Any Duplex Timing Chain Experts?????
Discussion
Yet again I need your help guys. I have just had an engine built for my mini, Really pleased with it apart from a very odd noise.
I have had a very faint noise coming from my engine at 2000 and 4000RPM, only found out the latter just the other day. It sounds very metallic but also very light, almost like a piece of brake pipe vibrating against the body work. If I put my foot on the clutch the noise would change, but not disappear. It would do it stationary and in all gears.
The engine has been running in for the past 1000miles with an oil change @ 500. Nothing too bad on the Mag. plug during the oil changes. Over the last week it got alot worse, so it went back to the engine builders on Monday. I called in today to see the engine and box apart with the Engineers looking at the box. I didn’t think it could be this as it seemed to be engine related and not gearbox, but I let them get on with it.
They walked away scratching their heads, we had a chat then all the main caps were removed, thrust bearings checked, all perfect. The timing chain cover came off. There is a throw washer on the crankshaft which had score marks in it from the Duplex Timing Chain, they said it was normal and most 'S' type engines did it, but I am not convinced.
My theory is they fitted this washer around the wrong way causing the washer to contact the timing chain and by pressing on the clutch that Crank moves fractionally, and thus a slight change in the noise.
Does anyone know the correct way of fitting these? Am i barking up the wrong tree? Its just I don’t want to pay for a gearbox rebuild if it was just this washer.
Hope you can help! Cheers peeps!
>>> Edited by TVR SLag's BiL on Friday 5th March 18:47
Wotcha, M8,
The correct way to fit the thrower ring is difficult to explain. It goes in so that the outer part is closest to the chain rather than closest to the cover. I hope this makes sense.
The thrower ring should not ever get marked by the chain, however, as it is touching the sprocket face and can't move relative to the crank and chain. Thus if the crank end-throw pushes the crank towards the timing chain cover then the whole lot moves together. Bear in mind that the total crank throw should not be any more than 0.005" and less in a newly built engine.
I have had a problem in the past when going to a Duplex chain. The timing cover which has the breather pipe also has an oil deflector flange welded in and this needs to be ground away to clear the duplex chain. The first time I did this there was just a little bit of chain touching the flange and it made a bit of a noise. That would cause a problem and it's worth just checking out.
Other than that, could it be transfer gear end float (unlikely)? How about a mis-aligned water pump. If one or both of the water pump dowels is missing (not unheard of) the water pump impeller could just 'kiss' the block (it's happened before).
The only other thing I've ever had to cause a strange noise at the front end of the engine was recently when the front plate fatigue fractured where the alternator bolt goes through. This caused a low-speed vibration which went off at about 2800 rpm. I thought it was a cracked cam-follower and stripped the engine down after taking it out only to find it was just that.
I'll be very interested to hear what it is.
I hope this helps.
Peter
The correct way to fit the thrower ring is difficult to explain. It goes in so that the outer part is closest to the chain rather than closest to the cover. I hope this makes sense.
The thrower ring should not ever get marked by the chain, however, as it is touching the sprocket face and can't move relative to the crank and chain. Thus if the crank end-throw pushes the crank towards the timing chain cover then the whole lot moves together. Bear in mind that the total crank throw should not be any more than 0.005" and less in a newly built engine.
I have had a problem in the past when going to a Duplex chain. The timing cover which has the breather pipe also has an oil deflector flange welded in and this needs to be ground away to clear the duplex chain. The first time I did this there was just a little bit of chain touching the flange and it made a bit of a noise. That would cause a problem and it's worth just checking out.
Other than that, could it be transfer gear end float (unlikely)? How about a mis-aligned water pump. If one or both of the water pump dowels is missing (not unheard of) the water pump impeller could just 'kiss' the block (it's happened before).
The only other thing I've ever had to cause a strange noise at the front end of the engine was recently when the front plate fatigue fractured where the alternator bolt goes through. This caused a low-speed vibration which went off at about 2800 rpm. I thought it was a cracked cam-follower and stripped the engine down after taking it out only to find it was just that.
I'll be very interested to hear what it is.
I hope this helps.
Peter
Check the backplate had been sufficiently countersunk, and c/sunk screws used such that they didn't contact the chain; and the 'dimple' in the (A+ only) timing cover was flattened to avoid contact, as well as the lip around the breather hole...
Also, if the engine was built, was the crank pully shimmed to align with the cam pulley??? This is often missed, and can lead to all kinds of problems!
Agree with the above 'orientation' of the oil thrower...
Also, if the engine was built, was the crank pully shimmed to align with the cam pulley??? This is often missed, and can lead to all kinds of problems!
Agree with the above 'orientation' of the oil thrower...
Hey, TurboDave, that's a thought. I bought some socket head 1/4" unf bolts some time ago and the heads were too big in diameter for this. In the end I had to grind them down after fitting them to get the clearance. I'd completely forgotten about this.
I never think the shimming is all that critical, even though I always do it.
I never think the shimming is all that critical, even though I always do it.
A bit late i know but jus got back from a beautiful skiing holidsy in ze alps so i know ull forgive me!!
I had the same problem and its was the chain cover.
The solution i found was to bash the crap out of the cover till it fit! lol
Taking great care not to warp the cover!
Make sure u tell us if this was the cause
I had the same problem and its was the chain cover.
The solution i found was to bash the crap out of the cover till it fit! lol
Taking great care not to warp the cover!
Make sure u tell us if this was the cause
Got the car bak last night, drove it to Stansted Airport this morning, and its perfect!
There were two prroblems. First the oil thrower was catching on the timing chain, nothing too serious but not right. The real cause was all the bolts coming undone on the Verto clutch
causing this vibration. The engine came apart before they found the problem.
Big thanks to everyone on here and Carlow Engineering, who sorted it out FOC.
Cheers guys
There were two prroblems. First the oil thrower was catching on the timing chain, nothing too serious but not right. The real cause was all the bolts coming undone on the Verto clutch
causing this vibration. The engine came apart before they found the problem. Big thanks to everyone on here and Carlow Engineering, who sorted it out FOC.
Cheers guys
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