Can someone tell me where my oil leak is?

[Chancer]

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

Its digging deep in the memory banks but I think I once had exactly the same problem, quite possibly with a brand new block, I have vague recollections that it was a plug in an o?l gallery at that position, possibly the rear of the X/flow camshaft and I think the plug was a ball bearing hammered home.

sorry to be so vague but the picture and description gave me a sense of d?j? vu.

I think my leak was minor and covered all the area of the plate by capillary action and then just dripped a little like yours, leaks onto the rear of the flywheel always leave a sticky dusty trace.

Look a bit deeper at this plug, use a loupe if need be, I think you are on the right track.

[Craven]

Hi,
Just had a quick look at a block, the small plug seems to be into the WATER jacket. It?s in line with the old push rod holes but I don?t think is in any oil way. Really difficult to see.
I still think the oil has come from above, Wotsisname, not a daft question at all.
FWIW
Ron.

[types26/36]

lotus-twincam-f39/oil-gallery-plug-removal-t29839.html#p198425

[Craven]

Hi,
Looking again at the back of the block, the crank oil seal carrier also returns any oil that may pass the jack shaft rear bearing. May be the cover/carrier has a poor seal to the block.
Ron.

[promotor]

That rear plug is like your appendix, an evolutionary reminder of days gone past! It is no longer needed when used in a Twincam as it's a remnant from the pre crossflow blocks using pushrods - the plug blocks a drilled gallery that allows oil to drain and flow between the pushrods and tappets to keep thigs lubricated. The oil in there isn't under high pressure as it isn't part of the pressure fed oil system but is under crankcase pressure so they can leak.

To remove it (if you think it is the problem) you need to make a small hole through it (preferably with a punch and not a drill as that way you shouldn't get much - if any - metal swarf to deal with), then screw a tight fitting self tapping screw in to it with a small washer (hole in the washer to be smaller than the screw head) under the head. You can then use two screwdrivers/levers from opposite sides of the screw head to lever it out. If you don't put the washer under the head the levers tend to slip out easily.

If it's a ball bearing plugging the hole and not a plug then you've got little chance of getting it out (if done it before by welding a nut to the ball bearing but it took several - probably 10!! - attempts to get it out. If a ball bearing just cover it with some really good sealer.

[StressCraxx]

The "plug" looks like the bearing ball that is in all kent blocks. Its part of the oil pressure galley that is drilled on the right side of the block and supplies the cross drilled line between cyls 2 and 3 to the main bearing galley. Highly doubtful its leaking.

If you want to find your oil leak without tearing it all apart, make up a low pressure air connection to the dipstick tube. Plug the vent fitting at the rear of the head behind the intake runner. Fill a spray bottle up with soapy water. Apply 1 PSIG air pressure (no more! You don't want to blow out your rear or front main seals) to the dipstick tube.

Spray the soapy water over all the joints on the engine. Any leaking joint will start bubbling away.

Good luck.

[billwill]

That plug (with the green ring marker) probably covers a hole where a drill was used on the block to create the oil gallery.


See:
lotus-twincam-f39/oil-gallery-plug-removal-t29839.html#p198335

And this picture from the Workshop Manual.

[rgh0]

There are two plugs in the back of a block.

The upper one circled in green is a plug for a drilling that goes through the pushrod holes to drain excess oil from above the followers in the original push rod configuration. This is not under pressure and is rarely a source of leaks. it is either a plug like in the photo or a ball bearing in some later engines

The lower one is NPT threaded and seals the end of the pressure gallery on the left side of the block. In the earlier photo this one has the plug standing out of the block about 1/4 of an inch. This is normally the sign of an BSP plug being used as it will thread in part way but not fully like the correct NPT plug does. This could be the source of your leak.

cheers
Rohan

[promotor]

Just to clarify my post earlier I made it sound like the plug isn't needed - it is still needed as oil can still escape. It is the drilling itself that isn't really needed in a twincam as the pushrod holes themselves allow oil to drain from the head. You can buy the core plugs on ebay - I think they are 10mm ones (don't know if you can buy imperial ones anymore). So although I mentioned removing (but not replacing it) it does obviously need replacing!
Sorry for any confusion!
It's better to fit a plug rather than a ball bearing as the plugs are much easier to remove if needed in future.

[TroonSprint]

Thanks Rohan. I am thinking that the projecting screw plug is the culprit, especially as it will be under full pump pressure, not just splash. I bought the plug from QED Motorsport and would have expected them to supply the correct one. But, when I look on Burton Power's catalogue they mention that the plug is 1/4" NPTF, so I will buy that one.

Is it worth the extra cash to buy the genuine Ford double lip crank oil seal? (http://www.burtonpower.com/parts-by-fitment-type/parts-by-engine-ford/ford-lotus-twin-cam-8v/oil-seal-crankshaft-rear-double-lip-type-fp709a.html). I don't want to have to do this again!

Mike

[Chancer]

I have no memory of it but I reckon fitting the wrong plug is what I did when building the new block, I would have thought it was BSP and always had them kicking around, its only on this forum I learnt of the NPTF.

I probably just used a pipe sealer to stop the leak.

The one thing that I do recall is that the o?l that leaked out was completely clean like new o?l which is always the sign of a microscopic leak which effectively filters out the particles, as it was the main pressure gallery it alls seems to fit into place, I just wish that I could recall but at the time I certainly didnt realise I had used the wrong thread and would have fixed it (bodged more like) with sealant.

Clean o?l only on the contact area of the plate and dripping from the bottom is in my opinion undoubtedly from that o?l pressure gallery plug, I take my hat off to the person that suggested it.

[StressCraxx]

Changing the plug may stop the leak, but it's all the same oil. I'd recommend a pressure test just to be sure.

[TroonSprint]

Unfortunately I had already removed the sump pan before you mentioned the pressure test. But thanks for the suggestion. I would have tried it if I had been able to.

Has anyone any thoughts on the twin lip crank seal I mentioned in my last post?

Mike

[rgh0]

Has anyone any thoughts on the twin lip crank seal I mentioned in my last post?

Mike

The original ones were a reddish brown rubber and I have always used these.

cheers
Rohan

[promotor]

Has anyone any thoughts on the twin lip crank seal I mentioned in my last post?

Mike

The double lip seals have one lip as the oil seal and one lip as a dirt seal - so in effect aren't a "belt and braces" oil seal to give you twice the chance of keeping the oil in. Once oil is past the seal it will drip out. However, the dirt stoppage helps prolong the life of the seal as there are less micro particles to abrade the seal.

Having said that you can't really get better than genuine Ford parts which is what I think that seal is. The material is much softer than most of the seals you see around now - I removed a genuine Ford double lip crank seal from an engine today and it is still amazingly supple.