L98 engine and balancing
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
L98 engine and balancing
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...
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...
Last edited by devilfish; Apr 28, 2014 at 10:44 AM.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
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
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
Team Owner
Joined: Sep 2003
Posts: 25,388
Likes: 2,741
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.
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.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
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...
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...
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
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?
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?
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Leave them alone, IMO.
Team Owner
Joined: Sep 2003
Posts: 25,388
Likes: 2,741
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.
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Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
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.
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 )
Last edited by devilfish; Apr 29, 2014 at 11:13 AM.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
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..
Se last posts by "Bluewasp"..
http://forums.corvetteforum.com/c4-t...rpm-lt4-2.html
Good info in that thread..
Team Owner
Joined: Sep 2003
Posts: 25,388
Likes: 2,741
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.
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.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
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
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
Last edited by devilfish; May 1, 2014 at 08:12 AM.
Team Owner
Joined: Sep 2003
Posts: 25,388
Likes: 2,741
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
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
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.
Last edited by WVZR-1; May 1, 2014 at 08:33 AM.
Thread Starter
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
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.
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.
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..
Last edited by devilfish; May 1, 2014 at 11:29 AM.