SU carb inlet manifold on 3.9 efi engine --- water jackets

dogdog1 · Post by **dogdog1** » Sat Apr 07, 2012 4:48 pm

Hi All , Just wondering the significance of the following : I've put the carbs and inlet manifold from a P6 on a 3.9 efi , but on the 3.9 heads the rear water jackets are blanked off , unlike the P6 where they are open . The engine hasn't been run yet , I'm just wondering how it'll affect cooling ? Thanks , Gerry .

ChrisJC · Post by **ChrisJC** » Sat Apr 07, 2012 5:46 pm

Odd, all the inlet manifolds I have seen blank off the rear waterways. Have you a picture?

Chris.

dogdog1 · Post by **dogdog1** » Sat Apr 07, 2012 6:49 pm

Hi Chris , Unfortunately not , as the manifold is now on the engine . It came off a P6 .

harvey · Post by **harvey** » Sat Apr 07, 2012 7:42 pm

The rear of the manifold has no waterway, and blocks the waterway in the head. If it looked like there weren't any waterways in the head then they were jammed up with crud. (Technical term) There has to be a waterway in the front of the head into the manifold, and both of the heads are the same.

mgbv8 · Post by **mgbv8** » Sat Apr 07, 2012 8:14 pm

Maybe someone has modified the manifold you have?

The rear water ports should be blocked on the manifold. I do have a manifold which has a temp sensor tapped into one of the rear water ports but I dont use the sensor as I dont believe it would read accurately as its not in full water flow.

A picture would really help mate !!