Timing chain rattle at motorway speed.

herbie

herbie

Member
Hello All,

With my 2200 sc I get the initial top end timing chain clatter for a second or so on start up, I’m guessing that’s until the tensioner with the oil feed wakes up.

Then at motorway speeds 70+ I am fairly certain I can hear it again. Car runs perfectly and has plenty of go.

Would advice be to fit an oil pressure gauge, check top tensioner for blockage in oil feed and condition? Before getting involved in bottom tensioner and chain wear?

Grateful for anyones experience, tricky as this car does a fair bit of motorway driving I’m guessing compared to most, plus I have been eliminating various noises along the way which means you find new ones!!
 
That’s an odd one. If anything it should be fine at higher speeds. A pressure isn’t a bad idea of course. I’d take off the cover behind the top tensioner and check the plug is still in place at the back. I’ve seen one engine where they didn’t use either the tab washer or loctite to hold on place and it backed out.
 
sdibbers said:
That’s an odd one. If anything it should be fine at higher speeds.
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I agree. I'd personally declare it undriveable until I had investigated that. Not only should the tensioners be fully operating at that speed (3500rpm), but the driven side of the chains should be held taut in operation.

I'd remove the cam cover and check the integrity of the chain guide at the top. It may have sheared a bolt and be flappering around against the chains. If nothing is evident there, it warrants deeper investigation.

Unless of course you can verify it is not a timing chain rattle, which is worth considering. Hold the throttle open with the bonnet up and listen around.
 
If you rev the engine to say, 3500RPM, can you hear the rattle then? MIght be worth trying that and seeing if you can zero in on where the noise is coming from?
 
Thanks for the replies everyone. It could be more of a clank than the chain, it’s difficult to say. When it’s started from cold it’s a similar noise, doesn’t sound unhealthy just ‘Clanky’ and the car really quietens down and loses its resonance over 70 and I can then hear it again….
 
I have seen a noisy 4cyl engine which took a lot of work to isolate the cause - the lower drive side neoprene faced rubbing strip (steel backed, bolted to the block) had broken its mounts, and was slipping down into the sump. I would pull the access plugs and inspect inside the timing case.
Dont know how unrestrained chains move at speed, but I have seen film of a timing belt on a SOHC V8 (928) That runs the water pump, oil pump, an idler and a tensioner develop some very surprising standing waves at certain rpm.
 
Jp's example is not uncommon, it would be one of the first places i'd be looking at. The second would be manually adjusting the two tensioners but if they are fully out i'd be thinking of replacing both the chains and praying the wheels are still good. Due to the head design a broken chain equals at least two bent valves and a head rebuild....plus towing from the most inconvenient spot the car can find....
 
I have taken a video of it this morning, just need to figure out the best way of getting that on here…
 
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