164 3 litre engine to 90 or 75, bellhousing adapter plate?

[VeeSix]

Can anyone confirm that if you are going to put a 164 V6 3 litre into a 90 or 75 that you need an adapter plate between the rear of the engine and the bellhousing?
I am hearing stories that 164 V6 3 litre blocks are shorter than a 75 V6 3 litre block, has anyone here personally done this conversion and can confirm?

[Duk]

I think the problem revolves around a flywheel issue more than anything.

[Storm_X]

yes i have also heard the same thing

[VeeSix]

What is the flywheel issue Duk? 

Has anyone on this forum actually personally done a 164 3 litre to a 90 or 75 conversion that can give details?
I would like to get the details before i go ahead with anything 

[Duk]

I think it was something to do with needing a 4mm thick spacer between the flywheel and the crankshaft.

[JOHN G]

To help you with your question..

Firstly you are using a 164 12v into which car the 90 or the 75 ?

Is the engine for the conversion comming from an auto ?

And are you going to run the GTV6 or 164 plenum and runners and which computer are you going to use?

I have two GTV6's with 164 3.0 12v in them so I can help you with info there.

So far what Duk replied is spot on re the 4mm spacer required to align the starter ring gear.

John.

[Sheldon McIntosh]

I just finished a 164 3 litre into a 90.  Yes the 3 litre is 4mm shorter.

Yes you need a 4mm spacer between the shaft and the flywheel so that the starter lines up.  You also need to take off the little 'cup' washers on the starter motor so that it lines up to the front mount.  You need to shave enough off the back of the (2.5) sump so that it doesn't foul.  If you're keeping the 2.5 Ljetronic there are a few other problems to get around.

For the spacer I just took the adaptor plate off the 3.0 block to an engineer and he made up the spacer from that.  

[Sheldon McIntosh]

Ah, forgot to say, reminded by John G's question

Is the engine for the conversion comming from an auto ?

Assuming it is an auto, you'll need to use the bolts from the 3 litre flywheel, as they're longer than the ones off a 2.5 manual and will mate up perfectly with your new spacer.

[Domenic]

I thought the 4mm spacer was only used when fitting a 24v V6 into the rwd cars?

When i put a 164 engine in my 75 3ltr I never used a 4mm spacer and everything lined up perfectly, even the reduction gear starter motor.

[VeeSix]

Thankyou for your reply Domenic
But would that be because the 75 3 litre already has the 164 3 litre block in it?

[BradGTV]

everything you need to know about putting a 164 v6 into a gtv6/75/90 can be found here:

http://alfagtv6.com/msdocs/3L_update_Conversion.doc

a little off topic, but has anyone converted to a 164 v6 and keeped the motronic? obviously the dizzy needs to be removed from the back of the head, but can a jetronic dizzy be used instead?

cheers, Brad

[aggie57]

The different blocks are between early build and late build cars regardless the final use of the engine.  The flywheel and quite a few other details on a 3-litre is quite different to a GTV6 or early 2.5 as a result.  If you put all three engines side by side (GTV6 2.5, 75 3 litre and 164 12-valve 3 litre) the differences are very apparent.

So yes, 164 block should go into a 3-litre 75 with no issues but a GTV6 using the original will not take a 164 block without the adaptor plate.  Not sure about a 90 or early 75.

[ARQ164 Shane]

I have found this website very helpful ,just so I can see what involved in a 2.5 to 3lt swap.
http://www.alfamilano.com/projects/verde_rebuild/finishingup.html