compression test results

[Anonymous]

I was having smoke at idle when warm but none when accelerating, and I was getting plugs fouled shut, so I assumed this might be the valve stem seals. Well, I finally did a compression test, and they all came in at 140, (I can't really read the tester because the guage needle is angled, and I'm not sure if it was 140 or 150), but anyway only one of them read about 5 psi higher than the rest. So then I decide to pull the valve cover and look in the springs with a flash light, and I see a couple of the rubber seals or bushings are missing, and the rest are cracked or halfway gone, and I even found a couple small pieces there laying on top of the head. To make a long post short. I guess this sounds like good news. I can replace the seals and I should be good, but I always pictured these seals to be like o-rings, and they are actually shaped like umbrellas. I've heard of umbrella bushings, but are these the same? What do I have to ask for at the auto parts store? I guess I also need a spring compressor, and either a air compressor fitting or use the rope method. If anyone has any experiences/advice I'd much appreciate it. This might make sense with what was thought of the car by the PO and myself. It was believed that the 60k miles could very well be original but nobody could verify it. So this is in sync with a car that has been parked a long time. Of course I cleaned up the plugs and started it up to move it back into it's spot in the garage, and man, with clean plugs, it runs very very smooth and beautifully. Plus this engine has always sounded very very solid since new. I drove it from Phoenix 600 miles to NM, and it only lost 1/2 quart of oil. Thanks in advance and sorry for the long post.

 

[mustang6]

Deteriorating and failed valve stem seals will definitely contribute to a problem like the one you are experiencing. You may also have worn valve guides, when you have the springs off you should check to see if you can rock the valve stems at all. If you can, they are worn too and need to be dealt with - unfortunately that involves removing the head.

Stock Ford valve seals are umbrella shaped, there's no need to ask for anything other than the stock valve spring seals for your engine at the parts store.

Just because the seals are shot does not rule out a low mileage engine, they can get hard and brittle just from age. If your valve guides are worn though, that would indicate higher mileage. The best indicator of all is probably the timing chain, the more slack it has in it the higher the mileage, regardless of how often the oil was changed.

 

[Anonymous]

Thanks, I'll definitely check them. Will I need any special tools to remove the keepers from the valve stems?? Also does the rope trick work pretty well? Thanks

 

[Anonymous]

I just did this about two months ago with my 72 comet (200/C4). I had just purchased it and noticed the smoke. It needed a valve cover gasket anyway so I dove in. The umbrella seal pieces were everywhere, there was more laying in the head than was on the valves. No wonder the plugs were very oily!! I used a small valve spring compressor, and an air line fitting in the cylinder. I wondered how well the air would keep the valve in place but don't worry, it stays in place well. One thing I wish I would have had is one of those small extenable magnets to grab the keepers, but you can grab them with your fingers. I have one of the mags now and have used it for many things. You might also have to give the spring assembly a good whack to loosen the keepers, you'll see what I mean. It's an easy, straight forward job, just take yor time. Oh, and my car has 53,000 original miles so sitting and age is the culprit here. Another thing, when using the compressed air fitting, I blead off the tank when I filled the cylinder and let it pump up from 10-20 lbs instead of applying 110-120 lbs from the start. That way it doesn't want to push the piston down from top dead as bad. Watch if you have a wrench attached to the crank bolt!!

 

[Anonymous]

Thanks PeytonMaterne....
What does the valve spring tool I'm looking for look like. I was looking at one online that looks like kinda like a c-clamp. On the keepers what holds them onto the valve stem? Do you have to like twist them off or just pop them off to the side with screwdriver or pinch them with pliers or what?

 

[Anonymous]

I found a overhead spring compressor online that looks like a battery terminal remover. Would this be it?