Landy1979

Member
Hello, I daily a series and have been having a knocking problem for a few months now and can't seem to find the problem. The noise it the worst when cold and it vibrates the gearstick and make a very quick knocking. I have replaced the whole ignition system and timed the car to tdc which is factory spec for a 1979 3 main bearing peteol. Please could I have some advice on what else could be causing it thanks
 
CA3D1238-BAEC-4044-8579-C4D87A98751A.jpeg


Some times it helps to record it on you tube so peeps can hear , also useful to work out its frequency ie once per rev twice per rev etc

Is tappet gaps correct
 
View attachment 222373

Some times it helps to record it on you tube so peeps can hear , also useful to work out its frequency ie once per rev twice per rev etc

Is tappet gaps correct
Thanks will do the tappets soon. What would cause piston slap? But it seems like the worn main bearing from what it says on that list, is there a test or any other sign that it could be that
 
Last edited:
Thanks will do the tappets soon. What would cause piston slap? But it seems like the worn main bearing from what it says on that list, is there a test or any other sign that it could be that
You can whip,the sump off and remove main bearing cap to inspect bearing shells I think I did that at the time as I thought it was mains
Normally a nice white metal colour if worn you will see copper showing through
 
You can whip,the sump off and remove main bearing cap to inspect bearing shells I think I did that at the time as I thought it was mains
Normally a nice white metal colour if worn you will see copper showing through
Cheers for all the help I'll be sure the next time I do an oil change to do that which won't be too long now
 
Check the engine mounts and gearbox mounts. I doubt its worn pistons, they don't knock, its more a rattle sound, same with little ends. Most knocks from bottom end wear get worse when the temp goes up as the gaps get bigger and the oil gets thinner. Wear on top end can go the other way as heat expands the pistons and valve gear and it reduces clearances. Check water pump and fan too.
 
With kind of mileage on an old engine there is likely to be some significant wear in virtually all moving parts, especially the bores/pistons and big ends. When you rev the engine, does the knocking noise quicken in respect of the revs? If so, I'd suspect the big ends.

Col
 
With kind of mileage on an old engine there is likely to be some significant wear in virtually all moving parts, especially the bores/pistons and big ends. When you rev the engine, does the knocking noise quicken in respect of the revs? If so, I'd suspect the big ends.

Col
No the engine knock noise doesn't quicken, it's more constant at full throttle, but does get louder uphills. Doesn't knock on flat or downhill.
 
I've got a bit of an update I have just redone the timing to tdc with the vac advance discounted and the revs as low as possible. The knocking has been greatly reduced but there is still a slight knocking/ rumble up hill when full throttle
 
Maybe try retarding it just a fraction more? Timing mark may not be spot on allowing for wear in dizzy gear etc
 
So let me get this straight:-

Rythmic noise not engine or road speed related?

Noise does get louder with engine speed?

Messing about with timing has made some sort of effect?

####

^^^^^^^^^^^If that is correct^^^^^^^^^^^

I would be considering something like a hole / crack in the exhaust system / manifold.


#######

As for timing there are kinda "two types" to consider. You've got spark timing and camshaft timing.

If you look in the workshop manual there is a section on checking the valve timing => This often gets ignored / overlooked - and to be fair is more often than not on a petrol engine less of a problem than it is on a diesel engine but worn cogs and chains do happen...
 

Similar threads