GEO
Sarcasm Inc.
I'd personally buy new pistons and buy modern heads and get rid of the 1970's technology stuff
Why build or spec an engine around "leftovers"? Although those are cool.
You said a mouthful right here..... Having thrown dollars at a project based on a single component (pistons to be exact) the best advice I can give is don't do it. I am sure there are people who got lucky and made it work but starting off with a single component and then trying to make everything fit is a recipe for disaster....
JW
70aar... how was this engine used? Strip? Street/strip? Nice that they have been used by someone here, but I think it would be more useful to the OP to know how they were used.
I'd personally buy new pistons and buy modern heads and get rid of the 1970's technology stuff
Well the current trend is flat top pistons and small combustion chambers which work better than the old domed pistons and open chamber heads. Figure the rest out your self I'm not your momExplain how that piston is so obsolete compared to a piston from today, with the same pin height and dome volume.
If you are paying attention, they aren't that much heavier, have a standard ring package and the skirt design is actually pretty damn good.
It's not nearly as obsolete as some of you seem to think it is.
Small combustion chambers only work better as far as quench which the intent is primarily to run pump gas without detonation.Well the current trend is flat top pistons and small combustion chambers which work better than the old domed pistons and open chamber heads. Figure the rest out your self I'm not your mom
Because he has the parts. I agree he could go a different route, but at what cost. The J heads and his 340 block will work with those Pistons. He could build it and use e85 without a problem.Why build or spec an engine around "leftovers"? Although those are cool.
Well the current trend is flat top pistons and small combustion chambers which work better than the old domed pistons and open chamber heads. Figure the rest out your self I'm not your mom
Small combustion chambers only work better as far as quench which the intent is primarily to run pump gas without detonation.
Some designs of small chambers inhibit the breathing of the head.
Flat top Pistons on a modern build are really only possible on a stroker build because of the increased swept area, otherwise it would be very hard to get any kind of decent compression.
Each type build has its pro and cons. It depends on the intended goals of the build and operating costs of the fuel.
Can you elaborate on what you are saying here.You said a mouthful right here..... Having thrown dollars at a project based on a single component (pistons to be exact) the best advice I can give is don't do it. I am sure there are people who got lucky and made it work but starting off with a single component and then trying to make everything fit is a recipe for disaster....
JW
My thinking is that he is compromising some of the street ability he is looking for by using the pistons he has.
In my mind, and I could be wrong but this would increase cost of build substantially? Or sounds like a cam/lifters/valve train purchase is needed regardless. So would there be any real price difference?
I know someone has mentioned E85. Is the compression high enough for that?
Here's an ethanol chart. Notice that even E60 is good for 13:1.I know someone has mentioned E85. Is the compression high enough for that?
I,lol say it again,I do not believe those pistons with a typical Chrysler open chamber will measure 13:1. Secondly, thicker head gaskets would knock it down some more. IMHOMy thinking is that he is compromising some of the street ability he is looking for by using the pistons he has.
In my mind, and I could be wrong but this would increase cost of build substantially? Or sounds like a cam/lifters/valve train purchase is needed regardless. So would there be any real price difference?
I,lol say it again,I do not believe those pistons with a typical Chrysler open chamber will measure 13:1. Secondly, thicker head gaskets would knock it down some more. IMHO
Small combustion chambers only work better as far as quench which the intent is primarily to run pump gas without detonation.
Some designs of small chambers inhibit the breathing of the head.
Each type build has its pro and cons. It depends on the intended goals of the build and operating costs of the fuel.
- Flat top Pistons on a modern build are really only possible on a stroker build because of the increased swept area, otherwise it would be very hard to get any kind of decent compression.
That's what I would call decent.Depends on what you call decent, my 340 ran a flat top with a 55cc chamber aluminum head. It was 11.4-1 and ran on pump 93. With the same heads and a 21cc dish my 408 was 10.8-1.
I agree with your comments about the shaping under the crown.Mmmmm not really so much savings on the stroker. The big changes in modern pistons is in the crown underside shaping, the general crown thickness, and the areas around the pin bosses. That's where 80+% of the weight is. That applies for stroker and non-stroker pistons.
KB's for 340 for example are 588 grams vs the stock 719 grams.... so minus 130 grams just in the casting and shaping changes. Drop another 22 grams in the pins. (And those KB's for the 340 are a bit thicker in the crown to push the dome up.) Those old forged domes ain't gonna be any lighter than stockers with the older designs.
The 360 stock stroke KB's are 510 gr vs stock 576 gr stock; drops to 478 gr for an equivalent KB stroker. Not all that different a change versus than the stock stroke ones; the general casting design makes a bigger difference.
You can see these same general casting/forging design changes for lighter weight show up in the 90's in production pistons in GM and Ford engines at the least.
BTW, not the place to do this, but at some time, I'd like to discuss this idea of power difference based on the head material.... This has showed up again recently.
Aluminum versus cast iron headsMmmmm not really so much savings on the stroker. The big changes in modern pistons is in the crown underside shaping, the general crown thickness, and the areas around the pin bosses. That's where 80+% of the weight is. That applies for stroker and non-stroker pistons.
KB's for 340 for example are 588 grams vs the stock 719 grams.... so minus 130 grams just in the casting and shaping changes. Drop another 22 grams in the pins. (And those KB's for the 340 are a bit thicker in the crown to push the dome up.) Those old forged domes ain't gonna be any lighter than stockers with the older designs.
The 360 stock stroke KB's are 510 gr vs stock 576 gr stock; drops to 478 gr for an equivalent KB stroker. Not all that different a change versus than the stock stroke ones; the general casting design makes a bigger difference.
You can see these same general casting/forging design changes for lighter weight show up in the 90's in production pistons in GM and Ford engines at the least.
BTW, not the place to do this, but at some time, I'd like to discuss this idea of power difference based on the head material.... This has showed up again recently.
Aluminum versus cast iron heads
#7---Choosing Heads: Aluminum vs. Iron (Which Ones Do You Need?)