Rattle on Start Up - Timing Chain Again??

Steve316

Hi all,

the last few weeks I've been trying to mop up the effects of Vauxhall's timing chain design after hearing the ominous noise. Unfortunately that has not put an end to the saga.

I've been scouring the relvent topics on this awesome forum, and I'm confident you guys can help me!

I've put a brand new timing chain and balancer chain kit with new seals/gaskets not two weeks ago due to the worrying rattling noise which began to develop after I let me car stand un-used for 3 weeks (very bad idea for an old car!). One thing I must confess is I must have bought one of the older style kits because it did not come with the Z20NET tensioner. Regardless, the car was fine for 50k with the old style, it should be good for another 50k at least! Oil nozzle was the latest version thankfully.

The constant rattle has certainly gone, and the car idles beautifully (it was a bit lumpy before, plenty of dips) and sounds like it should. However, upon start-up a rattle, even worse than before I changed the chain, happens. This lasts for between 0 - 2 seconds then disappears completely.

I've checked the exhaust manifold fasteners (two nearest the chain were loose), but this has not solved the problem.

I'm of the opinion that for the initial start up the tension on the chain is too low, and it takes some oil pressure to apply the correct tension. Is this a fault of the tensioner? Is there a non-return valve to keep oil pressure in which is faulty?

Apologies for the long post, this problem is starting to worry me greatly.

Car details:
2002
Astra Bertone 2.2
58 200 miles
0W-40 Mobil one fully synth

vocky

is the exhaust manifold cracked between 2+3 ?

also you could just fit a z20net tensioner, available from the z22se shop too :thumbup:

Steve316

To be fair i did only give the exhaust manifold a top-down look. I could not find any obvious cracks. I can have it up on ramps to look from underside tonight.

Although when removing the heat shield last night, I sheared off one of the three steel studs despite the warnings on the forum. In my defence that thing was corroded in there pretty bad though!

I would really consider the Z20NET tensioner, but I read here that it can only be fitted with a new style tensioner guide? (I don't want to forke out £200 on a new timing kit if I can help it).
Plus at £70 it's a hefty punt, what are the odds a garage would let me try one to prove it worked first?!

Steve316

Exhaust manifold is not cracked.

Will the Z20NET tensioner fit into an old style guide?

Steve316

Bump.

Update on happenings:

Having got into my head that it was the tensioner at fault, I decided to shove the old tensioner in place of the new tensioner to see if that had an effect (kept the new spring piston insert and bonded washer, but used older housing bolt).
I no longer get the 0-2 second rattle on start-up! However when I cranked the engine for the first time with the old tensioner in, it was idling poorly for a minute or two and even stalled itself 3 times. I reset the ECU and tried again, and everything seems to be fine. Idle is steady at about 750 rpm and don't seem to get any drop in power at any point.

I'm assuming the chain hasn't jumped a tooth since that would throw up plenty of other symptoms.

I think this shows that something was wrong with the last tensioner, I will keep you updated after I've used the car for a week or two to see if there are any changes.

Am I at risk from using an old tensioner with the new kit?

vocky

I would get a z20net tensioner and reset the timing, I have had a couple of cars where the chain had jumped one tooth and the owners were unaware, but they did love the extra power after the new chains were fitted with correct timing 😃

Steve316

Can you really jump a tooth and not notice?! Certainly wouldn't mind a bit more power! 😃

I really do want to buy the Z20NET from the shop, but it won't fit with my "old style" chain kit... :crazy: