Misty oil from oil filler after first start in 4 years

[MartBlak]

Can anyone please give me any advice.

I have given my 289 engined rebuilt GD Mk3 Cobra a first start up today after nearly 4 years of being off the road. It is a 1965 block 289 with Edelbrock Performer RPM heads and Edelbrock 600 cfi carb.

After a great start-up and a lovely sounding tickover I started having an airlock problem with the rad and a thermostat that did not initially work properly. But these are issues I can resolve I think......though that is not what is concerning me.

When the engine got hot I noticed a small amount of fine oil mist coming from around the oil filler cap and a slight drip onto the exhaust manifold which of course was smoking as a consequence. I have checked all the cylinder pressures and all are good....ranging from 175 to 180 lb/sq.inch......so I am worried it might be something more serious.

After a 4 year (in August) gap between being started up I am hoping it might take a bit of time for the seals to start operating properly. Is this possible or has anyone any advice as to what I can do to look for something else?

Many thanks.....I must confess to being a bit worried.

Martin

[colinA]

What breather arrangement do you have on your valve covers?

[MartBlak]

The breather feeds to the carburettor......if that is what you mean?

[MartBlak]

The breather feeds to the carburettor......if that is what you mean?

[peterc]

4 years stationery is not good for any machinery. I suggest it’s 4 years of condensation and as you suggest seals not working correctly. I hope you didn’t just warm it up in the driveway. You need to raid it for a proper drive to warm it up.
My thermostat doesn’t like it after only a few months inactivity.
If it is running reasonably OK take it for a blast to blow the cobwebs away. Obviously keeping an eye on the temp.
Peter C

[colinA]

The breather feeds to the carburettor......if that is what you mean?

Both valve covers should have provision for venting (to the atmosphere via a catch tank or recirculating to the carb) the internal pressure of the engine.Size should be 1/2" oe 5/8". Have you changed the spec of the engine since you last ran it?

[MartBlak]

No I have not changed the spec of the engine.
One valve cover vents via the carb and the oil filler cover is also vented I believe.
I only had it running on the driveway but we could not get water circulating properly. Removed the new thermostat and checked it was OK in a bowl of boling water. Big problem with an airlock in the rad that I tried fixing by placing the car on all inclines but still not clear so water temp was too high to run it for too long but then I noticed the mist and smoking from drips on the manifolds.
While it has been laid up I have put a squirt of oil in the cylinders occasionally and hand turned it over. That shouldn't have caused glazing of the cylinders should it? The engine has only done 12.5k miles.
MOT booked for next Thursday so am more than a bit concerned!

[colinA]

Since your cylinder pressures look good, the rings should be good and the oil problem isn't going to be caused by blowby. Overfilling the oil can cause this type of problem; do you know the capacity of your oil pan and does the dipstick actually measure to that level ?
You could try a vacuum filler kit for the cooling system (£29 on ebay)to fix the airlock. Having a bleed on the top of the rad would help and preferably connected to the header tank so the system is self bleeding.

[StewbieC]

Did you change the water pump as they are directional? Is the bottom of rad connected to the water pump inlet? Have you got a thermostat bypass hose fitted? Are you getting a decent vacuum from that carb port?
I'd be more worried about frying the engine over a bit of oil mist. I always use a PCV valve (connected to the carb vacuum port) on one valve cover and a vented filler on the other usually connected to the port on the air cleaner. If you are using rollers on standard valve covers sometimes people take out the diffuser plate and mesh which can create more mist and even more so if you have positive crank case pressure ie no vacuum take off.

[MartBlak]

Thanks for all the responses. I checked today and it took +/-3 litres of water so clearly there had been a big burp overnight! Filled up again and had it running for 30 minutes with a good, solid, water temp, good oil pressure and oil temp got up to proper operating levels.

The oil mist was less than yesterday and only a drop or two of oil landed on the manifold. I will do the same tomorrow and see if things have improved again. It may well be "gummy" seals after 3/4 year layoff? An engine guy suggested I should do a long run with a high detergent performance diesel engine oil to clean the engine and to stop the sticky deposits forming again. I can then revert to the "normal" engine oil. Does this make sense to you?

Colin, my dipstick was removed and replaced but I have no idea how accurate it is. I have a racing sump so a high volume of oil......I cannot remember how much I put in but will check.

I will look into the PCV valve Stew as I have never heard of one of those before.

Thanks again all.