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

Loosening head nuts need not be sequential.

Probably a good idea to loosen each stud nut just slightly first up, maybe 1-2 flats initially? Can't do any harm taking this approach as all sorts of tension may have built up over the years

When it is time to 'loosen' the head you'll find a lot written about that. It can take quite a bit of time and persuasion with a plastic hammer / hammer plus wood block to break the 'seal'.

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I am often in the same boat so I bought a remote starter switch which lets me turn the engine without anyone around.

More progress, finally

Got the head removed. Found about an 1/8" of carbon build-up on each piston. They all looked the same. Also observed all valves moving up and down as they should - nothing stuck! Yay!! Now the question is....is the lack of compression in 7 cylinders due to rust build up and carbon build up on the valves/seats? Last tags were 1993......

My facilities are basic (outside driveway with tarp). Of course, the Oregon weather makes working on it a hit-or-miss situation. Should I put the head back on and wait til summer hits with the good weather and better economic situation? Can I just reuse the old head gasket to seal the engine up with?
Is there something I can do with the valves that doesn't require a machine shop?

I've played with plenty of "V" engines. Taking the heads in for a valve job is easy. This engine....not so much. And what should I expect to pay for a valve job? (assuming nothing needs replaced - supposedly a 68,000 mile car that was stored outside)

So many questions....so little time and money, lol!

Regarding compression - did you find any scoring of the bores? If none then it's doubtful that you have broken rings. They could just be worn.

A very worn engine will typically have a step at the top of each cylinder where top ring finishes its travel, and bores may be shiny.A reasonable check for worn rings is to add a few aquirts of heavy oil down plug holes, then crank and see if the compression rises considerably compared to original readings done without oil. If it does then suspect worn rings.

When the valves are open you could check if the seats and valve faces are pitted or burned, causing compression blow-past.

You could fit the old head gasket just temporarily to re-test compression but a new one is necessary eventually.

Also - ensure each valve closes fully when it should. If any stay open (mis-adjusted lifters, etc) this affects compression readings also. Best of luck with the project.

Quote:At this point you need to find out whether the loss of compression is due to valves or rings. Having not run for some time the rings could be crudded up and not liking to move freely. I'd start by putting some ATF on top of the pistons and running the starter for several short crankings of the starter, separated by lenghy rest periods (for the starter) then some kerosene. You'll want to drain the oil and replace it after this. You could perform a simple test to see if the valves are sealing by pooling ATF around the valves and see how long it takes to leak down into the sump.

Quote:--yes, as a temporary measure until you can complete your work to free it up. You'll need a new head gasket when it comes time to fire it up.

Quote: In the old days guys used to lap in valves right in the block, if you were to do this you have to get all of the lapping compound out, it's a paste-abrasive. You may find that you have bigger fish to fry in the valve department, or you'll find that things are basically good there--you won't know until you know.
Quote:I can't really put a current number on this, but what you may find is that there could be issues in other areas of the engine, and before you know it you are doing the whole engine. Many people today have hardened valve seats in the blocks when they do anything with the heads. Of course, we are talking about removing the engine to do all this.
One trick I learned is to coat the valve stems with a special lubricant that Briggs and Stratton developed for their flat head engine valve stems, you can purchase it at any good lawn equipment dealer. It helps prevent stuck valves, especially in flat head engines that are not run on a daily/weekly basis. Our lawn equipment gets packed away for 6 months at a time here, then fired up in the spring.