7.3 idi turbo piston rings

[Thelebowski]

Howdy yall,
In a bit of a pickle.
Searched threads but found no definite answers:
1. Anyone have MAHLE or Hastings part numbers for KEYSTONE piston rings?
2. Is it true that 7.3 powerstroke rings will work for 7.3 idi turbo?
i’ve come to learn these things are needles in a haystack.

 

[FrozenMerc]

According to Rock Auto...

Hastings 2M4741S
Mahle 41548

This is a different part number than what is listed for a 1995 7.3 Powerstroke.

 

[NaiveRancher]

I’m not a professional mechanic or engine builder. I have a couple questions, I’ve seen “total seal” or gapless 2nd rings for IDI’s I think. Has anyone used them? My 7.3idi runs great, I run low psi out of turbo, max 8psi. My truck barely has blow by. When the time comes would anyone recommend the gapless style or should I just stick with mahle rings?

 

[FrozenMerc]

Stick with Mahle or Hastings. No reason to reinvent the wheel here.

 

[Thelebowski]

According to Rock Auto...

Hastings 2M4741S
Mahle 41548

This is a different part number than what is listed for a 1995 7.3 Powerstroke.

*facepalm* i was looking at the wrong years for rockauto, i see now. My bad.

 

[Finn]

Hapless rings plain don’t work.

The engine power cylinder is designed with cutback top lands, an accumulator volume between the top and second ring grooves, and a large second ring gap to prevent / control interland pressure and keep the ring seated in the groove. Lots of science and experimentation there to minimize ring and groove side wear and carbon buildup on the lands,mwhich leads to bore polishing and wear.

Hapless rings may work for short runs, but won’t last very long before the groves and lands pound out.

Junk aftermarket stuff.

 

[Black dawg]

Hapless rings plain don’t work.

The engine power cylinder is designed with cutback top lands, an accumulator volume between the top and second ring grooves, and a large second ring gap to prevent / control interland pressure and keep the ring seated in the groove. Lots of science and experimentation there to minimize ring and groove side wear and carbon buildup on the lands,mwhich leads to bore polishing and wear.

Hapless rings may work for short runs, but won’t last very long before the groves and lands pound out.

Junk aftermarket stuff.

So, what is the answer to the obnoxious blowby that the 6.9 and 7.3 have, even with like new sealing conditions? Seems like we could reduce the ring gap spec without issue, but I dont know??

 

[KansasIDI]

So, what is the answer to the obnoxious blowby that the 6.9 and 7.3 have, even with like new sealing conditions? Seems like we could reduce the ring gap spec without issue, but I dont know??

Both CDD and R&D, especially R&D, are fine with gapless rings… I know Justin at R&D really likes them, if it’s good enough for him, it’s damn sure good enough for me, and probably for the rest of us.

Everyone has their own opinions and has had different experiences, maybe they aren’t for everybody.

I didn’t put gapless rings in the 7.3 I built for my 86, they weren’t available at the time. No big deal though. Has a hint of oil vapor, but no excess pressure. I’m not sure whether or not I would have if they were available, but probably so.

 

[u2slow]

Basic keystone style rings (what the factory TiDi uses) are the default for industrial diesel engines.

Like @FrozenMerc says... No need to reinvent the wheel.

 

[IDIBRONCO]

I feel that if you're trying to get every .25 HP possible out of your engine, then go with gapless rings. Otherwise, I feel like they're a waste of time. You have to file the rings down to get a perfect gapless fit in your cylinders, You definitely can't use them in cylinders with very much wear. If you fit the to the top of the cylinder, where most of the wear is, the they will be damaged when the piston moves down in it's travel to the lower, less worn part of the cylinder. If you fit them to the lower, less worn part of the cylinder, the they aren't gapless at the top. That's why they need to be used with a fresh bore. There's nothing wrong with gapless rings, I just don't see the point of all of the time that you need to spend in order to use them. Also, I don't feel like they would be of much benefit to 90%+ of us anyway because we use our engines as a daily driver or maybe even rarely instead of trying to race them.