Lotus Elan

Weber head condition

PostPost by: dunclentdr » Sat Nov 26, 2016 4:33 pm

I have recently picked up an early head which has been stripped and cleaned. The cleaning has revealed pitting in the chamber surrounding the valve seats (see photos) - I am unsure whether there is any adverse consequence to this and if so how it is rectified - advice welcomed!

Thanks

David
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PostPost by: rgh0 » Sat Nov 26, 2016 10:38 pm

It looks like the head was either badly corroded after sitting unused for many years and / or was very aggressively cleaned. What do the other faces of the head look like?

The head gasket face will need a significant amount of skimming to bring it back to a clean machined finished surface. The combustion chambers don't need to be machine finished like the gasket surface but you need to remove any sharp edges.

I would measure the combustion chamber volumes and then use the work to bring them all to a common size as the opportunity to smooth them out and eliminate the worst areas of pitting.

cheers
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PostPost by: Mr.Gale » Sun Nov 27, 2016 2:56 am

It look like it has been sand or bead blasted. Nether are recommend for an aluminum head.

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PostPost by: el-saturn » Sun Nov 27, 2016 12:42 pm

i'd say corrosion to begin with (no plugs and rain) ................ then some kind of blasting: making everything nice and visible - yikes! sandy 36 4982
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PostPost by: dunclentdr » Sun Nov 27, 2016 12:48 pm

All of the valve seat areas look good and I assume that the corrosion in the chambers isn't too important as it just marginally changes capacity, I hope as per Rohan's advice that a good skim should do it...
David Rose
1963 S1 - Bourne bodied
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1965 S2
1966 S3
1969 Europa - 210bbhp by Banks
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PostPost by: Grizzly » Wed Nov 30, 2016 12:13 pm

As Above, I had a badly pitted no1 combustion chamber and all i did was gently smooth the sharp edges off but i didn't try and remove the pits. As long as the valve seats and valves aren't damaged (and Lapped in properly) it should be fine but looking at your pictures the pits in the Gasket surface needs Tigging up before refacing, i don't think there is much meat on a Lotus head so you want to remove as little as possible.

You also want to be very sure you have all the media out of the oil and water ways.
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PostPost by: gus » Thu Dec 01, 2016 1:18 pm

I would first have it checked for straightness/flatness. One of the ways I can think of for it to look this way is sitting after popping a head gasket
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PostPost by: dunclentdr » Thu Dec 01, 2016 1:59 pm

Thanks for all the advice - will take it my friendly engine builder and update on the advice, for future reference and others in a similar situation.

David
David Rose
1963 S1 - Bourne bodied
1963 S1 - Bourne bodied
1965 S2
1966 S3
1969 Europa - 210bbhp by Banks
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