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Hello to everyone again. working on my engine yesterday and i was matching parts. I opened my box of seal power ring's part # E-251K and compared them to the old ones. The diameter from the old ring going from the inside groove to the outside of the cylinder wall is slightly larger than the new rings. The pistons I'm using are the old ones / originals 464664. 1982 crossfire 350 block original to the car. When i looked up and order the parts that was the part number that came up. Moly coated upper ring. Am I missing something or will these rings be fine. A lot of articles stating their old TRW pistons, but that's about all that i can find. Any help would be appreciated.
Thanks, Bubbagum
As long as the new rings are the proper thickness and large enough to meet the recommended gap you should be fine. I would identify the pistons, cast vs forged take different gaps. With molly rings in an old bore you need to pay particular attention to the hone job. I would also check the taper at the top of the bore and make sure it's not too large or you will have blowby. Use a good set of stones of the recommended grit, not a ball hone. Molly likes a finer grit stone.
those are L82 forged flat top pistons. i doubt the crossfire short block used these pistons OE. double check this. and if they are the forged pistons, get the correct ring for those pistons.
Hi Storming N. I did all that .It’s not perfect but within tolerance just barely. Checked 3 time with my scope.Your right about the stones to they worked good. Touching on all side. The piston are the original 464664. When I look them up what I could find is trw made them for gm. I believe them to be forged. I also called seal power the only thing they could tell me is they were the ones they call for and they probably made improvement to them over the years. ??They do fit well in the bore with close to the upper end gap.It just was the upper compression ring in question. Thank you for responding. Helps me out a lot.
Hi DerekD. My understanding is they are forged. This vette had lower mile on it. It was running good when I got it other than a couple of vacuum leak. I took it off the frame to repaired all the rubber mounts and dry rotted rubber on the front and back control arms a trailing. Then I decided to freshen the engine ring bearing seals. Yes it a crossfire. The crank is cast the intake going to need some work the head are not going back on. The piston are 464664 pistons. From what I’ve read they put them in from the factory 1982 and 84. If they were cast I would have got new ones. Not much money into it just a learning curve. Would you recommend a diff ent set of rings. I post a pic.where I’m at and the piston.
I didn't know the crossfire used forged pistons, but I don't think there is any difference in rings. Just gap them right and measure them 1.5- 2" down the bore. A stock N/A motor should be 4/5. .004 per bore inch on the top ring and .005 per inch on the second compression ring. So about .016-.021 on the top ring and .020-.025 on the second ring. Forged pistons will have a little more cylinder to bore clearance than cast in order to compensate for expansion. Just take your time because gapping the rings properly is really important, and you want nice straight clean ends. Shoot for minimum down the bore and hope it's not to much past max at the top since the top is always larger due to wear.
When I refreshed my 77 about 5 years ago I replaced the factory forged pistons with hyperunetic flat tops.
2 reasons. Wear in ring lands. And a firm belief that the tighter fitting more modern hyperunetic pistons with modern skirt coatings are far superior.
Now, your engine may have zero ring land wear. And you may be comfortable with the high expansion rate of forged pistons.
But I found that new hyperunetic coated pistons were VERY affordable from Summit. With Hastings rings.
I do own a sunnin block hone. So all that was easy. I found my 90 thousand mile engine had VERY little wear in the bores. But a fair bit of piston skirt wear and ring land wear.
Things for you to think about.
looks like at least some L83 engines came with forged pistons. just double check that the rings for forged pistons are the same as for cast pistons. maybe PM bucaneer. he is the most knowledgeable around for 82 quirks and details.
Thanks to everyone for the help. I’ll be taking your advice and checking those clearances. I will be reaching out to buccaneer in the near future for my head and cam combo. Going to have to do a little porting. Renegades are tough to find. I’ll let you know how thing go but it probably going to be spring.
Yea,on my 1981,the guy building my engine now,although not replacing rings,but replacing on bearings crank,rods and cam bearings and the guy told me to get all parts clevite and not seal powered.so I’m assuming Clevites are original
Golderdad ,I was going to use Clevites but decided on king bearings. Both are good bearings. I have the crank back in the block they are the si. Aluminum. The engine I believe a from gm used aluminum on mine. I found some information on the ring set I have on a sight it’s an old post but I having a hard time pulling it up. It’s on DON TERRILLS speed talk. E251K Ring set. If anyones interested try to google that. It talks about top ring compression and the top ring size with an explanation on the smaller top ring width.
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Piston ring match
