alexandervdr

I checked the compression of my 1963 327 Not sure what version it is, looks like basic 250hp, but may have been modified.

Following are the readings:

Cyl 8: 163 psi
Cyl 6: 165 psi
Cyl 4: 165 psi
Cyl 2: 175 psi
Cyl 7: 154 psi
Cyl 5: 160 psi
Cyl 3: 185 psi
Cyl 1: 175 psi

I had the engine run, idle was not very stable (but the carb is definitely not well tuned), higher rpm seemed to be ok with not strange noises.

Is this block still useable? Or should I consider a replacement? (I don't wanna race with it, just cruising)

devildog

Compression number look OK.
Tell us about 'strange noise' if we are going to help you.

alexandervdr

There is no strange noise at all.

Highest/lowest compression are about 17% apart (lowest reading 154 divided by highest reading 185 is 0.83).

Is that acceptable?

MikeM

That would be VERY acceptable to me unless I wanted to spend a bunch of money for little return for a cruiser. Especially if it doesn't smoke or knock or lose water.

The SB's will run on less than 100lbs/cyl.

bcwaller

Ideally you want less than 10% variation, but if the engine is running fine then you may as well wait for something else to go wrong or for one of the numbers to really drop. What I like to do it track my numbers over time so I can tell if there is something going on. If they hold steady, then there is no wear related issues and the car should maintain as it is.

If it ain't broke, don't fix it. As a cruiser, you might be able to go ten or more years with an engine that does have problems, assuming you are not driving a ton of miles.

I would also guess the engine has been rebuilt, as those numbers imply a static compression ratio of over 10:1 (maybe 12:1?).

ErminewhiteC2

My best cylinder has only 110. It has been runnng like that for years.
Rick

Bluestripe67

Those numbers look very good. How many miles on the engine? If you start to consistently see a puff of blue smoke after startup, the valve seal are waring. It's an easy fix if necessary. Dennis

gwalker

Those seem like great numbers. Mine are all around 120.

plaidside

Assuming your gauge is accurate, according to one book I have it states that it should be 160 #’s, +/- 20 #’s.
The higher readings could be carbon on the pistons.
Providing there is no sign of oil deposits on the plugs and as you say there are no noises, I see no reason not to put it back in service.
Joe

alexandervdr

gauge is brand new and of the screw on type (versus push on), so no leaks. I took the carb off, should not make difference in final compression, may be on number of strokes to build up compression.
I measuered it all twice, to be sure.
All my readings were after 3 compression cycles. 90% of the value reached after first cycle.

alexandervdr

hi Dennis,what is 'an easy fix', working on valves sounds scary to me ;-)

MikeM

The easiest "fix" is to shut the hood, keep it shut and quit worrying about it until something happens worth worrying about.

62Jeff

Joe is that what you meant to type? That the engine should not be reused?

DansYellow66

If your not ready to take MikeM's advice you should probably look for a leak down testing gage. It will provide a better picture of the condition of the engine and if the rings or valves are leaking some compression.

Hitch

You've made a lot of assumptions there...

1snake

I don't think so. My 300HP 327 with 50K miles just tested at 185 in 6 cylinders and 180 in the other two. It's advertised as 10 to 1 but I think in reality it is less than that.

Jim

alexandervdr

My dilemma is that I just bought the car, will do a body off, but try to keep everything as original as possible. I don't have a problem replacing the engine with a new crate, but I would prefer to keep the original one, provided it's ok for tens of thousands more miles. But I don't want to spend 5000 euro refurbishing the old engine and carb, while I can have a all dressed up crate for less. So I try to find out how good/bad the engine is. Following the compression test, I did drain some oil around the worst pressure piston (154psi) and it immediately went up to 175. This may indicate that the valves are still fine.

This may be a very stupid question, don't shoot ;-) Given that I have one piston a bit out of range with the others, is just replacing the rings on the worst piston a possible fix?

MikeM

You should have said this upfront.

Westlotorn

These cars sit a lot. Drive it a while and retest. Your numbers are not bad. You may see the compression come up in the weak cylinders just by driving it some. Take it up a good hill, something that keeps your engine loaded for a bit. A loaded engine puts pressure on the rings and might seat them better. Adding oil to your cylinder as you did makes the rings seal better. You are not far off, drive it and see what happens.
Good luck with your new toy.

plaidside

Oops!!!
You are correct. I should not be answering questions at 6:30 in the morning with only drinking one cup of coffee
As MikeM say's, "shut the hood" and drive the car.
Joe