164 conversion balance issues

[BradGTV]

Recently i have been reading up and buying parts for my gtv6 restoration and 164 3.0 engine swap. Still in a bit of confusion regarding engine imbalance when using the 164 engine, 164 front pulley and gtv6 flywheel. Heard a few different stories of people doing it without issue and some people saying it will have crazy imbalance issues. Opinions? Info from people who have done it would be appreciated . Cheers brad

[Mat Francis]

Hey Brad,

Why the 164 pulley? Are you keeping the motronic?

In the 90 I've used the 2.5 flywheel and pulley, on a 164 motor with no issues. When it isn't affected by fueling issues, it is dead smooth.

[Sheldon McIntosh]

In the 90 I've used the 2.5 flywheel and pulley, on a 164 motor with no issues. When it isn't affected by fueling issues, it is dead smooth.

+1

[aggie57]

Personally I wouldn't take the risk. Get the 164 flywheel and front pulley matched to the GTV6 ones.

[BradGTV]

Thanks guys, yep planning on keeping the motronic. So basically I need to get the 164 front pulley balanced up to make it the same as a 2.5 front pulley, leave 2.5 flywheel as is and it should be sweet?

[aggie57]

No Brad - I should have said "Get the GTV6 flywheel and front pulley matched to the 164 ones."  Sorry. 

In your case if the 164 pulley you will be using is off the 164 engine then that will already be balanced to the crank, so you'd only need to get the flywheel matched.

I hear what Sheldon and Mat are saying regards their experiences but if the engine is out and both flywheels are in your hand I don't know why you wouldn't make sure everything is balanced correctly.  Call me a belts and braces guy.

[BradGTV]

Ah I understand now, cheers.

[Fylnn]

Resurrecting and old post.  I have a 164 engine which I want to put into a GTV6.  I have a 2.5 flywheel.  I want to use the 164 front pulley since I run a Haltech and and the Motronic sensor would give a clean signal from the front pulley.  So I want to keep it on there.  I know the V6 is externally balanced, so at the risk of appearing obtuse just want to clarify a couple of things:

    1.  I gather then from the above if I took the 164 flywheel along with the 2.5 flywheel to a balancing shop, I need to ask them to make the 2.5       flywheel same 'balance' as the 164?
    2.  From what I can see and remember from times I have disassembled the flywheel.  There is no key or location on the flywheel so it can go in any orientation.  Is that correct? 

So if I have a 2.5 flywheel that has been balanced to be 'same balance as the 164', I reinsert it in any orientation and it all should work?

[Fylnn]

Simple once you know how.  Now I see that I do seem to recall the first time I tried to put the flywheel back on having to rotate it until the holes lined up.  Seems I forgot that bit.

[LukeC]

Coming from someone that worked in an engine reconditioning shop (albeit 30 odd years ago), and has balanced V engines: To replicate the balance factor correctly without a full disassembly of the engine, you must make a jig to mount the 3.0 flywheel (with an indexed dowel to ensure correct placement relatively), mount the flywheel and balance to 0, then mount the 2,5 flywheel and re-balance to 0.

I recently asked my favorite engine shop (been around since the 60's in Canberra) if there was another way to do it.... They said no. I researched and found that nobody had had issues so went ahead.

Smooth as silk. But this was a quick and dirty job and if doing a full rebuild would do it properly.

[martym00se72]

When I did mine the shop asked for a spare crank so front pulley and rear flywheel could be matched up at the same time - made life easy for them and assured of correct results.

Also, surprising to see that no-one has mentioned that this is also a prime time to get the front flywheel lightened somewhat.