Lads and ladies, I'm in way over my head!

My mini is running a morris 1500 oh motor and gearbox... or it used to be running. Last year after having it on the road for only a few months the rebuilt motor dropped a valve and smashed a piston to pieces and brought that era to an end.

We got the motor rebuilt with bigger piston and rings again and put a spare head on the motor. Since then (December 2016) it hasn't run right once! It has had constant misfires that we haven't been able to easily diagnose until recently.

We found that the custom intake manifold doesn't seem to be sealing to the the head properly and there is constant vacuum leaks. We've redone the custom gasket, had the intake manifold mounting face machined flat (it was pretty bad), put all new gaskets through the carbies (twin webers) including new soft mount gaskets between them and the manifold.

Today we tested it again and the miss is still well and truly there, and when we spray accelarant near the intake manifold the car nearly stalls, apparently not specific to any certain area of the manifold.

What are the chances that the back of the spare head we are using is warped? Because up until the motor blew up last year it was running perfectly fine with the exact same intake / exhaust/ ignition setup that it has now.

Or is there a certain type of gasket paper we can use to make the intake manifold gasket that will "squish up" more around the ports and stop the leaks?

Any and all help is appreciated, as I'm pushing to get this heap back on the road for hay!

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normally revs would increase when you spray stuff around the manifold, because you're adding fuel to the air coming in...



there's every chance of it... put a steel ruler across it with and test with a .002" feeler gauge



I use the gasket paper you get in a roll from supercheap etc. I used to make my own gaskets for both sides of my supercharger. There are 2 thicknesses, I used the thick one and it filled little divots in the aluminium. However it wasn't directly against the head, so temperatures were a lot different to what you want.

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did I tell you that I won a trophy?

Thanks Simon!

We did a similar test with a straight edge against the mounting face of the aluminium intake manifold to find out that it was warped out of shape. The fact that the manifold won't seal before or after machining the mounting face flat is what made me think that perhaps this head is a little bent out of shape.

I've got some work to do I think.

Cheers,

Andrew

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Talk to Terry Pollard on the moke forum I think he has the same engine
fitted to one of his mokes