dgood

I took my intake and valve covers off to fix a oil leak on one valve cover and the back of the intake. I was looking around in the passenger side and notices several pieces of broke plastic near the oil return hole and around some of the valves. They were just laying on the head. The pieces are all about 1/8 inch in size. I had the valve covers off about 1 year ago and they were not there. The plastic is very hard and is not a piece of the gasket or any part of the valve covers. could not see where they come from. Every thing looks normal in there and the engine ran fine. Any ideas? It is black plastic. It is a 350. There were not any pieces on the drivers side.

'75

It sounds like petrified pieces of the valve seals.

dgood

'75, does this mean a valve job or is replacing them somthing I can do with the heads left on. I don't think the engine has ever been overhauled. looking in through the engine, it looks like the valves are pretty gunked up. What do you think?

'75

They can be replaced with the heads on. Do you get a puff of blue smoke when you fire it up?

dgood

yep. I just wrote it up as an old engine. with the valves looking nasty should I pull the heads or just go with chaning the seals? I drive it a few times a week and with the exception of a differnet cam, headers, intake and carb, it is all original. Opinions?

dgood

should I replace the rods and springs while I have it a part? What else do you think I should replace/fix.

'75

How many miles are on it? It's cheap and easy to just replace the valve seals and eliminate that start-up puff.

dgood

The odometer has about 12000 on there, I would have to say 112000 but not sure. The previous owner said that there was only 12000 but he also said it was a very good running car. I had to redo all the front bushings, all the break lines, shocks, water pump, radiator, carb, intake gasket, oil pump, fuel pump, starter, power steering lines and pump, vacuum hoses, and a bunch of other stuff so I don't know if I should believe him.

71corvette

You could wind up with a lot of opinions on your situation but I will offer mine if it helps. The plastic you found is definitely the rubber valve seals that have hardened over time and broke off. If there is a fair amount of gunk in and around the valve stems, it also means there is probably going to be the same gunk throughout the engine. If for example you decided to pull the heads, clean them up and do a valve job, you would just create more problems after you reinstalled them because the piston rings are more than likely worn out and with the increased sealing from the valve job would create an oil burning situation as the increased vacuum would pull oil past the rings. So to shorten this response and based on what you had said, I would just change the valve seals and clean out the gunk around the valve cover area. In order to change the valve seals, you will need to remove the spark plugs and hook up an air line to keep air in the cylinder. Then you use a valve spring compressor tool that can be used with the heads on. You can rent or buy this tool. This is a simple job for those who have done it before but taxing for those who have never done it. I wouldn't get into changing valve springs etc. as I'm guessing the entire engine probably needs some work.

I hope this helps.

dgood

71, thanks for the advice, I will stick with just changing the seals. I have a feeling you are right about the engine probably needing work...some other year. Thanks again.

Dan

Rich's'78

Be sure to keep a close watch on your oil pressure. Some of the pieces may have already dropped into the oil pan and could obstruct your pump pickup. Maybe wise to drop the pan to check.

dgood

Rich, I guess I will do that. This one repair is really turning into a long one. SHould be done with everything here in a couple of weeks. Replacing all the brake lines and cleaning up the engine compartment.

rob75383

In my case, the umbrella seals weren't hardened, nor did they break off.
I purchased assembled heads from Jeg's or Summit. All I did was inspect visually, and mount 'em. After a few months, I found the pieces of the umbrella seals near the oil drainback.
After some further inspection, I noted that the dampener springs' inner diameter had zero clearance for the umbrella seals' outer diameter. So, as the dampeners compressed, they would act like scissors, and snip off pieces of the seals. Out of the 15 seals, only 1 was without damage.

I wound up pulling the heads, and having the guides machined for $40 to accept the teflon seals. No more puff at startup, and no more burnt oil.

dgood

I am going to start pulling them tomorrow. Have the seals and orings ready. We will see how it goes.

dgood

Well I pulled all the rocker arms and springs off the drivers side and there were 3 of the "umbrella seals" that were shot and all 8 of them were very hard. What I thought was weird was there were not any o rings on any of the valves. I put new ones on. Are there supposed to be the oring seals on them. The book I have says yes. Do you think they all came off over time?

larrywalk

O-rings on the valve stems...
Formerly stock heads used them with steel oil shields under the retainer on top of the spring. There was no seal used on the valve stem as it went into the guide.

Later designs use a seal on the valve guide where the valve stem enters the guide. With a good seal at the guide, it no longer matters whether an o-ring is used at the top of the valve stem.

dgood

So do you think it ok to put the little oring seals on? Will it hurt anything?

larrywalk

Won't hurt, but not necessary if you use seals at the valve guide.

dgood

Well, that project was a pain in the rear. had to pull the headers off in order to hook the compressor up to the spark plug holes. Everything went ok. Of the 16 umbrella seals, about 8 of them were in pieces, 4 were gone and the rest were hard as rocks. Time to put everything back togother. I think I am going to try to paint my headers while they are off. Got to get the rust off them though.