Guest eddscruff Posted February 16, 2007 Just come home in the car and noticed quite a loud knocking noise. The knocking gets faster as the revs increase but you can't really hear it on tick over. Its definately coming from inside the engine but can't work out where from. Seemed pretty smokey too but don't know whether thats a coincidence. Any ideas anyone? Share this post Link to post Share on other sites
travill 0 Posted February 16, 2007 First off i would stop revving it... What was your oil pressure like? Usually big ends on these had you been going round any corners fast before the knocking? Share this post Link to post Share on other sites
Pugnut 9 1 Cars Posted February 16, 2007 big ends are easy to diagnose : accelerate = knocking decelerate(overrun) = knocking maintain rpm/speed = no knocking Share this post Link to post Share on other sites
Miles 331 1 Cars Posted February 16, 2007 They normally knock from tickover with a little throttle, But if this is the case if you;ve been driving it for a while the Crank and the rod/s will be scrap I'm afriad. Share this post Link to post Share on other sites
Normski 1 Posted February 17, 2007 big ends are easy to diagnose : accelerate = knocking decelerate(overrun) = knocking maintain rpm/speed = no knocking It's the opposite of the above if big ends are the trouble. I've had two failures of big ends. Share this post Link to post Share on other sites
Guest badboyracer3500 Posted February 18, 2007 It's the opposite of the above if big ends are the trouble. I've had two failures of big ends. what do you say the prob is then? as one of my MIs is doing that and was told by 3 different people that it is big ends gone. Gavin. Share this post Link to post Share on other sites
Normski 1 Posted February 19, 2007 (edited) what do you say the prob is then? as one of my MIs is doing that and was told by 3 different people that it is big ends gone.Gavin. The symptoms of worn out big end bearings are a heavy knocking noise which is loudest when the engine is not under load i.e. maintaining the same speed driving. The noise is quietest when the engine is under a slight load, i.e. very gentle acceleration or deceleration. At this point you won't be able to hear it at all. I drove my car 25 miles back home from a track day with shot big ends (oil surge), driving slowly but using the acceleration/deceleration technique as much as possible to minimise the knocking. Back home I dropped the sump and replaced the big end bearings which were very worn on two or three of them. No major damage to the crank. It was fine after that. If it's not doing the above then it could be the main bearings that are worn out. The symptoms for that are a knocking/rumbling noise that doesn't go away due to the loading of the engine but gets worse the higher the revs are and may not be heard at idle speed. I've just re-read your first post (eddscruff) and from that it seems most likely the main bearings are the problem. Not as easy to fix unfortunately. Edited February 19, 2007 by Normski Share this post Link to post Share on other sites
