Puff of smoke

[Jim M.]

My 69 is a 350/350 and I've noticed that on re-starting the engine after it's hot, I get a puff of smoke and I think it's a blueish smoke and it takes a couple more cranks on the starter to get her started. I just did a compression test with a warm engine with the following results

1) 152
2)152
3)149
4)145
5)151
6)149
7)149
8)151

Afer shutting off the engine it does smell gassey too. I'm wondering if maybe this is coming from some bad valve seals? Any thoughts?

[Joe L.]

Re: Puff of smoke

My 69 is a 350/350 and I've noticed that on re-starting the engine after it's hot, I get a puff of smoke and I think it's a blueish smoke and it takes a couple more cranks on the starter to get her started. I just did a compression test with a warm engine with the following results

1) 152
2)152
3)149
4)145
5)151
6)149
7)149
8)151

Afer shutting off the engine it does smell gassey too. I'm wondering if maybe this is coming from some bad valve seals? Any thoughts?

Jim------

The greatest liklihood for the source of the smoke you describe is worn valve seals and/or worn valve guides. These are common problems with small block Chevrolet engines. If the engine has never been rebuilt, either completely or just the heads, you can be virtually certain the valve seals are long-gone.

If the problem involves just the valve seals, they can be replaced without removing the heads from the engine. However, if the valve guides are worn, the heads must be removed and completely serviced.

[Patrick H.]

Re: Puff of smoke

If they've never been replaced, or even if they have but not in many years, it's probably the valve stem seals.

You can replace these yourself if you wish. Harder than replacing spark plugs, probably about the same level of difficulty as replacing a rear main seal.
You will need a tool to compress the valves (cheap ones are L-shaped and available thru NAPA and similar) as well as an insert to thread into the spark plug holes and apply compressed air into the cylinders. I bought that adapter too at NAPA, then bought a short hose with flexible end at Tractor Supply so that I could actually connect it to my air hose.

Here is the "whip hose" adapter:

http://www.tractorsupply.com/tools/air-compressors-air-tools-accessories/air-hoses-hose-accessories/air-hoses/whip-hose-3433113