M30 death knock

[johnl320]

Having nearly finished my project (trying to find prop) I regulary run the engine just to make sure all is well. Tonight however I started it up and heard a nasty knocking noise. I took the fan belt off to eliminate the water pump etc and the knocking is still there, I'm having real trouble locating the noise not deep enough for bottom end knock but not tappy enough for top end. Gonna flush it tomorrow and put fresh oil in.
Any ideas ( long shot I know )

john

[Yaninnya]

Chain tensioner? Is it on front of the engine slightly on right side (exhaust side)?
Jan

[DRIFTBOY]

Very rare for bottom ends on the M30 to give trouble purely through high mileage, my 186,000 mile crank was still well within tolerance for standard bearings!
But in my experience big end knock isn't always a deep rumble.

Something that happened on mine once was that one of the circlips on a rocker shaft pinged off and the rocker moved to the side of the valve stem and was pushing down on the valve spring cap, obviously causing an alarming rattle due to the massive gap! Might be worth taking the cam cover off and checking...?

[johnl320]

Thanks for the replies. Further investigation today has pointed at the clutch or gearbox, if I hold the gearstick further forward in 3rd the niose goes away mmm strange

john

[DRIFTBOY]

Was the engine originally in an automatic car?

Is there a spigot bearing in the crankshaft?

Just a thought!

[gareth]

i know getrag boxes often develop a very loud rattle in idle. my M20 one used to rattle so loud it could be heard over my scorpion exhaust

does the noise go if you dip the clutch?

[johnl320]

Was the engine originally in an automatic car?

Is there a spigot bearing in the crankshaft?

Just a thought!

Yep brand new spigot stuck in before assembly

john

[johnl320]

i know getrag boxes often develop a very loud rattle in idle. my M20 one used to rattle so loud it could be heard over my scorpion exhaust

does the noise go if you dip the clutch?

Clutch not bled yet,only just fitted the flexible pipe to the slave cylinder, will bleed and let you know. Oh best check the gearbox oil while I'm there

Cheers for the replies fellas

john

[gareth]

check that you need gearbox oil and not ATF... my manual box takes ATF!

[DRIFTBOY]

check that you need gearbox oil and not ATF... my manual box takes ATF!

Mine too!

It also rattles at idle, but goes when you dip the clutch. Release bearing was brand new!

[Dan318-is]

i know getrag boxes often develop a very loud rattle in idle. my M20 one used to rattle so loud it could be heard over my scorpion exhaust

does the noise go if you dip the clutch?

Lay shaft, common on e30s as you like!

[DRIFTBOY]

i know getrag boxes often develop a very loud rattle in idle. my M20 one used to rattle so loud it could be heard over my scorpion exhaust

does the noise go if you dip the clutch?

Lay shaft, common on e30s as you like!

And E34s I presume as well then! ?

[johnl320]

i know getrag boxes often develop a very loud rattle in idle. my M20 one used to rattle so loud it could be heard over my scorpion exhaust

does the noise go if you dip the clutch?

Lay shaft, common on e30s as you like!

Its an E28 M535i dogleg gearbox not known for there robustness. Its been completely silent for for the last month with only the odd run up to check everything is okay. No propshaft attached yet ( still trying to find one)

john

[Dan318-is]

i know getrag boxes often develop a very loud rattle in idle. my M20 one used to rattle so loud it could be heard over my scorpion exhaust

does the noise go if you dip the clutch?

Lay shaft, common on e30s as you like!

And E34s I presume as well then! ?

Assuming your using an e34 box im not so sure! But getrag 240 boxes (m20, m42 etc) are known for it!

[johnl320]

Now sorted thanks fellas, It was the clutch lever rattling around in the end. Fitted a slave cylinder and bled it, noise gone. phew!

john