worn valve guides/seals

[tonyk72]

I suspect I have worn valve guides/seals...I notice bluish smoke coming from the exhaust on startup...it stays like that for a couple minutes and goes away...
I'm going to do a compression check as well...
Anyways, I was wondering if I am causing any further engine damage by driving it this way?
Is this something I can fix myself? I have gone as far as intake manifold removal/install as far as experience...
I've read that the seals are easy, but the guides require machine shop work. Am I right? Ball park figure, what would that cost me?

Thanks!

 

[The73vetteman]

Worn Guides etc

I have the same problem with my 350. I ran a compression test which came out good (150 psi) so I believe the problem is in the head.

I'm told you can buy valves with oversized stems to compensate for guide wear, but I'm not sure what this would do for concentricity with the seats.

Anyone ever tried this?

Any one got any suggestions for getting heads rebuilt - is it a DIY job or should I go to a Pro?

 

[69autoXr]

In my experience this is normal for small block Chevy's and not something to worry about, that the phenomena is due to a small amount of oil running down the valve stem when the engine is shut off. You said yourself that the smoke goes away after a few minutes, do you notice the engine burning a significant amount of oil? If not, I wouldn't worry about it.

Chris

 

[Jack]

Re: Worn Guides etc

or should I go to a Pro?

Unless you've got access to valve seat & valve face grinders & various pricey gages ... & experience with them ... take your heads to a reputable auto machine shop ... they probably need to be "serviced" ... more likely than not that the bill will be less than you might expect. Your 30-year-old valve springs are probably weak ... get a new set of "Z-28" springs ... under $30 for full set. You may need a few valves ... under $10 each ... and few guides replaced ... under $10 each. Even with all that you may get away for under $200 total (you R&R heads) ... so long as heads are not warped/cracked and you're not looking for port-polish or multi-angle valve job ... just go for a standard service job & new springs & ask for PC valve stem seals. Don't fall into the trap of having your old guides "knurled" to save a few bucks... it'll tighten em up for a while ... but not long.
JACK:gap

 

[Copdogcorvettes]

This is a normal problem with the SB Chevy. If you don't have a big oil lose problem then don't worry about it that much.

As to repairs, Take it to a GOOD shop to have it done. Replacing just the rubber seals can be done without removing the heads IF you have the right tools. Many GOOD shops have the tools to change the seal on the car. It is done by putting compressed air into the cylinders by way of the spark plug holes. Then the valve spring are removed with a tool. The rubber seals replaced and the springs replaced. The compressed air keep the valves in place. It is spendy to get it done, but cheeper than pulling the heads. Or you can pull your heads at home and take them in to the shop and have then fixed. If You go that way just have the heads rebiuld and be done with it.

Good luck,

Gary

 

[kbelcher]

I suspect I have worn valve guides/seals...I notice bluish smoke coming from the exhaust on startup...it stays like that for a couple minutes and goes away...
I'm going to do a compression check as well...
Anyways, I was wondering if I am causing any further engine damage by driving it this way?
Is this something I can fix myself? I have gone as far as intake manifold removal/install as far as experience...
I've read that the seals are easy, but the guides require machine shop work. Am I right? Ball park figure, what would that cost me?

Thanks!

I had the same issue with my 79. I think this is common and will not cause any long term issues for the engine. I replaced the value stem seals and the problem went away. I did this without removing the heads. I forced air into each cylinder which holds the values in place and keeps them from falling. I then removed the springs and replaced the seals. This worked well for me.

Good luck!

 

[AV8RSVT #1]

I agree "seals"

 

[lone73]

Had the same prob on my orig L-82 motor after I bought the car. I was advised to put in new seals as others have stated, in addition, I also was told to try adding the umbrella seals which I think are common on Fords. I did that and no more smoke at all on start up. I recommend the umbrella seals in addition to new stock GM seals

good luck with it..
lone73

 

[tonyk72]

OK, I'll hunt around for a good shop...in the meantime I'll check the compression & keep on drivin' till the snow falls.

Thanks guys!