9 replies to this topic

[tootgarook]

engine knocking sound recently developed, car starts well, no lack of power, and not blowing any smoke.
sound appears to be from top of engine/head.
have noticed some water droplets collecting in rocker cover cap. no water on main engine .
mini 1964 850cc.
have taken car to x 2 garages, one said "blown piston " the other said " big end gone".
I was wondering could it be tappets ?

Any advice would be much appreciated.

thanks

[clambert81]

I'd check the tappets first but the tend to rattle not knock though. check the cylinder compressions when the engine is hot. If these are all OK then it is either a littl end or detonation. Detonation is when the ignition is too advanced usually with a weaker than normal mixture.

[MRA]

does it still knock when under load ? if so then its probably not big ends

[nomininolife]

engine knocking sound recently developed, car starts well, no lack of power, and not blowing any smoke.
sound appears to be from top of engine/head.
have noticed some water droplets collecting in rocker cover cap. no water on main engine .
mini 1964 850cc.
have taken car to x 2 garages, one said "blown piston " the other said " big end gone".
A blown piston, does the engine only run on 3 cylinders. Big end gone, that would generally be a thud from the bottom end rather than a knocking.
I was wondering could it be tappets ?

As said tappets would be a rattle rather than a knock. I think a cylinder leakage test is in order, it sounds like the head gasket to me.


Any advice would be much appreciated.

thanks

[tootgarook]

does it still knock when under load ? if so then its probably not big ends

if i drive up hill and don't change down gear and make the engine struggle , the knocking disappears. the higher the rev the worse it gets. if i drive really conservatively at low rev can aviod knocking noise !

[MRA]

that sounds like big ends to me

A head gasket would get worse under load..... tappets would just rattle more with the increase in engine revs

[nomininolife]

He does say it gets worse under load


David

[MRA]

Does he ? I must have missed that

However I did see this

if i drive up hill and don't change down gear and make the engine struggle , the knocking disappears. the higher the rev the worse it gets. if i drive really conservatively at low rev can aviod knocking noise !

[tootgarook]

thanks for advice.

think I will buy a compression test kit to start with, unfortunately local garages here are
reluctant to mend mini's, so it's down to me with limited knowledge +book.
Have just bought complete 1000cc engine off ebay which is mean't to go, worst case it might be good for parts !

[tootgarook]

850cc engine, just completed compression test ,ranging from 95 - 100psi dry, with oil in cylinders went up to 120psi. !!!
Knocking appears to be getting worse from inside engine.

Have a complete secondhand 1000cc engine being delivered Saturday, is a change over
that difficult ? never done one before.

any advice would be great.

thanks