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swapping flywheel and pully between 2.5l 12v engines

Posted: Sat Jan 14, 2012 12:53 am
by Alfa GTV6 NZ
Hi guys quick question. I have been searching, but I cant find the answer.

I have a head gasket problem after 350,000kms and wanted to swap out the original 12v 2.5l with a spare good 12v 2.5l that I have in the shed, its only done 200,000kms.
The only problem is I only have one flywheel and one front pulley.

Would it be ok to just swap these between the two engines?
I know that crank assemblies should be balanced as a set, but I don't want to pull apart the good engine.

Should I just give it a shot and hope it doesn't destroy its self?

Many thanks

Re: swapping flywheel and pully between 2.5l 12v engines

Posted: Sat Jan 14, 2012 12:38 pm
by kevin
Sounds like you not racing these engines . It's not ideal obviously but it's far closer than guys swapping from 2.5 to 3.0 and ordering custom flywheel. I guess it all depends what you're expecting the engine to ( or last).
Where's Jim when you need him :?:

Re: swapping flywheel and pully between 2.5l 12v engines

Posted: Sat Jan 14, 2012 12:58 pm
by Alfa GTV6 NZ
You are right about not racing it.
Its just a road/touring engine to keep it going while the other engine gets a full overhaul and upgrade.
The overhaul may take a year due to available funds and my engine builder doing it when he has spare time.

Re: swapping flywheel and pully between 2.5l 12v engines

Posted: Mon Jan 16, 2012 12:13 pm
by Jim K
Like I've said many times, swapping flywheels/pulleys is a roll of the dice. Results can range from no harm at all to destruction. The fact that many have gotten away with it don't mean $hit. What's right is right and the any 'success' stories don't negate the rule or need to do things properly. I fully understand the financial and time implications of ripping and engine apart and rebuilding it, but unfortunately, that does not have any bearing in the discussion!
Jim K.

Re: swapping flywheel and pully between 2.5l 12v engines

Posted: Mon Jan 16, 2012 2:10 pm
by Giuliettaevo2
How about copying the imbalance from one pulley to the other?

If you determine the imbalance on one pulley and have the other one balanced to the same imbalance will that be enough? Same for the flywheel offcourse...

Re: swapping flywheel and pully between 2.5l 12v engines

Posted: Tue Jan 17, 2012 9:05 am
by Zamani
It should be ok. But it's not the right thing to do. Balancing the whole assembly is the best. Copying the imbalance may be the next best thing.

But think about it, if your GTV6 was new and it broke a flywheel will the dealer take out everything and balance the whole assembly. No way. They will simply replace they flywheel. It doesn't mean it's right, but life goes on.

There are people out there who use 2.5 flywheels with a spacer on 164 3.0 conversions, now that is rolling a couple of dice a coupe of times.

Re: swapping flywheel and pully between 2.5l 12v engines

Posted: Wed Jan 18, 2012 1:43 am
by Alfa GTV6 NZ
Thanks guys.

I know it is not the right thing to do, but the spare engine was cheaper than a set of head gaskets so I will give it a crack.

If it was out of balance, what should I look or listen for?
Or will I only know when it throws a rod?

Thanks Again

Re: swapping flywheel and pully between 2.5l 12v engines

Posted: Sun Jan 22, 2012 11:31 pm
by benski105
Hi Karl,
i can probably lend you a flywheel and pulley if you need?
its been a while since iv been through my engine parts stash, but im sure ill have something that will help?


why not build a 3.0 instead?

Ben