Saving Old Seagulls

Mrs Sticky is your boat? Must be as any ref to another like that could be dangerous

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Hi, I obtained a new head gasket for my Super Single fromLipscombe & Hessey who make many replacement gaskets, I think they are still in buiseness, based in Windsor, 01753 864413/841545 this mwy help someone.

Well first test in open water was a fail Ran fine for about 5 mins. Sped across Falmouth harbour at a rate of knots and a grin on my face but then it died and would not restart. On inspection the gasket had failed at 3 of the waterways. Gasket was just standard gasket paper, as a more substantial gasket had already failed on a tank test.
Could it be just the gasket material at fault? what have other people used? Anybody got any ideas on why its failing, before i destroy any more, or do more damage. The waterways all seem clear, and i wouldn't have thought this system has that much water pressure anyway. If it was a bad seal, it wouldn't fail only at the waterway holes (would it?). Pondering trying a double gasket to try for a better seal and lower compression. Don't really want to start using sealing fluids/potions for a head. Any and all suggestions appreciated. I'll get there eventually.
Thanks for the tip hansom, might try them next.

Did this stop through no cooling or was it something else?

Not sure. It wasn't running for very long but it did get quite hot. I think it was the water in the cylinder that caused the stop but would overheating cause the gasket to fail at the water apertures? If it is overheating that quickly its going to be an arse to track down, being unable to run it in a tank.

Sounds as though the head has overheated at some stage and is a tad distorted. Give it a light grind...

Hugz, I guess you mean the mating surfaces ? Why would that cause it to blow at the water apertures? Surely a bad join would just go at some random point rather than specifically at those openings . I'm not an engineer, by any stretch of the imagination, so I'm not doubting your diagnosis, just wanting to fully understand what im looking at. Thanks

The head gasket is not a "paper" one, it is asbestos type silver covered, they often track from bore to a water port even if properly fitted, try to get a real replacement (see above) & use red hermetite on refitting My replacement has lasted five years of heavy use with no probs.

Lipscombe and Hessey are no longer in business Now looking around for a local marine engineer to help out with the material, if not the making of the gasket. I've had an offer of some copper sheet but not sure if it would be suitable. I don't see why not. Any experience of copper gaskets on outboards anyone ?

If both faces of the head cylinder interface are lapped perfectly flat & you have sufficient clearance between the piston & the cylinder head you could get away with not using a gasket.

Gaskets were used to save manufacturers having to get this interface to a very high finish, the gasket allows a few surface inperfections & machining marks not to affect the seal, more so on motors with low to medium compression.

I've made gaskets from copper sheet, old offset litho plates that are 6.5, 12.5 & 20 thou aluminium sheet, they all worked perfectly but must be annealed before use or reuse.

As your Anzani has a vaccumn cooling system any leaks however small will not cause water to dribble out but permit air to leak in, preventing any cooling water flow.

Aluminium pistons when very hot expand a lot more than cast iron cylinders at the same temperature, making them run very tight, not helped by the very hot lubricating oil running & burning off the bore, this could cause an overheat seizure!
You can usually see symptoms of this by skuff marks on the side of the piston usually on the exhaust port side, sometimes partially obstructing the piston ring grooves.

Remove the cylinder & check it out.

"& use red hermetite on refitting "



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Ebay item 200803265659, Triple layer composite gasket material, is the correct stuff for the head gasket.

Doesn't the Anzani head gasket have a copper bit around the cylinder.

This is one instance where I'd say don't use red hermatite, cast iron cylinder, aluminium water cooled head, both with different rates of expansion, as hermatite dries to a hard brittle material it might fracture under the different thermal expansion movement, & as it's a vaccumn powered system any cracks will let air in, dare I say that the stretchy properties of RTV might be more suitable.

Charles, my 1955 Anzani had a composite gasket from new & when this failed I replaced it with a similar one which has given no trouble. I agree that in a perfect world Hermetite is the last thing you would need but when you are dealing with 70year old corroded & pourous castings a little help is necessary!

I agree that you need all the help you can get, but any leaks in the vaccumn cooling system are a big time show stopper.