devilfish

As far as I know, the L98 89-91 rotating assembly is internal balanced in the front of the crank, and external at the rear, correct?
Does this mean that my dualmass flywheel is matched and "unik" to my rotating assembly?
Or can I put my flywheel, or a brand new one, on all L98 motors between 89-91 with 1 piece rear seal?

Or im I thinking wrong here?

Hope you can help me shed some light on this..

Cheers...

devilfish

I know some guys out there has done this, and know what the deal is.
I must get a replacement engine, or a new rotating assembly for my car.
And this is a crucial part of information.

I also wounder about the small weight inserts, that the DMF has, and if I need to take those in to consideration when I get a replacement engine or new new rotating assembly.

Thanks

WVZR-1

It is assumed that you could use any "correct" off the shelf flywheel for the replacement and so long as the engine was stock or built to OEM specifications you would be fine. It would have a "bolt on" weight on the engine side of the flywheel. You could use your old to "match balance" to the same "offset". Don't remove the pins and don't sell your flywheel until your running and happy.

You need to make sure that everyone is on the same page when buying an engine OR buying what you refer to as a rotating assembly.

Location for you I would think maybe critical when buying the parts. The confirmation of the "match balance" can be done by any competent shop. You need to explain the procedure that you want done well though.

Tom400CFI

Your DMF will fit and work on any stock balanced, 1 piece rear main seal, SBC.

devilfish

Thank you..

To complicate things even more.
If i go with a replacement engine, i only found engines for my car here in Sweden that where using auto trannys.
According to you guys i should be abel to just bolt on my dmf to that engine and go..
But in that scenario, what about the fine tune weights, that is now inserted to my dmf?

Tom400CFI

That is correct, assuming the engine is a 1 pc RMS.



Leave them alone, IMO.

devilfish

Got it!

Thanks all

WVZR-1

Yes to both responses - 1 piece rear main it should be fine and the balancing pins should stay where they are.

What might be interesting is maybe post a link to the assemblies that are available to you if it's an Internet buy. You mentioned they were A4 assemblies, is there a flywheel supplied with them? It might be interesting to see how large the weight is on the flywheel if it is.

devilfish

Thanks for helping!

Yes I only found A4 89-91 engines used here in Sweden.

There is one engine with low milage and ( and according to the guy I talked to, also good compression ). Its 89 MAF engine. I have a 1991 MAP car.
But that should not be any trouble ,as I have all the required parts to make it fit my car.

http://www.bildelsbasen.se/se-sv/Che...odelyear&asc=1

( its in swedish )

devilfish

I also found this info, regarding the DMF and why GM used the small weight pins on some DMF.
Se last posts by "Bluewasp"..

http://forums.corvetteforum.com/c4-t...rpm-lt4-2.html

Good info in that thread..

WVZR-1

I didn't realize we were discussing used engines but it will make no difference. The information in that link is only specific to those that had problems and the fact that yours has pins does NOT mean that it did and they were placed there. It's just the balance of your particular flywheel "at the time". I'm still with the comment "touch nothing" and install "as is".

Might you make notes and make a copy of the post in that thread - I'd think so. That mentions that 65 engines were done and they were LT1's. If you had no issues with the removed engine you should anticipate NONE with the replacement engine.

Tom400CFI

What ^he said.

devilfish

Thanks!

I feel confident now to get that used engine and start my swap..
She will live again!

devilfish

One thing that keep coming up when I searched about this, both here and other places is that many say "you MUST match balance your new FW to the old one" even if you convert to a singel mass FW etc.

But If the "balance" weight on the flexplate/flywheel is the same for all of the 1pc rear seal cranks. Then why would you do that?
(if you have a stock internals )

I read this from people that both get new DMF and convert to singel mass like SPEC.

SPEC offer singelmass flywheel with the correct 1 pice rear balance weight. That should bolt right on, correct?


Is it that people are misinformed, or is the match balance "just" to be super safe..

Im just trying to understand this corret

WVZR-1

Your concern is the "quality" of the product that you just purchased. It (the new flywheel) is not shipped with any "certification". It would be foolish NOT to confirm if you had a "known" against the "unknown" that you just purchased.


The balance of the clutch assembly can be equally as important!

Your "used" engine should come with a A4 flywheel also I would think since it's mentioned as such and you could actually accomplish a "check against that one" but I'd suggest only as a matter of interest. I wouldn't change a thing with yours IF there were no issues in the previous install.

devilfish

Ok got it.

From some posts you read, you can get the feeling that new or used FW for the same type of engine/year is not interchangeable at all...

I will install it, and if feel and vibration, I pull it and have it matched to my flexplate.
Should be easy to test on the jack stands, with no tranny connected.
Install FW, pressure plate, disc. Spin the engine from idle to 3-4000rpm. If not vibration, put the tranny on..