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MG TD TF 1500 - Problem with TF 4887 'Figaro'

After moving the car under it's own power for the first time in almost 45 years I have a problem.

The car is blowing white grey smoke after about 10'.

Doing a compression test number 1 is down by about 45lb compared to 2,3 and 4.

I can't remember (an age thing) if I can remove the head and sump in situ and remove number one piston as I suspect cracked or broken ring(s).

Has anyone done this successfully?

Regards, Don TF 4887 'Figaro'
Don Walker

Not sure if you can do it on an MG but you can sometimes remove the sump and pull the bearing caps and rotate the crank to drop the problem piston and swap the rings.

Taking off the head would not get you anywhere unless it was a valve problem.

Just for the heck of it did you try the tablespoon of oil in the failed piston chamber compression check to see if some or most of the pressure returned? If no change then it could most likely be head related versus ring.
Christopher Couper

It sounds more like a leak from water jacket to cylinder to me (white smoke). If that's the case a head gasket or incorrect torqueing of head nuts is more likely.
Lew3

Thanks Chris, you've pricked my memory, I did try the oil bit but thought it was the other way around, no change is ring problem. I will pull the tappet cover off and check the workings.

Not the best of days here with a predicted top of 44c, that's about 111f. Already 40c at 11 am.

Regards, Don TF 4887 'Figaro'
Don Walker

Thanks Lew, if it's the head gasket I would be more than pleased.

Regards, Don TF 4887 'Figaro'
Don Walker

White smoke os usually a blown head gasket,blue smoke would be oil.
Steve
Steve Wincze

Thanks all, I think the hot weather has fried my brain, I re-did the oil in number 1 and the compression came up to the same as the others.
Groan.

Regards, Don TF 4887 'Figaro'
Don Walker

Could be stuck rings - the archive will probably have ways of dealing with this, but I'm too idle to look for you.

Luck, David
David Provan

Hi Don,

Something I have learnt with TFs over the years is if one thing like a ring is a problem on your precious motor,other problems may follow.
I assume you have not re built the entire motor?

TFs are such a beautiful looking machine,however the trade off for their sleek appearance,is that they are difficult to work on once they are all together and not in pieces!!

If your front guards are still off the car,pull the motor and do a rebuild
if you have not already done so. Believe me,it would be worth it.

Your SA state is getting as bad as our WA with regard to hot weather-a shocker for you at the moment.

Cheers for now.
Rob Grantham
TF3719("Arams"),TF9177("Athos").
R GRANTHAM

Hi Rob, the motor was rebuilt by me, runs smoothly and idles evenly.

I have decided to pull the head and sump, push the offending piston up through the bore so I can see the rings.

I have 3 spares as I broke one assembling it in the first place.

Unfortunately I'm a lot older than the car so maybe I was having a seniors moment.

Hasn't reached 44c yet....only 43c. I'm lucky being down in a town where the Murray meets the sea...only 42c.

Regards, Don TF 4887 'Figaro'
Don Walker

If it is stuck rings you might try speeding the engine up and squirting ATF through the carbs. This tends to loosen the rings. Also toss a bottle of Marvel Mystery Oil in the petrol tank with a load of fuel.
Bill Chasser Jr

White gray smoke likely water. Are you loosing any coolant? Does it make pressure in the cooling system when hot? Any bubbling or foam in the top rad tank when idling? Check that stuff first. If the motor sat for a long time, rings could be stuck, and Bill's ATF idea may well free them. I suggest checking that simple stuff first before disassembly. I wouldn't think a broken ring or piston would not show compression change with oil? George
George Butz

Don

Not good after all your labor, put it on the back burner until the cooler months.

If you were closer I could lend you my cooling system pressure tester, bonus is they arent that expensive to purchase.

A pressure bleed down test will prove if you have water leaking into the combustion chambers.

I dont know the viability of removing the sump with the engine insitu, I tried once on my TF to no avail. If you can the bigger issue will be re fitment to get those pesky sump gasket components to seal. If you have to I would pull the engine and work on it in a more accessible environment.

Graeme
G Evans

Sure sounds like stuck rings to me. Running she engine until warm and removing the spark plug then filling the combustion chamber with a 50/50 ATF acetone mixture and letting it sit for a couple of days may well cure the problem. It is worth a try.
David.
D. Sander

The plot thickens.

I decided to drop the sump, fairly easy job, and check the rings on no.1.

All OK, bum!

It may well have been the head gasket but I couldn't risk putting a new gasket on only and then find it was the rings.

I'm at a loss as to why the compression came up with the oil in the bore.

Anyway, half a day's work, order new gasket tomorrow, so I should have it up and running again on Tuesday.

The motor has only done about one hour's work including the 20' for the camshaft run-in.

The head was pressure tested, block re-bored by a reputable firm, new pistons and rings (Aerolite brand)

Nothing can go wrong...go wrong...go wrong.

At least is cooler.

Don TF 4887 'Figaro'
Don Walker

It does seem odd that the compression came up with the oil. And you are going to be real mad if David Sanders was correct and the rings WERE stuck and you freed them with your oil test and then took everything apart because you could not find a source. :-)
Christopher Couper

Chris, I discounted the stuck rings as the motor has only done just over one hour, there was no sign of gunk or anything to stick the rings.

I have now completed the work and just waiting for the head gasket to arrive.

I strongly suspect the gasket as it did have a slight 'kink' in it originally.

Regards, Don TF 4887 'Figaro'
Don Walker

Success! just an update on my result.

I replaced the head gasket, re-fitted sump etc then started the motor.

It blew a little 'assembly' smoke but now runs even compression, and no smoke.

Must have been the gasket, and good news also, it doesn't leak oil !!

Regards, Don TF 4887 'Figaro'
Don Walker

Don, very pleased to hear that it was nothing diabolical.
Michael
M R Calvert

Don - remember to re-torque your head gasket a few times - I do it after the first start-up, after an hour of running, at 100 and 500 miles.

Tom Lange
MGT Repair
t lange

Good news, we'll keep our fingers crossed!
Geoffrey M Baker

This thread was discussed between 18/12/2015 and 07/01/2016

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