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MG Midget and Sprite Technical - Timing cover seal oil leak again

Good afternoon, it’s my first post here, so please be gentle!

I acquired my latest midget about six months ago, a nice original 1275 Mk III, 1972 RWA.

It had oil consumption problems and many oil & water leaks which I decided to sort in one go. The car has only covered about 1500 miles in the last 20 years, so I guessed gaskets and seals would all be in poor condition.

I appear to have fixed all but the timing cover oil seal. I have done this job on three or four other midgets in the past with no problems at all.

The first go, I did this:-

All parts cleaned. Checked timing cover for signs of over-tightening and dressed back any minor distortion around the bolt holes, checking with a straight edge.

All parts cleaned, with new gasket with blue hylomar, new oil seal. Loose fit, then crank spun with the pulley in place for a few times to centralize, then remove pulley and torque bolts to 6lbs and 14lbs. When the engine was run a few weeks later, at first a constant drip of oil off the timing marks, this slowed to a slow drip once warm. The gasket is sound and the problem appeared to be the hylomar had prevented the timing cover from centralizing on the crank properly. When pulley removed, the crank shaft was clearly not central, but down to the right.

After dismantling everything for the second time, I did this:-

All parts cleaned, with another new gasket and oil seal. Using hylomar again, instead of using the pulley to centralize, I used a tapered card feeler gauge / spacer, cut so the distance between the side of the crank and the lip of the seal could be measured, then pushed the cover around until the space between the seal and the crank was the same all round. With the rad. out, this was easy to do from the front. I felt I had got this spot on.

The engine was run - just a few drips at first, then once warm a steady drip, drip drip.

I thought, before I had a third go, I would ask the experts!

A few observations, while doing the above:-

The new oil seals were a good “push fit” into the back of the timing cover, no sealant was used here.

The timing cover bolts were difficult to locate in order to maintain the equal distance around the oil seal, the cover had to be wedged in place while the bolts were tightened. Could it be that the timing cover has been distorted – it did not look damaged when inspected and cleaned etc.

When I tried the new oil seal on the pulley (off the car) it was not a tight fit, could it be that the pulley is not the correct one. It looks fine and original, with the timing notch and rubber “harmonic balance” insert. Are there any similar pulleys around with slightly smaller diameter shafts?

Am I being silly and the seal will bed down and stop leaking in time?

Your help will be very much appreciated, Tony
A Glynn

Hi Tony, welcome to the warm world of this BBS, where not everyone is as serious....

2 options spring to mind re your problem;

1) the oil thrower ring behind the seal. Is it there and correct side front?

2) sump pressure. How is your engine hooked up to the evac system. Original or modified?

I rebuild my engine last year, and with a new cover and seal but old pulley with running marks it still took like 10.000 mls. before it started to become slightly incontinent. And I didn't bother to centralize it.

BTW hylomar can be dangerous in oil systems. It can form slugs on the inside (and outside, but you see and remove those) which can block oil passages. Better to use well seal or something like that.
Alex G Matla

Hi Alex, thanks for your prompt reply, in answer -

The oil thrower is in place and "F" forward.

The engine is unmodified, with a standard crankcase breather system (tube to the carbs) and a good negative pressure.

I am thinking the timing cover has been distorted in the past (accident maybe)and I will need a replacement. Where did you get your new cover from?

Next time I will not use a jointing compound to allow the cover to align with the crank properly. (also easier to dismantle!!)

Regards, Tony
A Glynn

I got mine from minispares.
I got this one (see below) which needed some mods, but the timing teeth are on top which is easier and has the flattened cannister. I did have to grind out the plate on the inside. I have a duplex chain and tensioner.

BTW, about cannisters, are yours open or clotted with dirt? Another option for sump pressure.

LJR10168

Description

Timing cover for single point injection cars only with brackets for pick up points to provide timing /ignition sensors--This has the flattened type breather cannister for clearance also. If fitting with duplex timing gears the metal indent by the oil seal will need tapping out to stop fouling on the chain. The plate on the inside should not foul but check for clearance. Always check for fan blade clearances.





Alex G Matla

Thanks for that Alex,

The breather cannister is clean and clear.
Will the new cover fit a standard 1275 midget engine, it looks a different shape, or does it bolt onto other holes on the front plate?

Regards Tony
A Glynn

Hi Tony,
Welcome here!

You have pushed the oil seal in the correct way round I presume? Sorry if this is way too obvious, but it is the sort of mistake I might make, and simply not notice!

Other than that, it seems odd that the oil seal lip should be loose on the pulley. It shouldn't be tight, but close enough so that the lip of the seal is displaced a fraction as the pulley is slid on. What is the condition of the pulley where the seal runs? - They can wear into a groove with time in which case a Speedisleeve might fix it.
http://www.skf.com/portal/skf_gb/home/products?contentId=895668

Guy
Guy

Actually you'll need to drill and tap some holes. IIRC one in the block and one in the front plate. Maybe it's easier to source an original, non tensioner one. They don't list it at minispares, although they do list the gasket.
Alex G Matla

Could be weep from the head or rocker cover gasket which drips off the timing case. Best to get everything spotless and dust with talcom powder.The source of the leak will become apparent.
F Pollock

Hi all, thanks for your comments.

The engine is clean and tidy, with the timing cover seal the correct way round!

The leak is coming from the seal for sure.

The speedi-sleeve looks like a great idea, however, looking at the removed oil seal, (it was only in place and run for about 1/2 hour) it shows signs of wear about 1mm in from the edge, around half of the diameter.

Looks like when you tighten up the bolts it pushes the cover out of line, even though its central when loose - I feel a replacement timing cover is needed - going to Beaulieu Autojumble in the morning to find one.

Presumably an old mini cover would also fit?

Regards, Tony
A Glynn

Sorry to impune your common sense with my suggestion the seal was the wrong way round!
Yes I think the mini cover fits. And has the added benefit of timing marks at the top where you can see them. You would need to just re-mark the pulley edge to match.

Guy
Guy

No problem Guy,

Are the timing marks on a mini just 180 deg. out from the midget?

Regards, Tony
A Glynn

No, it won't be 180 degrees or any exact amount as far as I am aware. Someone may know different.

You would either need to turn the engine to the tdc marker with the old cover, then fit the new cover without turning the engine, and make a new tdc notch on the pulley. Or better, fit the new cover and use a dial gauge to accurately find tdc, and then mark the pulley.
Guy

This thread was discussed between 09/09/2011 and 10/09/2011

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