if the cost was much less than $200 to coat a set of pistons.
In short, when you build a sprint car engine you can build one as cheaply as you want but, if it doesn't live through the abuse it's going to take, then where's the savings? There are several other outside influences that affect the motor. For instance, hitting the wall with the rear tires while on the gas sends shock waves through the drive train affecting the crankshaft, rods, etc. You can build a motor with a cast crank and stock rods very cheaply but they won't take the shock loading experienced and will soon break, sometimes with dramatic and impressive results.
And, yes, I do understand keeping motor costs down. The car we race with in Indiana, against 410 aluminum block competition, has a stock forged Chevrolet crank, Eagle SIR rods, TRW forged pistons, stock Chevrolet block with original caps, Brodix Track I heads and 2-3/16" injection. Oh, and it's a wet-sump motor as well. I'd gladly take $4000 for the entire motor, which is what I gave for it in 1997. The latest RaceSaver engine I saw on EBAY was going for $5000.