A couple of years ago, whilst servicing my car, I changed the original PCV for a new one I had on the shelf and I binned the old one. It was a case of whilst I'm here, I might as well... The only apparent result was that the engine idle speed increased by about 100 revs, an issue soon sorted by altering the idle control valve to compensate.
Recently, I have added larger throttles to the inlet manifolds and, of course, larger throttles pass more air which has again increased the idle speed. The bad news is that, despite renewing every gasket and setting everything with extra care, I no longer have sufficient adjustment on the idle control valve to bring the idle back down to the 750 revs I'm comfortable with. Hundreds of car models are fitted with physically similar valves which can be bought for less than £10 each. Trying to cross reference the part numbers, Jaguar doesn't appear to share its version with any other car manufacturer and sells its PCV valve for £67. Understandably, I'm reluctant to order another new one only to find it works the same way as the existing one. Nonetheless, I'm curious enough to want to open up an old Jaguar one and compare the internals with a £10 generic valve. Does anyone have one or two scrap valves kicking around that I could have to play with and report back? Mike (This is a subject worthy of a new anorak logo!).
