323i noise

Post Fri Aug 14, 2020 8:52 am

Hi All

Hoping you you can help me play a game of 'whats that noise!'.

History - High kms 323i. I dont drive the car a lot but plan to do a few more kays in it now. When purchased it had a lumpy cam, which was removed at sale by the last owner for a standard cam. I'm told the cam belt had been done not long before the sale, but i'm suggest when the cam was done at sale it was reused which i'm reading may be a bad move.

Recently developed a sound in the front of the engine and i was convinced it was the water pump. Booked into the shop for water pump and cam belt /tensioner but with a bit of time today i started pulling belts off just to make sure.

Noise has not gone away with all belts removed, so i guess indicating its not any ancillary items nor the water pump. Appreciate any suggestions? I dont want to throw money at the work and find its not the issue.

Also, the noise goes away when the car gets warm.

Please ask any questions that may help.

Post Fri Aug 14, 2020 9:40 am

Sounds like a worn tensioner bearing to me.

Post Fri Aug 14, 2020 11:32 am

Thanks Speedtouch. I'll look at that some more in the morning

Post Fri Aug 14, 2020 2:51 pm

Speedtouch wrote: ↑
Fri Aug 14, 2020 9:40 am
Sounds like a worn tensioner bearing to me.

Thought it sounded like that myself too. if the tensioner bearing has gone probably best to do the cam belt at the same time.

Post Fri Aug 14, 2020 10:03 pm

Yes, indeed. Maybe water pump also.

Post Thu Aug 27, 2020 9:32 am

Hi Guys
So getting to the shop proved difficult at this time so have ordered timing kit and water pump and will have a crack myself. While waiting for the parts i 'm starting to remove bits and wanted to look at the timing marks.

When i line up the arrow on the cam gear its out by quite a few mm at the crank. Is this ok/normal? Should i do something to re-align? Does it matter if i go clockwise or anti when lining these up?

Hopefully the attached pic worked.

Thanks

Post Thu Aug 27, 2020 10:24 am

Only turn the engine in the way it normally runs.
Timing mark that far out is definitely not good, assuming the cam pulley mark is accurately aligned, but I can't judge what parallax error there might be from a 2D pic, and if the belt has lost tension at all, it could be because you turned the engine backwards to reach that point.
Since you are changing the cam belt, don't worry about it for now. Turn the crank to line the cam pulley up, with the crank mark almost right, remove the belt and line the crank pulley accurately, and don't forget that on these old versions of the M20, that the oil pump drive pulley also drives the old type distributor, so has to be aligned as well before fitting the new belt.

Post Thu Aug 27, 2020 11:11 am

Be careful of the idler cog for the oil pump, it also drives the dizzy on early engines and it is quite easy to put the dzizy timing way out.

Post Thu Aug 27, 2020 11:20 am

Thanks Brian and Blanca
I'm wondering if i caused this issue by turning the engine over using the cam gear rather than the crank bolt. On these early models they are not a 22mm bolt on the crank, but more like a 26mm which i did not have so have been using a 1/2 inch socket to turn the cam gear. I assume (maybe wrongly) that this does not matter, its all connected and the belt is not slack.

Blanca, yes been searching the forum since i posted looking for thoughts. I see on these i need to mark third cog to ensure it stays in the same place.

Ok, so line up the cam mark. Turn the crank anti clockwise if i need it to come back a little. See how it looks in the light of day.

Post Tue Sep 01, 2020 9:26 am

So got the new bits.....

I pulled bonnet and hoses off this arvo prepping for the timing belt. As i was feeling around the intermediate gear felt a little loose. Then i played with retainer plate and sure enough it was quite loose and when rattled.......sounded like this. forgive the fat fingers in the way

The chief mechanic (insert wife) happened to be passing by so she listened to the original clip and the sound this was making as i rattled. I reckon I agree with her, it does sound like the same rattle. Shame i did not notice this before i dropped the coolant as I have nipped it up and would be good to conclude that was the noise before i change the belt and tensioner (will still do these regardless)

I'm sure it may help someone else down the track so i may just put the hoses and harmonic balancer on to verify with a quick start

Post Tue Sep 01, 2020 2:11 pm

There is a known problem with a large batch of M20 tensioner pulleys where the mounting stem for the pulley comes loose and cants over, slackening the belt, but more importantly, throwing it towards the front cover, where it rubs and wears way.

Post Tue Sep 01, 2020 9:19 pm

also have a new pulley to go on. i can see that the belt is a little loose and the front cover has been worn

Post Tue Sep 01, 2020 9:48 pm

It's the belt that wears away, more than the cover. I removed a belt once that was about one third of the width it should have been.
A secondary effect is that the belt wears away the fixings for the clips that hold the duct that keeps the water pump pulley from savaging the wires from the crank position sensor and the ignition lead sensor, allowing the wires to get damaged.

Post Wed Sep 02, 2020 10:11 am

Ok, close this one out.

The source of the rattle in the first video was in fact the loose bolt holding the the intermediate gear. The plate was rattling around. A quick nip up and a short run and noise is gone. Hope this helps someone in the future.

Thanks to those offering up advice. Brian, belt has been wearing, about 2mm has been affected against cover. On to the water pump and belts now.......i may be back for more help