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MG MGA - Oil Consumption

I have a 1960 MGA with a reasonably new balanced motor. Compression across all 4 cylinders is good and equal but the motor is using oil. There are no leaks and people who have followed me say the car does not blow any smoke except for a little puff after trailing the throttle on a downhill run. There is no oil smoke at startup. When the engine is pulling hard uphill we get a whiff of oil which suggests it is coming from the breather. I replace the original hockey stick breather plate on the engine with one from an MGB and I wonder if this is causing the problem somehow. Any other suggestions?

Cheers Brian
Brian Woolmer

Brian, all MG's use some amount of oil, how much is the important question.
My engine is not in the best condition and uses about 1 litre per 500-700kms.

Neil
Neil Purves

"Any other suggestions?" - Valve seals?

When you say you replaced the breather plate, how is the crankcase ventilation set up now?

As usual there is a good explanation of the function of this on Barneys site: mgaguru.com
Neil McGurk

With my lateral thinking hat and not attempting to answer the cause of the problem, but instead addressing the effects. If you are getting oily smells in the cockpit at speed you may not have your firewall very well sealed. Putting grommets in unused holes is one thing, but if you look underneath the dashboard up into the top corners you will likely spot some noticable gaps in the body work that should be sealed. I used to get a lot of fumes through this area.

Steve
Steve Gyles

My oil consuption was pretty horrendous when I began using my restored car a good few years ago, complete with re con engine.

On trips to France and back I would use about a gallon of oil yet saw very little smoke!!

I put up with this for a number of years until finally I decide to do something about it.

Removing the cylinder head I could see the original style Valve Stem Seals were damaged, they are crap! I had the guides machined to accept modern stem seal and the difference was extra ordinary. I go to France touring now and do not have to top the oil up at all!!
Robert (Bob) Midget Turbo

I agree with Bob on this. I was using i liter per 200 kms and it was making me crazy. I installed new valve seals recommended on Barney's web site and the difference was amazing. Now I use about a liter or so per 4000kms.

Kris
Kris Sorensen

Brian, If you have replaced the side cover with a blank you have likely increased the crankcase pressure. The crankcase needs to be vented. Could be the oil is forced out through the seals as you drive. Try the old walking stick vent pipe for a time and see if it makes a difference.
Barry
BM Gannon

Brian,
I agree with Barry about putting the draft tube back on. The crankcase needs to be vented so it doesn't build up pressure. I experienced what I considered to be excessive oil consumption after rebuilding my engine. After 10,000 miles I pulled the head and had the guides machined for modern valve seals. Oil consumption was greatly reduced. These engines will never be as easy on oil as the modern engines we are now used to. They just don't have the materials or fit that modern engines do, but that's why we drive them isn't it.


Ed Bell

Thanks for all the feedback. Sounds like the betting is on valve guides and I'll take steps to investigate as suggested. I do have a breather on the engine but it is the MGB type which contains wire mesh and the tube comes out of the plate in an upwards position and I thought this might increase crankcase pressure??? From some comments it may be that I am not using that much. On a recent trip I did 550 km and used about 1/4 litre. Still too much for my liking.

Brian
Brian Woolmer

Brian,
I don't know how old you are, but I remember that in the 1950s we checked the oil just about every time we gassed up. It was not unusual to be down a quart after a couple of tanks. That is the era that these engines were designed and manufactured in so we should expect the same level of performance. I top my oil up about every 500 miles and it takes about 1/4 to 1/2 quart depending on how hard I have been driving.
Ed Bell

Every Chevy 3500 we have at work goes thru 1qt of oil in under 500 miles so it's not just the old engines. These have the 502 in them. Rumor has it that to get this displacement out of the old 454, the cylinder walls are thin leading to flexing.They are all 2002's with about 60k on them
gary starr

May be I am just lucky, but I never have to top up between annual oil changes and my car is a daily commutor. Yes, I have had the odd leak around the oil filter (now fixed), but otherwise, the oil level never drops. 1800 5-bearing.

Steve
Steve Gyles

This thread was discussed between 11/03/2009 and 14/03/2009

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