Fast240Z

I'm going to be rebuilding my L24, and I wanted to know if anyone has had any experiences with Total Seal rings. I've been told they were excellent, but I've also heard that they have some issues. I was originally considering chrome top rings from Kragen Auto Parts, so which set would be better?

theramz

The draw back on chrome rings is they take much longer to seat and they cost more.

BoulderZ

Stock rings on the L28 were chrome, and they're used in a lot of famously durable engines (e.g. Toyota 22R). They can be made to seal well. But, as genomz mechanic friend mentioned, they have a pretty widespread reputation for being difficult to seat/seal correctly in rebuilds.

It's probably not an issue if you're a factory with a dedicated precision clean-room build facility. But if you're an enthusiast with a home garage, or a professional mechanic that has to pay at least some attention to repair throughput to stay in business, then doing everything exactly perfect to get the chrome rings to seat probably isn't practical. And it's not like good moly rings aren't durable. ITM ships moly rings with their aftermarket Z pistons, and plenty of people use them in rebuilds because they are easier to seat. If you purchase a decent name-brand set from a good supplier, you'll get many happy miles from the motor.

happy wrenching,
Dave

Fast240Z

Dave, is there a chance you might be able to refer me to the company that makes those moly composite rings you were talking about? I may end up going with an iron set, unless I get the whole Total Seal gapless compression ring set (where only the top ring is gapless, and the rest are standard iron/moly composite).

BoulderZ

Funny you should ask. The rings came as a set with the pistons, which are ITM:
http://www.itmengine.com/
You can get them through most decent auto parts stores, though they may have to order them (likely same day, from a daily truck run to the regional warehouse).

I went with the ZX NA "flattops" upgrade (0.020" / 0.5 mm over on a '78 280Z block/head). The ITM site says that they ship rings that match whatever OE specs are for material. Well, the stock rings were chrome, so that can't be true. My machine shop guy and I both believe the new ones are moly. But, to be absolutely sure, I checked with Black Dragon / Vic Brit, where I ordered my pistons/rings set. They weren't 100% certain about the ring material, and are currently out of stock, so they couldn't check. My rings are at the machine shop, so I can't reconfirm first hand, either. So, I've emailed ITM. I'll post what they have to say as soon as they reply. I'm 99% certain that they are indeed ITM rings, and that they really are moly composite. But I want to be 100% sure, given I'm posting it here.
more soon,
Dave

BoulderZ

ITM got back to me very quickly (seem like a good bunch of people), and they swear they put in ring sets that match whatever is/was stock spec for the motor for which the kit is intended. In this case, that would be for an 81-83 NA ZX, and they were sure that should be chrome rings (which would match what was stock in my '78 L28). So I went over to the machine shop again, and the machinist and I are both sure that they're moly rings.

I asked ITM to re-confirm about the chrome, asking if maybe the outer friction face was chrome and the inner part was iron or something else, because you can see the two very different materials, and I haven't heard back.

This leaves a lot of potential scenarios. Maybe the ZX actually had stock moly rings (unlikely, but I don't know, never taken a ZX apart, only 280Z's)? Or maybe ITM actually ships whatever was stock, unless it was chrome, and then they ship moly? Or they shipped chrome and Black Dragon switches to moly? Or maybe Black Dragon orders piston-only sets and puts there own moly ring sets in there? When I called and asked Black Dragon (no email, how retro), they weren't sure and didn't have any sets in stock that they could look at.

If you might like that ring set, I'd say go ahead and have your local non-Checker-Schucks-Kragen auto parts store get a hold of an ITM set for you, and see what shows up. It'll likely be a nice set of moly rings. If it's not what you expect, it should be no big deal for them to send them back.

Dave