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Oil burning at cold start

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DirkRoels

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Hi,
When I start up my engine after a couple of days, it always gives a lot of smoke for a few seconds. Once it idles normal, the smoke disappears and the car runs without smoke.
I'm just back from a 1000 mile trip, and the oil level is almost at the same level when I left, so I don't consider that it burns a lot of oil during normal operation only at start. Has anyone an idea what might be the cause of it?
The oil gets black farely quickly.
When starting with the engine still warm, I don't have the smoke.
????
Thanks
Dirk
 
DirkRoels said:
Hi,
When I start up my engine after a couple of days, it always gives a lot of smoke for a few seconds. Once it idles normal, the smoke disappears and the car runs without smoke.
I'm just back from a 1000 mile trip, and the oil level is almost at the same level when I left, so I don't consider that it burns a lot of oil during normal operation only at start. Has anyone an idea what might be the cause of it?
The oil gets black farely quickly.
When starting with the engine still warm, I don't have the smoke.
????
Thanks
Dirk
Click to expand...
One thing comes to mind...worn valve guides and seals. There's a rubber type of cap that is much better than the original "O" ring but I don't remember who makes them.
Patrick
 
Perfect Circle are the brand of valve guide seals on mine, but thy've been on there so long, I can't remember if the guide had to be machined to accept them.

But your symptom definitely sounds like the oil is getting past the valve stems once the "explosions" stop.

Another (driving) test, is to be going down the highway (4th-direct) at about 4000 RPM (or higher) and quickly lift completely off the throttle; the high-vacuum condition should try to suck anything that will move into the combustion chambers (oil past the guides being the most likely).

Then there are combustion and leak-down tests you can try...
 
My Healey did the same thing after a rebuild and it was definitely bad valve stem seals. In my case, the aftermarket umbrella seals my rebuilder used interfered with the valve springs and they worked the seals off the stems. We replaced the seals with smaller ones and there is absolutely no smoke now.

This happens on a cold start because oil on the valve stems and rocker arms drips down past the seals and pools into the cylinders by gravity after the engine is stopped. The leaking is normally too slow to produce any oil smoke when she is running or when restarted after sitting for a short time (warm start).

If your oil consumption is low, this is mostly a cosmetic problem, though it left heavy black deposits on my intake valve stems. Fixing the seals requires removing the head, though some mechanics say it can be done with the head in place. The valve springs and keepers need to come off to get new seals in place.

Good luck!
 
Thanks guy's for the advice, I have seen some valve stem seals at AH spares in the UK, will first try to replace them. If that doesn't work I see to replace the valve guides.
 
My knowledge is not very deep here, but just wondering...wouldn't worn valve guides result in continuous oil entry into the combustion chamber, not just at cold start? Or does the metal expand once warm to produce a better seal? 1000 miles without oil loss doesn't seem so bad.
 
nevets said:
My knowledge is not very deep here, but just wondering...wouldn't worn valve guides result in continuous oil entry into the combustion chamber, not just at cold start? Or does the metal expand once warm to produce a better seal? 1000 miles without oil loss doesn't seem so bad.
Click to expand...
That, plus the presence of positive pressure (75% of the time) keeps it from sucking in the oil while running. Of course if the guides/stems are worn enough, you will get some oil consumption then too, hence my "driving test" above.
 
Hi Dirk,
Has the engine ever been rebuilt? If the oil gets black quickly, you may have some worn piston rings too. FWIW
 
Yep lke every one has said he has Bad valve seals snd guides and a bit of blow by too.--Fwiw--Keoke
 
I have done the accelleration test as Randy explained, but don't see a lot of smoke when doing so (I saw modern cars with more smoke coming out of the tailpipe).
After the test I took out my spark plugs and saw that the n° 2 and 4 spark plug have some greasy look, whilst the other ones are nicely dry and gray.
Think I will take the engine appart this winter and look what is going on (in Belgium winters are too cold and wet anyhow to drive a convertible)
cheers

Dirk
 
DirkRoels said:
I have done the accelleration test as Randy explained, but don't see a lot of smoke when doing so (I saw modern cars with more smoke coming out of the tailpipe).
After the test I took out my spark plugs and saw that the n° 2 and 4 spark plug have some greasy look, whilst the other ones are nicely dry and gray.
Think I will take the engine appart this winter and look what is going on (in Belgium winters are too cold and wet anyhow to drive a convertible)
cheers

Dirk
Click to expand...
You can save the expense of a major $$$$ job and do just the valve seals(get the "aftermarket" ones that actually work)and you'll be satisfied with the results and have money left over for a hardtop! I had the same problem several years ago.
Patrick
 
If #2&4 are wet,they aren't firing properly, if at all. I would check wire resistance,compression,clean plugs w/propane torch&switch to different cylinder. Run engine for a bit &recheck,If still wet plugs,do a leak-down on cylinders. Hope this helps, cheers Genos2
 
I replaced the valve stem seals in my AH 3000 a year ago with the umbrella style from Moss. 1000 miles later and my engine has been burning as much oil as gas (darn near), so I pulled the head to get a closer look. The cylinder bores look pristine and I had good compression before I pulled it apart. The first thing I noticed after looking at the disassembled head is the valve stem seals I replaced a 1000 miles ago are SHREDDED. The valves are nice and tight in the guides, but the seals are gone. It was blowing smoke badly, mostly under acceleration. What valve stem seals are the "good ones"? I guess it's time for a total head rebuild?
 
I have exactly the same problem. You can change the seals with the head on the car you need to feed rope into the cylinder through the plug hole to stop the valve from dropping. Then you need a tool to lever the spring down so you can remove the valve spring locking mechanism. There are some video's on Utube that show how it's done but not on a Healey.

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://www.youtube.com/watch?v=fZ5nZhDdAMs
[/FONT]
Worth a try, if it deosn't work then you have to take the head off.
Yes a winter job for me.
Dirk, are you going to the Belgium Classic in Brugge this weekend. If so, see you there for a chat. Red BJ8 Registration No. ending 134D
AJ
 
Here's a crazy thought....could it be condensation in your exhaust system? Maybe the smoke isn't oil burning, but the condensation vaporizing??? just wondering...
 
Take one of the cheap neoprene seals that are supplied in the head gasket set to a good hydraulic supply house and ask them for the Viton equivalent. They should be either brown or a greenish colour .
I have them in both my Running Healeys and also in the Tri Carb engine I just rebuilt . No modifications needed , direct replacement , last longer , no oil burning .
 
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