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255 Adjusting the engine mounts Stuart Middlemiss (Nightfire Red 1215) from Norfolk provides a useful tip on curing contact between the offside exhaust manifold and the inner wing aperture or steering pinion based on some hard work done by fellow RV8 enthusiast, Max Porter. (Oct 06) My village RV8
chum, Max Porter - yes, two RV8s in the same village; is this a
record? - had found the common occurrence of his offside exhaust
manifold touching the edge of the inner wing aperture and almost
touching the steering pinion. On some cars, the manifold touches
the steering pinion before the edge of the inner wing aperture and
causes a lot of vibration and knocking up the steering column. Assuming that the offside engine mount had begun to collapse, he bought a replacement from Clive Wheatley. However, on examining the original rubber mount, it showed no sign of collapse, over-compression or deterioration whatsoever and was the same dimensions as the new mount (37-38mm including the oval steel plate, for the thicker offside mount). Looking then at the nearside mount (the thinner of the two), Max realised that the hole in the bracket (welded to the chassis) which the single stud bolt of the mount passes through is vertically slotted, to allow for engine positioning when the engine is fitted, of course. He also realised that the nearside exhaust manifold had plenty of clearance to the edge of the inner wing aperture. The 'Eureka' moment struck; Max supported the engine under the offside of the sump with the trolley jack (with a block of wood to prevent damage), with the car supported on axle stands, and loosened the single bolt fixing each side with an open-ended spanner (access is very constricted on the offside). He noticed that neither nut was very tight, which further confirmed his suspicion that the engine had |
 RV8 offside engine mount (1). (Source: RV8 Parts Microfiche) rotated under torque of acceleration. The engine was then very slightly raised on the offside, only 3 or 4mm, which of course lowered the nearside by the same amount - the engine was very slightly rotated on its axis. After checking that the clearances between the exhaust manifolds and inner wing aperture edges were now the same each side (about 8mm, with minimum 5mm clearance on the steering pinion, but this may well vary between cars), he then tightened both nuts as much as possible. The restricted access prevents a socket or torque wrench being used, but the nuts were now much tighter than they had been originally. Problem solved, without the need to replace the mounts, which necessitates dropping the steering rack out to access the offside especially. Checking exhaust manifold clearances should obviously be included on each service and the tightness of all fixing bolts checked, as it's quite likely the large amount of torque produced by the engine will cause slight rotation again in the future. It should also be borne in mind that, in time, the rubber engine mounts will compress and require replacement, and that these mounts (as far as I've been able to check) are quite possibly unique to the RV8, at least in as far as being different sizes. Copyright
reserved by the V8 Register, PO Box 888, London SW14 7YT
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