I have an 87 4A-c powered, 5 speed rolla hatchback.

Yesteday while driving home the motor developed a loud knock.

Wondered if anyone has had this happen and what the prob turned out to be.

It gets faster and louder as the revs increase. Fingers crossed it aint a rebuild.

Coolants fine, oils clean so i've ruled out head gasket.

I think it could be one of two things :

1. Big end bearing

2. Water pump (bearing)

All comments welcome.

Dingo.

Knock as in metal knock or pinging?

Sounds like a knock, and it's quite loud. Not pinging.

Dingo.

Edited October 21, 200817 yr by GASRB6

Maybe try a long screw driver and putting it on the bearing and with your ear on the end of the screw driver and see if you can really hear the knock through the screw driver on that bearing.

 

Seen foremans and mechanics do this so I would suggest to try.

Sounds like piston slap to me.

Happened to me many years ago on my old 4ac powered ae82 rolla auto .

At first I thought it was just the tappets needing adjusting but the beat of the sound was too slow at idle to be that and as time went on it became more of a clunking noise, till it let go on me at a set of lights.

Put a huge crack in my block but somehow I still managed to limp it home about 5km, just jeeping the revs above 200rpm and dumping all the oil and coolant in the process.

A week later got a low km jap import 3a motor for it and was a happy little P plater pizza delivery boy for 5 months till I rear ended it into the back of a starlet (It was about 10 years ago)

http://www.rollaclub.com/board/?showtopic=16966

 

Eeep!

 

I doubt its that bad but chances are you're going to have to tear the motor down to find the problem.

http://www.rollaclub.com/board/?showtopic=12429

have you heard it before it was loud like, when it was quiet?

 

and from what i read it sounds like a big end

 

max

gotta agree.

either big end or oil pump they have a similar kind of clunk/knock noise

and if its the oil pump, it will be the big end soon anyway...

Oil pressure light hasn't come on.

Oil, coolant and all ancilaries are fine. :wink:

Piston slap could be a real possibility.

The motor is breathing quite heavily from the oil cap when running.

The sound seems to be coming from the combustion chamber.

Looks like it's tear down time for the old girl. :lolcry:

Fingers crossed it's not too costly.

Thanks for all the replies.

Dingo.

Edited October 24, 200817 yr by GASRB6

Update : Turned out to be the air conditioner fan belt. It had delaminated with around 4 inches missing on the inside of the belt. At idle it was just noticeable but moving it would expand and hit the alternator fans hence sounding like a knock. So I changed the belt and all was good. Got new tyres and clutch 3 weeks ago and the little 87 rolla hatch is purring like a kitten. Also got new hubcaps, woohoo.

Thanks for all your input.

Long live the rolla.

Dingo.

Edited May 23, 200917 yr by GASRB6