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Discussion Starter #1
It seems the higher compression pistons are gone from the common places. ITM sent me the correct part number and of course low compression called them and they looked at the low compression pistons and they are the same. enginetech orders from ITM. DNJ doesnt have them anymore. everyone stocks the low compression ones. This sucks. ITM and enginetech are the biggest suppliers. rockauto=itm

This engine is obsolete.
I do have some .20mm toyota pistons and rings I didnt want to use They are slightly used. after I rebuild this 6m engine and run it for a few months its coming out and being sold while I move to something with more availability.

even ebay for gods sake!
 

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So negative wow… I bought some just a few months ago. Go to a machine shop if you can't find them on your own.
 

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Discussion Starter #8
New update. Thanks for the phone number they were very helpful. As it stands now I was correct it appears no one makes oversize pistons in the higher compression pistons. Most just have standard bore size.
Topline ,safety, itm, dnj. However after talking to my machine shop the difference is negligible after decking the block. so i will just use the new piston setup. Engine parts international states they havent had oversize of those kind in well over a year probably more.
I ended up ordering the parts i needed through cleggengines. nice people gave me a break on parts and carry all of the vendors.
This engine is just not popular and is being phased out. too bad because built well its a solid motor.
 

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Dshif got new .20 over high dome pistons from Engine parts international just recently. IRCC only 82 was the low compression 8.8-1 low dome pistons.
 

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Dshif got new .20 over high dome pistons from Engine parts international just recently. IRCC only 82 was the low compression 8.8-1 low dome pistons.
Is the name of the company Internal Engine Parts Center?

So I assume that this is the URL:

http://store.enginepartscenter.com/caststock-c94.aspx
The 800 number is:
EPC Atlanta, GA - 800-690-4334

I could not see a listing for any 5M pistons on their web site so I guess you have to phone the 800 number and ask.

Dale
 

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Man up and call one of the forged piston companies. They can make you a set in probably any compression you want. Honestly these engines rarely need an overbore and you can probably just get by with a hone and cleaning up the old ones. Really people don't rebuild engines anymore IMO. All the engine machine shops in CA here closed up. It seems like people either scrap the car or buy a crate engine from some mail order place. Its kind of turning into the TV repairman business model.
 

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Discussion Starter #13
I hear that. I bought this supra and it had a 6m i didnt know it came with. Problem was the head was off and the bores had some rust. machine shop said it had to be bored out.
I did call engine parts international, I spoke to a rep named Dustin. Super nice guy looked everywhere for oversize pistons. Even sent pics of the ones he did have. He tried all vendors and no luck.
I am not going forged simply because its not worth it for the power it will produce and the driving style. Just a cruiser and the engine I am rebuilding with good parts in the hopes of selling it in about 9 months and dont want to sell a half done motor.
Eventually I will put in the 7mgte i have sitting there.But i am going to rebuild that one and take my time.
Now to leave my 4.30 rear end or put in the 3.73 i have?
 

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bpatrol,

I didn't realize that you are doing a stock refresh of a 6MGE rather than a maximum power effort. If this is the case, you should be looking for the 82-83 low compression pistons.

The 6MGE is a stroked version of a 5MGE and as such has a 91mm stroke versus an 85mm stroke for the 5MGE. To prevent the compression ratio being too high for the gas/electronic controls of the day, Toyota used the 82-83 pistons to bring the compression ratio down to about 9.2:1. If you use the 84-86 pop-up pistons, the compression ratio will be about 9.6:1.

https://www.celicasupra.com/forums/showthread.php?69186-6MGE-thread-(JDM-inside)

The link above is to Tanya's definitive 6MGE thread which talks about this. Post #1 on this thread states:

"pistons (from 82-83 are the same as stock 6M pistons, making it 9.2:1 compression, using the 84-86 pistons will bring it to around 9.6:1 compression)"

She has photos of the low compression versus the high compression pistons in Post #1 as well.

If you plan on keeping the 6MGE in the car it might be worthwhile going to the higher compression, but for a daily driver with low maintenance, it may actually be better to get a set of the low compression pistons and be done with it. Not trying to be a downer, but if the rest of the motor and the electronics are stock, you could run into detonation problems with low octane gas.

Tanya may be the person to ask about these sort of issues.

Dale
 

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Yeah the 6m has the early pistons so that is probably the way to go. That said, the later pistons work very nicely in one and make much better power without the side effects of a really high compression track motor. But you should probably just run it on 91 after that. If you really want overbore and high compression, you can always run a metal head gasket thats been thinned down. They are all made of multiple layers, you can take them apart and get whatever ratio you want (or mill the head a lot, though I prefer doing it with the gasket).

It really is too bad we can't get later style oversize pistons now, but the writing has been on the wall for awhile sadly.

Disagree about the comment about these motors not needing over bores. Sure, if you have a cherry motor with something like 200k kms on it thats lead a decent life, you might have straight enough bores to get away with stock bore. But most motors that are getting rebuild have not had such a life, and ring wear at the bottom of the bores is pretty common and impossible to fully correct without an overbore. I used stock diameter pistons in my rebuild and I still have a cylinder down a touch in PSI and it burns a touch of oil. Wish I had gone overbore and later pistons back then, as they were still available.
 

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Hey rtomascik67, you have to get out of your probation period here to send PMs now I think.

Ugh, I was hoping someone had a stash of them online somewhere.
 

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I don't know why you guys keep using Toyota parts deal. Their catalogs are years out of date. Use Roman at Cool Springs Toyota. They actually update their stuff regularly.
 
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