Carburettor overflow pipes N.W.Geeson A most recent unfortunate occurrence...seeing the aftermath of a fire on a MKVI Bentley, prompts me suggest the following to owners of all the early post war Bentley and Rolls-Royce chassis. Not for the first time have I witnessed these fires and a similar situation exists on the Silver Dawn and Silver Wraith chassis from the manifold drain pipes. I should add that the MKVI in question was not my own car but one attending the same rally. Although at the time it was not possible to prove the cause due to other factors the fire was around the front carburettor area and the dynamo wiring at the dynamo end had burnt...listers can make up their own mind as to the cause after reading on. The front S.U carburettor overflow pipe on the MKVI chassis was originally routed between the engine block and carburettor, the end of the pipe terminating at the rear of the dynamo. This was an accident waiting to happen as in any overflow situation it was possible to ignite the fuel from arcing of the dynamo brush gear. Certainly some MKVI chassis were lost through this cause. Rolls -Royce issued a modification to re-route these overflow pipes at the side of the carburettor away from the dynamo on the side facing the inner wing panel. Most cars were modified at the time and common sense dictated that the pipes were extended to egress below the alloy under sheets on BOTH carburettors. Unfortunately some cars were not modified and subsequent to this, frequent dismantling for top overhauls has also resulted in many mechanics and owners shortening the pipes for stripping accessibility. In some cases, again routing the pipe on the inboard side of the carburettor because it looks neater. It is important that owners realise the implications of the pipe routes if they are to avoid fires. At the same time it is also important that the pipes terminate below the alloy under trays. Any pipe egressing above the under tray will allow overflow fuel to run rearwards under the drivers seat ( on RHD cars ) and battery area. If the drain hole is blocked on the engine right hand under tray, the fuel can run rearwards to the extent of the rear end of the gearbox. Implications of the ignition of the fuel vapours in this situation should not need explaining. The moral is to check that your overflow pipes are routed correctly and terminate below the trays. The fact is that many of these cars have incorrectly routed pipes. The problem can exist on all the Bentley models up to and including R types. In respect of the Silver Dawn and Silver Wraith, I have seen many cars were the inlet manifold fuel drainpipe has been cut off just below the manifold or terminated above the trays. In one instance less than two years ago I stopped a mechanic trying to jump start a very late 1955 Silver Dawn which had petrol pouring from a broken off inlet manifold drain pipe. The fuel was being directed by the under trays right under the battery area where he had connected the jump battery leads. It goes without saying that owners should ensure that the drain holes in under trays are clean and not blocked with debris.