[PMD1969]

How many have reused the pistons for a 68 / 69 250 ? If you did what did you do to clean them up for installation?

[Half-Inch Stud]

Reuse em I did. Even the one that ate a Q-JET Screw ( somehow, before my time). Engine still ran fine with the Original slugs to 7500 RPM. Simply scraped the tops with a Stanley box-cut blade, because there was lots of fine pocks from detonation.

GOOD Question, now I recall how the risk of super-smooth engine REVs might get degraded by replacement slugs/pins.

[TheSilverBuick]

Read my thread? I put a flat wire wheel on my 4.5" makita grinder and hit the top and sides of the pistons with the wire wheel. Cleaned up real quick. I'm sure a wire wheel on a bench grinder would work good too. Hosed them all down with brake cleaner afterwards to remove the dust. All these pistons are .030" overbore.



And actually after this picture was taken I took a small screw driver and lightly scratched at the remaining carbon then took a red scotch bright to the valve reliefs to get a bit more out.


All of them were carboned up like the first picture. I'm pretty sure the ground strap came off a spark plug on cylinder 4 at some point in the history of this engine.

[PMD1969]

Well it seems that the original pistons in the OHC are indestructible. Just clean them up an stick them back in.

[TheSilverBuick]

I don't know about that, two of mine looked to be newer than the other four =P

The head had markings on cylinder 4 also is more reason I figured sparkplug ground strap.

[Cammer-6]

a cast piston isnt indestructible
I myself wouldnt put a worn piston back in.
Examples you ve seen above arent stock OEM.
I ask this when doing a rebuild.
Is it worth doing all over again and possible replacing many more new parts to save a little?
I have pulled apart quite a few stock motors and had the pistons fall out in pieces.

[PMD1969]

Originally Posted by Cammer-6

a cast piston isnt indestructible
I myself wouldnt put a worn piston back in.
Examples you ve seen above arent stock OEM.
I ask this when doing a rebuild.
Is it worth doing all over again and possible replacing many more new parts to save a little?
I have pulled apart quite a few stock motors and had the pistons fall out in pieces.

That is sort of what I thought. If I am going to go to all of the trouble and expense a $350 dollar set of pistons is all that much. So is EGGE the only source for these 250 pistons? Years ago a OHC buddy sent me a piston and I went on a quest to search out a mfg that would make some hyper pistons. No go since there was not enough interest or a big enough group order for them to make the dies.

So is EGGE the only place in town?

[TheSilverBuick]

12bolt.com is ran by a pretty good guy and has some high quality flat top forged Ross pistons for sale, unfortuantely they only come in .040" overbore and do not have valve relief's. Of course being forged they are more money at $565 a set not terrible.

From the measurements I took you should be able to safely have valve reliefs cut into the pistons.

http://12bolt.com/250292_products/pistons

[UnchainedGTO]

Ross pistons are a great way to go. I used them in my OHC6 build a few years ago and have used them in my Pontiac V8 motors for years. You can get the correct piston without having to have valve reliefs cut. The Ross part number is for the 250 piston is 33-11. They still have the part number in their system. I sent them one of my old pistons as they wanted to make sure the valve relief cuts were a match. The set I ordered came back perfect.

[rexs73gto]

Yes Ross & SRP same co's have a special order section so you can buy pistons for what you need not just what they have available to sell you. It cost a little more but you get a great quality piston when you go this way. Always make sure you buy Forged pistons when you order as the forged piston are very strong & very forgiving, & you need that with todays gas,(junk gas). You can get acontact number on line by typeing in eitheer Ross Pistons or S R P pistons.

[Cammer-6]

for a daily driver Ross forged is overkill.
I may have some replacement cast ones.
Last time I checked on hyper pistons KB was about the only one remotely interested in doing some.

[PMD1969]

Originally Posted by Cammer-6

for a daily driver Ross forged is overkill.
I may have some replacement cast ones.
Last time I checked on hyper pistons KB was about the only one remotely interested in doing some.

KB is not interested unless our group comes up with a number we can not support. I threw away my notes but they said no go since the numbers were not there to support them makes the product(s).

[Cammer-6]

Just came back from PRI and the amount of piston manufacturers was astounding.
Keep in mind that 250 and 307 Cheby pistons are close enough to use with a little attention.

[rexs73gto]

Forged pistons are the only way to go with the junk gas we have in the tanks today, thats why almost every auto mgf. use's either forged or hyper pistons in the new engines being produced today. If you want to keep the tops of your pistons in tack the little extra for forged is the only way to go. I won't use anything else & I'm pratically broke. But I can't afford to put pistons in a second time because the lack of a few dollors the first time around.

[hpp]

http://www.ebay.com/itm/Pontiac-OHC6...fea4cc&vxp=mtr

Im looking into these its a stock photo shown but they say you will receive the correct piston.

[hpp]

http://www.ebay.com/itm/Piston-Ring-...685d80&vxp=mtr

Rings also

[Cammer-6]

to me a cast piston is not worth $75 each.
Last time I check Wiseco wanted $60 ea for forged

[hpp]

Originally Posted by Cammer-6

to me a cast piston is not worth $75 each.
Last time I check Wiseco wanted $60 ea for forged

Link,info or part # on these Wiseco pistons?

[GTOWAGON]

I used forged Ross pistons in my current build

[1969GTO]

GTOWAGON
I think I saw that same red engine just yesturday in PA......sharp )