Sigma timing belt help please.

[DJ.]

I'd be grateful for your advice about this

I have just swapped the timing belt and water pump for the second time on my Sigma 125. When I started the car, I could hear what I can only describe as belt noise from the front of the engine. It wasn't really noticeable at idle but became much more noticeable at 2000rpm.

I have tried running the car briefly with the accessory belt removed and it sounds the same. I have never noticed this sound from the car before.

I have only done two things differently to the last belt change:

1. I couldn't get a Gates belt kit from a reputable source (all out of stock), so I bought a Dayco one from www.buycarparts.co.uk

2. I fitted the Caterham parts to convert the tensioner to a fixed one used on the 150 engine. It shouldn't be possible to get the tension wrong as the spring in the unit is used to start with and then the bolt nipped up to secure it in the correct place. I suppose the lack of movement in the tensioner may make it sound different though.

Any ideas?

Thanks

Duncan

[K7 VCT]

Timing belts can make different noises, had or tin top one replaced a while ago, belt turned out to be very noisy for a few thousand miles, now as quiet as old one

[DJ.]

Thanks that sounds encouraging.

I'm planning to remove the cover and have a good look at the tensioner and belt while it is running just for peace of mind.

[DJ.]

OK, I've run the car with the belt cover off and it's more of a whining noise. I used the stethoscope trick using a piece of wood pushed against parts of the engine and the noise was a lot louder from the bolt securing the timing belt tensioner. I have a bad feeling that the tensioner bearing is faulty (can't really take a chance on that failing!), so I'm going to replace that and see whether that gets rid of the noise 

[Tom_Arundel]

How tight is the belt...can you twist it on the tension (other) side?

[DJ.]

Thanks Tom, I haven't checked the tension as the spring loaded tensioner is supposed to apply the correct tension to the belt before the bolt is tightened. I made sure I turned the engine over with the tensioner free to move and checked the timing before and after locking the tensioner in place.