Annoying oil drips

[mole42]

I am anjoying using my Stag after the rebuild and I'm gradually sorting out a few little niggles but one thing that's annoying and persistent is a couple of oil drips from the rear of the engine. They form two little marks on the floor under the lowest points of the rear engine plate. I thought it was the new rear cam cover seals but I checked and made sure they were good with Wellseal. The rear crank oil seal is new.

Any ideas?

[jbuckl]

The flywheel / torque plate bolts go into through holes in the crankshaft.

means that unless the threads are sealed, a small amount of oil can pass down the threads and seep out.

issue is often more pronounced on autos due to face clamping differences.

i omitted to seal these up last year on a stag.

the leak isn’t awful

however it needs a transmission out to fix

[FrenchStag]

Expect all these were renewed when engine done but worth checking filler cap gasket, and the felt dipstick gasket just in case. And the oil transfer cover gasket & oil pump gasket (although i think they would probably drip off the oil filter / sump).

[DJT]

I know you partially stripped your engine, but did you check the block decks for flatness? I didn't when I did the heads in 2014 and not long after noticed similar drips to yours. Checked the usual suspects, as you have, but failed to stop them. Early in 2022 I had a water leak from the rear of the LH cylinder head gasket - proven by pressure testing the system with a bicycle pump. Took the heads off again and decided to go further as the bores were glazed and a straight edge showed that the rear end of the LH side of the block was not level. Had the bores lightly honed and the block and heads given a minimal skim. Rebuilt with BGF thick head gaskets and not a drop or drip in 10,000 miles. I think Neil flying farmer has mentioned this problem before.

[Lingen]

Mole.
If all else fails, do what I have done and put some old carpet on the garage floor, then you won't see it. .

[jbuckl]

I once built my stag engine up and it was dry.
Amazing and also disconcerting.

Soon after a few other things needed attention.

Subsequent work put it back into normal slightly leaky and comfortable triumph territory again

Currently the worst oil leak is from the zf transmission!!!!

[Philip Wardle]

Whilst we were finishing some other jobs my ZF was installed in the car for some time before we filled it. As soon as we did the whole lot drained onto the floor in a couple of days, it turned out that the seal on the extension was mangled at both bottom corners - no way was it ever going to be leakproof in that condition. Wasn't me guv, honest - that's how it was delivered to me. No oil leaks now, from anywhere - not a drop.

IMG_4083.jpg

[Goldstar]

I’m suspicious of a stag that has no leaks. Usually means it’s got no fluid in it

[mole42]

I know you partially stripped your engine, but did you check the block decks for flatness?

Yes, having read about Neil's discovery I checked mine with a straightedge and feeler gauges, I didn't find anything to be worried about.

As soon as I have a spare hour or two I'll get under and see if I can find where the leak is. Meantime I'll just keep driving (4,500 miles since the rebuild so far!) and topping up the sump.

[mole42]

The source of the oil leak is found - the overdrive stopped working so I checked the gearbox oil level - needed 1..5 litres to top up. Now, where is it leaking from? Must be the front oil seal, the four screws that hold it in place or the layshaft cover plate. Bugger, that means I'll have to pull the gearbox again.

[jbuckl]

So gear oil then, not engine?

[mole42]

So gear oil then, not engine?

Yes. Engine oil wasn't dropping much anyway, at least if I refrained from using above 4,000rpm.

[richardthestag]

I use engine oil in the manual stag gearbox. Runs sweetly enough and smells less fishy than EP

That is a bit of a swine Richard, but at least you identified root cause. May need to take a careful look at clutch friction plate while it is apart as may be contaminated by oil working it's way down the gearbox input shaft..

[mole42]

That is a bit of a swine Richard, but at least you identified root cause. May need to take a careful look at clutch friction plate while it is apart as may be contaminated by oil working it's way down the gearbox input shaft..

I hope it's not contaminated - it's a new B&B clutch and I suspect that the leak is from the layshaft cover screws. I remember using new Locwel screws and new copper washers on the front nose cover but I don't remember whether I used the same for the layshaft cover plate. As soon as I have time I'll slide the gearbox out and find the real culprit. I'll order a new oil seal just in case - is there a double lip one available anywhere? I note that Chris Witor offers a leather lip seal - has anyone tried that on the gearbox input shaft?