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After reading up and watching videos, I decided to tackle this project.
The heads were re-done in 1971, so I was past due!
I used the "pressurize the cylinder" method to hold the valves in place while you remove the springs.
I used the spark plug adapter from my compression tester to pressurize to 100 psi.
The compression tester was cheap (Harbor Freight), and leaks... so that was a challenge. My compressor could barely keep up with the leaks. I'm not to sure about it's ability to measure compression now, either!
Had to fidget with it all the time to try to slow the leaking.. A better adapter that you could snug with a socket would be much better.
After doing a few, it started to go pretty smoothly... until #5
I was replacing the keepers.. got the first one in.. went to grab the other, and when I looked back, the first keeper was gone!
I looked EVERYWHERE.. spent 30 minutes looking for that bastard... on the ground, in the head, around the motor, could not find it.
Meanwhile, my compressor is cycling about 50% duty cycle to keep up.
Clamped the valve to stop it from falling in and shut off the compressor.
Gave up finding the keeper and decided to try to locate one at any nearby auto parts store..... Yeah right!
Best I could do was NAPA - they said they would try to get it on an afternoon delivery from their regional warehouse, but it would likely be tomorrow. (they were right - it never arrived)
Went back one last time to look and FOUND THAT SUCKER with a magnetic stick -- hidden in the frame rail on the passenger side!
So morals of the story: Use a quality adapter to pressurize the cylinder, and have a few spare valve keepers handy (they are .79 cents at NAPA, but not in stock!!!)
After reading some threads here, I went with the Viton umbrella seals (ebay, $18 for a set). Should be a big improvement as the old O-ring seals were either gone, or petrified.
After reading up and watching videos, I decided to tackle this project.
The heads were re-done in 1971, so I was past due!
I used the "pressurize the cylinder" method to hold the valves in place while you remove the springs.
I used the spark plug adapter from my compression tester to pressurize to 100 psi.
The compression tester was cheap (Harbor Freight), and leaks... so that was a challenge. My compressor could barely keep up with the leaks. I'm not to sure about it's ability to measure compression now, either!
Had to fidget with it all the time to try to slow the leaking.. A better adapter that you could snug with a socket would be much better.
After doing a few, it started to go pretty smoothly... until #5
I was replacing the keepers.. got the first one in.. went to grab the other, and when I looked back, the first keeper was gone!
I looked EVERYWHERE.. spent 30 minutes looking for that bastard... on the ground, in the head, around the motor, could not find it.
Meanwhile, my compressor is cycling about 50% duty cycle to keep up.
Clamped the valve to stop it from falling in and shut off the compressor.
Gave up finding the keeper and decided to try to locate one at any nearby auto parts store..... Yeah right!
Best I could do was NAPA - they said they would try to get it on an afternoon delivery from their regional warehouse, but it would likely be tomorrow. (they were right - it never arrived)
Went back one last time to look and FOUND THAT SUCKER with a magnetic stick -- hidden in the frame rail on the passenger side!
So morals of the story: Use a quality adapter to pressurize the cylinder, and have a few spare valve keepers handy (they are .79 cents at NAPA, but not in stock!!!)
After reading some threads here, I went with the Viton umbrella seals (ebay, $18 for a set). Should be a big improvement as the old O-ring seals were either gone, or petrified.
Fred
I've always used the 'rope trick' for this exact reason.
After reading up and watching videos, I decided to tackle this project.
The heads were re-done in 1971, so I was past due!
I used the "pressurize the cylinder" method to hold the valves in place while you remove the springs.
I used the spark plug adapter from my compression tester to pressurize to 100 psi.
The compression tester was cheap (Harbor Freight), and leaks... so that was a challenge. My compressor could barely keep up with the leaks. I'm not to sure about it's ability to measure compression now, either!
Had to fidget with it all the time to try to slow the leaking.. A better adapter that you could snug with a socket would be much better.
After doing a few, it started to go pretty smoothly... until #5
I was replacing the keepers.. got the first one in.. went to grab the other, and when I looked back, the first keeper was gone!
I looked EVERYWHERE.. spent 30 minutes looking for that bastard... on the ground, in the head, around the motor, could not find it.
Meanwhile, my compressor is cycling about 50% duty cycle to keep up.
Clamped the valve to stop it from falling in and shut off the compressor.
Gave up finding the keeper and decided to try to locate one at any nearby auto parts store..... Yeah right!
Best I could do was NAPA - they said they would try to get it on an afternoon delivery from their regional warehouse, but it would likely be tomorrow. (they were right - it never arrived)
Went back one last time to look and FOUND THAT SUCKER with a magnetic stick -- hidden in the frame rail on the passenger side!
So morals of the story: Use a quality adapter to pressurize the cylinder, and have a few spare valve keepers handy (they are .79 cents at NAPA, but not in stock!!!)
After reading some threads here, I went with the Viton umbrella seals (ebay, $18 for a set). Should be a big improvement as the old O-ring seals were either gone, or petrified.
