Can someone tell me where my oil leak is?

[TroonSprint]

I have spent three years rebuilding my Sprint, including a complete engine rebuild. After having driven only 40 miles the engine is out again because there is a significant oil leak which drips off the plate between engine and bell housing and falls onto the exhaust. I can't use the car without being asphyxiated.

Please look at my photos. There is no sign of oil on the cylinder head or on the area of the block above the aforementioned plate. The oil is almost certainly emanating from the engine and it has covered the plate on its engine side. So it seems to come from the top and run down - or does it? The rear crank seal was new 40 miles ago and there doesn't appear to be any leakage from it or its housing.

If you have an idea where the damned oil is getting out, I'll be your friend forever.

Mike

[joe7]

Had a rear oil leak on a brand new rebuild. Replaced pan gasket 2 or 3 times. Didn't help. Put on a NOS pan, no luck. Pulled the engine thinking a hex plug was loose, again no luck. With the help of Barry at PHP found out the spring around the crank seal wasn't tied together causing an oil leak anytime I was running over 3,000 rpm. Easy fix but tough to find.

[delle]

Hello Mike,
it looks like the rear seal of the crank is incontinent.

Regards from Germany

Delle

[Craven]

Head to block oil return trumpet at head end.

[Spyder fan]

I vote for crank rear oil seal

[Hawksfield]

Hi

Something I learnt many years ago regarding lip seals, I always remove the spring and make sure its screwed together properly I even have some spares that suit the TC seals just in case
Also make sure you check the crank seal surface is ok.
Good luck on the search

[pharriso]

Oil is being flung everywhere so it's "hitting" the back of the flywheel & being flung... therefore it's got to be either the real seal or the sump gasket & seal...

What a giant pain, feel for you

Update: Why is that Oil gallery plug so far out???

[TroonSprint]

OK, thanks everyone. It definitely isn't the head to block oil drain - that's as clean as a whistle. I'm going to get the clutch and flywheel off tomorrow, but strange to say, the back of the flywheel seems clean - no sign of oil contamination. Also there's no oil on my finger when I wipe it round the crank seal housing. There is oil lying on the sump flange and the cork gasket looks squashed out, so maybe that's it, but then how does it get up so high? And has that lying oil simply dripped from somewhere else?

Yeah, the oil gallery plug is far out isn't it. It's a long time since I screwed it in, but I'm guessing that was as far as it would go. I'll check it. The other blocked hole is visible in my first picture below the threaded hole - what is that for? It is blocked off with a plug of some kind and is good and oily, but then it is in the line of fire, so to speak. Is there an oil gallery behind it?

Phil is dead right - it's a giant pain. I had hoped to be enjoying the car in the summer weather. Huh!

Mike

[rgh0]

The plug is probably a BSP plug rather than NPT - they screw in and normally seal OK but due to the slightly different thread dont go in the correct distance

As for the leak I would guess the rear crank seal or the rear sump gasket

cheers
Rohan

[wotsisname]

If you continue to see the problem, is there anyway you can mount a gopro and see what's going on ?

[mbell]

Could you connect a pump of some sort to the oil pressure gauge take off and pressurise the oil system?

Probably won't show the leak but might help rule a few possibilities out.

[TroonSprint]

I've got the flywheel off and sad to say there is nothing obvious. I will change the sump gaskets and corks, and the rear crank seal and housing gasket. I will also remove that threaded plug and see if that could be it.

What is a gopro? A term I've never heard.

Here is my first picture again with the only other possibility circled in green. What is this plug and how is it inserted? Could this be the problem? There is oil in the plug recess, but that could be secondary to another leak.

Keep the comments coming.
Mike

[wotsisname]

Mike.
Gopro. A small video camera..there are other makes available... [this comment was obviously for the situation where you reinstall the engine and still have the issue]

http://shop.gopro.com/EMEA/cameras/?gcl ... oC6kfw_wcB

[wotsisname]

daft question!

it's not oil poured down the back of the engine during oil filling/ out of the cam cover and the only reason the back of the head is dry is because you have driven it.... ?

..told you it was daft !

[TroonSprint]

I thought it ought to be coming from the cam cover, but all external surfaces on the cover and head are completely dry and oil free. If only it was that simple. I still want to know what that small inserted plug is for.

Mike