Club Cobra - Flywheel bolt spacing, unequal

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Flywheel bolt spacing, unequal

Hi Guys,

Okay I'm just about to test attach to my all new, all aluminium 427 FE, the flywheel, clutch and trans for the first time. The engine is neutral/internally balanced so therefore the flywheel is plain and has no bolt on weight.
I've noticed that the spacing for the bolts that attach the flywheel are on the same PCD but not equally spaced. Is this simply to index the flywheel, just in case the engine was externally balanced and needed the weight? Does having the bolts unequally spaced, when using a plain flywheel, not cause vibration? I must say there's a small drilling on the back side, which maybe is to counterbalance it ??
Also if anybody has a torque setting for the clutch pressure plate bolts (Mr Gasket #911 5/16") I'd be most grateful. I believe the flywheel itself is 75 ft/lbs

This page may be of help: Flywheel patterns for the clutch Now, when I had my FE built, I had it internally balanced because the SCAT stroker crank made that easy on my 428 block. The builder balanced my pressure plate, by welding a small chunk of metal, with the neutral balanced flywheel (which, of course, is never perfectly neutral) and marked both with a little, easy to line up, "X" -- that's the traditional way to do it. If you're going to the trouble of building a nice FE, you'll want to balance your clutch with your flywheel, but there are different bolt patterns and they all have to line up.

Just bolt it up. Fords have an offset pattern, so when you use an external balance flywheel, you can only bolt it on in the correct way.

Chevys have a dowel in the crank.

Accomplishes the same thing.

The flywheel is supposed to be neutral balanced and the clutch plate neutral balanced. If both are new you may just have to bolt them up and go. The slight offset of the one flywheel bolt is not going to be an issue.

You may be able to get your flywheel and clutch plate balanced together and index marked over there. I tried to get both flywheel and clutch on my 66 Vette re-balanced this last summer (new flywheel) and was unable to locate anyone within 75 miles or so who had equipment to do it with anymore. Ten years ago it wasn't a problem. Everyone now wanted my stripped block components (crank, rods, pistons) and my flywheel and clutch to balance all together. I didn't want to mix new and older index balanced parts so I ended up buying all new components and just throwing it all on the engine - seems to be running smooth.

Quote:

Originally Posted by AC Ventura (Post 1434808)

The flywheel / crankshaft rear flange bolt pattern is asymmetrical, regardless of whether it's internally or externally balanced. Yes, solely for purposes of indexing the flywheel.

The small drilling on the back of the flywheel is almost certainly for balancing when it was made - it's easier to remove weight from the heavy side than add weight to the light side.

Torque Specs:
Flywheel to crankshaft: 85 ft/lbs, with threadlocker
Pressure plate: 35 ft/lbs, with threadlocker
Source: Ford 352 360 390 406 427 428 V8 Engine Specs | Torque Specs - Cylinder Numbering - Firing Order - Distributor Rotation

Summit Racing has slightly different specs:
Flywheel/flexplate bolts: 75-85 ft.-lbs.
Pressure plate bolts: 35 ft.-lbs.
Source: https://www.summitracing.com/experta...rd-torque-spec

Summit doesn't mention using threadlocker, but I'd be inclined to use it.

Seems pretty straight forward. Will do all this.

Use the blue threadlocker - it's sufficient and you won't have to struggle if you ever have to take it apart again.

double check the length of the bolts to make sure they do not hit the block. My new Pond block, OE flywheel and bolts. The bolts were too long.
Nothing was damaged or anything like that, it was just one more discovery during test fitting.