60psi in all 4 cylinders... should it be running?

Hey there...

So after warming the '46(orig L-head) up with a couple laps around the block I decided to compression test it... 60psi in every cylinder!!

It seems strange because it seems to cruise just fine and doesn't smoke, knock, etc. Could it be possible that my valve timing is off? No head gasket whatsoever?

I put a little oil into 1 cylinder to re-check and didn't see a noticeable difference.. (I'm thinking that I didn't wait long enough though and will try again tmw)

Where do I start with this one? I'm not so sure how it's cruising at 45 with 60psi compression.

The beast:

 

The real value to doing a compression check is the balance between the cyls------seems you have a pretty good engine from that standpoint.

Do you have any idea what the psi should be?? A 1946 engine is going to be pretty low compression----

Actual pressure is not as important as balance IMHO.

Do you have any idea if your gauge is accurate??

Did you pull all plugs before cranking the engine over??

Throttle held down???

These all have an effect on the reading, all will cause lower reading if not done.

My $.02? as long is it is running well, drive it.

If you want a better analysis, do a leak check like we do on airplanes.

 

normal psi for a L-head is supposed to be around 90-110 IIRC

 

I would just drive it. Valves are probably all good or your readings would have some spread. If you are not leaving a smoke screen, the rings can't be too bad either. What do the plugs look like?

 

You can put a little oil in the cylinders through the plug holes (a "wet" test) and retest. A pump oiler works well for this. If the pressure comes up much, you have worn rings - the oil on topof the compression rings will improve the seal.

Yeah, evenness is more important than average pressure. Check your plugs to see if you have any oil fouling. I expect you have a lot of miles left before you have trouble. When the rings get leaky, you'll start oil fouling the plugs. Even then, you can install anti-foulers and use a hotter plug and it'll keep running.

What's the oil pressure, at cruise and at idle at high temperature (ie after a highway run)?

 

My plugs look like this:
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They aren't oily at all... I just think things are running super rich. I'm still trying to figure out how to tune the Solex. It's rich enough now that it will die if I pull out the choke at all after it starts.

Oil pressures are pretty low with the 10W30 I put in...
600rpm(idle):5-6psi
1000rpm: 15psi
1500rpm: 20psi
2000rpm: 25psi

Today I'm going to put in straight 30wt and pull off the oil panto desludge things...hopefully that should help

 

Oh... I'm also going to hook up my compression tester to my air compressor and see if they agree on tank pressure... probably should have done this first

 

Ideally you'd like to see the oil pressure come up from idle and stay constant. A good rule of thumb is 10 psi per 1000 RPM, minimum.

If you are going to take the pan off, you might want to inspect the rod bearings and plastigage them. The oil pump is in the pan too IIRC; a new oil pump might bump up your OP some. 134s are not my thing, but some of the others here could comment on how useful replacing the oil pump is.

Yeah, calibrate your compression gauge, and try that wet test.

 

Dont mess with it just drive it

 

If it aint broke dont fix it I ran my flathead for 4 years with a cracked block. when i finally rebuilt it i found the top two rings in every cylender were broken into many pieces. But it still ran fine

 

Oh I plan to... I was just intrigued by the numbers I got....

Didn't get a chance to look any more into the matter... busy painting and putting body panels back on.

 

Replacing the oil pump = not useful for me. The one the machine shop sold me locked up. It didn't do any damage, just wasted $100 and the teeth to it are sitting in the bottom of the oil pan.

 

Heh. Even less my thing than I thought.

 

I already did... you can see the adjusted tappet on the left... the other ones are how I found them