Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Cat Converter

Hi All

1999 Morgan 4/4 1.8 Ford Zetec engine

The following might be of some help to others

Earlier this month whilst driving along, the exhaust suddenly started to blow. This turned out to be a failed ball joint clamp knuckle adapter that is welded to the Catalytic converter output pipe. The pipe itself looks to be in good condition.

Sourced a new cat converter made by BM catalysts part number BM91634 from this place https://www.ebay.co.uk/itm/143524186403 It cost around £290 but I have since found other ebay companies that sell it cheaper.

The cat converter has a clamp around its canister that has two M6 bolts countersunk within it, to which is attached a heat shield. The clamp was badly corroded so decided to replace it with a large Mikalor supra W2 heavy duty stainless steel hose clamp and a aluminium spacer made from a 3mm x 25mm strip cut from a piece of 3mm sheet aluminium. I managed to form this strip into a “C” shape around a 4 inch sewer pipe straight coupler. I sourced the clip from this place
https://www.bearingboys.co.uk/Mikal...r-Super-W1-Heavy-Duty-Hose-Clamp-86215-p

The original cat converter is about 130mm in diameter across the canister, the replacement is smaller at 100mm diameter. I turned out a couple of stainless steel spacers to fit over the M6 bolts so that I could use the original mounting holes in the heat shield see second picture.

Out of curiosity I spoke to Andy at BHM and enquired about the cost of a MMC replacement cat converter. That was in the order of £1000. Andy said they fit the BM ones and they are o.k. as long as you get them nice and hot for the MOT.

Also interestingly the one listed on Melvin Rutter's site is £1075 plus pp and the listing states they are slightly smaller in diameter than the original. I can't help wonder if this is a BM one. If so someone is adding an eye watering mark up!!

I think the original cat converter is salvageable as it looks to be in reasonably sound condition. The question is, is it possible to grind off the remains of the adapter and its weld and weld on a new one without damaging whatever is inside the cat converter we will see.

Regards Tony