intermittent knocking charger noise ??

[mr. clive]

hi guys my charger has suddenly started making unhealthy sounding knocking noises,
i heard it after i started the car so i got out, opened the bonnet for a look,
gave the throttle a little blip with my hand and it stopped.
i thought nothing of it and drove about a mile back to my house,
as i was parking it  started again briefly and then stopped again.

any ideas??

cheers, chris

[samg40]

Are you running toothies? If the belt is slack they sometimes 'slap' at idle but sound ok when the revs rise.

[grungeisdead]

have you ever had the charger serviced in your ownership, or have any history relating to any charger rebuilds.

if you havent, now is probably a good time to split, inspect and replace all bearings and seals. luckily its easy to do, PeteG40 sells all the rebuild gear and has even put up a guide showing all required steps!

but id be doing the following

-check belt tension
-remove belt
-spin engine by hand listening for any unsettling noises
-same with the alternator
-same with the charger
-check the torque of the bolts holding the crank, alternator and charger pulleys

i'd be whipping the charger apart to have a look but then
refit or replace charger belt(s)
tension belt with a friend and a breaker bar on the charger plate 1/2" drive hole

my toothed belts have become slack and caused a slapping noise, the alternator has come loose on its mounts and knocked against the ARB mount,as well as causing the belt to loose tension!

good luck!

[mr. clive]

had a look today and i notice the belt is quite slack, but i went tension it only to discover its at the max adjustment and you cant get a nice taught belt, the belt is brand new so im guessing ive got the wrong size belt??

[scotsjohn]

1040x8x20's the commonest belt size, however some kits used a 1000mm which is a bit harder to find.

[AlexG40]

had a look today and i notice the belt is quite slack, but i went tension it only to discover its at the max adjustment and you cant get a nice taught belt, the belt is brand new so im guessing ive got the wrong size belt??

Mine was like that too, try adjusting using the small amount of play in the alternator, it's not much but it all helps.

[scotsjohn]

Size will be on the belt.

[mr. clive]

ive had a look and i cant seem to get any adjustment on the alternator.

and the markings on the belt have warn away, ant other ways of telling the size?

its a toothed belt  with a 65mm pulley by the way

started it up thismorning and let it idle, and there where no odd noises, just sounded sweet to me :s

[PeteG40]

they alloy or steel pullies?

[mr. clive]

there alloy,
i have noticed the teeth on the charger pulley are wearing,
could this be causing any problems ?

[scotsjohn]

Tell size by counting teeth then multiply by 8(pitch in mm). IE 1040 belt will have 130 teeth, 1000 belt will have 125.

[PeteG40]

if they are alloy 99% sure they will be psd ones and take  a 1040 8m belt.

are you sure your belt has all the teeth... they make a shit sound on idle with a few teeth missing

pete

[ereeiz]

Mine is on the max. adjustment with a 1040 belt and it's only just enough to tension it, I'm going to look at getting a slightly shorter one and see how that fairs. I've done about 5-6k miles in the past 2months on it with no issues though.

[PeteG40]

there is a weeeeny bit of play in the alternator, which can make the difference between slack and tight...

shorter belts are very hard to get hold of... ive tried!

[samg40]

Yep dont underestimate the alternator adjustment. I struggled to get my belt tight and adjusting the alternator for max tightness made the belt a lot tighter.