Packard Forum Index » Pre-War (1899-1942)

Just got the flywheel and pressure plate back from the shop. Those of you near San Jose Ca, FleetPride ( formerly BnA friction I think)did an utterly fantastic job on the pressure plate, looks better than new

Looking at the flywheel, I see the mounting holes for the pressure plate are counterbored, why? Bolts, as I recall, were not shoulder bolts

Question today is the torque specs. What torque for the flywheel to crankshaft and what torque settings for the pressure plate to flywheel bolts?

And don't recall seeing lockwashers on bolts holding pressure plate on. Same with flywheel to crank, although these are shoulder bolts. I think they should have them, replacing with all new grade 8 stuff

Thanks

John

Hi John, The machine shop that rebuilt my engine also resurfaced and replaced the flywheel, so don't know what torque specs they followed. They did, however, replace the 6 bolts for the pressure plate with grade 8, WITH lock washers and when I tightened up the pressure plate, I just slowly cranked them down in a diametrically opposed pattern, until they were 'out of movement', that is, as tight as I could get them by hand with a combination wrench. They're of a size that I think if you really cranked on them, you could twist them off, so it was possible to get them 'universally tight by feel' and not damage them. I know this isn't very 'technical' but I guess its somewhat like wheel bolts - they have a torque spec and lots of garages nowadays use that number and actually torque the lug nuts, but lots of guys still use the 'grunt and a half' spec and it has worked for a lot of years!! LOL Someone will probably chime in here with the correct specs and scold me, but just telling you what I did. Chris

In the 46-50 service manual, Clutch and Trans section page 12, it suggests 25 to 28 ft/lbs. Very similar flywheel and clutch setup as prewar so I would imagine those numbers would also work for yours.

Great info, thanks all!

I was planning on replacing with grade 8 bolts and lock washers.

Still trying to figure out why the holes have a counterbore

Excuse my ignorance John, but not familiar with 'counter bore'. What is it?? Chris.

It's been decades since I've worked on a Packard clutch but as I recall the counterbores are there to make it easier to align the bolts during installation.

Chris, a counterbore in this case is where the first few threads are bored away leaving a smooth, round hole that acts as a guide. A counterbore is also used when putting the bolt head below the surface.

Also watch the height of the head on the bolts, about a year ago someone had replaced the bolts and notice he had a noise every time he engaged the clutch. Just a suggestion.
Wes

Correction: Disengaged the Clutch.

The correct clutch bolts have an unthreaded area under the head which fit into the counterbores. This in effect makes them work as dowels as well as bolts and insures accurate alignment of the pressure plate for balance reasons.

all very informative and instructive - thank you for explaining it to a neophyte! Chris

Again, all good info, thanks for the support!