Lotus Elan

5 Speed Box: Whirring in 5th after Redline oil change

PostPost by: h20hamelan » Thu Jan 02, 2020 6:00 am

Is it water, or oil leaking Jon
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PostPost by: richardcox_lotus » Thu Jan 02, 2020 7:58 am

Jon - sources of engine leaks which appear across both sides is either the timing chest top gasket or the oil pump, where it leaks and can follow the topmost seam of the sump around the engine to then drip down on the exhaust side of the sump.

I can?t remember which seals you finally changed but may be worth rechecking the oil pump as you shouldn?t need to remove the engine for that.

Let us know how you get on.

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PostPost by: 2cams70 » Thu Jan 02, 2020 9:26 am

JonB wrote:Well, I?ve done it, and the results are... disappointing.


My condolences. Regarding the engine oil leak I must say that cork gasket between the top of the timing chest and the cylinder head is a totally sh** design. You've essentially got a highly compressible material stuck between two immovable objects - the timing chest and the cylinder head. When you tighten those three 5/16" bolts between the two you're essentially bending the flanges to get compression on the gasket because being cork the gasket offers similar resistance to compression as thin air!! No wonder it fails. I tightened the three bolts on mine to the top of the recommended range (15ft/lb) but in hindsight would have only tightened to the miniumum (10ft/lb). The gasket extruded a fair bit at 15ft/lb even though clearances were checked prior to assembly. Other manufacturers (eg. Toyota twin cams) have a gasket here that is integral with the head gasket and made of the same material.
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PostPost by: JonB » Thu Jan 02, 2020 10:02 am

Well, I?ll have to try something else. Like a new gearshift with intact anti sizzle bush. On the plus side, I?m pretty sure some other noises coming from the box have abated but that?s highly subjective, of course.

When fitting the timing chest cork gasket, I attached it to the lower flange with RTV and let it go off overnight. Can?t recall whether I smeared Wellseal or RTV on the top prior to fitting the cylinder head.

The oil pump was not removed so I doubt it is a culprit, though there?s some oil dripping off the filter housing. Which is tight! I?m going to have to retreat and regroup on this one, or I will go mad.

The other issue is I am reaching the point where costs have exceeded resale value, something I swore I?d never allow to happen again after I spent over 10k on a Spitfire many years ago that was subsequently sold for 1500 quid.
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PostPost by: vincereynard » Thu Jan 02, 2020 1:52 pm

2cams70 wrote:My condolences. Regarding the engine oil leak I must say that cork gasket between the top of the timing chest and the cylinder head is a totally sh** design.


Whilst I cannot argue about the sh** design it seems to vary between engines.
Mine is "blessed" with a Burton water pump which leaves a fair sized step twixt front cover and block.
(Why??) However it does not leak (yet.)

I fitted the head bolts first and torqued then down in stages as recommended. Left over night and did them again. Only then did I torque up the 3 front fasterers. The gasket was liberally coated in Permatex (?) Aviation Gasket stuff which looks and smells exactly like thin Wellseal. (Although far more expensive.)

I'm not recommending this but it seems to have worked for me. For now!

Leaked like a duff tap before but that had been done by professionals.

I actually tried some nitrile rubber as a gasket but it squigged out worse than the cork. However I believe there is one is available from somewhere. Just needs to be firm enough. After all there should be little pressure in that area.
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PostPost by: alan.barker » Thu Jan 02, 2020 3:42 pm

Sorry to drift a little but while we're talking about the step between the top of the Block and Spacer/Front Cover.
Has anyone when fitting a Burton/Capsule Water Pump fitted one for the taller Block to the standard Block.
Then measured how much it was taller and got it machined to be exactly level with a standard Block.
So NO STEP. The taller Front Cover/Spacer could be assembled with fitted Bolts/Dowels.
Maybe OTT but more chance to stop Oil leaks.
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PostPost by: h20hamelan » Thu Jan 02, 2020 4:12 pm

My short experience of RTV and Aviation on these cork gaskets is that Aviation releases better. But the RTV may be better for reuse.
In past, I very lightly coated top of cork (as it seems to me, the oil sits on top of the cork as the cork protrudes into/past valve cover) therefore, oil sits on top of cork. And given the opportunity for oil to find its way back to the earth.
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PostPost by: JonB » Thu Jan 02, 2020 4:43 pm

h20hamelan wrote:Is it water, or oil leaking Jon


Definitely oil. Quite a bit of the stuff too. :(
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PostPost by: vincereynard » Mon Jan 06, 2020 3:44 pm

alan.barker wrote:machined to be exactly level with a standard Block.
So NO STEP.


