Jay Wellwood

Unless of course, the chain tensioner (which is supplied with oil pressure) is merely compensating for a slightly stretched cam chain. Increasing the rpms results in more oil pressure, which in turn applies more pressure to the chain tensioner - thus the noise disappears. Reducing rpms is the converse action.

Just a theory -

mike_hammond

Thanks Alex, fancy bumping into you, this is the price you pay for buying a bargain

I'm trying to stay phylosophical (Spelling ?) about it, but its hard work especially as it looks like I'm going to be stripping the top of the engine which is going to be no mean task having just read thro' the 968 manual, dial gauges, special tools, at first pass it looks like a major headache as well as some major costs.

Big bummer is as you know I've just bought new shocks + struts and only as yet managed to replace & service the rear brakes, so they're still sitting in the garage collecting dust could have saved my cash to sort this instead. Now this comes along which has got to take priority and I'm strapped for cash until the MG is sold, I hope as they say trouble only comes in three's cause if 4 and 5 come too soon It might just see me throw in the towel and sell it on.

Glad I found this site tho' lots of sound knowledge here so hopefully i'll get to the bottom of this soon.

Mike

mike_hammond

You could be right Jay, thing is if I do lifters then the chain & pads will be done too. So the question is can I do the chain and pads first without removing the cams then at least it would prove the point and I've nothing to lose.

Mike

RajDatta

In order to do the chain you have to remove the cams, how else will you get the chain around the cams?
Just make sure you have your orientation right and you will be ok.
Raj

mike_hammond

DOH !, thanks for pointing out the obvious RAJ

OK the next installment,

I decided to take the bull by the horns and drive the car to work this morning, (12 miles) what I noticed since changing the oil is that now it maintains a slightly higher pressure when warm, 3 at idle and 4.5 to 5 when cruising.

Now the tapping only comes in when I'm at idle and dissappears as soon as the oil pressure starts to build.

A lifter seems now to be the prime culprit, if so how much time have I got before this absolutely has to be done ? i.e. can I continue to drive the car short term without a catastophic failure.

Cheers

Mike

BruceWard

Im sure someone will correct this but I thought noisy lifters were the norm with 968s and not so much something to worry about. Although the level of noise you were getting must be something to be handled. What oil did you put in, assuming you changed from the 0W40?

Mobil 1 15W50 is frequently recommended here, so that is what I use. I thought about the 0W40 but it does not get cold enough here to make the 0 useful but does get warm enough to make the 50 a good thing. From my time in the UK I would guess that you do not need the 0 because it never gets that cold and probably the 50 is overkill for those two weeks of summer.

mike_hammond

Hi Bruce,

I put in some 15W40 el'cheapo semi synth just to run it through to see what affect it would have, I've spoken to 9m racing today and they agree 99% lifter noise, and have said to give it a bit longer and perhaps even do an engine flush and change the oil again after a few miles.

If I'm lucky it may clear itself but from what I hear at idle I think its going to be a replacement job sooner rather than later, I've never heard one this loud in any of the cars I've had before, strange how it came on all of a sudden

Oh well I'm now waiting for the quotes to come in.

Mike

nick_968

Sorry to hear of your problems.

I did have the chance to hear another 968 that had a diesel type rattle on tickover, which was the chain, so it could be that..

Although in your case I am leaning more towards the lifter. It may cure itself from a couple of oil changes, maybe change the filter as well to stop any more crud from getting involved.

If it is a lifter, they are quite expensive, and normally you have to replace them all to be sure you got the dodgy one or two.

While you are in there you may as well change the chain and pads as its good preventative maintenance.

If you need any advice on where to buy parts, let me know and I will see if I can help.

Good luck.

mike_hammond

Hi Nick,

I've had a quote off Specialist cars of Malton and they reckon the lifters, or tappets as we Brits call them, are £20 each so £320 for the full set, Tensioner Pads around £16 and the chain was about £25, with probably 5 to 6 hours of labour so it'll end up a full day !!

Still tempted to have a crack at it myself, take a couple of days off work and buy a big bottle of scotch to drown my sorrows when it all goes horribly wrong

Anything else I need to look at if I go for it, bearing in mind the belts have been done recently. The guys at 9M mentioned that the lifters need to be shimmed ? have I missed something I thought once the cams are off its just a straight swop job and bolt it all back together.

Mike

nick_968

I have never heard of shimming the lifters, what does it entail?

If your in there then obviously you will see straight away the condition of the cams.

There is nothing else I can think of that you should do while you are in there, just make sure you put it all back together right, and use good quality tools inside the cam housing.

RajDatta

It would make no sense to shim a hydraulic lifter. I thought the whole point of a hydraulic lifter is that it does not require any adjustments over time. Why would one need to shim a hydraulic lifter? I am not questioning Colin's knowledge as he probably knows more than I ever will but it just doesn't add up.
I can see the need of priming the lifters where one can inject oil into them before install to avoid any running without oil.
Mike, I think the same way as you do. I would try to tackle it myself as well. If things go wrong, that is the price I am willing to pay to learn . Just make sure you have the cam orientations down right and you should be okay. This will require you removing the timing belt and reinstalling it again.
This is what I see being involved.
Getting yout TDC
Installing a flywheel lock
Removing timing/balance shaft cover.
Removing tension on the timing belt and sliding it off. You might be able to get away with not losening the balance shaft belt.
Removing cam covers.
Indexing cams in reference to chain and TDC
Removing cams
Installing new primed lifters
Swapping chain and pads on tensioner
And the rest is all opposite of removal.
I might have missed a step or two that will soon be pointed out.
Good luck and let us know if we can help further.
Regards.
Raj

mike_hammond

Raj,

With regard locking the Flywheel, if I get everything aligned, could I not put on the handbrake with the car in gear to prevent any movement of the crank or does it have to be locked ?

Mike

nick_968

I would think there would be too much movement and it must stay exactly where it is. If you could do it like that there would be no need for the flywheel to be locked off.

BruceWard

Mike, I suggest you call or email SunsetPorsche.com for a quote on the lifters. They offer parts at cost + 15% so you should get a good price in $s. Plus with the pound at $1.90 or more you could get a real bargin.

Even I might try it myself but then Raj and Scott would never be able to get me off of their phones.

mike_hammond

Thanks Bruce, I'll get straight on it