Spark plugs

[administrator]

UMB 386 was originally fitted to L431, a 1936 2 seater DHC.  It suggests your engine is a pre-war block with a post-war cylinder head.

[mmouss]

Here it is Robin, so, post war isn't it?

[administrator]

That is a post-war block with the front engine mounts at the side, so it shouldn't be stamped 386.  Perhaps 1386 - probably from a 2 Litre saloon?

[Robin A Woolmer]

As has been said by the Administrator, it is a Post War engine, the water jacket looks fairly good but the picture does not give enough definition, if you are going to remove the head studs be very careful as they can be weakened at the junction of the head & block due to corrosion of the steel stud , effectively making a notch where they often shear!
Unfortunately the studs become tight due to them corroding down the stud drilling!
As you have a 16/80 it should have a Cats Paw block. Unfortunately these are very difficult to find & often very corroded!     

[mmouss]

Yes Robin, the water jacket is in very good condition and I do not think I will have to remove the head studs as the top face seems correct.
Even if it is not original, I will keep this block and fit it with new liners & pistons.

I checked and cleaned the cylinder head and noticed the ports castings were very rough from new, so I spent some time smoothing and adjusting them with the manifolds.
Also noticed the gas holes in the intake gaskets between manifolds and head were protruding 2 or 3 mm all round into the ports, which seems far from optimum in terms of efficiency!!!
 

[Robin A Woolmer]

You will clearly have improved performance when it is reassembled, hope all will go well.

Robin

[mmouss]

Hope so Robin, but still a lot of work to do in rebuilding it!