post-rebuild vibration, any experts?
Discussion
Had a very unusual cam lifter failure on Audi 4.2 V8. UK specialist rebuilt the bank 2 cylinder head, valve had bent so head was sent away and prepared with new valve stem seals, exhaust guides etc new (pre-loved) camshaft used. Total cost = value of car
They know these well and knew I was in Scotland, total 350 miles one way. Collected car, seemed to run fine. He admitted they hadn't run it much, trip showed only 1 mile since battery connected but you can't tell before this. I didn't think of running in at all I just had to get home, it's only new valves bottom half engine untouched. We assumed any lifter bearing debris was exited in oil and clean of sump.
First 200 miles could be considered perfect 2-3000 rpm in congestion doing 50-70 mph, As roads cleared I managed a bit more but generally 80 mph and a couple of 90 mph sections, engine didn't go over 3500 rpm and was at temp all the time. Next day it didn't feel right. no bad noises, warning lights etc but just not revving properly and above 2k rpm you can feel a vibration that at 3k rpm you don't want to rev any more and can feel subtle vibration in cabin. Making good power/mpg just feels rough
Was in denial, slept on it and then cleared my diary and drove down slowly back them for 1st thing monday. Good mpg, again nothing untoward. So don't need emotional support (yet), their main guy is on holiday and I think it's f*cked and maybe bent valve again, needs engine out and maybe a difficult discussion of money etc. clearly should be under some sort of warranty
I've done usual AI type search and suggests running in shouldn't be an issue, I know it's difficult and we can only speculate but does anyone have any real insight? could this caused by running in procedure, swarf/debris from lifter bearing or something else such as installation error
Thoughts??
They know these well and knew I was in Scotland, total 350 miles one way. Collected car, seemed to run fine. He admitted they hadn't run it much, trip showed only 1 mile since battery connected but you can't tell before this. I didn't think of running in at all I just had to get home, it's only new valves bottom half engine untouched. We assumed any lifter bearing debris was exited in oil and clean of sump.
First 200 miles could be considered perfect 2-3000 rpm in congestion doing 50-70 mph, As roads cleared I managed a bit more but generally 80 mph and a couple of 90 mph sections, engine didn't go over 3500 rpm and was at temp all the time. Next day it didn't feel right. no bad noises, warning lights etc but just not revving properly and above 2k rpm you can feel a vibration that at 3k rpm you don't want to rev any more and can feel subtle vibration in cabin. Making good power/mpg just feels rough
Was in denial, slept on it and then cleared my diary and drove down slowly back them for 1st thing monday. Good mpg, again nothing untoward. So don't need emotional support (yet), their main guy is on holiday and I think it's f*cked and maybe bent valve again, needs engine out and maybe a difficult discussion of money etc. clearly should be under some sort of warranty
I've done usual AI type search and suggests running in shouldn't be an issue, I know it's difficult and we can only speculate but does anyone have any real insight? could this caused by running in procedure, swarf/debris from lifter bearing or something else such as installation error
Thoughts??
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