Looking at a Chimaera - cam wear, should I be worried?

[rotaryjam]

I had a look at a Chimaera 4.0 HC today, it looked very nice overall, great bodywork, no signs of rust underneath, very tidy engine bay, however there was one thing that worried me.

I saw an invoice from not long ago that said 'Cam wear (tune)' - this caught my attention! The owner didn't have much to say about it.

Should I be put off? I have since done a bit of Googling which suggests the cams do wear out.

What would a 'tune' do for a worn cam exactly?

[Belle427]

No idea but they are known to wear out quickly so I’d personally budget for changing it.

[PhilF329]

I would imagine its intended to quieten it down, which is disappointing behaviour! I’d also budget for changing it.

[rotaryjam]

Hmm doesn't sound great.

What's a rough cost to change the cam with labour??

[NicBowman]

It’s quite simple to do yourself. But budget £1k to £2k, allowing for other stuff. So not serious serious. Plus if it runs well, don’t change it.

Nic

[Steve_D]

The RV8 can still run sweetly with no noise even with a very worn cam. If you had owned it for a long time you may notice a fall off in performance but in this case you will be none the wiser.

It's not a big job.

Steve

[Belle427]

Average decent cam kit is around £600 and labour possibly about the same so not a deal breaker.
Good cars though as I believe they all have valve reliefs in the pistons to accept a slightly more aggressive cam, maybe someone can confirm that.

Edited by Belle427 on Tuesday 23 August 06:38

[rotaryjam]

Thanks all

Doesn't sound like the end of the world then but I'll factor this in to the price

[geordiepingu]

Belle427 said:

Good cars though as I believe they all have valve reliefs in the pistons to accept a slightly more aggressive cam, maybe someone can confirm that.

Yep, HCs should have valve reliefs, almost certainly all later ones, although some earlier ones are a bit frankenstein and just used whatever was lying around. I've seen some without a cam but equipped with ported and polished heads from the factory, one of which we had in for service. There are some cars that TVR just "sent" and have been ok. Best way to be sure is stick a boroscope in through the spark plug holes and take some photographs of the piston, if you're not willing to take the heads off and play with some plastigauge.

Think of a cam change as an opportunity to upgrade... If you are on the original ECU you will likely want to stay with some of the 'milder' cams such as the V8D Stealth, which is popular amongst most with aftermarket cams running the original ECU.

If you wanted to keep it completely original, you'll still notice a bit more power than before. You just won't know if the grass is greener if you know what I mean.

Any specialist worth their salt should be able to help you install an uprated cam if you wanted to go down that route, as I don't think the cost is much more for a Kent cam. I've never bought a Stealth but I know the 404 is a bit more expensive (although you want an upgraded ECU at the very least for a 404).

As a few on this thread have said, you can enjoy the car and still have a reasonable bit of torque with a worn cam. You just won't be opening the valves fully and getting the full potential out of the engine. If you see the right condition car that's been looked after, albeit the cam needs changing, I wouldn't let it put you off if it's a car you want to keep for a few years.

If you're up near the North East and have either bought a car or are on the fence, and want to chat cams and get taken out in a couple of different V8s just give me a shout. Always happy to talk V8s over a coffee

Short of it though, budget about £1k, that should safely change a cam at a specialist and probably sort out any small defects that may be found while swapping. If there's more things on the front of the car that are buggered, you may find that goes between £1-1.5k, depending on parts and labour (and luck).


EDIT:
Forgot to answer the tuning conundrum. I've found on my development car with MS2 that idle and cruise tends to want less fuel as the cam is wearing on mine (got a fair bit of abuse when testing oil). There are some other hacks people have done to make the cars a bit 'pokier' that don't quite resolve the lack of lift from the cam lobes, but add a bit more low end torque back to make the wear less noticeable. Disconnecting the vac advance and resetting the timing on the distributor either to spec or someone's tuned spec is quite common. It could also be that someone has put some sort of map chip in the ECU to try and mask the problem although this is less common I believe as there's only a few of us that are willing to modify 14CUX maps (although that is my speculation, as I'm not keen on datalogging to run back to my computer, flash a chip, then stick it back in repeatedly to test the improvements...).

Edited by geordiepingu on Tuesday 23 August 11:19

[andrewcliffe]

A standard cam has a life expectancy of circa 65,000 miles.

There are options on replacements - a new standard cam or various upgrades (which can bring compromises).

Have to remove Y piece exhaust, possibly radiator, part of cross member. Normally done with timing chain, valley gasket and cam followers/ hydraulic tappets.

I did mine myself.

[rotaryjam]

Thank you for help on this, really good info.

I'm not too good with a spanner so a DIY job is out of the question unfortunately!

I did get a quote from V8 developments of £1250 all in to replace the cam (s) so at least I know the worse case scenario