Lotus Elan

Front cover oil leaks

PostPost by: jono » Thu May 18, 2017 3:24 pm

I've got a multitude of oil leaks from my front cover and gearbox which have been bugging me for ages.

The engine has only done 10k miles sinse a complete rebuild and otherwise goes very well indeed.

I'm going to pull the engine to deal with these leaks and intend to remove the front cover and then meticulously re fit it taking care to seal it properly. One of the main culprits is the horrid cork timing case gasket which has extruded.

I have one question - is it possible to do this without removing the cylinder head? I don't want to do that because it took tow attempts using different gaskets to achieve a seal last time (eventually using an Ajusa gasket) and I don't want to disturb it if I don't have to.

I would welcome any comments or tips on doing this. If it's a complete non starter that's fine, I'll bite the bullet.

And is there a better timing gasket that the crap cork one?

The water pump is perfect but should I replace that as a matter of course at this point?

Cheers

Jon
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PostPost by: billwill » Thu May 18, 2017 4:49 pm

You can't get the front cover off, with the head on, without lowering the sump, so then you have the problem of the sump gaskets. :?

If your cork gaskets are extruding, you are doing the bolts up too tight.

With the head on you will need to slice a cork gasket to fit on top of the front case, and you will need a bit of extra silicone in the top back corners to fill in any slit in the cork gasket.
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PostPost by: MarkDa » Thu May 18, 2017 7:39 pm

Have to agree about head removal being essential to get the room to work if you want a good seal
Again the cork gasket doesn't need a lot of load to work provided it is loaded evenly.
If it's distorting then there's either mismatch in head and cork gasket thicknesses or the top of head and timing case.
Start again from scratch checking for a good match as above. RTV both sides of the gasket should ensure a good seal.
If the full rebuild 10k ago included a new water pump them leave it.
If not, with the time and cost commitment already made taking the timing case off it would seem sensible to replace it.
Hope you have more success this time.
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PostPost by: Hawksfield » Thu May 18, 2017 8:11 pm

Hi Jono

I suggest you research this topic as there is a huge amount of good advice on the rebuild of the twin cam available on this forum.
Read up on it first before you tackle it, as it can be built free from leaks with the standard gaskets



Good luck
Regards

John

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PostPost by: rgh0 » Fri May 19, 2017 11:24 am

If the major issue is the cork front cover gasket squeezing out then you need to get a suitable front cover top gasket thickness and you really need to remove the head. The aim should be to have a top front cover cork gasket that is compressed approximately 30% when the head is fitted. and torqued down. Different thicknesses are available to achieve this

While possible to do without removing the head it is extremely hard to get the needed compression on the top gasket on the front cover while centering the cover on the front crank seal and getting it all oil tight. If yoru doing this to stop leaks then you really need to take the head off unfortunately.

cheers
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PostPost by: jono » Fri May 19, 2017 12:32 pm

Thanks Rohan,

What you say is exactly what was at the back of my mind in asking this question.

I'll take the head off.

Thanks for all the helpful comments.

I took what I though was great care building this engine - then engine is great but the oil leaks are a pain.

Cheers

Jon
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PostPost by: englishmaninwales » Fri May 19, 2017 7:34 pm

Check that the backplate and front timing chest cover are not distorted, otherwise you will never get the timing chest oil tight.
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PostPost by: el-saturn » Fri May 19, 2017 7:48 pm

i reckon many of us have gone apeshit while trying to fit just the sump with the engine in: those front seals, regardless whether cork or the modern ones (burton ef) : the rear is a real mutha...once finished, the front seal moves everywhere and you can yell STAY (like to a dog) but it dont stay!!!! and drives ya ape............ sandy
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PostPost by: gjz30075 » Fri May 19, 2017 9:55 pm

Don't discount high internal pressure causing the leaks. I've resealed my engine a couple of times in the
last 7k miles or so. Once I fitted a breather tube to the cam cover, all leaks subsided. I can even take
the oil filler cap off and watch the cam go around and not get splashes with oil.

This said, I realize I'm fixiing symptoms, not the real problem, if one exists. Engine runs great and a
leakdown test shows 15% leakdown, across the board. Even now, there is no residue or oil in the
catch can I have attached to the breather.
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