The Stovebolt Site Forums The Shop Area Engine Shop Pressure Plate to Flywheel Assembly Alignment

Hey there shipmates. I'm back & in need of some more adult supervision.

The 58 Apache is coming along. I just got the engine (283) back from the machine shop. I've been working along with Vizard's How to Rebuild your Small Block Chevy and everything's been going smoothly (except, of course, for the random attacks of stupidity that I sometimes suffer).

I had replaced the tranny, clutch & pressure plate before I decided to pull the engine so the clutch & pressure plate have fewer than 50 miles on them. Per Vizard, I marked the alignment of the pressure plate to the flywheel when I removed it. After looking at the flywheel, I decided to install a new ring gear & have the machine shop resurface the flywheel.

Hah! I didn't think about the process removing the paint of the alignment mark that I put on the flywheel! (Dang, I love this trial by ordeal stuff!)

Vizard stressed the importance of reassembling the pressure plate to the flywheel in the same position as it was removed (his italics).

What I'd like some feedback on is:

How important is this?

Does the alignment matter since the pressure plate & clutch are new?

If the position of the pressure plate to the flywheel does make a difference, how in the heck can I figure out how to align it correctly?

Any help you real mechanics can offer to help me get my head out of my exhaust manifold on this will be greatly appreciated!

THX,
Bodega Bob

I don't think the pressure plate is "indexed" to your flywheel on your application. You will need to align the disc to the flywheel though. You should still have your clutch centering arbor from your clutch kit, that should be all you need. If it is indexed, it will only go on one way so you can't really screw anything up anyway,
Scott

The flywheel and pressure plate are supposed to both be neutral balanced, so you can replace the pressure plate if necessary without having the whole thing re- balanced.

Thanks shipmates. I appreciate your help.

That makes perfect sense to me. I wonder why Vizard made such a big deal out of it?

To tell the truth, I've already torqued the booger in. Before I did I rotated it thru each of the six possible positions & saw no real difference in how it matched up with the flywheel.

I'll let ya know when I fire it up if I start taking frags thru the floorboard!

Bodega

I installed my first clutch in 1962, and didn't mark anything. Maybe it's a habit by now, but I've been getting away without marking them ever since. I can't really see any advantage to doing that, unless the assembly has been spin-balanced in one position. Even then, I think position would make little, if any difference.
Jerry

I did a lot of clutches when I was younger. [too much abuse of the clutch] I never heard of indexing the pressure plate. I never had any problems. Be sure you get the disc lined up right or you will have trouble getting the transmission back in.

A lot of imports index the plate to the flywheel, but I've never seen domestics do it (unless they are equipped with an import drivetrain)
Scott

I dont see any reason for lining anything up like you said. The only thing that needs to be lined up as far as I know are the splines the they slide onto the Trannies input shaft. Another little tip I learned from a mechanic today, is when you resurface/turn your flywheel, you can take sandpaper (something like this) and make an arched, back and fourth motion in the shape of a C, creating a rough surface going the opposite direction that your flywheel turns, so it grips better. I hope that made sense....

- Shane
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The 1948-51 Chevrolet Truck Shop Manual reprint and the 1947-54 GMC Truck Shop Manual reprint both mention an X on the flywheel and an X on the clutch cover. I assume the flywheel/clutch was balanced as an assembly at the factory then marked thus. I highly doubt you can find 10 trucks now with the same clutch it left the factory with so I wouldn't imagine it makes much difference.

I have done a bunch of clutches professionaly and never seen anything "indexed". There may be a call to do it for high rpm racing applications but not common street use.
Brad B

FYI - I just pulled my 51 3100 AD 216 flywheel and clutch and there is a small X stamped on the flywheel and there is a small X stamped on the pressure plate housing...The clutch, at least the clutch plate is remanufactured and there is no way I can get the two X's to line up fooling with it on the bench... it must have meant something back in 1951 but it doesn't seem to matter now...I would like to replace with a new clutch from one of the name brand clutch manufacturers rather than a rebuild from one of the popular truck parts suppliers we all know about. Various manufacturer's websites offer clutches going back to early GM 265 V-8's, 9", 1-1/8" X 10 spline which describes my old clutch... would these clutches fit the 216 flywheel? Thanks for any help on this, Regards - Bug!