Opps wrong pistons

YJMike92 · Sep 9, 2023

Well, I messed this one up. I was installing my rings on my pistons and no go. The top ring groove on my new pistons is too narrow for the ring to fit. What's up with that? Cross-referencing numbers say the rings are correct. Cross-reference the pistons says the pistons are for a 94 Powerstroke @#$&&$#@.
Okay, I'll order the correct pistons for a turbo engine. Looks like that's easier said than done.
Then I get to thinking could a guy use Powerstroke pistons in a IDI?

IDIBRONCO · Sep 9, 2023

YJMike92 said:
Cross-reference the pistons says the pistons are for a 94 Powerstroke @#$&&$#@.

It's easy to tell the difference. Our pistons don't have a very relief on top. Powerstroke pistons have a HUGE relief. At the very least, you'd have to have Turbo rods or modified Powerstroke rods in order to use the Powerstroke pistons. That's just for the wrist pin diameter. As for the rest of the fitment, I have no idea.

YJMike92 · Sep 9, 2023

IDIBRONCO said:
It's easy to tell the difference. Our pistons don't have a very relief on top. Powerstroke pistons have a HUGE relief. At the very least, you'd have to have Turbo rods or modified Powerstroke rods in order to use the Powerstroke pistons. That's just for the wrist pin diameter. As for the rest of the fitment, I have no idea.

I have the turbo rods. I have the pistons mounted on the turbo rods. everything was good there. The top ring grove was too narrow on these new pistons, which is why I ran the part numbers. The valve reliefs seem about the same. In fact, the pistons seem very similar. Maybe these are the correct pistons and do I need a different set of rings? My new piston Mahle part number is 224-3512HA.

YJMike92 · Sep 9, 2023

I guess this is a Powerstroke piston. I'm not sure what I have going on here. My new rings fit the old pistons, but not the new pistons. I'm not finding a set of rings that spec out to the new pistons ring groves.

1mouse3 · Sep 9, 2023

Turbo pistons need keystone and na dont. do you need standard or oversize?

1mouse3 · Sep 9, 2023

I found this in a search...

Thewespaul said:
The na IDI rings are not keystone like the idit rings, here’s some specs on the various IDI rings.
IDIT rings top to bottom:
1/8” 6* keystone
5/64” 3* keystone
9/64 oil control ring

1994-1989 na 7.3:
1/8” conventional
5/64” conventional
9/64” oil control

The 88 7.3 is 5/64, 5/64, 9/64 and the 6.9 is even smaller at 5/64, 5/64 and 7/64.

Im finding these from total seal. I will check the Mahle piston I have to conferm gap and part I got, tomorrow.

Conventional Top Ring Sets
Gapless 2nd Ring Sets

IDIBRONCO · Sep 9, 2023

YJMike92 said:
In fact, the pistons seem very similar.

No they don't appear to be. The old pistons look like they have the smaller N/A wristpins.

YJMike92 said:
Maybe these are the correct pistons and do I need a different set of rings?

They are, in fact, Turbo pistons, not Powerstroke pistons.

YJMike92 said:
I guess this is a Powerstroke piston.

Correct.

1mouse3 said:
Turbo pistons need keystone and na dont.

This is the correct answer.

YJMike92 · Sep 9, 2023

I'll look at this keystone ring thing.

YJMike92 · Sep 9, 2023

1mouse3 said:
Turbo pistons need keystone and na dont. do you need standard or oversize?

I'm using oversize on a standard piston and filling the ring to the proper ring gap.

YJMike92 · Sep 9, 2023

Upon further investigation, the keystone ring may be the answer.
A drill bit inserted into the groove shows a tapered ring grove.
So where to find the correct rings? I have found this part number (mhlS42104)

YJMike92 · Sep 10, 2023

IDIBRONCO said:
No they don't appear to be. The old pistons look like they have the smaller N/A wristpins.

They are NA pistons. They're the old pistons. I'm switching to turbo pistons

1mouse3 · Sep 10, 2023

YJMike92 said:
Upon further investigation, the keystone ring may be the answer.
A drill bit inserted into the groove shows a tapered ring grove.
So where to find the correct rings? I have found this part number (mhlS42104)

Im not finding info on those rings

1mouse3 · Sep 10, 2023

I have the same Mahle 224-3512HA pistons but mine are .020 over vs your standard bore ones.