Facom DM.16 Belt Tension Gauge

the_weaver · Post by **the_weaver** » 26 Sep 2010, 00:24

Has anybody used a Facom DM.16 Belt Tension Gauge, particularly on an XUD? I've bought one to check the cambelt tension on my ZX 1.9D. The instuctions are just pictures, with almost no words. See here for a pdf:-

http://www.facom.fr/fr/telechargement/n ... .16-99.pdf

I set up the tension on the cambelt using the ZX auto-tensioner. Then I checked it using the DM16. It went to the top line (max allowable) - (diagram A). I think this is correct for a new cambelt. Then the instructions say (in pictures - diagram B) to check it again after 5000 km, and it should be somewhere between the max. and the min. lines. Then diagram C says to change the belt when it reads below the min. tension line, or when it's done 90,000 km.

Have I interpreted the instructions correctly? Do you start off setting the tension to the top line on a new belt? The instructions seem to suggest that the belt will have stretched a bit after 5000 km. Does an XUD belt stretch? Do Dayco belts stretch?

I put the gauge next to the engine mounting. I didn't remove the engine mounting, so the gauge isn't quite in the middle of the belt span. Does this matter?

Can this gauge be used to check the tightness of the alternator belt on my car? It's just a simple belt that drives the alternator with no aircon, ABS or anything.

Paul

Deanxm · Post by **Deanxm** » 26 Sep 2010, 08:30

Hi

I dont kow a thing about the belt tensioner sorry but any belts will stretch in use, ive got a goodyear one on the xm now but have used many others and i find it needs re-tensioning after about 500 miles so i usualy leave the top belt cover off to keep an eye on it and re adjust when needed.

D

JohnD · Post by **JohnD** » 26 Sep 2010, 09:05

the_weaver wrote:
Then the instructions say (in pictures - diagram B) to check it again after 5000 km, and it should be somewhere between the max. and the min. lines. Then diagram C says to change the belt when it reads below the min. tension line, or when it's done 90,000 km.

My guess is that 95% of car owners have their cambelt changed by a garage. How many of those owners go back after 5000Kms to get it readjusted? And how many check to see if it needs replacing after 56K miles.

The gauge I use is a Burroughs and the instructions make no mention of rechecking at a later mileage. It does mention choosing a mid-way point to take the measurement:-

Deanxm · Post by **Deanxm** » 26 Sep 2010, 11:05

My guess is that 95% of car owners have their cambelt changed by a garage. How many of those owners go back after 5000Kms to get it readjusted? And how many check to see if it needs replacing after 56K miles.

Indeed, i cant see it will do any harm to the belt running slightly too slack i just dont like doing it, certainly all the ones ive changed are fine, in fact on the tct xm i had the belt was so loose it could almost be slid off the cam pulley by hand.

D

Kowalski · Post by **Kowalski** » 26 Sep 2010, 16:53

Deanxm wrote:
My guess is that 95% of car owners have their cambelt changed by a garage. How many of those owners go back after 5000Kms to get it readjusted? And how many check to see if it needs replacing after 56K miles.
Indeed, i cant see it will do any harm to the belt running slightly too slack i just dont like doing it, certainly all the ones ive changed are fine, in fact on the tct xm i had the belt was so loose it could almost be slid off the cam pulley by hand.

D

Its all a question of whether the belt may slip teeth or come off completely, whether it keeps the timing as exact as it needs to and whether the belt may wear prematurely.

I've seen the guides to belt failure along with pretty pictures, insufficient tension can cause the belt teeth to wear which can lead to the teeth disappearing (being torn off) and then belt failures. I don't know how bad the tension has to be before this starts to happen.

kenhall1202 · Post by **kenhall1202** » 26 Sep 2010, 18:24

Deanxm wrote:Hi

I dont kow a thing about the belt tensioner sorry but any belts will stretch in use, ive got a goodyear one on the xm now but have used many others and i find it needs re-tensioning after about 500 miles so i usualy leave the top belt cover off to keep an eye on it and re adjust when needed.

D

The reason why new timing belts apparently 'stretch' after a few thousand miles is because the inner belt profile of teeth and hollows gets smoothed off and slightly compressed. The belt will then sit fractionally lower in the pulley teeth and this gives the impression that it has stretched. Many belts are reinforced with glass fibre - when did anyone manage to stretch a piece of glass?!!

Having said that however some recent cars have a newly introduced type of belt which has to be stretch fitted (using a special tool) because the tensioner has been done away with - there's progress for you!!

EDIT Just to clarify, these new stretch fit belts are the multi rib type and not timing belts. Apologies for the confusion.

the_weaver · Post by **the_weaver** » 27 Sep 2010, 02:03

Thanks for the replies. I didn't realise that the instructions say to put the belt on at max allowable tension to start with. Then readjust the tension after 5000 km to the middle of the range. If you used the XUD auto-tensioner to do the re-tensioning after 5000 km, it would set it to the max allowable again. So you must have to do it by hand, if it's not already in the middle. The XUD tensioner must be just for new belts.

Paul

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Facom DM.16 Belt Tension Gauge

Facom DM.16 Belt Tension Gauge

Re: Facom DM.16 Belt Tension Gauge