Oil Leak !

[buzzer]

I have a major engine oil leak, drip every 15sec or so and maybe more when driving. from the rear of the block
I thought this was the sump so it's been off twice and still no better. So I have now taken off the gearbox.
Oil is all over the rear block face and under the spacing plate, it is also in the bell housing but the rear of the flywheel is clean. externally to the bell housing it hits the Right hand side more than the left so covers the RH driveshaft and nothing on the LH driveshaft.
Oil is coming out of either
sump (been off twice and both times the seal looked look ok and I couldn't find signs of seepage through the gasket)
rear oil seal (no sign of oil on the rear of flywheel)
Rear oil seal housing, this does look ok.
Block top right oil way plug. (hmm could be)
Block left hand oil way plug (threaded) this looked ok.
I plan to try and start the engine and see where it leaks when I can mount the starter rigidly.

Any thoughts on this guys?

[jbcollier]

You don't need to start the engine.  Just spin it up to get oil pressure.  A leak that has a drip every 15 seconds should show up pretty quick.

Is the cylinder head dry?

The #1 source for an oil leak, and by a huge margin, is the valve cover gasket.  I had a drip off the sump.  Like you my flywheel was dry (whew).  I had the sump off three times.  It was the valve cover.  Didn't look like much.  No oil on the bell housing.  But that's what it was.  I ended up having a custom valve cover gasket made.  All dry now.

[buzzer]

Top of the engine and cylinder head is dry. Been all round that lot first. The issue I have on spinning the engine up is the the starter is not mounted rigidly enough. I hope to rig something up in the next day or 2.  The leak is contained within the rear of the engine within the bell housing area.

[jbcollier]

We used to spin up MGB and Triumph engines on the bench all the time.  Great way to make sure you finally got the damn oil leak solved.  Let us know what you find.

[Gmg31]

Are you sure its the engine?  Mine leaks out of the bottom of the bell housing but its my gearbox main shaft oil seal. The smell of the oil is very different.   

[buzzer]

The main leak is engine oil as you say they smell different. I do have a separate leak from the gearbox output seal which was caused by the seal not being pushed back far enough into the bearing locating ring.

[buzzer]

Well I found the leak. I did manage to spin up the engine without the plugs but no sign of any leak. That at least proved that the high pressure plugs were ok. So stripped off the sump pan AGAIN 🤪🤪🤪 no sign of a compromised seal. Then took off the rear seal cover, signs of leakage and a distorted housing, I didn’t check this when I originally assembled the engine.

[BDA]

Glad you found it, buzzer!

I hope your fix is quick and successful!