Burning oil - Possible reasons?

[69_Dream]

I need help guys

I've got an original 69 427/390 that has started to burn oil and it's coming out the side pipes, ouch! :cry

Oil seems to be leaking from the rear of the intake manifold. Is that even possible? Somewhere near the distributor? Again, I'm a little stressed right now so maybe I'm not being clear, or else I'm explaining it wrong.

It seems fine if I just start it up in the driveway. The problem develops after driving a few miles.

2 items that have changed just a few miles prior to this starting:

1. Found a plug that hadn't been connected - and here I was thinking I had a timing problem :L
2. Added half a bottle of lead additive to the gas

Can anyone point me in the right direction? Keep in mind I am NOT mechanically minded, nor mecanically capable. I can hold my own pulling apart a door or fixing a convertible top, or else a radio or redoing a carpet... just not really good when it comes to engines. With all that in mind, I'm more than a little worried right now, seeing as this is its original block and all.

Should I be driving it at all or should I have a tow truck come get pick it up and bring DIRECTLY to an engine rebuild shop? Can anyone out there help? Anything to point me in the right direction would be great. Thanks.

Sly

 

[Rowdy1]

One At A Time

I'll try to address your dilema as you listed it.
You say it's burning oil and it's coming out the side pipes, is it smoke or is it raw oil?
Oil can most definately leak from the back of the engine, either under the intake manifold OR from the distributor. There is a gasket for both but "most" engine builders use high temp silicone under the intake. Do you have a solid feed oil gauge or is it a sender meaning electrical?
As the engine warms up, the oil becomes thinner and will leak more or faster. Find out WHERE the leak is before you panic, the only damage you will do is if you leak so much oil that the level goes low enough to not be picked up by the pump which is probably 5 or 6 quarts. See what you can figure out and let us know, I'm sure somebody else will be along shortly with more ideas.

 

[matchframe]

Is there oil under the car after it sits for a while?

Did you change the timing? If so, there could be a leak where the distributor goes into the intake. You might have to change out the round gasket under the distributor. Not a big job, but need to be careful going back together so not to throw timing off.

Also, if you had a plug not firing for a while, now that it is firing, you may be burning carbon that has built up in that cylinder.

The lead additive acts as a cleaning agent, and what you see could be the carbon being cleaned out, and not neccesarily oil smoke. If the smoke is black, it is carbon, blue is oil.

Hope this helps!

Bill

 

[69_Dream]

Thanks for the responses!

Bill, you nailed it with the plug. I pulled the plug off and smoke stopped. Talk about not running on all cylinders :crazy

Looks like it might be carbon related, but somehow the smoke did have a blueish hue. I think that might be another problem. One at a time.

So... all that being said, any home remedies that I could try before bringing it in? I don't suppose a good can of engine flush and all good?

Once again, this forum comes through for me. What would I do without you guys? ;worship

Sly

 

[matchframe]

That's great to hear!

Man, I would love to have a Vette like yours, an original Big Block, WOW!

I hope it all works out well for you!

Bill

 

[WhalePirot]

I pulled the plug off and smoke stopped

What plug? A spark plug? A vacuum connector? The PCV plug?

How much smoke and what color?

Did it start slowly and build in amount? Does it stop?

I hope you checked the oil level and continue to check it at least once/week, if driving this beaut!

I'd suggest this, even if it slams one's ego a bit: The Complete Idiot's Guide "RM" to Car Care and Repair Illustrated covers maintaining, troubleshooting, and repairing your car from bumper to bumper. It clearly covers selecting tools and parts, changing oil, checking transmission and steering fluids, replacing filters, troubleshooting engine noises, installing brakes, fixing door dings, and keeping the car's battery alive longer. We can always learn somehting; then move higher.
Mike

 

[Rowdy1]

I Know?

I was thrown off a bit by the reply also but, I guess he's happy so, we are too, "I think?":confused

 

[69_Dream]

I don't use the car as a daily driver, far from it. So when I noticed that a spark plug was disconnected, I plugged it back. That's when the smoke began. As for color, it was more of a dark color, but like I said, there was a blueish hue. That might be there on a regular basis, just never noticed.

As far as happy, well... not quite. Just a bit relieved. A bit. Now my next step is probably to bring it in where they can check compression and see what else they can suggest. Firing on 7 cylinders isn't my idea of a big block

Mike, you're suggestion is a good one, I do have a manual that describes most everything, but this threw me. I find those manuals good, but not nearly as complete as say... a forum full of knowledgeble corvette enthusiasts.

I'm definately leaking some oil too.. since the back of the engine seams full of it. Just where the intake manifold joins up. This car has me up at night! It's like I said, one problem at a time.

For what maybe carbon built up over years of neglect, is there anything I can do? Is it safe to run like this? Is there a "magic" product I could just dump in the carb to clean up the cylinder?

Thanks again for all the responses.

Sly

 

[Rowdy1]

Run High Octane

There are additives that will "help" clean, so they claim, I'll leave that question to someone else with more experience in that area. When's the last time you had the carb adjusted or rebuilt? How long did you drive it on 7 cylinders? If you now have all eight running, I'd suggest putting all new plugs in it and see if the smoke goes away before I went for ANY compression testing or the likes. Especially if you don't know or have a close friend or shop you can truely rely on. You may not have a problem there at all once the excess carbon burns out of that hole and off the valves.

 

[WhalePirot]

Old cars...Lovely, aren't they?

I'd want a good look at each of the spark plugs. They can really tell the story of what is going on in the cylinder. Hopefully, the unplugged cylinder did not wear from raw fuel washing the lubricating oil from the walls. Steam from seeping anti freeze can do the same thing. I suspect the smoke was the burning of whatever that mixture was; which is not necessarily a bad thing. it may, however, foul the plug; a simple problem.

For now, I'd do a complete tune up and fluid change with a good shop that can analyze the signs rom the fluids and plugs. Then, I 'd not worry, but drive it conservatively until you know the car is okay.

Big blocks are great, but due to the power and mass, they can mask some run issues that are quite apparant in the mouse motors.

I hope you truly enjoy the car. If not, give me a call and I'll offer you a ridiculously low number for it.
Mike

 

[red70vette]

Have you disconnected the plug again and the smoke stopped? It appears that is what you infer. That is not an answer but it is a clue.

If that is what you have done replace the plug and reconnect it. run the car a while and let the excess carbon and oil in the cylinder burn off. That should be done before you start to lay your wallet at the feet of a mechanic or engine rebuilder. Keep a close eye on your oil level to make sure that you have suffivent oil to keep the engine lubricated.

In all likelyhood the leak and the exhaust smoke are not related.
Work on the smoke and keep an eye on the other.