Lotus Elan

Sudden oil leak

PostPost by: Mick6186 » Mon Oct 15, 2018 4:57 pm

I am nearing the completion of recommissioning my +2 130/5. The engine ( a 1700 tall block) was built in 1990 and since then has only done about 500 miles by the previous owner (my brother). I stripped, checked and rebuilt the engine with all new gaskets. The engine was running well, albeit mostly idling in my garage occassionally.
Today I ran it up to the point that the cooling fan operated, with the oil pressure at idle being 30psi on the gauge. At this point I heard an ominous dripping and looking underneath the car there was a good impersonation of the Torrey Canyon oil spill!!
The oil appears to be coming from the area near the head to block drain tube, but I am pretty sure that item is not leaking.
Does anyone have any idea of the cause? I am about to remove the head as I can only think that there must be a pressure leak from one of the head to block oil ways but not sure if there is a pressure fed oilway in the rear carbside of the head.
Thanks for any advice,
Mick
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PostPost by: 512BB » Mon Oct 15, 2018 6:06 pm

Could it possibly be the welsh, or should that be welch plug that has dropped out of the back of the head. It is located directly behind the rubber block to head tube. These should always be removed when rebuilding a head for proper cleaning and if the head is being skimmed. Have a look with a small mirror Mick, or you might be able to feel with your fingers if it is still there or not.

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PostPost by: Grizzly » Mon Oct 15, 2018 6:14 pm

If i was you i'd invest in a cheap ebay Endoscope and have a good look round that area, they can be bought for peanuts and most connect to your phone or laptop so you get at least a 720p image..
Chris
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PostPost by: Bigbaldybloke » Tue Oct 16, 2018 12:24 am

Bought my endoscope from Aldi, basic but works fine, about ?20 if they have them still.
Change is inevitable, except from a vending machine!
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PostPost by: Mick6186 » Tue Oct 16, 2018 6:46 pm

Thanks for the replies. I have explained in the thread ' What did you do to your Lotus today' that the problem was a split drain tube. I was 'sure' it was not leaking but there was oil everywhere and the split was at the back adjacent to the block and the only part I couldn't feel.
I am going to attempt to replace the tube without removing the head!!
Mick
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PostPost by: Mick6186 » Thu Oct 18, 2018 4:01 pm

Following up from my oil leak problem.
The engine is a 1700 tall block so the gap between the block and the head for the drain tube is approximately 6mm bigger than standard. The extra gap is reduced by a piece of fabricated tube pressed into the block drain hole.
I dug out the old drain tube and found it was slightly shorter than the split tube, but perfectly serviceable. I only changed it during the rebuild because I had purchased a complete set of gaskets and seals.
It appeared that the metal tube in the block had possibly cut into the rubber and started a split, which grew to a huge tear.
I believe when the engine was originally built the metal tube was made to length by measuring the original, shorter drain tube.
Has anyone found that new oil drain tubes are longer than original equipment?
Mick
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