Buzzing noise that stops when warmed up

[KMG]

Hi, I have a '64 156 THP GT with 36000 miles on the clock, and for the past year I've had an intermittent 'buzzing' noise like a wasp in a tin can when driving from cold at around 3000 revs. This noise stops when I accelerate and when I slow down, and it disappears by itself when the car warms up after a couple of miles. I've just had the car in for replacement seals in the turbo oil return pipe, and the mechanic says he experienced said noise. He thinks it could be the Cam Chain Tensioner, or the VVT unit. He's put a special additive in the oil that is specially to treat this symptom and says hopefully it will cure it, as it could just be a bit 'sticky'. He's advised me to ask on this forum if anyone has experienced anything similar. He also says if it continues he will change the offending item to be on the safe side. If anyone has any thoughts on this I'd be grateful for their advice.

Thanks,

Kevin

 

[Kenneth]

I had a noise like that but it was only when the engine hit about 3000rpm. It drove me nuts for a while until I realised a bit of that bendy heat shielding stuff hadn’t been moulded back round some wires and pipes on the left hand side of the turbo after I’d been mucking around with something down there…. Turned out it was THAT. And it did really only do it until the engine got hot.

 

[KMG]

Just as an update, this was the timing chain and I had a new one plus tensioner etc fitted, and all good again. Work was carried out by C&G Cars in Leicester, who I can't recommend enough. The whole job was carried out in one day, and they are extremely helpful and professional.

 

[EddieJ]

For the tupence it’s worth my 308cc (same Ep6 engine as my Z) reached 50k at 15years old and I took the decision to do the chain for age rather than the miles. Useless bit of info, at initial release the RCZ was to be called 308 RCZ, but then the numbers were dropped on release of the model.
Car had no issues, or startup rattles and drove excellent.
Ordered up the full kit from local autofactors (who I’d been using for years). Stripped the car down, done some cleaning etc.
When I went and collected the kit and it was a NAPA on the counter. I should have stopped there and waited for the BGA kit I ordered to come in, but was advised it was OEM quality or better, and they have never had any issues. NAPA timing chain kits ARE ABOSLUTELY NOT OEM quality…..here’s why I say that, of course it’s my only opinion.

Fitted and running it had a little rattle on startup and on driving the car felt okay cruising but when on the boot it felt restricted, settling in time?? Trying to kid myself.

I kept the kit in for a few thousand miles but got to a point where I could not stop focusing on it, the rattle, the power loss and also now an oil leak from the alt end of the valve cover. Once I changed it all out again for a decent kit I examined the parts and found;
The tensioner was ‘lazy’, and the plunger also felt scratchy and it did not retain oil (=Startup rattles few minutes).
The vanos was loose feeling, shake with a rattle, and put under pressure it did release but did not achieve full advance rotation (=Power loss).
The guides where showing wear on both the long ones, tensioner side it was worn on the lower 3-4” and on the top 2-3“ on the dip stick side. The bridge showed wear on the mid section. I did talk to the autofactors about it and because it hadn’t failed wasn’t seen as an issue, really.
Just for info, NAPA wasn’t a cheaper alternative and it was installed incorrectly……it was just sh1te.
With the new kit fitted all was well and is well with the world again.

 

[Kenneth]

For the tupence it’s worth my 308cc (same Ep6 engine as my Z) reached 50k at 15years old and I took the decision to do the chain for age rather than the miles. Useless bit of info, at initial release the RCZ was to be called 308 RCZ, but then the numbers were dropped on release of the model.
Car had no issues, or startup rattles and drove excellent.
Ordered up the full kit from local autofactors (who I’d been using for years). Stripped the car down, done some cleaning etc.
When I went and collected the kit and it was a NAPA on the counter. I should have stopped there and waited for the BGA kit I ordered to come in, but was advised it was OEM quality or better, and they have never had any issues. NAPA timing chain kits ARE ABOSLUTELY NOT OEM quality…..here’s why I say that, of course it’s my only opinion.

Fitted and running it had a little rattle on startup and on driving the car felt okay cruising but when on the boot it felt restricted, settling in time?? Trying to kid myself.

I kept the kit in for a few thousand miles but got to a point where I could not stop focusing on it, the rattle, the power loss and also now an oil leak from the alt end of the valve cover. Once I changed it all out again for a decent kit I examined the parts and found;
The tensioner was ‘lazy’, and the plunger also felt scratchy and it did not retain oil (=Startup rattles few minutes).
The vanos was loose feeling, shake with a rattle, and put under pressure it did release but did not achieve full advance rotation (=Power loss).
The guides where showing wear on both the long ones, tensioner side it was worn on the lower 3-4” and on the top 2-3“ on the dip stick side. The bridge showed wear on the mid section. I did talk to the autofactors about it and because it hadn’t failed wasn’t seen as an issue, really.
Just for info, NAPA wasn’t a cheaper alternative and it was installed incorrectly……it was just sh1te.
With the new kit fitted all was well and is well with the world again.

I got the chain kit from pug1off. It presumably it’s good coming from them.

my car will be back on Monday. There were no issues with it but I just wanted it done now and I’ll maintain oil etc so it should be fine for a good few years to come