Lotus Elan

Remove Weber carbs before removing head?

PostPost by: skelteanema » Fri Dec 01, 2023 1:40 am

Hi all,
I need to replace the head gasket on my engine (Elan S3 DHC) as it is weeping a bit of oil. It is not critical at the moment and I still use the car without problem, but I want to get it sorted before is fails catastrophically.

I recently changed the water pump and should have used a Ajusa head gasket rather than the copper type which was supplied in the kit I ordered. The water pump replacement was an engine out job that went quite smoothly considering it was the first time on the Elan.

I am going to change the gasket with the engine in the car.

The one question I have is whether I should/need to remove the Weber carbs before removing the head? Most of the books I have describe an engine out job rather than just a head gasket change.

Any other tips appreciated.
Skittle. 1967 Elan S3 DHC
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PostPost by: Billmack » Fri Dec 01, 2023 3:54 am

Seems to me I have removed the head complete with carbs. Exhaust has to come off for sure
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PostPost by: 2cams70 » Fri Dec 01, 2023 8:33 am

A copper/composite head gasket should work fine. It's what Lotus used originally. Did you check the head bolt torques? Are you sure it is the head gasket that is leaking oil and not for example the head to timing cover cork gasket?
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PostPost by: bitsobrits » Fri Dec 01, 2023 3:17 pm

More than once I've quelled a minor TC head gasket leak by retorquing the head.

Also worth checking for head bolt washer recession into the cylinder head preventing a proper torque loading. Some TC heads are soft, perhaps from being repeatedly overheated over the decades.
Steve

Elan S1 1963-Bourne bodied
Elan S3 1967 FHC pre airflow

Formerly:
Elan S1 1964
Elan S3 1966 FHC pre airflow
Elan S3 1967 FHC airflow
Elan S4 1969 FHC
Europa S2 1970
Esprit S2 1979
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PostPost by: alanr » Fri Dec 01, 2023 4:08 pm

If the the recent fitment of a Copper head gasket hasn't sealed then and than an Ajusa gasket won't seal either. You obviously have a problem and, assuming the head is torqued down correctly, the most likely outcome will be that you will need to have the cylinder head skimmed.

Alan.
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PostPost by: skelteanema » Fri Dec 01, 2023 9:53 pm

Thanks for the replies. I am certain it is from the head gasket and not the front cork gasket. It is a very slow weep around cylinder2 to 3 mainly on the exhaust side. I have retorqued the head and it did improve the situation but not completely. I backed off the bolts and retorqed in the correct sequence. They did not required much additional rotation from their original positions so I think the torque loading was pretty good.

I noted the following thread:

viewtopic.php?f=39&t=44621

These indicate that at least a couple of posters have had problems sealing the copper-type head gaskets and when replaced with Ajusa the issues were solved.

I will look at getting the head skimmed once I have it removed from the engine.
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PostPost by: rgh0 » Fri Dec 01, 2023 11:53 pm

I always remove the carbs as it makes removing and refitting the head and timing the cams much easier without them. also get yourself an extra long ring spanner so you can rotate the engine more easily for setting up the timing

cheers
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PostPost by: 2cams70 » Sat Dec 02, 2023 3:00 am

I don’t think there are any oil galleries on the left hand side of the block. Did you check the cam cover gasket and the oil gallery plugs on that side of the head?
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PostPost by: skelteanema » Sat Dec 02, 2023 4:41 am

It is not the oil gallery plugs on the head they are dry, and it is not the cam cover gasket as it is dry below the gasket. I will investigate further before pulling the head.
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PostPost by: JonB » Sat Dec 02, 2023 9:24 am

When you fitted the copper head gasket, did you smear Wellseal on it (both sides)?
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PostPost by: Craven » Sat Dec 02, 2023 12:19 pm

Definitely remove the carbs, the flex rubber drain from the head to the block needs careful attention when refitting, fit new if you can. This is a leak area if not done well trying to get it fitted with the carbs in place would be difficult. Don’t forget the underside bolt through the front cover into the head. Original Payen copper gasket works just fine no need for any sealant as this is already on the gasket, softens on the first run up to temperature.
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