Lotus Elan

Oil seal variation

PostPost by: david.g.chapman » Thu Nov 02, 2023 7:10 pm

I ordered a bottom end gasket set for my twin cam, but have noticed that the large oil seal for the rear of the crankshaft in the set is different to a couple of older oil seals I have in the garage. There are some minor changes, but the main one is the spiral marks on the seal, presumably to deflect oil away from the sealing lip.

On the new seal, these marks go right up to the seal lip, so that if you run your finger around the lip you can feel the spiral marks. On the older seals I have, the lip is smooth and the spiral marks are shorter. Also, there is lettering on the old seals but the new seals are blank.

Unless anyone knows anything about this, I think I'll be using the older seal. I done think its age of 8 years or so is a big issue.

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PostPost by: Hawksfield » Thu Nov 02, 2023 10:26 pm

David
Who supplied it?. Is branded.
Can you supply an image.
This will help others to help you.
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PostPost by: david.g.chapman » Fri Nov 03, 2023 2:58 pm

No it's not branded. I'm definitely using the older seal. It's more supple and those spiral ridges on the new seal's lip are ringing alarm bells. It's different to all other seals I've had if you look closely, and it's where it matters.
I'll try and capture it on a photo....

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PostPost by: david.g.chapman » Fri Nov 03, 2023 3:32 pm

Hopefully you can see the new seal (lighter colour) above the seal I took out (stained by engine oil). if you look closely you can see that the spiral ridges on the new suspect seal give a serrated appearance to the seal lip, which you can feel with the finger. The older seal has a smooth lip.

Unless someone can dive in and say this serrated feature is desirable, I would avoid fitting any seal that looks like this.....

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PostPost by: 2cams70 » Sat Nov 04, 2023 12:34 am

I'd suggest that the new seal is not a problem - at least insofar as the spiral grooves are concerned. The purpose of the spiral grooves is to help direct any oil that leaks outward back inward toward the seal and to ensure that the seal lip always floats on a film of oil rather than there being direct seal to shaft contact. Extending the grooves further inwards may have been done as a preventative measure to further assist the seal during the initial bed in process by improving lubrication between the seal and shaft. True it may leak a little more just during the initial bed in process but it will only be for a very short period until the peaks of the spiral grooves wear down.

With the original seal there is a risk that if the seal lips are not properly lubricated during initial assembly that there will be direct rubber to metal contact upon start up and the seal surfaces will be damaged. This risk is far less with the later design.

Whatever the seal it's always very important to lubricate the lips and shaft before assembly. I always smear the shaft with the lubricant that the seal will be sealing whilst in service and I smear the area between the inner and outer lips of the seal with some lithium grease.

Note I often read people saying that you need to smear the outer casing of the seal where it fits into the housing with sealant. Don't waste your time with that rubbish and you could in fact be doing more harm than good. If it's a rubber encased seal just smear a little of the lubricant the seal will be sealing in service on the outside surface of the seal to help ease it into the bore is all that is required.
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PostPost by: 512BB » Sat Nov 04, 2023 9:46 am

'Unless someone can dive in and say this serrated feature is desirable'

I think it is highly unlikely that a manufacturer of seals, albeit a no name seal, or was it just a no number seal, would add serations, or indeed anything to the design of the seal, just to make it look pretty. They must have done it for a reason, and I too would have no hesitation in using it.

'Whatever the seal it's always very important to lubricate the lips and shaft before assembly. I always smear the shaft with the lubricant that the seal will be sealing whilst in service'

By this, I take it that the writer means engine oil. I used to do that, but no longer. I now lubricate with a rubber friendly grease, for this reason. If I am building an engine, maybe for myself, maybe for a client, whatever, you cannot be certain when that engine will be run. It maybe years in the future, even if that was not the intention. If you use engine oil to lubricate oil seals, by the time the engine is run, there maybe precious little oil left around the seal, and damage may result on start up. So as I say, I now lubricate seals with a suitable grease that will remain in place until the engine is run up.

'Note I often read people saying that you need to smear the outer casing of the seal where it fits into the housing with sealant. Don't waste your time with that rubbish and you could in fact be doing more harm than good. If it's a rubber encased seal just smear a little of the lubricant the seal will be sealing in service on the outside surface of the seal to help ease it into the bore is all that is required.'

I agree in the main, but there is nothing wrong with using a smear of Wellseal on the outside of the seal to help ease the seal into position, THEN HEATING THE ALI HOUSING, and pressing the seal home. I heat the housing for both removal and insertion of a seal, makes both tasks so much easier............try it.

I once saw a U tube video where a seal was pressed into either a TC front cover or rear oil seal carrier, cannot remember which, using just the builders fingers, after warming the housing. That would be to loose a fit for me.

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PostPost by: 2cams70 » Sat Nov 04, 2023 1:08 pm

Leslie - I think you need to look at the thread concerning roller timing chains that use split rollers and chip in on that debate too!!
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PostPost by: rgh0 » Sat Nov 04, 2023 11:55 pm

FYi

A bit of information on oil seal styles

https://sealingaustralia.com.au/rotary-shaft-seals/
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PostPost by: david.g.chapman » Sun Nov 05, 2023 1:49 pm

Thanks everyone. Rohan's link information has convinced me to fit the new seal with ridged lips.

I usually use an old seal to push the new seal in. Just position a plate over it all, stick it in a vice and carefully squeeze.....

Cheers,

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