Understanding valve seals

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megavites

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so I've run into an issue of oil consumption and smoke on startup after sitting. Everything seems to point to valve seals. Unfortunately, I have 500 miles on a rebuild and the I'm not totally confident in the headwork. They came to me with different stem heights and I ended up with diff. push rod lengths and adj. rockers.
I'm trying to understand the diff. valve seals. The stock umbrella rubber seals I bought were not used by head rebuilder. He used a blue (Teflon?)with spring hold that I'm assuming is a positive seal style.
I'm looking at replacing the intake seals and assuming a good Vitron seal like: Hughes Engines
would work.
Am I on the right track?
 
At 500 miles and the builder using quality valve seal, I doubt its your valve seals. But if you do replace them, you only need to replace the intake valve seals. That will cut the time down in half for you. But I would inspect the valve guides for excessive wear.
 
SGBARRACUDA said:
At 500 miles and the builder using quality valve seal, I doubt its your valve seals. But if you do replace them, you only need to replace the intake valve seals. That will cut the time down in half for you. But I would inspect the valve guides for excessive wear.
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Shouldn't he do a leak down test before disassembly just in case it's the rings (or ring seating). If he plans to pull the heads (even though he doesn't have to) to replace the seals which is the only way he can check the valve guides??
 
Treblig said:
Shouldn't he do a leak down test before disassembly just in case it's the rings (or ring seating). If he plans to pull the heads (even though he doesn't have to) to replace the seals which is the only way he can check the valve guides??
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Absolutely, that is a good place to start. at a minimum a compression test. What do the plugs look like? oil fouled or? The different valve stem height would have stopped me from installing them.
 
SGBARRACUDA said:
Absolutely, that is a good place to start. at a minimum a compression test. What do the plugs look like? oil fouled or? The different valve stem height would have stopped me from installing them.
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compression test checked out. All cyl. btwn 135-145. Plugs look good. I could go out and get a leak gauge set..might be quickest diagnosis. From what I read..
no more than 20% leakdown is acceptable..air @ intake=int. valve, @exh=exh. valve, @ dipstick=rings, @radi=head gskt. The other thing is I haven't beat on it much, but they are iron rings.
As far as stem seals...are the Vitron positive stop seals the ones most use here? The ones with the spring around the top of the seal? Any Manuf. recommendations?
Thanks for the help!
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Is the tailpipe full of oily smut? On the valve seals under normal conditions it doesn’t take much to keep the oil from bypassing the intake valve stem. Have you ever seen a Chevy small block seal? It’s not much more than a O-ring. Those you pictured would be fine.
 
Also you said you have cast piston rings? Those are the easiest to break in and seal. But they also cause the most cylinder wear.
 
I would retorque the intake first /only takes one loose to suck oil in
 
mderoy340 said:
Check the PCV hose for oil. Do you have a good baffle for the valve covers?
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MOPAR black valve covers. I think the baffles are small, like this example. I was reading a thread about that. If hose is oily....I should make bigger baffles?
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what engine you have ? that cyl pressure seems low . by oil consumption , how much oil is consumed in how many miles . I had my engine rebuilt 2 years ago , don't remember using any oil in the first 500 miles . Changed it at 600 miles or so and have never used oil between changes every 5000 miles . if it were me I'd be having a talk with the rebuilder
 
You might b jumping the gun. If u only have 500 miles on the engine it might still b breaking in??
 
the issue seems to be valve seals. The head rebuilder was questionable. Stem heights were all over the place and I've had slight smoke from drivers side from the get go. We took video running out to the highway and letting off and its evident its smoking on decel and after loading up at stops and takeoff.
 
teringer said:
I would retorque the intake first /only takes one loose to suck oil in
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Yup. I chased the same type issue. Wasted my time changing valve seals. It was the intake gasket. Mismatch between intake and head. The cylinders will suck oil around the runners. What do the plugs look like?
 
Does it start to smoke just at idle after a few minutes? Smokes after you let off from WOT?
Were the heads ported? Cast Iron Rings?
As Above I would check PVC
I would check Intake Gasket , might be easier to pull the intake and look for oil in a port just for piece of mind.
Pull the valve cover and give a wiggle test to on each cylinder when the valve is closed , hopefully this helps
 
ordered Vitron seals. We're going to use an endoscope today or tomorrow and look inside. Seals are pretty quick but not saying it couldn't be intake gasket. Plugs are good and no smoke on hard accel. Head work was rebuild only. Cast iron rings.
 
I would attempt to estimate stem wear while you have it apart to replace seals. If you can't do anything else, rig an indicator to the stem so you can get an idea of stem side play. It just might be that the guides are worn far beyond what even teflon seals can control
 
you won't need to pull the heads to check guide wear. with the cylinder you're checking at bdc poke in as much cotton clothes line rope through the spark plug hole into the bore as you can then turn the motor toward tdc. you can now remove the valve spring/s with no fear of the valve dropping into the bore. if the rope's jammed tight against the valve drop the piston slightly so you can feel for guide wear then back up tight for reassembly. i always do it this way when changing seals, i don't like the idea of compressed air stopping the valve dropping and i know it's common practice but the rope method is guaranteed to hold the valve. :thumbsup:
neil.
 
mygasser said:
you won't need to pull the heads to check guide wear. with the cylinder you're checking at bdc poke in as much cotton clothes line rope through the spark plug hole into the bore as you can then turn the motor toward tdc. you can now remove the valve spring/s with no fear of the valve dropping into the bore. if the rope's jammed tight against the valve drop the piston slightly so you can feel for guide wear then back up tight for reassembly. i always do it this way when changing seals, i don't like the idea of compressed air stopping the valve dropping and i know it's common practice but the rope method is guaranteed to hold the valve. :thumbsup:
neil.
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Don't they sell a small inflatable balloon for that now?
 
so we ran a boroscope on all cyl. on drivers side and saw what look like small drips on cyl #5 piston. Swapped out
int/exh. seals. Don't see smoke on the road but tapping the pedal after idleing and get a little puff on this side. Going to change all seals on this side this wknd.
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megavites said:
so we ran a boroscope on all cyl. on drivers side and saw what look like small drips on cyl #5 piston. Swapped out
int/exh. seals. Don't see smoke on the road but tapping the pedal and get a little puff on this side. Going to change all seals on this side this wknd.
View attachment 1715609316 View attachment 1715609317
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I would change them all. Some people don't use the sleeve and screw up the seal installing them.
 
mderoy340 said:
I would change them all. Some people don't use the sleeve and screw up the seal installing them.
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used air into cylinder. Just to be clear the Blue Posi-stop seals are what was on there. I switched to Viton umbrella seals..just didn't take a pic after.
 
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