1996 4.6 P38 - knocking sound on idle

[argonaut]

That's quite the breakage. If it has pressed against the flywheel, be sure to check if the crank doesn't have any excessive play in its bearings, I've heard of bad TCs putting so much pressure on there that they wear out very quickly.

Indeed - I'm already planning to drop the sump (the gasket leaks and it's much easier to do without the gearbox in position) and I will check crankshaft endfloat at the same time. Have you heard of TC's causing this fault (flex plate failure) previously then?

[elbekko]

Not the flex plate failure alone, and not on Rover V8s, but I've heard of them permanently killing the bottom end because of a bad or underperforming TC. That were big and small block Chevys though, but I guess something similar could be possible on a Rover V8.

[nicksmelly]

That's an awful lot of bad luck you have been having.

I hope you get your problem sorted and the Range Rover back on the road.

[argonaut]

That's an awful lot of bad luck you have been having.

I hope you get your problem sorted and the Range Rover back on the road.

Well, to be honest, it's a bit of bad luck and a fairly steep learning curve. I bought my Rangie of the Fleabay, unseen and probably paid too much for it. I was under the impression that anything built by Land Rover was built like a tank and shouldn't give many problems - how naive can you be? ;-) I think like many people, Land Rover have a great reputation but it's not built on reliability. Anyway, I did my research on buying a RR pretty much after I'd bought one. On the plus side, other things that give people a lot of trouble seem to be OK with my car. I just really want to get this flex plate issue sorted and I'm determined to suceed now - yesterday was quite encouraging as it's the first time I've found anything that could be described as an "ah ha!" moment in the search for a common cause of flex plate failure.

Thanks for the encouragement, I will get it fixed :-)

[argonaut]

Sorry for the long delay, some more progress on what has now turned into a full engine strip and rebuild/restoration job:

Episode 4, A New Hope.

Well, the engine strip down continued today. So far, I hadn't found anything wrong but today I removed the Main Bearing caps and found that the bearings are shot. They are all in pretty poor condition which means I will be getting the crankshaft checked out thoroughly and will probably be looking at a re-grind. BTW, can anyone identify the size from this number "ERR 1765"? I have googled and searched on suppliers' websites but was unable to find that number. I know I can measure the crank to find out if its already had a re-grind but I was wondering if someone out there can identify anything from that number.

Anyway, I also removed the spigot/flywheel alignment boss from the end of the crankshaft and found the shim behind it. I haven't measured it yet but it's a tad over 2mm thick. Checking on Microcat, I find that there are 10 different thicknesses listed, all of which are described as being for the V8 engine. Unfortunately, Microcat doesn't offer any more information as to which thickness belongs with which set-up. I should point out that my engine is not the original. Here's my new theory: the engine was at some point replaced, probably just dropped in without much checking of anything. It may be that the gearbox is the original. Could it be that the replacement engine came with the wrong thickness shim? If you check my picture Nr. 2 a few posts above above and look at the flexplate remains you can see the marks caused by contact with the flywheel reluctor ring rivets. I'm wondering, if the wrong shim was fitted could this cause the distance to be so far out that the flexplate is pushed from the centre and flexes causing bending and contact with the flywheel rivets? A kind soul on a different forum pointed me to the correct pages in RAVE to see how to check and adjust the shim thickness (they range from 1.2 to 2.1mm according to Microcat) but as usual, RAVE isn't 100% clear on this point. It mentions fitting the flexplate "assembly" - I assume theat this means including the flywheel?

Cheers