Hey guys, I have an 80 L48 and when its been running for a while or better yet , gone for a ride, on restarting it blows a small puff of smoke. I was told it most likely needs new valve seats. I just changed over to syn. oil but it smoked before that,It has 65,000 so called orig. miles on her, other than that she runs great, but want to get it fixed before it gets worse. Any thoughts that might help? Thanks Scott

 

Good morning 80, it's not the valve SEATS that cause smoke on start-up or deceleration, it's the valve SEALS, these are rubber o-rings that are fitted around the valve stem and seat against the retainer to keep oil from running dowm the stem into the combustion chamber. As long as your in there you can add another typeof seal that fits around the valve guide, the two combined will reduce oil consumption quite a bit.

 

[sm=exactly.gif]Bad valve seats would only effect compression. There isn't any oil in the seat area to leak into the cyl. So,......yup, it's the seals.

 

What Chevy doesn't smoke when you start it? Like the other guys said it's probably the seals or the valve guides could be worn also which makes things worse if the seals are worn also. If it just gives a puff of smoke when you start it, it isn't worth the aggravation to change the seals. I would drive it and have fun. It's not going to cause any damage.

 

Hi Batesy, if the smoke bothers you and you want to change the seals it's on page 2A-4 under # 5 in haynes. PG

 

My bad ,I meant to type seals. Thanks for the replies everyone. You sure it won't create probloms? I'm not a big engine guy, but can hold my own with mechanical stuff. If it's not an issue I will wait a bit to take care of other items. Thanks again and here's a pic. of my ride, stole it for $6400

 

My 74 has been know to blow some smoke on start-ups. In my case it's not oil but fuel (white/gray) smoke. If you are blowing (white/blue) it's oil. You should be able to smell the oil.
Either way I would not worry about it until it starts blowing smoke when you are driving around.

 

If a new set of o-ring type seals doesn't stop the smoke at startup, then your valve guides are probably worn and need refreshing. The umbrella seals that fit on the valve guide boss really don't allow enuf oil to the guides.

 

78Buckshot said it, it's the seals. And "Schoon,"BLACKsmoke is excess fuel.

 

Thanks all, I don't feel as bad as the guy in the C4 I saw today. He had smoke every time he got on it