Changing valve stem seals

[AMXguy]

I'm going to change the seals on my 440 using the proform tool and the air fitting ( heads on engine ). would it be worth the effort to change them in the firing order and rotate the crank to TDC on each cylinder?  I'm worried to death about breaking the air hold and dropping a valve into the cylinder clear out of the guide. any advice?

[Moparal]

Each cylinder you do should be at tdc. Leave the plugs installed on the rest so it will not spin by your air pressure. I have seen that happen before.

[GoodysGotaCuda]

I've just used the fitting for my compression tester and hooked shop air up to it. That works too if you don't have another tool already. I'd put the cylinder on TDC as well, when coming up to TDC go a hair past where the piston stops...to move the rod more directly under the piston. Cuts down on it trying to spin when you put air to it.

[bordin34]

For you guys that replaced your seals, what were they symptoms that led up to the replacement.

[AMXguy]

If when you start your engine up you get a good puff of smoke it's probably your seals, or seals and guides. I'm getting a little smoke on start up and at idle.

 In my case the bulider poked holes in my seals for what he said was the break in on the new guides and valves and I should run it for at least 500 miles then I could change them if I wanted. he said he'd do it but I want to keep my engine bay and fenders to stay looking the way they are so I'm gong to do it myself.

[bordin34]

Did you notice any loss in performance, fouled plugs, or backfiring?

[GoodysGotaCuda]

Probably a little burnt oil/carbon on the plugs, performance shouldn't be effected too much..backfiring wouldn't be a symptom.

Valve seals will let a little oil into the cylinders, so blue smoke out the exhaust, carbon on the plugs, and it drinking more oil than it should be.

[ShelbyDogg]

I've used the air pressure to keep the valves up, but also had the piston push down due to the pressure. Another way to do it is to pull the plug, shove in a little rope, then turn the crank slowly (by hand) till the piston pushes the rope up against the valves.  Then reverse rotation to take it out.

Hint:  Before you put your valve spring compressor on, take a 1/2' drive socket. Something that sits on the retainer and doesn't touch the keepers or valves. Hold it against the retainer and give it a real quick tap with a hammer. That will loosen the hold of the locks in the retainer.  Do it before you bring the piston up to hold the valves.

You'll see why you have to do this after you don't do it on the 1st valve.

Rob

[BIGSHCLUNK]

I had a small block back in the day that needed seal about every 30-35K/ you could tell by the oil use. I got real good at it.. 

[bordin34]

What if the seals leaked enough to foul plugs and caused them to misfire? Would that be possible?

[Moparal]

What if the seals leaked enough to foul plugs and caused them to misfire? Would that be possible?

Yup , then some use the dreaded non fowler extentions 

[willard]

It seems that it is my problem too. My 383 is hard to start if it is warm and stays off for more than 5 minutes. If it is warm and I turn it off and then crank it starts with no hassle. But when I try to start it (warm) after let's say 15 minutes I have to crank 5-10s and floor the pedal...
Today I decided to check the plugs right after the drive (mainfold damned hot!) and I started with left bank. First was black but I thought it's my eddy carb (holley on the way!), when I extractef #7 I was shocked as it had a fres oil on it, same with #5 and #1. Then I checked the right side and #8 was also covered with fresh oil. When I cleaned them and put them back I tried to start and it went on with only a little hesitation.

In fact when I fire it after a week it makes a white smoke cloud and idles unevenly (shakes). I see no other possiblity for oil to enter a non working cylinder like throu the top eg. valve guides. 
The engine is said to be some 1000 miles after rebuild but it leaks by the fuel pump (little) and at the rear of oil pan or maybe rear main seal (large leak) and is not runing as it should...

[Chryco Psycho]

sounds like a bad rebuild if it actually was rebuilt , if the plugs were wet I assume it was not excess fuel & the plug quit firing due to fouling ?

[willard]

Plugs are all covered with black deposite and first I thought it is too rich. But this time I examined the plug right after engine switch down and they were covered with oil (I think it was oil as it was dark, very slowly evaporating and it was also on plug thread and base). If it was just to rich and engine flooded with gas it would not start up after I shut it down. But it starts immediately. Waiting longer makes it reluctant to start...

The problem of the engine being rebuild or not - it is painted, has new gaskets, hoses, distributor, good compression. However  I have no receipts fro mthe sellor and did not disasemmble it to check...

[nivvy]

I've used the air pressure to keep the valves up, but also had the piston push down due to the pressure. Another way to do it is to pull the plug, shove in a little rope, then turn the crank slowly (by hand) till the piston pushes the rope up against the valves.  Then reverse rotation to take it out.

thats what i do......