replacing valve stem seals
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Freshman User
Joined: Jan 2002
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replacing valve stem seals
I'm planning on replacing the valve stem seals on my 390 later this week...the manual says to keep to valve in place with an air compressor, and I don't have an air compressor. My dad tells me the shadetree method is to shove some rope in the spark plug hole and turn the engine until the rope is pushed up against the valve... anyone ever try this method and had good luck? or would I be better off just getting an air compressor? thanks.
Senior User
Joined: Mar 2003
Posts: 378
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From: Corvallis oregon
replacing valve stem seals
Rope would work fine, but I always have the heads of when I do that kind of stuff. You might be able to use fine wire and wrapp it around the valse stem to keep it in place.
Postmaster
Joined: Nov 2002
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From: Littleton, CO
replacing valve stem seals
Hey Trix:
I just did the rope deal a few months ago on my 352. Worked pretty good but here are a few pointers. Of course, turning the motor is done by hand on the crank nut, not with the starter... Get a rope that is just a little slimmer than the spark plug hole. The bigger rope is easier to work with. I also sinched mine up then compressed the valve spring and tested the secureness of the valve. Some took a little re-jockying to get it to the point where I was comfortable. The whole process of 16 valve seals took about 6 hours, off course that was broken out into two evenings between favorite car shows on the tube... Rope is only about $1.00, compressor is considerabley more expensive, but then you have a new toy in the garage to play with!
--MG
I just did the rope deal a few months ago on my 352. Worked pretty good but here are a few pointers. Of course, turning the motor is done by hand on the crank nut, not with the starter... Get a rope that is just a little slimmer than the spark plug hole. The bigger rope is easier to work with. I also sinched mine up then compressed the valve spring and tested the secureness of the valve. Some took a little re-jockying to get it to the point where I was comfortable. The whole process of 16 valve seals took about 6 hours, off course that was broken out into two evenings between favorite car shows on the tube... Rope is only about $1.00, compressor is considerabley more expensive, but then you have a new toy in the garage to play with!
--MG
Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
replacing valve stem seals
The 390 is the first engine I have taken apart with this type of valve stem keeper, so I had problems doing mine. I *thought* I was doing it correctly until I hit the keeper hard enough to break the air seal and push the valve into the top of the piston. I had my compressor at 110 pounds so air pressure was not a problem. There was enough pressure to actually turn the crank. I think I heard air leaking away though the manifold, so maybe I was not doing it correctly.
When I have more time I am going to do it with the rope as doing it with the air keeper valve seems a real "hit or miss" affair.
My question is is the valve stem shield suppose to ride up and down on the shaft or is it suppose to remain seated while the valve stem travels through it? The flexible rubber ones from Autozone just did not seem to do the job.
When I have more time I am going to do it with the rope as doing it with the air keeper valve seems a real "hit or miss" affair.
My question is is the valve stem shield suppose to ride up and down on the shaft or is it suppose to remain seated while the valve stem travels through it? The flexible rubber ones from Autozone just did not seem to do the job.
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Joined: Jul 2002
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From: Long Island USA
replacing valve stem seals
Those OEM "seals" are really just umbrellas to keep the oil from dripping directly onto the stem and down the guide. They usually just go up and down with the valve. They are no good if oil is pooling on top of the head and running down the guides.
I have "positive-seal" valve stem seals on mine. They are a real rubber seal held in place by a metal ring. Of course, it's a good idea to use these with bronze guides because if you use them with iron, NO oil gets down there and you wear out the guide real fast.
ak
I have "positive-seal" valve stem seals on mine. They are a real rubber seal held in place by a metal ring. Of course, it's a good idea to use these with bronze guides because if you use them with iron, NO oil gets down there and you wear out the guide real fast.
ak
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