What kind of rings to buy?

[GrimJack]

Machine shop originally ordered Moly rings from Hastings. Unfortunately, the set they had 'in stock' is evidently incomplete, and it will be another 4 weeks before they can manufacture a new set. Machine shop cannot source another set of Moly rings.

So... the choice then becomes either Black or Chrome. They are not too happy with Chrome rings, say that the chances of proper sealing are lower. Black might not last as long.

Any advice from the crew?

PS: I expect to top out at mid 400 rwhp, and I'm not entirely certain that will happen on this engine - but a good chance that it will. I do not expect to run anything other than gasoline - no juice, propane, water injection, or anything else for that matter.

 

[IJ.]

No recommendation Grim as I'm using the Rings Ross supplied with their piston set but a word of warning on the Moly's if you get detonation the Moly will flake/detach from the ring then you're left with the 2 ridges/channel where the Moly used to be and this wears very fast!

Just thought I'd mention it as it's a bit of a trap on pump fuel as the quality varies so much!
<ps> Try to steer clear of hard chromed rings as well as they don't seat in 7M blocks due to how hard the Cast Iron in our motors is.

 

[GrimJack]

I'm getting the idea that gas nitrided rings would be the best bet, (They are harder and can't flake like Moly can) but damned if I can find any real specs or who makes what types! Not only that, but I can't really tell if JE or Ross rings should fit in Toyota pistons. GAH! What a pain in the ass.

Does anyone even know what the stock rings are?

Or how much shorter the life expentancy on black (iron) rings would be?

 

[malloynx]

yea, i can't really comment. i run the ross pistons with their rings. give ross a call. i know they offer a piston in stock size, so they might be able to help you out.

 

[IJ.]

Grim: I've ran iron/iron sets in past Turbo motors where detonation was a concern and have gotten really good mileage from them and wouldn't be concerned running this combo again!

Not sure how the Niterided rings would go considering how hard our bores are.

 

[suprra_girl]

well speaking from experience and a recent teardown on two rebuilds we did... ACL chromoly rings were still in perfect condition
i still have my old rings (7000km/4350miles) which my machine shop told me to keep as they are good spares

but thats just experience
have drag raced and caned my supra and rings are still perfect

so ya.. my 2c

(IJ: i know i know lol)

 

[Idealsupra]

dave try these guys:

http://www.importperformanceparts.net/imports/togarings_toyota.html

the rings are moly and iron....and they offer many different sizes...

hth

 

[bluemax]

Nitrided steel is super hard. But its also brittle. It will wear the cylinders instead of wearing down.
Chromoly is just a good grade steel, an ANSI 4130 or ANSI 4140 low alloy carbon steel. It's used in steel race bicycle frames and aircraft because of the reasonably high strength to weight ratio. 4140 is a better quality steel than 4130 and is usually heat treated to 160/180 ksi but can be heat treated to I believe 205 ksi. 4130 is usually heat treated to 125/145 ksi.
I would think heat treated 4130 or 4140 steel would be harder than the cylinders. But I'm just guessing. Anyone know what material the cylinders are made from?

 

[TONY!]

...Does anyone even know what the stock rings are?...

The top ring is stainless and the second ring is cast.
More can be found on the stock setup here:
http://www.cygnusx1.net/supra/library/TSRM/em/EM_03.html


I am favoring the stock OEM rings for myself for a couple of different reasons.

Toyota, in my experience, has a better fit than some aftermarket rings.
I once bought Federal Mogul’s Sealed Power chrome rings. Well they are supposed to be file to fit rings, which means that you have to file them to get them to fit properly. You would determine how much to file based on measuring the piston ring end gap as in the TSRM:
http://www.cygnusx1.net/supra/library/TSRM/em/EM_79.html
The thing I found out was that not only did they not need to be filed, but the gaps were too big as is! Now you might think that the end gap would be too big based the cylinder being enlarged or worn – not so!. I only had the bores brushed which does not increase the bore size. The cylinders also had the original crosshatch patterns before being brushed; this means that there was next to no wear on the bores. Although I had next to no wear and next to no material removed on the bores, those aftermarket Sealed Power rings had gaps that were beyond the acceptable gaps stated in the TSRM. Just out of curiosity, I measured all of the end gaps of the old original Toyota rings and found that they were still within specs, where as all (top, second, and oil) of the new aftermarket rings were out of specs.

What I think of stainless (the composition of the top ring):
I inherited a watch that is made of stainless. I was trying to open one of the links to shorten the band. I still can't believe how strong that metal is. It took a considerable amount of force to open that relatively thin section of metal! I have dealt with lots of different types of metals (so I thought), but as I have told my friend, that metal that the watch was made of (stainless) is the strongest metal I have ever tried to mess with. Stainless is no joke. I should mention that I don't know if stainless comes in different grades (like aluminum does), or weather all stainless is the same strength and composition. All this really makes me wonder how much more beneficial it would be to have chrome over stainless.

When I ripped my motor apart, it had 143,xxx miles on it. I must admit that I did not beat on my car or race it, but then again, I was not the first owner either. Well when I compared the Toyota rings to the new Sealed power rings, I seen NO wear on the stock rings whatsoever as far as the appearance was concerned in comparing the two. If the stock rings had no visible wear in experience, why would one look for a different composition? Again, I never beat on my car or do I know its history as I did not buy it new, but still, it had 143,xxx miles when I dissected that motor.

As far as what rings to buy if you have aftermarket pistons, I heard that in that case it would be best to use the same brand of rings as the aftermarket pistons being used.

If chrome rings are to be used: I hear that because the break in process would take longer, it is recommended that the cylinders be honed to a finer finish than what you could get away with using OEM rings or comparatively less hard rings.

Here are some questions I wonder about:
Has anyone ever had a problem using the OEM rings?
Have the OEM rings ever been the cause of problems on any builds?
(I don't think I have come across any cases so far.)

 

[bluemax]

There's a lot of different stainless steels. Some are more corrosion resistant than others. Some are stronger than others. Some are of course garbage. As far as strength, stainless steels can be just as strong as carbon steels.
The TSRM was not very specific on what materials are used so no conclusion can be made on the hardness and wear properties of the rings and cylinders.

 

[suprabad]

It's hard to argue with 0 or near 0 wear on the stock rings after 143k mi.

I wonder if anybody else out there has had a similar or disimilar experience?

 

[GrimJack]

Yes, my rings on my 90,000 mile motor were perfect as well.

Looks like I am going with IJ's advice and putting in black rings. If nothing else, I'll get a good seal in short order.

 

[IJ.]

Grim: LOL I said I've done it before not that I recommend it

I think on pump Gas you'd be safer with a harder 1st ring Stainless or CroMo just steer clear of any that are hard Chromed as they'll never seal!