I've got an 88 GTA with the 305 TPI motor and a 700R4. It's all stock, and has 130,000 miles on it. Here's the story.

After sitting for an hour or more, when you start it, it smokes for maybe 30 seconds, a bluish-whitish smoke that smells like oil. It's not using antifreeze, and so I think the smoke is completely oil. The tailpipes are blackish inside, but liquid oil is not visible in them. It uses a quart of oil every 4-500 miles. After it warms up, it smokes visibly while it's sitting there idling. Not a lot, but it's there. If you rev it, you get great clouds of smoke. I pulled my #3 plug (because it was easiest to get to) and it looks normal; the insulator is whitish-tan and the electrode is clean.

The lady I bought it from says she took it to GM some years ago, and they replaced the valve seals on the right cylinder bank, then closed everything back up and told her she needed a new engine. It was long enough ago that the dealership doesn't have the records anymore. There is slight crud build up visible through the oil filler cap hole, but I've seen much worse. I think I can take care of it by running synthetic oil in it over a period of time. There is some grit in the engine oil, which is probably some of the aforementioned crud. I'll be changing it this week. The engine, cold, holds 60 psi oil pressure at idle according to the factory gauge, and 30 when hot. The pressure increases proportionately with RPM. The car runs fairly strong, although it's dead past 4500 RPM. I don't ever see the temperature gauge go past 180.

What do you think? Should I try replacing the valve stem seals, or what? Thanks for your diagnostic advice.

Joe

 

this is the world famious 3rd gen valve seal leak, you will need to take the heads off and have them rebuilt, then the buring oil problem will be fixed

 

Don't have to remove the heads. Just need to change the valve stem oil seals. unless you are very confident/lucky I wouldn't use the compressed air method of keeping the valves closed while you change the seals.
The way that works best for me has been to remove the spark plugs, get #1 started on compression, feed about 2 feet of nylon rope into the spark plug hole (put a knot in the end so it can't all go in) rotate the engine by hand, until the rope is just being pinched by the piston. Now you can go ahead and remove the valve locks, keepers and springs on #1. Change the seals with umbrella style seals and reassemble. Back the #1 off so you can get the rope out and move on to the next cylinder.

I have used this method several times and never dropped a valve.


~M~

 

Absolutely! Replace your valve seals!

 

Morley, Im looking at replacing mine also, My engine sat for a year and a half, before I got it. I'm getting the same smoke, although not as bad, mostly at startup, just a little on hard acceleration.....so if I use the rope method you described, Valve positioning isnt important? Do I just reassemble the valve springs and stuff the same way they come off?
This sounds real simple, I've just never done it before. Do the seals just slide onto the valve? Anything else I should be careful of. I'm not afraid to try new things and learn, I just dont want to mess things up.

 

You can change seals with the heads installed. Your description leads me to believe that you have valve stem seal issues and other problems. If the smoking continues for several minutes, your rings may be coked as well. Synthetic lubricants can clean this up, too, but will take some time.

The oil and filter should be change ASAP if you can see or feel particles in it. The synthetic should start cleaning your engine, but since it cleans so well, you should not extend the change interval just because you are using synthetic until the engine is clean.

Before you change the oil, You might want to try a new, cheapo oil filter, then add a quart of auto trans oil to the crankcase and run it until it is fully warmed. The ATF can help clean away a lot of free debris and deposits. Drain the oil and change the filter right away, and refill with synthetic. Monitor the level and condition of the oil closely, and change when it becomes dirty (or a maximum of 3,000/3 months). I wouldn't be surprised if the oil consumption diminishes to an acceptable rate after a couple of synthetic changes.

 

Valve position is important, you don't want a valve open when putting the rope in, each cylinder should be on the way up on compression when you put the rope in.
And remember which rocker and spring assembly came off of which valve and put them back there.

Yes, the seals just slide down on the valves, there is a groove in the valve stem that the seals sit in. There is a company that is supposed to be making teflon seals for SBC's that are supposed to last the life of the engine. I don't kow if it is true, but it may be worth looking into.

~M~

 

Another possibility ,since you mention the sludge buildup, could be plugged drain back holes in the head.I had the same trouble with a 70 Camaro I bought back in High School.It was really bad after driving out on the highway for 10 or 15 miles.I pulled the valve covers and there was so much sludge I couldn't find the drain back holes.Once I unplugged them the smoking stopped.If those holes are completely plugged or severely restricted, the oil from the rocker arms fills up the valve covers.The result is the oil level builds up higher than the seals and they will leak.You probably will still have some oil usage after clearing them, but it will be considerably less.Of course you will have to remove the valve covers to do this so, if you have time, you probably should go ahead and replace them anyway.Unplugging the holes is just going to make it better temporarily.Although I did drive mine for a whole year before I replaced the seals.

 

I think I'm going to try this, Aftr I get the new tranny in next weekend...I love these cars, always something to do....

 

Thanks for y'all's advice. I was a Dodge mechanic for two years, but I've never dealt with GM engines and was unsure what the weak points were.

Morley, I may have been just lucky, but I've changed valve seals before while using the compressed-air method, and haven't had any trouble. But now I only have my little pancake compressor instead of the shop's 120 + psi supply of 13+ cfm air, so I think I may go for the nylon rope trick. Does anyone know the size of the bolt going through the crank pulley right off the top of their head? Unless it's 1-1/2 or larger, I shouldn't need to go buy a socket. In the past, with manual-trans. 4-cyl. cars I just put them in high gear and pushed them to turn the engine, which was pretty lazy of me, but worked.

Vader, I've put a capful of ATF in an engine before to start cleaning it out, but I've never heard of adding a whole quart. I've always heard to either put a little ATF in, or to use synthetics, but never thought of using the ATF first. How much of a risk of plugging up the oil pickup screen would that pose?

TxTurbo, I know what you mean about really huge sludge buildup. Recent Dodge V8's are bad about the gasket in the underside of the intake plenum failing, and then the vacuum present in the intake manifold sucks oil from the lifter valley and burns it through the engine. This condition is characterized by heavy spark knock and oil usage. Anyway, we pulled some intakes off under warranty and found sludge so bad that you couldn't even identify the keeper strap for the hydraulic lifters! Needless to say, we took pictures of them for future use in case the owners brought them in under the service contract with a locked-up engine from oil starvation due to a clogged pickup screen. Can you say, oil filters stamped "Factory Installed" in vehicles with 30,000 miles on them????!!!! In any case, I think this sludge buildup is due to either infrequent oil changes or use of Pennsylvania-based crude oils.

 

My engine has just under 70,000 miles. It too has the valve seal issue. I have been using Mobil 1 20w50 or 5w30 for the past year and a half and the problem didn't seem bad at all. That is until recently when I switched back to crude oil All of the sudden it seems like a wildfire in Saudi Arabia! I mean it looks like the indians are trying to communicate via smoke signals! One time it read "Hey dummy, change your valve seals!" lol j/k

Anyways the difference was very noticeable. In about another 300 miles I'm going back to Mobil 1 and I'll let you know what happens.