Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Cylinder head crack

This is something that has been known about for some time but I cannot think I have seen anything on here before. Something to check if you get to remove your M3W X-Wedge cylinder head. They have been known to crack between the valves, as this one has in the photo. No signs of it before the head was removed, it all ran perfectly. This particular engine had only done 16,000 miles and both heads had cracks. The crack extended into the exhaust valve seat. Unless you have a reason to remove the head you will probably never know, ignorance is bliss! I am old that there have been some cases of the valve seat coming out....not ideal!

If you find the head cracked then Phil Bleazey certainly has exchange heads that have been repaired and upgraded with new seat inserts. They come in a vapour blasted finish, so will require polishing, if you have a polished engine. I expect that M3W Services also have a similar scheme.

The crack has no impact on the proper functioning of the engine. All cylinder heads crack between the two valve seats, more or less. On my 121cub engine, after engine overhaul, I noticed that an imperceptible crack only appeared after cleaning and polishing between the intake and exhaust ducts, which does not interfere with its proper functioning. After a certain mileage, it is good to rectify the valve seats as well as the valves which tend to deform and to do a manual lapping.
On cylinder heads with large valves this thing does not happen because after fitting the intake seat the cylinder head is machined again for the exhaust seat which ends up embedded in part of the intake seat.

I am curios where you are able to get head gaskets? Asking for a friend

MMC have had head gaskets remade. They should be available direct or via a dealer such as Krazy Horse.

Phil Bleazey also has gasket sets available

good to know, as mine is burning copious amounts of oil. I may need to be pulling the heads off.