Fred
The keeper traveled from cylinder #5 to inside the PASSENGER frame rail? .... man, that thing had wings and an escape plan!
I just replaced the seals on my '67 small block. It solved three problems I was having: 1) smoke on start up, 3) plug fouling on #2 and #4 cylinders, and 3) erratic idle. I had chased the idling problem for some time thinking it was a vacuum leak or carb issue. I found the old umbrella seals were rock hard with 4-5 of them having disintegrated completely.
I did replace the stock seals (using Felpro O-rings).
But I also installed Viton umbrella seals.. Like these: (photo removed because these were the WRONG type seals! - see posy #22
I had read there is really no need for both... but what the heck.. they don't interfere with each other.
The only issue I was having is some oil consumption (1 qt/1000 miles).. No smoking, but I run synthetic oil, which smokes less than dino.
I noticed a burnt oil smell on deceleration.. I'm thinking it was pulling the oil past the old seals under max vacuum.
We will see!
I wanted to follow up this thread with some results.. Incase future searchers can benefit.
My oil consumption problem is dramatically improved. I have put about 500 miles on the car, and it hasn't budged from the "FULL" mark on the dipstick.
Also, the burnt oil smell on deceleration is no longer noticeable.
Just for clarity for those that run across this thread which seals did you use? Umbrella seals are just rubber the seals you have pictured are metal clad positive seals. Pretty big difference.
Place the cylinder at TDC on compression stroke, remove the spark plug, stuff a length of rope in the spark plug hole to support the valves leaving enough hanging out so you can remove it, have at the valves, remove the rope, and move to the next cylinder.
There are risks with both methods. You could forget to remove the rope and rotate the engine...ugh. You could lose pressure and have a valve drop with the air pressure method. If you start with #1 at TDC and do both valves, you then rotate the engine 90 degrees and do the next cylinder in the firing order, continuing trough the entire firing order turning the engine 1 3/4 times. As some will discover, at 100psi the air pressure can rotate the engine if you leave it in neutral messing up your plan!
Place the cylinder at TDC on compression stroke, remove the spark plug, stuff a length of rope in the spark plug hole to support the valves leaving enough hanging out so you can remove it, have at the valves, remove the rope, and move to the next cylinder.
There are risks with both methods. You could forget to remove the rope and rotate the engine...ugh. You could lose pressure and have a valve drop with the air pressure method. If you start with #1 at TDC and do both valves, you then rotate the engine 90 degrees and do the next cylinder in the firing order, continuing trough the entire firing order turning the engine 1 3/4 times. As some will discover, at 100psi the air pressure can rotate the engine if you leave it in neutral messing up your plan!
My understanding was to stuff the rope in the cylinder just before TDC and continue to turn the engine by hand until the cylinder squeezes the rope against the cylinder?
I have used the rope trick a number of times. I use large, soft nylon rope and really don't worry about where the engine is in terms of TDC. I just make sure both valves are closed and the engine is NOT at TDC for that cylinder. I stuff as much of the soft rope into the cylinder as I can get (through the spark plug hole) and then using a wrench on the crankshaft (do NOT use the starter!!!), I crank the engine over until it stops turning. That fills the combustion chamber with the rope and very firmly holds the valves closed. After replacing the seals or springs or whatever you want, rotate the engine backwards and pull the rope out and go to the next cylinder.
Steve
Last edited by 67*427; Jan 12, 2021 at 08:38 AM.
Reason: Spelling error
Just for clarity for those that run across this thread which seals did you use? Umbrella seals are just rubber the seals you have pictured are metal clad positive seals. Pretty big difference.
Did you read my article on Valve seal replacement? I list FelPro umbrella seals which should be used instead of 'positive seals".
The ones shown look like the type you have to machine- the valve guide boss.
Joe
Just for clarity for those that run across this thread which seals did you use? Umbrella seals are just rubber the seals you have pictured are metal clad positive seals. Pretty big difference.
There's a good probability that the guides have been replaced in your heads. If the seals slide over the guide easily without having to push them on they are the wrong seals. Normally heads are machined for the .530 seal but if someone replaced the guides and left only the .500" dia guide then you should have bought seals for .500 guides. The original guide boss is approximately .625 but the the outside diameter of the boss is not concentric to the valve guide so shops machine them to .530. The metal clad seals are intended to be pressed over the guide and not float up and down like an umbrella seal does. I hope you have the correct parts and there's nothing to worry about.
Well.... "easily" is a relative term.. There was slight resistance, even with an oily surface... but no struggle to get them on. Snug, I would say.
So would they act as umbrella seals if they are moving with the valve? Seems like the same shape and size?
It's possible they could work similar to the umbrella seal but it's also possible if they are the wrong ones they could slip up and hit on the guide until it destroys them. This is what an umbrella seal looks like. If it gets to the point of bothering you, you could take a valve cover off and look inside the spring and see if they are staying in place or worked up the valve stem.
Last edited by Robert61; Jan 12, 2021 at 06:36 PM.
Valve stem seal replacement - lessons learned
