Compression Test

Compression test: Make sure the battery's FULLY charged. I give them at least 10 strokes or 'til the gauge no longer rises.
Re-check LOW ones, sometimes carbon gets dis-lodged when removing plugs & gets stuck under a valve.
A leak down tester is BEST! They give you the "REST OF THE STORY"--
Mitch//pa was ALWAYS HARPING about ALWAYS use a Leak Down Tester!!!--WHAR is HE???
Mitchs' KDad
A TIP: When checking valve clearances, check them BEFORE removing the plugs, in case some carbon gets dislodged & gets under the valve face.
 
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V4F it is one of the police heads with a big "D" on it. Like I mentioned, no history so I'm not sure what else. And who knows how many times it has been trued or milled to increase psi?
 
Kieran, once the head seal is broken, as in removing the head nuts, the head should come off to replace the gasket, age old etiquette. Although if any engine can tolerate re-useing a head gasket, it would be an A. I say, from looking at your post and the compression readings, that you have an exhaust valve leaking or bad rings or both. I would replace the nuts and re torque the nuts. Then, drain the coolant and crank the engine over with the plugs out. Look for coolant mist blowing out to verify that the seal has not been lost. If dry, your good to go to step 2, the wet test. Put about 1/2 tsp. of motor oil in each hole and retry the compression test. If the readings come up in #2 & #3, you will have shown that rings were leaking when dry but that they got help with sealing by adding oil. You did the cylinder leakage test already and that is good but would normally be step 3. Did you turn the engine over exactly 1/2 turn and then pressurize the next cyl. in the fireing order for each cylinder? The air pressure for this leak down test should not be more than 35 psi. If the engine turns, it was not at TDC or too much pressure. This test can be where all of the answers are but can be misleading if not done correctly. It is possible that you only need to adjust the valve lash or do some valve work which would require removing the head and gasket. Then would be the time to get the gaskets.
 
From all that you described it sounds like you have a couple mildly burnt exhaust valves. The engine that is currently in my A, I purchased used, had almost identical symptoms. It ran ok but had low compression on 2 cylinders. Looking down the sparkplug hole you could see a slight discoloration and the edges (valve margin) didn't appear perfectly round at the discoloration spot. This was almost imperceptible due to the angle of viewing the valves through the sparkplug hole. Removing the head revealed the 2 valves shown. The valves would partially seat due to the higher pressure during combustion, not so much during a compression check and even less with a leakdown test. The air leaking into the exhaust system is why you hear it in the tailpipe. It would be just a matter of time for total failure. I lightly dressed these valve to highlight the burnt spots. For me it was just a simple valve job. I've been using this engine for the last several years while I rebuild the engine that was in it.
 

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Thanks for all the input. Gives me a lot to consider. I will keep you all updated and I am sure there will be additional questions. All the best, Kieran
 
Initially decided to put all the nuts back on and torqued them. Unfortunately, one snapped off at around 35ft lbs. I then decided to remove the head. Head came off quite easily. Lo and behold, copper gasket looked good. No apparent leaks. I still learned a ton by removing all the parts to get to the head! I have attached a few photos. Based on the photos to date, any input as to what else I should be working on. When I get more time this weekend. I am going to try and figure out how all the vales are functioning. Thanks for any help.
 

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My view is sticking valves, exhaust most likely.

Get some MMO under your valves. Also get some around your pistons to help free any ring problems that can be helped.

Let it sit then do some more, soak it good.

I am assuming engine ran without smoking, knocking, before you got to this point.

Valve noise, ticking? MMO will help with that. Use in gas also.

Change oil, add high detergent oil, I would recommend 20-50w.

Trust me, this will help.
 
Kieran, on this day, the 100th anniversary of the Ford trucks, you are blessed by the gods, more than you might know. Looks to me like all of the studs came out without breaking off in the block. When you put the new ones back in, buy a whole set, I recommend anti seize on the NC threads that go into the block on the dry holes and permatex #2 for the wet holes. Don't torque the studs into the holes: run them in and then back out 1/4 turn. Now is a good time the drop the head off at the local machine shop to have them check the surface for flatness. Also pull the side cover and say Howdy to the valve train. A little oil on the stems to get ready for the fun this weekend. Good luck.
 
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