from a 4.5 to a 4.2 - differences.

[Byff]

I had a 4.5 Cerb until a moment of utter madness saw me sell her. It was when I was wiping away the tears, I realised that I needed another one, but maybe a bit cheaper with a few more blemishes on so I didn't feel so mad when the kids scrape it with their bikes and get muddy footprints up the backs of the seats.

I've been looking at a few 4.2's -pre 98 and have generally found them to be very tappety, despite being warm, so was wondering if it is a trait of the older cars as a 4.2 post 98 car sounded ok when I was looking for the first Cerb.

I know that the clatter cams wouldn't help things, but I thought all these had worn out and had been replaced with whisper cams by now.

[davidd]

Mine is on about 43k with clatter cams intact.

Have you been driving them? How did they feel?

I think the later cars have a deeper exhaust note, this might go some way to mask other noise (of course I might be talking bollocks).

D.

[Byff]

Would the clatter cams cause uneven idling, prehaps even on the point of stalling?

I go through a checklist when vetting the cars, and pretty much first on the list is to let the car idle and see if the fans cut in. Whilst waiting, I'm checking chassis, tyres etc, but have found that the engine is making that much racket, I can't help but think its knackered.

Remember - I had a 4.5 which would tick over beautifully with very little racket.

[suffolkfox]

The cams will be clattery, this does not mean there is a problem but simply the high/sharp peaks to the cam is making it noisy. My 97 4.2 has done just over 18000 miles and after the most recent cam adjustment still sounded like a bag of spanners. The indie told me that I should be more worried if the cam was real quiet, as this could mean a quiet cam or more likely on my model that the tappets are too tightly adjusted. The engine idles perfectly OK when set up correctly, but is more touchy around 2000 rpm than a later car due apparently to the conflict of cam lift vs fuelling for performance vs fuelling to protect the cats resulting in lean fuelling at this point and a common flat spot. Power delivery can also be a bit like turbo boost cutting in occasionally

If you have a look at some of the other threads on here you will find various comments supporting the opinion that an early 4.2 will often have higher bhp than either a later 4.2 or a 4.5 when tested on a dyno, all be it less torque than the latter, so personally I am happy to put up with the noise
Plus with sports exhaust, no one hears the engine anyway

[dannylt]

If you read the earlier threads carefully you'll see that the early 4.2 have problems that negate the higher lift cams - like badly designed exhaust ports and restrictive back boxes, according to Joolz anyway. The clattery ness is mainly due to the cams not being nicely designed with onramps to take up clearance - the later "whisper" cams have longer duration to make up for the slightly reduced lift.