PAW pistions

[Moparlee]

Has anybody bought PAW's Egge cast pistons for a 392, those 10.5 to 1's?

Lee

[392heminut]

I just bought a set. The pistons I'm taking out of my 392 were Egge's also (dropped a valve and punched a hole in one), and were bought directly from Egge. They were the ones rated at 10 to 1 for the 58 392, and the so called 10.5 to 1 pistons I got from PAW look identical to them. I can't tell if the dome height is any taller than the old ones for sure until I get the old ones out, but I'm pretty sure they are the same. They were about $100 less than what I paid for them direct from Egge. What else were you wanting to know?

[Moparlee]

Well in their picture they look like my 57 9:25 ones, just wanting to make sure of what they are selling. I've had touble with them in the past. That's a good deal on those pistons if they are what they supposed to be. Do you have any of the 57 ones laying around to compare them too also? Thanks for you time.

Lee

[392heminut]

Lee, I've got the original pistons from my 57 392, the new ones do have a taller dome than the 57 pistons.

[Moparlee]

Cool that's what I was wanting to here. Do they come with any information about was cc's the domes are. The reason I'm wanting to know is I want to try and get a true 10.1 or 10.5 compresion. I'm wondering how much should milled from the heads and what gasket thickness is needed to do so. Do the domes looks as high as the Ross pistons. Hot Heads as cool picture of the Ross pistons that if I'm not mistaken are the 10.1 pistons. Which take a lot of milling to the heads I would think if you had to go from 110cc's to 97cc's wouldn't they? Thanks for your time.

Lee

[392heminut]

Lee, it's hard to tell anything hrom that picture of the Ross pistons. About the only way to know for sure is to c.c. the pistons in the block. I am planning on doing just that with the new pistons from PAW, but it will be a week or two before I can get it done. I too am attempting to get into the 10.0-10.5 range. I just had my heads rebuilt with 2.11 Pontiac intake valves, but the guy doing the work took it upon himself to sink the intake valves a little when he opened up the seats, and I'm sure that will have some effect on the chamber c.c.'s. I'm hoping that the larger valve head will offset the c.c.'s added when he sunk the valves. At any rate, if you aren't in a hurry I'll post everything I came up with in this thread once I can get it all done.
Larry

[TrWaters]

Also keep in mind that the final ratio will vary based on the bore being 4.0, 4.030, or 4.060. I would be interested in seeing the weight of the pistons.

TrWaters

[Bailiesdad]

Any manufacturer of pistons will have the domes or size of their over bore pistons compensated for advertised compression, you need not be concerned. If they say 10:1 at any oversize it will be 10:1. If one needs specifics on a manufactures parts it is best to contact the manufacturer, that way they get the correct information.

[TrWaters]

While Mr. Ripley may be correct when ordering a set of custom made forged pistons, I highly doubt that the manufacturer of cast pistons that retail for under $200 (with rings) is going to make the adjustments in machining(dome OR pin location) for a .2 or .3 difference in compression. That is why they are sold as replacement pistons. The only sure way to know what you have is to check them in your block with your heads and your head gaskets.

[392heminut]

The only sure way to know what you have is to check them in your block with your heads and your head gaskets.

I agree whole heartedly!

[Bailiesdad]

While Mr. Ripley may be correct when ordering a set of custom made forged pistons, I highly doubt that the manufacturer of cast pistons that retail for under $200 (with rings) is going to make the adjustments in machining(dome OR pin location) for a .2 or .3 difference in compression. That is why they are sold as replacement pistons. The only sure way to know what you have is to check them in your block with your heads and your head gaskets.

Any person buying a 200 dollar set of pistons to perform a stock rebuild, Chrysler Corportation already did those calculations for them and any changes done while rebuilding the stock components will have a minimal effect of the compression ratio. That is why the manufacturer offered rebuild parts in the common over sizes of pistons that Egge makes for PAW.

It is overly confusing and an added expense for them to attempt to get the combustion chamber size, ( cc ing the heads fully rebuilt and ready to install) the quelsh area after the gasket is compressed, ( buying an extra set of head gaskets and r&ring the heads an additional time) and the exact deck height ( precision measured on a fixture) to compute ACR. It is not done on a stock rebuild.

These measurements, calculations, labor, and parts could easily exceed the cost of cast pistons and is a waste of money on a stock engine rebuild.

[TrWaters]

All that is correct. But if you read the original posts by Moparlee, he states that he wants to know the true compression ratio. To do so, some time and/or money will need to be spent to calculate it. Perhaps to him, this information will not be considered a waste.

[Bailiesdad]

All that is correct. But if you read the original posts by Moparlee, he states that he wants to know the true compression ratio. To do so, some time and/or money will need to be spent to calculate it. Perhaps to him, this information will not be considered a waste.

Read Moparlees' many posts, when the person realizes the cost to calculate ACR, a person spending 200 for pistons will not want to spend the additional money.

Very few machine shops have the equiptment to compute ACR. When it is explained that there is nothing to be concerned about in rebuilding a stock engine with stock replacement parts that will answer his question.

In real plain terms it is what or real close to the advertised ratio printed on the invoice from the maker of the pistons. Don't worry about it.

Moparlee there is a much better website for tech questions, try Moparts.com

[scottm]

I think we have enough info now, locking this topic.