Clunking from bottom end VN s1 V6

[JimmyH]

I just want to clarify, as I understand that it's most likely the harmonic balancer (I've even got a new one to put on!) I just want to be sure.

Loud rattling/clunking started a couple of months ago. Only at idle (I can put my foot on the throttle a bit at the lights and it goes away) and especially when the A/C is on. (because there's more pressure on the balancer maybe?) The reason I've only attacked it now is because I don't drive it much at all, I didn't really consider it a problem until it started getting really bad.

I'm going to first run the motor without the belt on, and if it stops making the sound then I can assume it's the harmonic balancer? If the engine STILL clunks what could it be? Crankshaft/camshaft? When the motor's running there's no change in the performance whether it's making noise or silent, so I don't think it'll be completely screwed. I just thought I'd ask.

[JimmyH]

On further inspection (taken belt off, ran motor) it definitely sounds like the clunking is coming from the rear of the motor. if I grab the harmonic balancer and turn it there's a metallic clunking coming from the rear of the motor. It happens maybe once or twice per full rotation of the engine.

Any ideas? I've got everything I need to fix, I just don't know what to fix.

[ToxicVn]

It sounds like its done a bearing - rebuild

[soop]

Sif rebuild.
Throw it in the bin and buy another one.

[jas98]

make sure teh flex plate aintr stuffed (if its an auto) as teh bolts can come loose

[Pub247]

make sure teh flex plate aintr stuffed (if its an auto) as teh bolts can come loose

yep good call could be a cracked flexplate. Motor i built for a mate ripped the wholle centre out of his

[JimmyH]

yep good call could be a cracked flexplate. Motor i built for a mate ripped the wholle centre out of his

What's the easiest way to access the flexplate to a) check to see if it's loose/cracked, and b) replace/tighten?

[jas98]

yep good call could be a cracked flexplate. Motor i built for a mate ripped the wholle centre out of his

yeh the wrecked VN i have, the center part where the flex plate is bolted to the crank was a separate pice to the rest and it had a nice crack from one side to teh other....looked nice hahah

[jas98]

What's the easiest way to access the flexplate to a) check to see if it's loose/cracked, and b) replace/tighten?

you will need to remove teh inspection cover between the motor and box


i believe that the later vn series 1 engines used a cast iron inspection cover between the motor and g box, which is a bitch to remove as you need to remove a few bolts from sump, steering rack and starter motor etc. (althou these may not necessarily have to be removed its allot easier with them off)... as with the earlier ones, it was just a thin steel cover which is allot easier to remove. However you will need to also remove the starter motor and exhaust pipes.

what i would do is get my head under there and listen while its idleing and see if teh noise is comming from between the motor and box, if its more pronounce it that area then id say its most likely teh flex plate loose as if it was cracked it would have flown apart in pices by now.

although the noise could be a fe other things this would be teh first thing id look at before i start worrieing about another engine

[JimmyH]

you will need to remove teh inspection cover between the motor and box


i believe that the later vn series 1 engines used a cast iron inspection cover between the motor and g box, which is a bitch to remove as you need to remove a few bolts from sump, steering rack and starter motor etc. (althou these may not necessarily have to be removed its allot easier with them off)... as with the earlier ones, it was just a thin steel cover which is allot easier to remove. However you will need to also remove the starter motor and exhaust pipes.

what i would do is get my head under there and listen while its idleing and see if teh noise is comming from between the motor and box, if its more pronounce it that area then id say its most likely teh flex plate loose as if it was cracked it would have flown apart in pices by now.

although the noise could be a fe other things this would be teh first thing id look at before i start worrieing about another engine

No worries.

I've loosened the whole inspection cover, but as was said, there's an exhaust in the way. I cannot fit any tools up to take it off the manifold, and as far as I can see there's no other way to take the exhaust off.. Can anyone explain how exactly I do take the exhaust off this thing?

[Bz Kn33z]

You need to drop the Y pipe and you could leave the manifolds on, but might be easy to take it all off, not sure if you can check the flex plate without taking the converter off, this will involve dropping the gearbox, its hard to tell sometimes if its stuff the cracks are so fine, i've done 2 flex plates so far in to different cars then just put a manual in. they usually crack around the bolts and even though they are a real fine crack they will make th loudest noise, also there is a small plate over the flex plate and the bolts go through it so really the flex plate will have to be removed to make sure its really stuffed.
If the flex plate isnt the problem its most likely a big end.

Edit: Also how many Ks has she done.

[JimmyH]

You need to drop the Y pipe and you could leave the manifolds on, but might be easy to take it all off, not sure if you can check the flex plate without taking the converter off, this will involve dropping the gearbox, its hard to tell sometimes if its stuff the cracks are so fine, i've done 2 flex plates so far in to different cars then just put a manual in. they usually crack around the bolts and even though they are a real fine crack they will make th loudest noise, also there is a small plate over the flex plate and the bolts go through it so really the flex plate will have to be removed to make sure its really stuffed.
If the flex plate isnt the problem its most likely a big end.

Edit: Also how many Ks has she done.

250,000km, had all the services. I'll tear the entire exhaust system off tonight and have a better look, not sure if I want to drop the gearbox though, could be a lot more work than it's worth.

[JimmyH]

Torque converter ended up being loose according to a mechanic that I took the car to. (could not take the exhaust system off)

But the problem doesn't end there, unfortunately. I started the car before and there was no rattle! I thought all my problems were solved, but there's now something else. I drove away and everything was fine, did a right hand u-turn and as I accelerated there was an unbelievably loud rattle. I stopped all acceleration and it stopped right away. As I accelerated away it did it again for a couple of seconds, but I got to speed and it stopped. In neutral there's no weird sounds, I can rev it all the way out to revlimiter and there's no weird sounds, but when I'm driving (most notably turning, and under hard acceleration) there's a really loud rattle.

It sounds like something could be in the bell housing, and is being picked up/caught on the flexplate and shot around, but I hit the inspection plate with a hammer (as I said before, can't actually take the thing off because the exhaust's in the way) and nothing seems to be loose in there.

Any ideas at all? This is killing me.

[JimmyH]

Well I've taken the VN back to the mechanics.

He said he noticed the rattle after he'd tightened all that was loose, but he'd assumed that since it was an old car (that I'm trying to FIX!) it would have a few rattles. I told him that it's ridiculously loud and it can't actually be having no effect, so he's going to have another look at it today.

Damn Holden.

[jas98]

ah dam ay...let us know what happens

[Pub247]

Loose exhaust or refitted incorrectly and is hitting on the body somewhere is my first guess. I wonder if he just tightened the torque convertor with the inspection plate off. It would be funny if it was still the flexplate