Camshaft

[Dave Meredith]

Persistant pinking is stopping me from really letting the Wedge off the leash.

I've set the timing to zero degrees advance and am using Shell V power which is the highest octane I can find. The ECU was replaced about 12,000 miles ago together with the injectors so I would expect that they are not the cause of the problem.

A previous owner also had the problem and it was suggested to him that the camshaft might be on the way out. The car has done almost 100,000 miles now and I suppose a few worn lobes could cause insufficient opening of the valve and hence an inadequate dose of fuel/air in the cylinder.

I'm ordering an SD1 workshop manual in readiness but what I really want to know is whether this can be done with the engine in the car. I've had a search on this forum but I can only get results going back 2 years. I've replaced cams before but not on a V8. Are there any pitfalls?

Thanks

Dave

[djc1001]

Cam can be changed with eng. in car. Clearance to rad. bit tight when withdrawing cam otherwise fairly straight forward. Fit new lifters and check clearance before the lifters are pumped up -shims under rocker pillars is adjustment method. Otherwise main problem is likely to be loosening the flywheel pulley the bolt has been known to snap.

Timing - have you checked pulley TDC mark is accurate, they are known to be iffy and therefore you may be more advanced than you think.

r's
David

Edited by djc1001 on Monday 4th August 12:32

[TVRleigh_BBWR]

Make a piston stop out of a old spark plug.
This will help you check TDC. *** ONLY TURN ENGINE BY HAND NOT STARTER WITH PISTON STOP ***

you can also use dial gauge on the rockers to check if the cam's worn.

[rev-erend]

Excuse me but but I think you should do a few more checks first..

Pinking is a sign of a mixture being ignited too early (generally) or very poor combustion.

So - is the spark system in good order (New plugs, dizzy leads, cap rotor arm).

Are all the injectors firing well - a lazer temp spot (£20) guage will show all the exhaust pipes with a similar temp. This will also show if a valve is not lifting (although the other valves then get at over rich mixture).

Check the timing figures seem reasonoble and that TDC is correct (remember that TDC lasts for about 10~15 degrees of rotation). With the vacuum blocked - 8 degrees at tickover is OK - 28 degrees at 4000 rpm should be the full advance figure.

[D1 MAD]

Might be worth checking the advance/retard weights and the vacuum valve in the dizzy to make sure they aren't seized up.

[adam quantrill]

I don't think the camshaft will cause pinking, just either a drop in power (inlet lobe) or front-firing and a dramatic drop in power (exhaust lobe).

Yes the cam is easy to replace but you have to jack the engine up a few inches to clear the front of the bodywork. Not a biggie though.

I would check -

a) ignition is good to all plugs (like wot the rev sed) go for a drive with one injector disconnected and repeat until problem narrowed down to one cylinder
b) timing, first idle and then through the rev range, with and without vacuum
c) mixture

[Dave Meredith]

Thanks guys
I have a tendency to charge in on a hunch so this will give me a few things to try first

[Dave Meredith]

Having just moved house I've got a long list of jobs to do especially if I want clean ironed clothes anytime soon.
I've got a little bit of money left over (don't tell the misses) and would like to get the pinking diagnosed by a garage even if I end up doing the remedial work myself

Can anyone recommend a garage in the Gloucestershire area who might have some experience with the Rover V8 or will any reputable garage do?

[D605]

If the lobes are warn to that extent on the cam then you got to consider where the metal has gone ie big end shells, what is the oil pressure like when warm.


camshaft wear loss off power and in bad cases you will get bow back out through the air intake,

the miles on the clock with a single cam is problbly near is time

my bet timing/fuel mix.

Regard Tony