Lotus Elan

Possible engine failure

PostPost by: Rusty » Mon Sep 21, 2020 5:11 pm

Dropped the oil Friday and put a filter at the drain to catch any pieces. Some disturbing ferrous material was caught which i can't recognize. Appears to be a thrust washer of sorts, dropping the sump. There seems to be excessive crank end play so that is where I'm going. Will check all the bearings while I'm in there.
Anything else I need to look at while I'm there specific to the 105E?
First trouble I've had since I purchased the car except it had a broken inner valve spring when I bought her.
Cheers to all you Lotus Lovers out there,
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PostPost by: h20hamelan » Mon Sep 21, 2020 5:55 pm

Good you noticed
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PostPost by: gjz30075 » Mon Sep 21, 2020 11:58 pm

If the thrust washers disintegrated, make sure the crank didn't score the block.
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PostPost by: avro » Wed Sep 23, 2020 11:22 am

Excessive end float and thrust bearing debris in the sump is most likely to be the result of the crankshaft thrust bearings having been fitted backwards . I’ve seen this on a number of occasions over the years and it’s a mistake that can quite easily be made if the engine builder is not paying attention. The steel backing of the bearing then runs against the machined thrust face of the crankshaft. If this is the case then it would certainly have caused damage to the crank and possibly the cylinder block. Although oversize thrust bearings are available unfortunately the damage to the crankshaft can be extreme and beyond recovery even with a regrind to suit the largest oversize thrust bearing available.


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PostPost by: rgh0 » Wed Sep 23, 2020 12:04 pm

I use converted Datsun L16 cranks in my Elans competition engines. After machining to fit a twincam these have a larger than standard gap between the centre journal spacing for the thrust bearings. It is possible and relatively cheap to get a custom extra thickness thrust bearing made by white metalling a standard thrust bearing steel backing. Most engine shops that do old engines can do this as its required when rebuilding engines made before the invention of modern bearing shells . I use the custom bearing on the front so it does not see the clutch thrust loads which are higher than standard in my competition engines with a heavier duty clutch spring. On the rear I use a standard thrust bearing. This arrangement has worked without issue for many years in engines that see lots of extreme loads

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PostPost by: sprintsoft » Wed Sep 23, 2020 1:20 pm

Hi Rusty, any chance of seeing a pic of the "disturbing ferrous material" ?

I bet someone on here could identify it for you...:)

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PostPost by: avro » Wed Sep 23, 2020 2:34 pm

Rohan’s reply has just reminded me that many years ago Vandervell Bearings were good enough to send me a piece of sheet thrust bearing material with the heavy duty Lead Indium overlay so that l could machine some extra oversize thrust bearings for damaged crankshafts Hopefully your Crank / Thrust Bearing issue may not be too severe, if indeed that’s the problem at all. But just in case it is l have found the last remaining bearing that l had machined for a Twin Cam tucked away in the back of my bearing drawer. These are 0.060” oversize .
The steel backing will require surface grinding to give you the correct oversize so just in case you find that you might need it to save the crankshaft I’ll happily pop it in the post to you.

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