Pre cat removal
Discussion
Why do you want to remove them?
Yes the manifolds need to come off (you don't want a debri damaging the main cat, or worse getting into to cylinders) then its a case of using a drill and chissel to break up the cats and remove them.
Act do decatted manifolds on exchange fitted with non reversal cones at a reasonable price, which was the way i went when i had a cracked manifold. Non reversal cone is supposed the maintain back pressure and smooth out engine, but many cars have been de pre-catted without the cone with no noticable effect.
Yes the manifolds need to come off (you don't want a debri damaging the main cat, or worse getting into to cylinders) then its a case of using a drill and chissel to break up the cats and remove them.
Act do decatted manifolds on exchange fitted with non reversal cones at a reasonable price, which was the way i went when i had a cracked manifold. Non reversal cone is supposed the maintain back pressure and smooth out engine, but many cars have been de pre-catted without the cone with no noticable effect.
Edited by Bluebottle on Wednesday 16th April 12:07
I removed the precats on my Griff 500 recently - the work involved is something like this. Undo the manifold bolts, which can be a real pain, due to poor accessability on a number of the bolts - replace with ARP bolts - smaller head and tougher material - better and easier job. Move plug leads out of the way. Disconnect the two clamp connectors at the 'Y' piece. The exhaust is bolted to the engine block just below the 'Y ' and although I removed the 'Y' at the same time, (ceramic coating the whole lot), this should be self supporting, while you set to actually removing the pre-cats from you manifolds. I'm sure there are more efficient and easier ways to remove them, but I basically pushed and hammered a large screw driver into the precat material until it was sufficiently distressed that large chunks of it fell away. The internal wall of the manifolds will retain some of this material and I removed this with a sharp kitchen knife. Replace your gaskest, (trim them as required, and tack them in place with a drop of silicone sealant). Refit manifolds - bolt them up tight. Next refit your clamps - I found a serious gap and misalignment between the 'Y ' and the manifolds which I got round by forcing in wooden wedges betwen bulkheads and chassis and manifolds to close up the gaps prior to fitting the clamps, tightening up clamps and then tapping the clamps up with a rubber mallet. I added silicone sealant here (prior to fitting the clamps). No leaks looks great and I have a sore back still. And by the way I found the sound to be totally different to its original condition.
PS can anyone recommend a tuner with rolling road in the north East/ North of England who knows his V8 Rover EFI engines please.
PS can anyone recommend a tuner with rolling road in the north East/ North of England who knows his V8 Rover EFI engines please.
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