Water pump/alternator belt tensioner

[ianc9]

I'm in the process of fitting Emerald/Jenvey fuel injection to my '68 S1.5 2+2 and I'm having a small problem fitting the timing cog wheel and sensor due to the belt tensioning pulley being in the way.

I'm wondering if the tensioner on my car is fitted correctly.

Currently it pushes outward on the belt as it travels up from the crank pully to the water pump (LHS when looking from front of car). To me this is an unusual way to do it as normally they press inwards - thus wrapping the belt a little further around the Crank and water pump pulleys.

Is my setup correct?

Thanks

Ian

[caveman]

Hi Ian,
Here’s a picture of a 69 engine:

And here’s the link to a discussion on similar topic:
https://forums.jag-lovers.com/t/idler-p ... d/353557/5

[abowie]

due to the belt tensioning pulley being in the way.

You can remove the tensioner if necessary.

[tim wood]

I had a similar issue when fitting EDIS . The trigger wheel being too close to the idler. Like you I thought I had assembled incorrectly. Not so I believe !

I had to space our the trigger wheel by a few mm to gain sufficient clearance. Works fine.

[ianc9]

I had a similar issue when fitting EDIS . The trigger wheel being too close to the idler. Like you I thought I had assembled incorrectly. Not so I believe !

I had to space our the trigger wheel by a few mm to gain sufficient clearance. Works fine.

Good suggestion. Spacing would mean the trigger wheel would be clear but the sensor mount would still not fit as its currently set up.

[ianc9]

You can remove the tensioner if necessary.

That would mean a shorter belt?
The 1010mm one from the 3.8?

[ianc9]

Hi Ian,
Here’s a picture of a 69 engine:

And here’s the link to a discussion on similar topic:
https://forums.jag-lovers.com/t/idler-p ... d/353557/5

Ok - So mine is set up correctly.

[tim wood]

I had a similar issue when fitting EDIS . The trigger wheel being too close to the idler. Like you I thought I had assembled incorrectly. Not so I believe !

I had to space our the trigger wheel by a few mm to gain sufficient clearance. Works fine.

Good suggestion. Spacing would mean the trigger wheel would be clear but the sensor mount would still not fit as its currently set up.

Yes, I had to adjust the sensor mount as well.
Many speak of removing the idler, which I seriously considered but my thoughts were that it’s in place for a reason and who am I to judge on this.

[ianc9]

Ok - So belt tensioner is gone and trigger wheel + sensor now fit.
However, the belt is not really tight enough at max adjustment. Is the only option to go with the shorter 3.8 belt (1010mm I think) or is there a size in between?

[caveman]

Some mention of belt sizes here:
viewtopic.php?f=4&t=17983&p=146538&hili ... er#p146538

[ianc9]

Some mention of belt sizes here:
viewtopic.php?f=4&t=17983&p=146538&hili ... er#p146538

Thanks for that. I had a read.
I'm pretty certain I currently have a 1100mm (I measured the outer circumference as 1120mm) belt as fitted to 4.2 cars with tensioner.
With the tensioner now removed I have too much slack.

I know others on this forum have removed their tensioner and I'm wondering what belt they used.

I can see there's a 1010mm belt for the 3.8 cars - is it that one?

[caveman]

More info here and the link within it has specifics, hope this helps:
viewtopic.php?f=3&t=16091&p=132013&hili ... lt#p132013

[caveman]

There’s a possibility that a Mk 2 belt will fit without tensioner but some have suggested that removal could put stress on water pump bearings;
viewtopic.php?f=4&t=8181&p=62081&hilit= ... ner#p62081

[ianc9]

I did see both those threads.
One US company is advertising the belt with the different part code (C26376) but it not mentioned anywhere else.
I would not be worried about bearing wear - Most older cars did just fine without a tensioner - and anyway, I have no choice since it doesn't fit along side my injection pickup.

I'm just trying to determine which belt people are using when they remove the tensioner.
Is it the 1100mm double V one with code C26376 (and how do they tension it sufficiently?) or the 1010mm double V one from the 3.8 with code C19524. Or... Is there another double V belt? :)

[ianc9]

Can I ask a different Q.
Are the belt lengths (1100mm, 1010mm) the outer circumference or the inner or some other measure?

Maybe someone with a double V belt of known "Length" could measure the external circumference?

This will help me determine what belt I currently have (1050 internal, 1120 external), which is a little too long, and determine which shorter one I should try.

Thanks

Ian

[mgcjag]

Belts should be measured on their outside.....Steve

[ianc9]

Thanks that help

[tim wood]

How about this:

https://www.normanmotorsltd.com/c19525- ... 7513-p.asp

1050mm double v belt.

[ianc9]

Measured again and outer circumference is 1100mm
Thanks Steve.
And so I've ordered the 1050mm belt. Thanks Tim

[ianc9]

I ordered fan belt C19523 (Double V 1050mm long) but the one I received was 1100mm when measured on outside :(

I've asked them to send the correct one.