V8S Fan belt spontaneously jumped off the pullies

[bicycleRepairMan]

I drove to my office yesterday. No problems, nothing unusual. No warning lights, "normal" engine temperature.

However, it seems that when I started the engine to come home, the fan belt spontaneously jumped off the pullies. At startup, the battery warning light stayed on, and after a minute the engine temperature shot up!

The fan belt had simply come off. It seems undamaged, pristine, even. It was simply hanging loose on the water pump.

I'm fairly certain the fan belt was properly tensioned. No screaming belt when I start up, no obvious slack when I checked it (it was serviced by Lloyds at Warminster, and they made a note of tensioning the belt).

There is no obvious damage to the belt itself, although it does now seem a little slacker than before, but I probably stretched it last night forcing it back onto the pullies as I had no tools to slacken the alternator first!

Looking at it today, it looks like the water pump pulley is 1-2mm forward of the line of the crank pulley - there is a slight bend in the fan belt.


Is this just a regular TVR issue that I need to live with? Buy a couple of spare belts and keep a spanner in the car?

Or should I adjust the pullies so they align perfectly (I'm not sure I know how to do that at the moment).

It seems odd there is no spring loaded tensioner on the belt - it's just the crank, water pump and alternator. Has anyone added a jockey wheel, especially on the longer run from the alternator to the crank?

Cheers


Ian

[magpies]

may be worth asking the same question on the Chim and Griff pages as they use the same engine.
Also the facebook S page is more active than this page.

[Penelope Stopit]

bicycleRepairMan said:

but I probably stretched it last night forcing it back onto the pullies as I had no tools to slacken the alternator first

If you mean you got the belt back on by hand, I think the belt was slack

[bicycleRepairMan]

Thanks everyone.

It sounds like I need to add "fan belt tension" to my weekly checklist. The belt was absolutely perfect when it came back from Lloyds 6 weeks ago...

Ian

[Penelope Stopit]

bicycleRepairMan said:

Thanks everyone.

It sounds like I need to add "fan belt tension" to my weekly checklist. The belt was absolutely perfect when it came back from Lloyds 6 weeks ago...

Ian

If it is a recent new belt it could have stretched

If it is an an older belt something could have moved

[Classic Chim]

I presume this is the reason for the tensioner pulley wheel on later engines.
To save a slightly loosening belt coming off!

[UpTheIron]

It's testing my memory here, but I recall on my Chim (although possibly only the second - serp rather than pre-serp) it was possible to fit the belt wrongly. Everything still turned the right way but as a result it was slightly looser. Only found this out after a service where the mechanic put it back the wrong way!

[v8s4me]

I've not heard of this one before. I've had my V8S since 2006 and this never happened to me or any other V8S I've know about. Chances are something is loose, alternator maybe? Also check you have the correct belt. If the 'V' section isn't correct the belt might be sitting too high in the pully.
You shouldn't have been able to get the belt back on very easily if every thing was adjusted correctly.

[GreenV8S]

bicycleRepairMan said:

forcing it back onto the pullies as I had no tools to slacken the alternator first!

If you can get a V belt back on without slackening off the tensioner, it's too loose.

bicycleRepairMan said:

Looking at it today, it looks like the water pump pulley is 1-2mm forward of the line of the crank pulley - there is a slight bend in the fan belt.

It can be deceptive because the pullies are not all the same thickness, but the belt itself should run completely in the same plane. If the pullies are not aligned, that could encourage the belt to climb out of the pulley. You would normally check the alignment with a straight edge, but if there's enough misalignment to be seen even without a straight edge then that's probably enough to be a problem.

[mk1fan]

You can buy a turnbuckle type tension adjuster for the non-serp RV8 with rose joints. Available in stainless. Need spacers and new bolts. Real easy mod and allows really easy tension of belt.

Ebay is your friend.

I suspect the 'factory' tensioning set up may have slipped.

[bicycleRepairMan]

Something like this:


Looks like an interesting idea. I wonder if you could take it a step further and use a gas strut in its place.

[phillpot]

bicycleRepairMan said:

Looks like an interesting idea

Looks like it should be on a barbed wire fence


Bought this from a guy on the Wedge Forum for my Griff but same engine as your V8s

[zombeh]

Fit a slightly shorter than standard belt, the rover length one is an utter bd to tension properly as the car is in the way.