Nick
Posted a lot
Posts: 2,483
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Jan 11, 2007 15:34:05 GMT
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Hi guys picked up a car for a lady friend of mine, it was cheap and we knew of the problems before hand, but obviously need to do something about it.
basically the car is a 1988 bmw 320i pretty mint. but the engine is making a knocking noise. i'm pretty familiar with e30's and the associated problems but i havent come across this one before.
i drove the car home and at 2krpm cruising the noise was very faint and almost unnoticeable. but when revving harder the noise was definately there, and below 2k aswell it was definately making itself known.
at idle revving the engine up the knocking increases with the revs. yet when driving it sometimes seems to rattle faster and not match the revs. especially on the ovverun. it sounds a bit of a "top-endy" noise to me.. i'm thinking along the lines of a valve stuck and the piston hitting it??
anyway heres a couple of video's the previous owner sent before hand
cheers for any help guys
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idea stolen from rattely eddie.
this weeks car count "5"
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ImpManiac
Part of things
Imps... Imps... Imps...
Posts: 868
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Jan 11, 2007 15:39:03 GMT
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If not a big end or a camshaft follower, etc, could be an ancillary problem. Water pump impellor sheared off? Is it an automatic? Torque converter problem? Might explain why it sometimes sounds faster than engine speed. "I'm"  |
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1966 Singer Chamois sprint/hillclimb car in white over blue two tone
1975 Triumph Stag long term project (over 20 years so far) in colour TBA
2003 Vauxhall Vectra GSi 3.2 in black sapphire
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Jan 11, 2007 15:44:44 GMT
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is the timing by belt or by chain. I have heard of worn timing chains causing knocking as they were rather than the traditional rattle.
Is the noise worse or better when the motor is warmed up? Bearings...
Is it a deep knocking or a higher tapping? (I can't hear the sound files at work)
I had an AMC which knocked the whole time I had it. The previous owner had it all appart and couldn't find anything amiss so we just decided "this one knocks".
And finally - I had a Chrysler which knocked something awful under load. Thought the main bearings were toast. Sounded just like it. But in fact the driver side exhaust manifold was slightly loose. Tightened it up and the noise stopped. Darndest thing, sounded JUST like bearings too.
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1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1994 Ford Fiesta
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Jan 11, 2007 15:46:00 GMT
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oh, and... A mates water pump bearings went, they caused a right nasty expensive sounding knocking from the front of the engine. Thought it was a thrust bearing gone, checked the crank end for play, but none, but there was about 3/4" slack on the water pump pulley!
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1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1994 Ford Fiesta
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ImpManiac
Part of things
Imps... Imps... Imps...
Posts: 868
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Jan 11, 2007 16:25:09 GMT
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I had an AMC which knocked the whole time I had it. The previous owner had it all appart and couldn't find anything amiss so we just decided "this one knocks. Could have been a little end bush. An ex-boss had one go on his Land Rover that used to run a Ford Essex V6. He never bothered to fix it - he just ran it. "I'm" |
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1966 Singer Chamois sprint/hillclimb car in white over blue two tone
1975 Triumph Stag long term project (over 20 years so far) in colour TBA
2003 Vauxhall Vectra GSi 3.2 in black sapphire
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Nick
Posted a lot
Posts: 2,483
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Jan 11, 2007 17:00:45 GMT
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its a manual, its a timing belt on these engines. atfirst i thought it was going to be a bearing in the bottom end thats gone, but when i actually got into the car and drove it i am not so convinced now. the noise seems to stay pretty constant doesnt matter if engine is cold or not.
i'll have a better poke round it tomorrow. thanks for the other ideas so far. keep em coming guys.
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idea stolen from rattely eddie.
this weeks car count "5"
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Jan 11, 2007 19:26:46 GMT
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I'd put my cash on the start of a big end problem.
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Engine problem helpbriandamaged
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Jan 11, 2007 19:54:47 GMT
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Sounds like two separate knocks to me...the constant tap from the top end somewhere, and then another one as you rev the engine....IMO that's almost certainly a big end, sorry mate...
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Nick
Posted a lot
Posts: 2,483
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Jan 11, 2007 20:02:13 GMT
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nope its no problem, its not my car and the girl its for i told her to factor in probably buying a new engine. the more i think about it the more it probably is just the big end and something else. the guy we bought it off.. although seemed to be mechanically sympathetic ..he really wasnt. and as he was using it to try learn to drift in (read:nailing it about on the street like a nob) i'm sure its just ragged.
i am much happier to just take an engine out of an e30 and put another one in than actually start spending money and time trying to diagnose and repair something.
i'll have another poke about but i'm already convinced its just far simpler to swap the engine.
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idea stolen from rattely eddie.
this weeks car count "5"
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Jan 11, 2007 20:32:39 GMT
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 Obviously it's very difficult to diagnose noises without being where the car is, but I would remove the auxillary belt/s and start the engine to see if the noise goes before doing anything major. Could well be an alternator or water pump bearing. I've been caught out before like this expecting the worst! 
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Jan 11, 2007 20:35:57 GMT
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sounds typical big end tap when revved, but the top end noise sounds like a stuck valve or when the very end of a rocker breaks. had a 325i that sounded like that before- the valve seat had fallen out!
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Obviously it's very difficult to diagnose noises without being where the car is, but I would remove the auxillary belt/s and start the engine to see if the noise goes before doing anything major. Could well be an alternator or water pump bearing. I've been caught out before like this expecting the worst! 
