Belt tension

JohnD · Post by **JohnD** » 20 Dec 2006, 11:28

Autodata quote belt tension in SEEM units but I've bought on eBay a Burroughs BT33 gauge which is scaled in Newtons. Has anyone got a conversion table?

Clogzz · Post by **Clogzz** » 20 Dec 2006, 12:25

Possibly somewhere in here,

though I can’t see it:

http://www.onlineconversion.com/force.htm

http://www.onlineconversion.com/torque.htm

http://hemsidor.torget.se/users/b/bohjo ... htm#torque

alan s · Post by **alan s** » 20 Dec 2006, 12:46

Don't like your chances; "Seems" is a "proprietary" (sp) measurement and is based on the same principal as tuning a geetar or violin/fiddle and I could imagine that info would be about as easily obtained as Blair or Bush's after hours phone number.

Alan S

jeremy · Post by **jeremy** » 20 Dec 2006, 14:19

Could you calibrate it using a spring balance or other form of measurement?

Kowalski · Post by **Kowalski** » 20 Dec 2006, 14:34

JohnD wrote:Autodata quote belt tension in SEEM units but I've bought on eBay a Burroughs BT33 gauge which is scaled in Newtons. Has anyone got a conversion table?

Can you use your gauge to measure the tension of the existing belt before you remove it?

That will give you an idea of what tension you're looking for with the new belt, but bear in mind, the tension on the new belt should be slightly higher than the old, since the new belt will need to bed in and will lose some tension while that happens.

bxbodger · Post by **bxbodger** » 20 Dec 2006, 15:21

According to this-http://www.honestjohn.co.uk/forum/post/ ... =i&t=18875 45 seem units = 240 newtons although I don't suppose anyone outside of an official main dealer franchise would use such a unit!!

Hopefully 1 seem then equals 5.33 newtons........

I've never actually measured a belt tension-I just crack the tensioner on until it's hard to push the belt by thumb on its longest run...after all, it's not going to get any tighter by itself, only slightly slacker which the tensioner will take up anyway.

AndersDK · Post by **AndersDK** » 20 Dec 2006, 19:46

SEEM units are in no way a standard "unit" - other than when using the mentioned SEEM manufactured tool.

AutoData offers this document which provides a comparison table for the different units :
http://www.autodata-online.com/uk/tbinfo.pdf

Here you can see that Burroughs and Sykes-Pickavant are the only tools calibrated in standard (but different) ISO units.
SEEM offers 2 different tools - NOT calibrated in the same units

Its pretty much like manufacturing an "AndersDK" gauge tool - which offers the readout calibrated in "AndersDK" units

Then later introducing "AndersDK-Mk2" tool - calibrated in "AndersDK-Mk2" units

JohnD · Post by **JohnD** » 20 Dec 2006, 19:56

Many thanks for that - it's exactly what I wanted.

citronut · Post by **citronut** » 20 Dec 2006, 20:33

rule of thumb for cam belt tenssion is you should be able to twist the driveing side length of the belt one quarter of a turn between you finger a thumb
regards malcolm

bxbodger · Post by **bxbodger** » 21 Dec 2006, 10:19

Thatas quite bizarre

- looking through that comparison chart it appears that Burroughs do a standard gauge,calibrated in newtons, and also do the same gauge, but for Rover, calibrated in some strange Rover units.....and Ford, VW, etc, also have their own units of measurement

Imagine what it would be like if they all introduced their own version of torque measurements-I wouldn't put it past them to do it as a way of preventing home servicing.

I'm sticking with the thumb test!!

David W · Post by **David W** » 21 Dec 2006, 10:38

I provided the data linked to on that Honestjohn post. The conversion of Seem - Newtons was given at a specific point and is not linear throughout the range. And as commented above the different Seem testers give slightly different results.

So to get a conversion you need to look up the comparison at the particular figure for your car and not do the maths worked from another point in the range.

Thank goodnes my thumb is calibrated to check the gauge is correct!

David

slim123 · Post by **slim123** » 21 Dec 2006, 11:48

I'm with Malcolm on his one, quarter turn on the longest run is good enough for any belt, when I have done it like this, then checked it out of interest with a gauge, it's allways spot on.

Regards
Slim

David W · Post by **David W** » 21 Dec 2006, 13:00

Actually we are lucky with Citroens because they have some of the most robust timing belt/tensioner arrangements of all makes so they are quite suitable for these DIY methods. The 1.9TD tensioner for example looks like part of the running gear from a tank compared with a pressed tin and plastic tensioner from a Ford/Fiat/Vauxhall.

Many other makes of cars have very weak arrangements with procedure traps for those without proper tools/info.

David

alan s · Post by **alan s** » 21 Dec 2006, 20:45

I see some strange set ups at times due in part to the business my son operates.
If you want a scarey moment, think about a Holden (early Nissan Skyline engine) that was here fitted with a single OHC that we converted to a DOHC head assembly off a Nissan GT-R.
Problems; where to fit extra tensioner(s) which belt profile, length and tension.

Must have got it right, because it was about 2 years ago it went into service and is still going.

I can always remember being told of the ways in which dealers service mechanics operated Seems testers; fit belt, fit tester. Set to recommended tension using tester as you go. On completeion check using thumb and forefinger and if tension doesn't feel right, adjust accordingly.

Which begs the question; are they really worth the trouble and cost?

Alan S

citronut · Post by **citronut** » 21 Dec 2006, 21:18

i think these tenssion testers will need to be used more on modern jalopys which have more and more cheaply shody tenssioner and jocky wheels,which seem to be very flimsy
regards malcolm

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