Packard Forum Index » Post-War (1946-54)

Packard Don wrote:
I’m not really sure that these heads need to be machined as the studs will easily pull them down flat. The only real reason to machine one is if it has some sort of localized damage. I always use a coat or two of well-shaken CopperCoat on both sides, let it tack up, then tighten it down!

On the studs, you said you didn’t removed them but perhaps someone before you did as some do not appear to be threaded in all the way. Put in properly, no threads should be showing.

kevinpackard wrote:
We had briefly considered using spacers on the spring seats but in the end decided not to. I'm really not sure how necessary they are on engines like ours. So far it seems to be working quite well without the spacers.

For copper spray, our engine builder friend told us to use 6 coats on both sides. We did not have the head machined. He may have been giving us an extra bit of security in case there were small defects in the sealing surface of the engine. '

Don - on both 327's I've had open (Rusty's and brother in law's '52) the head studs have all had at least 2 threads showing above the block. I know the '52 had the head off before, but almost 100% positive the studs were never removed. Rusty's engine has for sure never been opened before.

Pgh Ultramatic wrote:
Weak springs will give you valve float at a lower RPM and therefore your engine will have a lower effective redline. You will also have marginally worse heat conduction, which slightly increases your chances of burning a valve. I see marginal as the valves are positively sealed by the cylinder pressure during operation by a greater figure than the spring pressure.

I’m almost certain in the engine manual. It actually tells you the spring constant for the springs for this exact reason, so that you can check them with a valve spring tester.

The springs usually also have a right side up.