Engine Knock/other rattle

Post by **mowogg** » Thu Aug 28, 2008 12:06 am

I am getting noticable knocking noise from my engine at medium to high revs particularly when cold. This is most noticable when i dip the clutch to change gear while the engine is slowing. When the engine warms up it gets less noticable.

The engine was rebuilt a few years ago, and i have noticed a decline in oil pressure. I now get 25 on idle (when very hot after running for 30 minutes) and about 55-60 when cruising. It used to be much higher (70 most of the time)-but it this decling typical after about 15000 miles from a rebuild.

Have I got weat in the main bearings or shjould i be looking elsewher for the problem? Is it more likly my problems are with the exhaust?

Any thoughts appreciated?

Post by **bmcecosse** » Thu Aug 28, 2008 12:15 am

Oil pressure still sounds fine - so yes I would look to exhaust system or perhaps the engine steady bar has broken away from just below the battery box ?

Post by **PSL184** » Thu Aug 28, 2008 12:16 am

Sounds a bit like mine - Mains knackered !!!!
As long as your oil pressure stays where it is it will go on for a lot longer yet though.... Mines still going with zero oil presure at tickover and about 45 when running. 1275 on its way soon

Post by **dalebrignall** » Thu Aug 28, 2008 9:03 am

is the timing ok,,i had a new engine fitted 2 years ago i had done 10000 .iles and had a knocking that sounded like main barings.the sump came off and they were ok the timeing was out.try some stp in the oil if you are worried

Post by **bmcecosse** » Thu Aug 28, 2008 1:18 pm

Unlikely to be mains or big ends with that sort of oil pressure - assuming the gauge is working ok of course. Check all engine mounts/exhaust mounts/engine steady etc.

Post by **MoggyTech** » Thu Aug 28, 2008 3:40 pm

Check for loose starter motor, broken bendix spring, loose gearbox to engine bolts. Oil pressure is fine, but it could still be the center main bearing, which is usually the first to go.

Post by **bmcecosse** » Thu Aug 28, 2008 8:32 pm

Doubt it MT - when the mains go the oil pressure plummets! The other suggestions are indeed well worth following up.

Post by **MoggyTech** » Fri Aug 29, 2008 1:31 am

Yes I suspect other than mains, although I have seen a center main down to copper backing and the other two OK, and oil pressure was only slightly down. Just a pity you cannot get to the rear main with the engine in the car, the front and center are pretty easy with just the sump off!

Post by **bmcecosse** » Fri Aug 29, 2008 10:40 am

Well - for the front you need the timing gear off to undo the two little screws. The mains are on the main oil gallery - and if leaking copious oil the pressure soon sags as the oil gets hot. It's always ok when cold - and if the car is never used more than a few miles at a time - it can go on for years!