'Puff' on start up! valve seals need replacing....

[Jwernatl]

After 220k miles on the original motor and that’s literally the only thing wrong with the truck, I can totally manage that till I drop something else in there

Yes Sir - ride her out...

 

[Jwernatl]

just stick new seals and let it be until next time.

I think I agree.

 

[John Nes]

Yes Sir - ride her out...

Oh I do lol. Daily. And cuz the 700r4 I can even keep up with the flow of drivers on Atlanta’s highways (when it’s not rush hour obviously)

 

[75gmck25]

If you buy a valve spring compressor I highly recommend the type below. It works way better than the cheap ones you borrow from Autozone. I used this type of compressor on new heads with dual springs when I swapped to light springs to check the cam, and it worked great. https://www.jegs.com/i/JEGS/555/80521/10002/-1?gclid=Cj0KCQjwjPaCBhDkARIsAISZN7SGMf_gydH_uzaa_Y97UyyCX8lTFaHVKjH44qPbZrt1pge_X5LzzNEaAjwbEALw_wcB

Bruce

 

[Jwernatl]

I bought this jobby for the very reason you have stated.
Puff on startup and it won't pass DEQ emissions anymore.
New valve seals are on the bench and just need to installed.

I have not tested it thus far, but it looks simple enough and is priced pretty good for the average home mechanic.

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I could try that for sure. That spring compressor might work too.

 

[Salty Crusty]

If it's only a puff, I'd leave the seals on the bench and save 'em for the next valve job, but I'm lazy when it comes to what I consider to be an inconvenience but not a necessity. Put 20K more miles on it and it'll still be doing exactly the same thing. As long as your plugs aren't getting oily, it shouldn't affect anything else. If there's carbon built up on the pistons and valves (borescopes are your friend), spray water through the carb and the resulting steam will help clean 'em.

You have well lubricated valve stems/guides

 

[MikeB]

Sounds like what's happening is oil is slowing leaking past guides into cylinder(s) when engine is not running. If your heads don't have push-on seals, oil leaking past guides can be at least temporally cured by installing these "umbrellas" seals on the valve stems under the retainers. Al they do is deflect oil away from the valve stems.

https://www.amazon.com/Competition-...ams+502-16&qid=1617067594&s=automotive&sr=1-1

You must be registered for see images attach

 

[Madmacs]

Valve seals dry rot ,crack and leak oil . I've replaced many. I always use a nylon rope, and umbrella seals. Set valves ,when tightening turn push rod , when push rod stops , tighten slowly 3/4

 

[idahovette]

Don't think I've EVER seen a "dry rotted" valve seal, unless the engine has not run in over 50 years?.......or left open to the elements

 

[Octane]

Don't think I've EVER seen a "dry rotted" valve seal, unless the engine has not run in over 50 years?.......or left open to the elements

Heat hardens and even cracks them.So they do dry out and loose elasticity. And oil leaks past

 

[idahovette]

I doubt very much that they are "dry" running in an oil soaked environment. I guess we will have to agree to disagree. The oil will not leak past them if they are gone. the engine sucks the oil down the guides......yeah I know tomatoes, tomahtos

 

[Bextreme04]

I doubt very much that they are "dry" running in an oil soaked environment. I guess we will have to agree to disagree. The oil will not leak past them if they are gone. the engine sucks the oil down the guides......yeah I know tomatoes, tomahtos

Rubber "dry rot" has nothing to do with rubber actually being dried out. It is a condition that occurs from the polymer chains breaking down. UV, heat, exposure to hydrocarbons, and various other things can cause the polymer chains in rubber to break down. They will break down slower in a consistently run engine, due to stabilizing compounds that are placed in the rubber during manufacture being forced throughout the rubber from being compressed and moved around. A sitting engine will not have these actions and it will allow the polymer chains in the rubber to break down faster. This is why an engine that has sat for any amount of time will often start leaking as soon as it is run, whereas an engine that has run consistently for 200k+ miles can be still completely leak free.

 

[Octane]

Rubber "dry rot" has nothing to do with rubber actually being dried out. It is a condition that occurs from the polymer chains breaking down. UV, heat, exposure to hydrocarbons, and various other things can cause the polymer chains in rubber to break down. They will break down slower in a consistently run engine, due to stabilizing compounds that are placed in the rubber during manufacture being forced throughout the rubber from being compressed and moved around. A sitting engine will not have these actions and it will allow the polymer chains in the rubber to break down faster. This is why an engine that has sat for any amount of time will often start leaking as soon as it is run, whereas an engine that has run consistently for 200k+ miles can be still completely leak free.

The old fashioned valve seals were just little 'o' rings also.Understanding that rubber gets hard with age,heat. Even oil isnt kind to rubber is.That is why oil soaked hoses under the hood can go bad.I still have oil seals brand new from 25 years ago in my shop.No way I will ever use them,they are just in a drawer.

 

[idahovette]

Jeez, guys....SORRRRRRYYYYY...... Was just making a comment on the "dry" part....if they have oil on them how "dry" can they be.....old, hard, cracked etc. I know.......kinda describes me,....well maybe not hard

 

[Octane]

Remove those fine oil soaked seals then and see how much oil leaks past those perfectly good valves guides then.Geesh.