Well. The motor blew up. #3 and #4 detonated. Ring kinda scuffed up the very top of the bore.

I dunno if it will hone out, and its allready .030 over. Was thinking of boring it to .040, but I cannot find the piston I want in an .040.

Anyone here have any piston advice? I'm looking for a trouf
style piston (forged of course), with aprox -11cc relief/trouf. I want the dome portion however for a quench area, so no dish pistons.

Anyone have any suggestions lemme know. TRW doesn't make the 2441 in a .040 over.

-- Joe

 

did you actually call TRW? and what kinda money do you want to spend? Ross Racing Pistons will hook you up with a custom set, but they are like $750 for the set.

 

I think my limit for reasonable pistons is $400.00..

I didn't call TRW. Will do that in the AM. I called Summit, who said "no way man"..

Doesn't seem like TRW (according to summit) believes in a 4.040" bore.

-- Joe

 

And that's why you can't find them. That is an odd request, as you're finding out, but anything can be made. For a price. Ross, CP, JE, will all hook you up.

 

Why is .040 over an odd request??

 

the .040 oversize is VERY common, but your goal of $400 is going to make for a limited selection for sure. thats not but $50 per piston.
speedpro (formerly trw) should have something you could use, however. you just need to be somewhat flexible with your -11cc trough size.

mine are wiesco -11cc reverse dome, but they were a bit more than $400. matter of fact, their .040" over also!

 

Your right, and my thinking was all screwed up..

I have the block completely dissasembled now, and after spending a few hours looking at it, the crap is just piston splatter. It should come off/hone out fairly easily.. I think the 4.030 bore will remain.

I'm gonna use some 64cc alum heads. Thinking trickflow, but I may go with Dart pro1.

In any event, zero decking block and using TRW-L2441F30 with a floating pin.

Sooooooooo.. That makes about 8.66:1 c/r 355 with about .045" quench.

That should allow me to run either a t-trim head unit, or a ton more spark advance..

-- Joe

 

Sorry, should've been more specific. The bore size is common, but everything else w/ it and only spending 400 was the tricky part.

 

We hot tanked the block and then measured it.

The piston crap came off the wall, but the bottoms of those cyls where the piston rocked was pretty bad. Its goused about 4.033.

We're boring the block to 4.040"

Was thinking of running a SRP-139629 piston, which is for a 3.75" stroke crank. http://www.flatlanderracing.com/srpsbclowcomp.html

Run a 5.850" H beam rod, with a 3.480" stroke steel crank. The compression distance on the piston is 1.425".

I think that will work, and would make a 9.1:1 compression ratio motor.

Can someone check my math?

-- Joe

 

OK I understand what you are doing, the piston should fit.

1/2 stroke + rod length + compression height

1.740" + 5.850" + 1.425" = 9.015"

As long as you have the factory deck height of 9.025" (verify this) the piston will work.

For compression ratio, I use

2.1 cc for the piston being 0.010" below the deck
8.5 cc for the head gasket (4.125" bore x 0.039" thickness)
16.0 cc for the piston dish/relief
64.0 cc for the head volume
731.0 cc for swept volume from the crank

For the compression ratio,

(731.0 + 64.0 + 16.0 + 8.5 + 2.1)/ (64.0 + 16.0 + 8.5 + 2.1)

9.07:1 <--------

 

The TRW-L2256F30 pistons I was running are installed at 9.003, and I measured between .022 and .025 at TDC, so I should be just peachy!

Here is a post of my new setup. Only thing I'm stuck on is the cam. Check it out: https://www.thirdgen.org/techbb2/sho...13#post2074513