Piston rings

[604rail_king]

looking for a quick confirmation ...

im about to buy my ic944 .060 pistons however i have a choice of with or without the KB moly rings.
is there any sense in buying the pistons without the kb moly rings?

the seller does offer Hasting or Total Seal regular rings *(about $40-50 less than kb moly rings) however i havent found much info on peoples piston ring choices

[spdrcr137]

I am in the same boat, I would like any feedback on total seal rings for this build.

[Missourian]

I went with moly rings from a different supplier and if I had to do it over again I would have bought them from Summit Racing /Keith Black. It saves a lot of time tracking down all the parts and pieces that you need when you can get all of it from one shop.

[IH 392]

I've got MAHLE Molly rings for my IC944 pistons.
Wet fuel (gasoline) can use plain cast or molly, molly seats faster, probably by the time your cam breakin is done in, dry fuels (propane) need plain rings, the molly will flake right off!, chrome rings are for extreme conditions (DIRT/SAND) but they take forever to seat!

[604rail_king]

i was mainly curious as why someone would choose a different brand ring than their pistons. from digging a bit deeper, it looks like most people opted for moly rings vs cast. as most, my setup will be pump gas

ive decided on the moly rings and can get either Hastings, Perfect Circle, or the KB's. the plus side is the KB kit from summit is for a v8 (UEM-3875AM8-060), so having a couple spare is nice in case one breaks or is too loose when assembling the motor. KB confirmed this kit too when i emailed them.

[Retlaw01XJ]

I went with moly rings from Perfect Circle.... that's what Falcon includes in their engine kits.
Pretty sure Perfect Circle is now owned by Mahle.
I wonder if KB makes their own rings or gets them from PC or Hastings and reboxes them?

Note the KB944 pistons use the 5/64" rings like the ones used up to '95 or so, and not the metric rings used in 96-2006

[604rail_king]

well it is possible that KB rings are re-packaged for their 6 piston kits, however im looking at the KB rings only set which includes 8 SAE rings (which KB suggest to me via email). having spare rings is never a bad idea as ive seen it more than once how easy a ring can break, even by a skilled engine builder. im not buying a kit but will likely get a few items off FalconGlobal and the rest from Summit

i came across one thread where someone mentioned the SAE VS Metric sizing piston rings. the metrics were only marginally thinner but could still be used. they were "advertised" as low friction rings if i recall. maybe that person could confirm this?


i have 2 identical stokers to build.
one for my 95 xj using a 91 donor block/head. one for my buddies 98 xj using a 98 or 99 donor block using a 7120 head
from our calculations we should be in the 9.6-9.7 SCR, 7.95-8 DCR, with .043 quench

[SilverXJ]

the molly will flake right off!,

What causes the moly to flake? Heat?

[IH 392]

I don't recall exactly now??, when I worked at the machine shop we had the contract for HYSTER and we built a crapload of LP engines, they all had "plain cast" rings in them, the CLEVITE rep also told us that so there must be some truth to it?

[Retlaw01XJ]

someone mentioned the SAE VS Metric sizing piston rings. the metrics were only marginally thinner but could still be used.

5/64 = 0.078125 = 1.984 mm
The metric rings are 1.5 mm, so they're significantly thinner and won't interchange.

Thinner rings = less drag.

The 283 Chevy also has the 3.875" bore size.
You can look up the composition of the individual ring sets on the Hastingsmfg.com site and do some comparisons.
2M667 is listed for Jeeps, and 2M660 is listed for Chev 283. Both use #327 top ring, #126 2nd ring, and #860/732 oil rings.
http://www.hastingsmfg.com/RingFinderDi ... CD=3%207/8
Bet you can get a better price on the chev rings and end up with 2 extras! .....wish I did that.

[604rail_king]

correct, thinner rings will have less drag.

as far as using metric rings on a piston designed for an SAE ring, i wouldnt try or even debate it

the ic944 pistons are listed for my early 91 and my friends 98 or 99 block, and will use the SAE rings in both builds. its what the piston calls for and not the block.

i quickly searched 2m660 on ebay and found hastings moly rings for significantly cheaper! $38-58!
some listings were 3.875, others were .030 over or 3.905 which is what i need

http://www.ebay.com/itm/030-Moly-Piston ... 336f28753c

http://www.ebay.com/itm/Dodge-Chrysler- ... 336eea6138

[cruiser54]

When I built my Datsun Z stroker, I contacted Total Seal, gave them the dimensions of the rings I needed, and they made me up a set. I went Gapless BTW.

[LeviPittman]

machinist said that with a higher compression engine (9:1+)molyrings will hold that compression higher for longer so i went with them

thats why your HO's start to get a little blowby after 100k the rings are starting to loose their seal, the stock rings are plain cast

i was also told that for all but the most performance minded racing engine the gapless rings are overkill

[SilverXJ]

machinist said that with a higher compression engine (9:1+)molyrings will hold that compression higher for longer so i went with them

No truth to that. Moly rings seat faster than standard rings.

[Sailboy42]

I was looking at chrome rings. Yes, they take longer to seat but I can deal with that. Why else would I not want them?