Bad valve seals?

Dec 5, 2006
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Started smoking on take off and start up and not as bad when shes been running for 15 mins. Pulled #3 #4 plugs, # 4 being the worst, at idle it does not puff but when i add oil on the vehicle running it will start to smoke , ill give it a rev and ill get some smoke and when she comes down in rpms she smokes.

valve seals? I have the gt40x heads do i need special valve seals for them.
 
K i tryed to remove the keepers that hold my valve springs in place and the dam things won't come off, is there a trick to removing the keepers , the spring is compressed but there not coming off.
 
Before you compress the spring, grab a deep well socket larger than the diameter of the keeper circumference and that sits nicely on the valve spring retainer. Then, once centered over the valve & keepers but ON the retainer, give a few sharp quick raps with a hammer on the socket. The spring pressure combined with the raps with a hammer should loosen them. But, know in advance, that if hit too hard or at an angle, the keepers can come flying out and the retainer can come off quite easily (and if on the engine, the valve could fall in the cylinder). If your doing it on the bench, no big problem. But, if on the car, you want to tap much lighter to loosen before pumping up the cylinder with air. Its one of those things that experience teaches of how hard to hit without releasing them. However, you do have to hit it pretty hard to have them release and fly across the room. But, a good blow with the hammer usually pushes down on the retainer over-coming spring pressure for a fraction of a second, the keepers move just a bit to loosen, then the spring pressure pushes back up on the retainer after the hammer blow very quickly ... but this has then allowed the keepers to be jolted a bit and thus loosen. Sometimes one will come out or get wedged outside of its seat, but then they have been loosened. As long as one is in there, then you can compress the spring and remove them. If one comes out, and you lift the socket off the retainer, it can get lost very easily on the bench or in your head if doing on the car ... so be careful when you lift the socket off the retainer and be ready to catch a keeper or put a rag around things to catch it. Did it many years in a engine building shop. And definitely then inspect the insides of the keeper to make sure they were not damaged and all edges remain in tack because this can damage the insides of the keeper groove edges if hit too hard. If any edges have been damaged, those keeps must be replaced to prevent dropping a valve!!! And, also beware that if you really hit it hard enough, you could crack the top of the guide installed in the head. Ideally, you do not want any of the keepers to literally come out of the retainer when you hit the socket with the hammer onto the retainer ... on the bench is another story since it is an easy way to remove all springs very quickly. Any springs that I want to remove on the car, I go around the engine first and hit them with a socket on the retainer firm enough to help loosen them but not enough to disengage the actual locks and send them flying! You want to hit it so that you overcome spring pressure for just a second and only a couple thousands of an inch actual drop in the retainer. Hope this helps!
 
Thanks FoMoCo17, ill be doing this come the weekend step by step. I don't know if ill be using air to fill up the cylinder but rather rope, i here feeding rope through the spark plug hole then bringing it up to tdc works well.
 
Just take the heads off and have them valve jobbed and bowls cleaned up by a professional.
Worth every penny and is good for quite a bit of power, they will also take care of the spring seat pressure too.
Should only cost about $200.

With that said, oil burning because of valve seals is pretty rare, unless the heads sat for quite a long time.
Usually it's the rings, bearings or screwed up intake gaskets.
 
I just did mine a couple weeks ago. They're pretty easy, the hardest part was gettin the keepers out, was a pita. I just tapped the top with a hammer before compressing the spring. Then put the spring compressor and compress it as much as possible, then use a good magnet and take the keepers out. It goes pretty quick once you get going.
 
Yes, the rope in the cylinders works very good and prevents a potential break in seal when air is used. I used this method many years ago. Thought it might be a bit more difficult on a 5.0 though due to having the right size rope and feeding it in there ... you must compact it as you go to insure that the whole area is filled with rope. Too large a rope and it doesn't fill the cylinder properly and then gets too hard to push in ... and too small a rope and it takes a year to fill the cylinder and pack it. However, putting rope in the cylinder and then turning the engine by hand until it binds up against the valves sounds like a good idea! Not sure if this might pose any problems getting it all out ... sounds like it would work great. Anyone done this and then turned the engine over by hand to compress it against the valves and then remove the rope successfully?
 
Well i checked # 3 and 4 valve seals and they look good , don't know what else it could be but i'm at a loss . i uploaded a video of what the smoke issue looks like , under high rpm she likes the oil . Also when i take my pvc from the vac line off it smokes out the oil filler but ill start another thread on that :rlaugh: Her new name will be old smoky.

mustang :: AMBA0024.mp4 video by saw426 - Photobucket

This engine had just over 20 thous k on a rebuild.
 
With only 20,000 on the motor I doubt it is the valve seals.My guess would be to check the intake manifold gasket.

Hmm yea know what , i did have a look at ,the lower intake gasket and sure enough passengers side along the head is wet with oil, today i went and did a wet and dry compression test , wet meaning adding oil to the top of the cylinder with no change.

I do remember that i had the heads milled .020 and when it got put together in was good to go, do you think that having that much milled off the head is a cause for problems? Also should i go ahead and have the lower milled to, i guess it would only make sense to do that.

I'll have the lower off by next week and update this problem but am sure that oil is being sucked up from the lower intake to the ports #3 #4 .

Would a leak between the intake and head give me low compression? Compression is 120 #4 125 #3 and plugs are oily.
 
Thought id give an update to what i came across when tearing down the upper and lower. Heres some pics.

The first is oil sitting in the middle of port 3 and 4.
mustang :: 100_3819.jpg picture by saw426 - Photobucket

2nd is the oily gasket. When i pulled it off you could see oil on the under side as well.

mustang :: 100_3815.jpg picture by saw426 - Photobucket

3rd is the cork gasket that is toast.

mustang :: 100_3812.jpg picture by saw426 - Photobucket

I have got new gaskets ready to go on with some sealant called "the right stuff" and hear its the best , i will be doing the china wall and water jackets with it but would it hurt it to go along the bottom of the gasket just below the ports?

Any input is appreciated before i go ahead and put it back together.