Maybe a step in necessary as the cork will not compress to the same "thickness" as a head gasket? Have it level and the cork would be destroyed.
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PostPost by: promotor » Mon Jan 06, 2020 4:15 pm

to
vincereynard wrote:
alan.barker wrote:machined to be exactly level with a standard Block.
So NO STEP.


Maybe a step in necessary as the cork will not compress to the same "thickness" as a head gasket? Have it level and the cork would be destroyed.


You're right there - the water pump cover top face is around 0.030-0.040" below the block top in standard-ish unskimmed blocks.

If the water pump cover was level with the block I think that the timing chest part of the cylinder head would be under quite a bit of stress with a thick cork gasket (between water pump cover and head) being compressed when using a standard thickness head gasket - perhaps could cause damage to the head in extreme cases.

A thicker head gasket would reduce the issue slightly but that then affects compression ratio!
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PostPost by: alan.barker » Mon Jan 06, 2020 4:53 pm

If the Sandwich Plate and the Front Cover were dowelled it would help. Then the top and bottom of alloy can be machined flush.
As for the difference between top of Block and alloy that depends on what Gasket thickness is used between Timing Assembly and Head.
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PostPost by: JonB » Mon Jan 06, 2020 5:13 pm

I have had a look at the 1/2" bolts that secure the ends of the timing chest together. These seem to be where (most of?) the leaks are coming from. They weren't very tight so I nipped them up, then cleaned the leaked oil off the side of the casing. Maybe it will help..?
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PostPost by: vincereynard » Mon Jan 06, 2020 10:05 pm

As well as trying the nitrile gasket I did ponder on not having any.

Running a bead of suitable mastic around the joint and gentle dropping the head in place. Which would squidge the mastic out. (Apart from the gap.)

Torque head nuts but not the front 3. Leave overnight to firm up then tweak them up.
I recon it might work. I did the same with the cam cover and that worked very well.
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PostPost by: JonB » Thu Jan 09, 2020 12:53 pm

OK, I think I have some good news on the gearbox noise. Actually, on all the issues discussed in this thread.

Gearbox noise.
I bought a Cortina gearshift with an intact anti sizzle bush. Cleaned it up and swapped over the bellows circlip (missing on this one for some reason). Regreased the ball and fitted. Result? Virtually no noises in 1-4 and a very imperceptible whirr in 5th. That'll do nicely, except the bend in the gear lever itself is in the wrong place, leaving the stick leaning towards the left.

IMG_6383.jpg and
The gearbox is in neutral here.


But, at least I know what the problem is now. The anti sizzle bush is much more flexible than I thought and second gear is a little baulky - but I could always reinstate the Redline oil now I know it is not the cause of the noise.

Gearbox leaks.
I'm convinced they were caused by me overfilling the box with Redline. I just kept pumping until the filler hole overflowed. When I swapped it out for ordinary oil, I was careful to pump in the correct amount - 1.7 litres. This capacity is shown in the text of the 5 speed supplement of the Workshop Manual, not the Technical Specifications section so it's easy to miss. I went for a good run and we will see if there is any more leakage, but initial observations indicate the leak is either reduced or gone. Hard to tell as there's so much residual oil all over the box and chassis.

Engine leaks.
After today's test drive it looks as if this too is improved, but we'll see what tomorrow brings (in terms of oil on the garage floor).

I did enjoy the drive today, despite the horrid misty rain and slippery roads. It's because the noise has been masked. What a relief. Plus, POWER SLIDE off the A259 roundabout whoo hoo (only thing wet weather is good for in an Elan if you ask me). Easily controlled but great fun, and I really enjoyed hearing the very rorty intake and exhaust noise too as I was beaning it (since swapping the HT leads it's been going well)! :D
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PostPost by: vincereynard » Thu Jan 09, 2020 3:02 pm

Well done. That must be quite a relief.

Interesting about the gearbox oil cos guess what?
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