ProRace crankshaft damper - which belt?

Technical advice Q&A

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PhilBell
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#1 ProRace crankshaft damper - which belt?

Post by PhilBell » Sun Jul 01, 2018 5:34 pm

On recommendation I have replaced my failure-prone crank damper (the rubber was breaking up after just 20k miles) with a ProRace one which involved converting from single-V pulleys to double-V. Problem is that the 1050mm belt is too long, allowing the belt/tensioner pulley to cut into the bottom radiator hose despite the dynamo being at the limit of its adjustment strap. Measuring the new belt when fitted, it stretches to 1059mm, but relaxes back to 1050 when removed.

Measuring the pulley run and working out the required outside diameter, I've calculated than I need a belt more like 1040mm fitted/stretched, so 1030mm relaxed.

Anyone done this conversion and solved this problem? After seven months' work on the car, this is all that stands between the E-type and Le Mans Classic.
Phil
1962 FHC 885626

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abowie
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#2 Re: ProRace crankshaft damper - which belt?

Post by abowie » Sun Jul 01, 2018 11:06 pm

I think the belt for the MK2 is about 20mm shorter.
Andrew.
881824, 1E21538. 889457..oops
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

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Gerry
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#3 Re: ProRace crankshaft damper - which belt?

Post by Gerry » Mon Jul 02, 2018 12:40 am

I think there is a double row belt intended for an early 4.2 car that is a bit shorter,I used this belt and got rid of the tensioner about 15 years ago when I installed an alternator.

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mark10337
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#4 Re: ProRace crankshaft damper - which belt?

Post by mark10337 » Mon Jul 02, 2018 7:39 am

Hi

Try here.
http://www.bearingshopuk.co.uk/belts/v- ... ts/?cat=33
Different lengths and profiles can be selected on the left hand side.

Also stocked here. This will show you the GATES manufactured belts. Various sizes and widths.
https://www.radwell.co.uk/en-GB/Search/ ... goryId=311

Hope that helps
-Mark

1969 Series 2 OTS, Regency Red
'Life's to short to drive a boring car'

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PhilBell
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#5 Re: ProRace crankshaft damper - which belt?

Post by PhilBell » Mon Jul 16, 2018 10:25 am

The belts I have tried are:
Late E-type 3.8 (labelled 1010mm but all the ones I've found are 990mm).
Mk2 3.4/3.8 (1050mm) and therefore too long.
E-type 4.2 (1100mm and way too long).

I've measured what I need and it's 1020-1030mm, maybe 1040 at a push.
Phil
1962 FHC 885626

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#6 Re: ProRace crankshaft damper - which belt?

Post by Heuer » Mon Jul 16, 2018 10:53 am

Why not get rid of the tensioner pulley? It is pretty useless and not at all necessary - I have run my car for years without it.
David Jones
S1 OTS OSB; S1 FHC ODB

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PhilBell
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#7 Re: ProRace crankshaft damper - which belt?

Post by PhilBell » Tue Jul 17, 2018 9:54 am

Hi David

I've tested that idea by cable tieing the tensioner out of the way, and the belt is still way too short.

Of course, the problem is exacerbated by all the c19524 belts I've tried (marked SBS1010) being 20mm shorter than the 1010mm spec.
Phil
1962 FHC 885626

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mark10337
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#8 Re: ProRace crankshaft damper - which belt?

Post by mark10337 » Tue Jul 17, 2018 12:45 pm

Why not just order a belt sized according to the measurements you have taken instead of all the trial and error of various C.xxxx ones?
-Mark

1969 Series 2 OTS, Regency Red
'Life's to short to drive a boring car'

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Series1 Stu
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#9 Re: ProRace crankshaft damper - which belt?

Post by Series1 Stu » Tue Jul 17, 2018 10:33 pm

Hi Phil

Is your car still on dynamo or have you converted to alternator?

Mark, I think Phil's problem is the poor availability of Duplex belts. There's only about 6 lengths available and you can't just order whatever length you need for a one off.

Regards
Stuart

If you can't make it work, make it complicated!

'62 FHC - Work In (slow) Progress
'69 Daimler 420 Sovereign
'94 X300 XJR basket case

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#10 Re: ProRace crankshaft damper - which belt?

Post by Heuer » Wed Jul 18, 2018 8:53 am

You can run a standard V belt in one of the grooves which used to be a common fix back in the day as the Duplex belt was hard to find which is why Jaguar supplied a spare in the toolkit.
David Jones
S1 OTS OSB; S1 FHC ODB

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PhilBell
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#11 Re: ProRace crankshaft damper - which belt?

Post by PhilBell » Sun Oct 28, 2018 7:50 am

Problem solved.

Sourced a belt that was labelled SBS1010 (ie the one I thought I needed all along - late 3.8 to match the twin-groove pulleys that I fitted) and actually had the correct 1010mm outer circumference. Fitted perfectly, works perfectly.
Phil
1962 FHC 885626

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