flathead compression testing question

i was out tonite to look at a eab flathead. i was told it was pulled from a running ford, years ago from a friend of a friend. the engine looked good for sitting so long. we pulled out all of the plugs, and put in the compression tester. after turning the engine with a ratchet, we could only get 25-30 psi. we tested 5 cylinders that way and am left wondering...
does anybody have any idea if turning by hand would cause a considerable drop in compression?? is the engine probably good? any input is appreciated....

 

Did you put any oil in the holes?

 

A typical stored FH problem, often not difficult to cure, is valves draining and rusting in guides. In this case, though, problem is your ratchet...turning slowly allows the air to find ways to meander out of the trap before the piston...you need to spinnit fairly fast to actually find out what's up.

 

itll leak by the rings faster than you can turn it. throw some 12v jumper cables on it and check it again

 

25 pounds on an engine that has been sitting isn't all that bad. If it is more or less consistent across all the cylinders, you're probably ok. Once it gets running and warm they should all uniformly increase.

 

totally bitchin... thanks guys... i talked to a buddy and he mentioned that it's probably slipping past the rings faster than it can be turned. it's been stored indoors, so not so much rust, but gunk could be built up on the valves as well...the psi was consistant but more equal....thanks for the assurance!!

 

Even if you need to remove valves and lap'em in via an Okie valve job, no big...

 

You could learn more with a cylinder leak-down test than you will with a compression test, especially since you are turning it by hand. Use a good tester and make sure your test cylinder has both valves closed when you do it.

 

John,
Is this the one I found? good job! looks like you'll be back in action in no time.

 

yeah it is... ended up picking it up tonite..... doesn't look too bad. it might run... hopefully have it ready for the pumpkin run.... he has 2 53 fords out there. one being a hard top that needs floors/rockers. he wants 500 for both. if you know anyone interested.

 

Spike had my Merc at the shop last night and boy was I missin' her. If I didn't have too much on my plate already I'd love to have another 53. someday.........