Dupp Dupp Dupp noise......

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A

agew

Active Member
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Location
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..... best description I can come up with!!

Defender CSW X reg TD5 190k - when you start up (seems particularly cold damp mornings, which is why its bugging me again) on tickover this dupp dupp dupp from the air intake on the rh wing, really noticeable as I walk past to close the gate in the morning.

It will carry on for random short/longer time then suddenly just disappear, and rarely if ever does it when warmed up.

Sounds a bit like someone patting the bottom (steady...!!) of a dustbin?

Could be imagination, but seems to run a little rougher while 'dupping', and smooths out when it disappears.

Any ideas at all? Don't feel its doing any harm, but would be nice to know.

Cheers, A
 
jamesmartin said:
you only have 4 glow plugs rear cylinder may run rough for a few seconds till warmed
Click to expand...

Like your thinking JM. Would that feed some compression back into the intake....? Even if not ignited, the compressed fuel/air mix ought to be 'exhausted' on the third stroke...? Just thinking out loud about the noise apparently generated in the intake system somewhere......

Guess its possible one of the 4 plugs is u/s - they were all new with an AMC head 2 years ago, but I'll check them when I get a chance (2013 probably.....;))

Sounds v logical source anyway - and not life-threatening! A
 
jamesmartin said:
usually noise in intake is in correct valve opening or sign of leaking/burnt valve ,tricky one without hearing it
Click to expand...
My old TD5 engine occassionally used to make a similar noise heard through the intake vent. Turned out it was a sticky hydraulic valve lifter that was pumping up too much. It had a small piece of grit/swarf in it that jammed the adjuster and would not always let the valve close fully. Only found out the cause when the engine was stripped due to the oil pump sprocket comming loose. Scoring was easily seen on the adjuster pistion. As far as I know the adjusters are not servicable.
 
Shifty1962 said:
My old TD5 engine occassionally used to make a similar noise heard through the intake vent. Turned out it was a sticky hydraulic valve lifter that was pumping up too much. It had a small piece of grit/swarf in it that jammed the adjuster and would not always let the valve close fully. Only found out the cause when the engine was stripped due to the oil pump sprocket comming loose. Scoring was easily seen on the adjuster pistion. As far as I know the adjusters are not servicable.
Click to expand...
similar or the same adjusters are used on td4, cost a piston and head £300 to put right i check them all since
 
Well that's not so encouraging........:(

Will keep an 'ear' on it - of course all the valves were brand new with the AMC head, but the hydraulic 'tappets' were transplanted having been carefully stored during the cracked head diagnosis and subsequent fix, but who knows what might have drifted into the pot they were in, or which one might have been on the verge of sulking anyway.

Guess a compression test would reveal an constant problem, but as the dupp dupp disappears rapidly it would be one of those 'will it or won't it' tests......

Can't immediately picture the assembly, but hydraulic tappets only inspectable/removable with cam shaft out I think....??!! A
 
agew said:
Well that's not so encouraging........:(

Will keep an 'ear' on it - of course all the valves were brand new with the AMC head, but the hydraulic 'tappets' were transplanted having been carefully stored during the cracked head diagnosis and subsequent fix, but who knows what might have drifted into the pot they were in, or which one might have been on the verge of sulking anyway.

Guess a compression test would reveal an constant problem, but as the dupp dupp disappears rapidly it would be one of those 'will it or won't it' tests......

Can't immediately picture the assembly, but hydraulic tappets only inspectable/removable with cam shaft out I think....??!! A
Click to expand...
In the good old days we used to drain the engine oil on the Rover V8s and fill with ATF or diesel as it was cheaper and would go straight in the Tran**** (not a typo ;)) fuel tank when drained. Run the engine at idle until hot then take it round the block for a few miles at gentle throttle before draining out and refilling with engine oil. It used to flush the lifters 9 times out of 10 if they were playing up. Not so sure its a good idea in a high compression diesel engine like the TD5 though.

Our competition 400 bhp Rover V8 dragster engines only ever ran with ATF in the sump but they were stripped and rebuilt after every meeting.
 
Shifty1962 said:
In the good old days we used to drain the engine oil on the Rover V8s and fill with ATF or diesel as it was cheaper and would go straight in the Tran**** (not a typo ;)) fuel tank when drained. Run the engine at idle until hot then take it round the block for a few miles at gentle throttle before draining out and refilling with engine oil. It used to flush the lifters 9 times out of 10 if they were playing up. Not so sure its a good idea in a high compression diesel engine like the TD5 though.

Our competition 400 bhp Rover V8 dragster engines only ever ran with ATF in the sump but they were stripped and rebuilt after every meeting.
Click to expand...

...... might be a bit radical for me, but will keep an open mind!! A
 
Hope this helps & might not make any sense.

I had the same noise described mine as pop popping,it seemed to come through the snorkel.
My turbo eventually gave up the ghost fitted a new turbo changed the oil 2nd hand intercooler just to be sure, the guy who changed the oil didnt swap the spinner i couldnt here it running down after i turned the engine off and i dont think the quality of the oil was up to much. the poping dissapeared for a week or so then came back.
I then changed the oil for fully synthetic swapped both filters the noise has now totally dissapeared and has been gone for a couple of months so it seemed the filters & fully synth oil has done the trick although i dont know how. I also changed the front pipe which had hole in the flexi bit i iassumed this would allow it to drag in too much air this could have helped.
 
pat murphy said:
Hope this helps & might not make any sense.

I had the same noise described mine as pop popping,it seemed to come through the snorkel.
My turbo eventually gave up the ghost fitted a new turbo changed the oil 2nd hand intercooler just to be sure, the guy who changed the oil didnt swap the spinner i couldnt here it running down after i turned the engine off and i dont think the quality of the oil was up to much. the poping dissapeared for a week or so then came back.
I then changed the oil for fully synthetic swapped both filters the noise has now totally dissapeared and has been gone for a couple of months so it seemed the filters & fully synth oil has done the trick although i dont know how. I also changed the front pipe which had hole in the flexi bit i iassumed this would allow it to drag in too much air this could have helped.
Click to expand...

Oil and filter change seems the only logical common ground (but willing to bear in mind the turbo factor....).

Brand new fully synth and filters on mine, no effect (better or worse) on dupping.

Which 'front pipe' do you mean you changed? I think all hoses are originals on mine so some/many could be well past their best...... A
 
Hi agew

exhaust front pipe

Pat
 

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