3.6 conversion flywheel options

[William Miller]

I'm planning one of my last major cost items in the 3.6 conversion.
I know of the 2 typical options. Patrick and Timmins.
What are the pro's and con's of each.


Someone also mentioned another option to me which uses an 89-C4 flywheel. I'm looking for whatever details to make that work.

The part # is 964 102 239 00
They are sold here.

I did a search, but didn't find anything on this.

[mede8er]

I have the Patrick LWF....spools up very nicely.........

[William Miller]

Any reason you picked that over the other?
Herd anything about the 89 C4 conversion?

[wheatdog]

I used the Timmons one cause it was supplied in the kit and he said it was good quality stuff. Working fine so far (10k+ miles). Fit great without issues on buildup. Can't make a comparison cause I've no experience with the Partick piece.

Mike

[William Miller]

Forgot to ask. Will the same flywheel fit both the 964 and 993 engine.
I think it is but want to be sure.

[johnsjmc]

I think the C4 flywheel will only work with a G50 trans as in the 87 and later cars. I am told the Patrick flywheel for the 915 is slightly smaller in dia. than the one that Timmons sells. Timmons claims you might have a weak position sensor signal as a result of using the small one. I would shop by price and file fit the sensor bracket if needed to set the distance.

[mede8er]

Timmons claims you maight have a weak position sensor signal as a result of using the small one

He might be right..I had idle probs till I dremeled out my ISV and manually adjusted it.......

[Craig 930 RS]

Patrick flywheel I used in 2004 had fit issues.....rubbed against the case. When fixed, it was perfect.....not too light.

Some grinding took care of the rubs:

[ischmitz]

IMHO the 89 C4 route makes sense if you disregard the additional machine costs and the costs for the new sensor bracket unless you get a used one for a good price. If you have to purchase a new flywheel you migth as well go with a PMS or Timmens version. All flywheels require the same starter ring gear from your old engine.

All 964 and 993 engines are identical with respect to the crank bolt pattern (9 bolts) and the location for the reference pin.

The 89 C4 flywheel requires part # 964.101.187.00 for the reference sensor since the flywheel is shaped like a dish. Its reference marks are further away from the crank case. All later engines including all 993s require part # 964.101.187.01 for the bracket with a slightly different position of the sensor. It puts the sensor closer to the crank case.

[William Miller]

Ingo! Thanks.
Did you mean to write the same part number twice?
I have a 89-C4 flywheel avalible to me for $175.
I'll look up those part numbers.
The case is 993, but if you recall the engine is sort of a combination of parts.

If I may ask, what machine work is required. I recall you mentioned somewhere that new holes needed to be drilled and tapped for the 915 type pressure plate. Do you have any details or know where I can get them? I'll look up that part number in the mean time.
Thanks again for your help.

[William Miller]

Ok that part number is a $20 bracket so I'm still ahead of the game.
I'll see if I can find a part number on the sensor that is on the engine.

[ischmitz]

Nope, different part numbers. I highlighted the last two digits to clarify. If the engine is not coming out of a 89 C4 without dual-mass flywheel the bracket needs to be changed. It's as simple as that. One bolt that goes with the clamp is also different in length:

-89: 2x M6x20
90-: 1x M6x20 and 1x M6x30

You'll believe it when you see it. Ask me how I know I would take that C4 flywheel and your (new?) pressure plate to the machine shop to locate the thread positions. And while you are at it have them resurface it for 40$.

Cheers,
Ingo

[William Miller]

Bingo!
I don't think that showed up last time I looked.
Thanks again. I'm on my way!
Just to clarify, I don't need a new sender, just a new bracket.
The ....00 is the bracket I need and the ...01 is the one that's probably on the engine. Right?

[William Miller]

I went ahead with the used flywheel. They had the bracket and the extra screw as well. I should have it in a few days and I'll report back with some pictures. Nothing like having it in your hand.
Thanks again Ingo!

With the discussion about sensor clearance, what should it be?
Should it be fixed with the correct bracket and just something you verify, or do you have to set it?
Anyone know the correct value for the 89?
Is it in the workshop manual or do they have a little spec book for this?

[ischmitz]

1mm - same for all 3.6 engines

[William Miller]

Tanks!

[GaryR]

Bill -
I'm looking into doing the conversion to a 78SC, would appreciate pics (and any advice you may have!)..

[William Miller]

The flywheel showed up last Friday.
I haven't been able to do anything with it except take a few pictures.

Ingo, does this look like what you specified?



It was quickly apparent that the flywheel and PP don't mate together right away. The OD of the PP is a few mm larger than the recess in the flywheel. The ID of the outter rim will need to be turned on a lathe. This second shot shows the relationship. They aren't aligned perfectly but you can get the idea.



Ingo, is this what you were expecting? Do you have anay pictures of the finished product?

The part number on the back of the flywheel matches what I asked for.

It appears that once that edge is machined there will be little material left holding the toothed ring on. I need to take some precise measurements to be certain.

[ischmitz]

Yes, that is correct. The toothed area should be O.K. And the starter ring gear rests on the step of the pressure plate. I think you are fine.

[jevvy]

remember you may have to space the ring gear out a bit with washers or the starter might not engage properly - I know I had to do this for the G50 box

It's probably worth hooking the starter up with 12V quickly before you install the engine as it will be easier to correct spacing before the engine is fitted.