Flywheel fitting. What have i done wrong?

[PMNorris]

Hi,
I'm fitting a 3.0SC engine to my 70T, and this question is about the engine fitting, so apologies if this would better be asked on an SC forum....

I fitted a new lightweight Fidenza flywheel a few weeks ago and just about finished rebuilding the long block yesterday, so needed to adjust the valves. To my horror i couldn't turn the engine over to adjust the valves and wondered if something catastrophic had happened whilst i was rebuilding the engine. I removed the flywheel and was able to turn the engine over freely again. Presumably the flywheel is fouling on the engine block. Its a 79SC engine with the 9 bolt flywheel pattern, so no spacers should be required. I'm pretty sure the pilot bearing is fitted correctly and the flywheel was torqued on. Any ideas what i've done wrong?

The engine block


flywheel front


Flywheel back

[mike curnow]

This should be pretty obvious, but is the flywheel hitting on the nuts you are using as spacers on your engine yoke? Also I don't know if an aluminum flywheel on a street car is a real good idea?

[PMNorris]

Hi Mike,

Its definitely not interfering with the engine stand. If the lightwheight flywheel doesn't work out i'll change it for a stock one, but the cars evolving into more of a street racer.... We have fewer speed restrictions in Poland than you do in the US!

[edmayo]

Just bolt the flywheel back on with the bolts finger tight, now see if engine will turn, if it doesn't loosen the bolts slightly until it does, rotate engine now then remove and look carefully for scrape marks on the case and/or flywheel. Since it locks up the crank when fully tightened down it shouldn't be that hard to find. If the stock flywheel works then it has to be some dimension difference in the Fidanza. Always ASSUME an aftermarket piece is wrong until proven otherwise.

[gled49]

I also have had ALU flywheels hit the parting line of late crank cases. Gled

[PMNorris]

So... I refitted the flywheel and tightened the bolts up finger tight. Before i did that i smeared some lithium grease on it so could see where the contact was. What is clear is that this flywheel is clearly not compatible with the engine. I am going back to Fidanza for their suggestions.

You can see the marks in the grease, but i'm pretty sure its the rivets that stop the engine from turning over altogether


You can see a bit of grease on the bulbous part of the block. The photo is upside down, so this is on the top of the picture / bottom half of the block.


I am not impressed, but still hope i've done something stupid. I will wait to see what Fidanza say.

[gled49]

I wouldn't hesitate to grind a little off the case, plenty of metal back there. Here is my old Alu flywheel mounted and dismounted many times in its lifetime, but eventually failed. I always used a bolt plate or head washers with longer flywheel bolts, you certainly don't want any material removed from flywheel. Gled

[PMNorris]

Thanks Gled,

If i put some washer in, won't that interfere with the clutch? How thick were the washers you put in? I could do a combination of both grinding and washers, which would probably solve the problem, but just sounds a bit risky to me.

Regards
Paul

[gled49]

you misunderstood me, I didn't put washers between flywheel and crankshaft, I put them under flywheel bolts to save contact area under bolt head. You will have to check for clearance from bolt heads to clutch disc.

[PMNorris]

Ok thanks. Fidanza are investigating. They've been very helpful so far.