11 replies to this topic

[cressey]

Hey all,

Tried doing a search but can't really find what I'm after. At Christmas, I fitted an underdrive pulley and short belt. Afterwards, there seemed to be a weird screeching noise under hard acceleration and a bit of a squeeling noise as the engine runs down from being revved. At constant speeds around 2000rpm, there is a metallic chinking noise. The car went to Liam at MMG afterwards for some brake related issues and he noticed it but couldn't diagnose it without a more thorough investigation.

I also did a fairly major service but don't think anything else would cause this sort of noise. Have been back under it and checked the tension of the belt but the noise is still there. The belt definitely isn't slipping.

What I did find on the search was that someone else with a Tubby seemed to have similar problems after fitting the underdrive pulley.

http://www.vx220.org...ent-alternator/

Is there something about this mod that destroys alternators? Tried to take a video of it but you can't really hear the noise I'm talking about.

I'm in two minds as to whether to just take the pulley off after hearing about Simon's crank failing. Bit worried that the damper in the original pulley is there for a very good reason and I've not really noticed any increase in power. Don't want to start this debate as its been done to death but can anyone point me in the direction of a guide to replacing the alternator on a Turbo?

Thanks

[jakbvx]

I only owned a turbo for a few months but i got a whining grinding noise from my nackered alternator and then idle pulley started squeaking, this was all on standard pulley. So i brought a 2nd alternator for £10 off ebay, fitted bottom pulley kit and short belt and all noises disappeared!

[Bumblebee]

Can't say I've noticed any unusual noise and I've been running the smaller pully for 2 years now

[jakbvx]

If I remember correctly, you put the tension on the belt by the new elongated alternator bracket with the kit, if you have put too much tension on the belt then that would eat alternator pulley bearings eventually, and also screech. So like you say, definately not slipping but could be too tight, usually try to get half a twist on the belt on its longest run is a good way to measure tension.

[starlight]

Also, I had a similar sound on mine that I thought was the alternator bearings (i also had an underdrive pulley fitted), but was infact the waterpump failing - the bearing was collapsing and the impeller was scraping on the block. Take the alternator belt off and do a short run to check that that is the source of your noise.

[cressey]

Hmm perhaps it's a bit too tight then. Half a twist seems a lot as its quite a short run from alternator pulley to crank pulley. Do you mean a 90 degree twist or 180?

[cressey]

Ah okay the water pump is worth considering then. That was replaced a little while ago when the cam belt was done so I'd hope it wasn't that. Just guessing its alternator as I didn't fiddle with much else during the service. If push comes to shove, is the alternator a real PITA to change? That 17mm nut is a right sod.

[Pidgeon]

There are worse jobs. You need a decent tool kit and it's arms into the engine bay from the bottom. It doesn't appear there is enough room for the alternator to come out, but it does. I would check the water pump on those symptoms.

[TheRealVXed]

Probably made your alternater bearing go fabiform. Is your pulley solid or does it have a damper on it?

[cressey]

Just had to google what fabiform is. It's definition is "shaped like a bean." Actually made me lol at work. It's a solid pulley from CS and has the additional flange. Thought it was same as MMG's but its not.

[TheRealVXed]

we aim to please

[cressey]

Right I've sort of managed to capture the noise on video. If owning a VX has taught me anything, it's that I'm not very good at describing noises. It sounds louder in reality but you can just hear a kind of screeching as it runs down from being revved. Anyone heard this before?