Belt Tension Specification in Newtons

[pastaroni34]

Guy,
I am in the process of changing the timing belt and balance shaft belt on a 16v Lancia engine. I have attempted to set the tension with the "twist" method and have found there is an awful lot of room for error. I would prefer to have specifications for the actual belt tension, in Newtons, then I can set it much more accurately with my sonic tension gauge (Gates 507c). I use this gauge with my industrial equipment and it works fantastically. I can come up with the mass constant, belt width and span to measure the belt's tension but I don't know what it should be!

It would also be useful to have the same info for the 8v engines too.

Thanks,
-Jason Miller

[Guy Croft]

Sorry - I don't know the answer to this one.

(Server crash wiped my prev reply)

G

[tricky]

Lancia put a drawing in thier workshop manual of a contraption of bars and a wheight suspended on one end of a lever to put the correct tension on the T belt. It told you how long the lever should be but not how much the weight, wheighed. I think they left out the information as a practical joke for future owners :-)

Any how that is how it used to be done when the car was made and as such my point was going to be that maybe you wont find the answer to your question easily unless you know how it was setup and reverse engineer it.

I just use the 90 deg twist method on my 16v, and Guy's method of turning the engine backward and checking the tension on the slack side is a great 'gauge'.

[pastaroni34]

I assumed it would be hard to find but if the information was anywhere, it would be here.

My next course of action will be to build the OE tensioning tool, and then get some measurements of the tension.

[WhizzMan]

Someone here should be having the original tool and will be able to give us all measurements and weights?

[tricky]

It's possible, but unlikely as the qeustion has been asked on Lancia forums for years.

[pastaroni34]

While I could build the tools from some dimensions I found online, it turns out they're relatively cheap ($200 US). My course of action is still to set the tension with the factory tool, then use my sonic meter to get a real tension number instead of a goofball tensioning tool number. I'll report back when I get these numbers.

[Guy Croft]

with that technology at hand Jason they'll be flying you to the UK to set their cambelts!

G

[WhizzMan]

Unless he is being a good sport and will share the information for free with fellow enthusiasts.

[rossocorsa]

A few years back I had, and did try to use, the Lancia tensioning tool on a 16v engine specifically the Delta HPE HF turbo that I had a few years ago, tbh I wouldn't bother trying to make one as I found it frustrating to use and I was never 100% confident the setting was right at least not any more than by the usual rule of thumb methods.

Alan

[WhizzMan]

A few years back I had, and did try to use, the Lancia tensioning tool on a 16v engine specifically the Delta HPE HF turbo that I had a few years ago, tbh I wouldn't bother trying to make one as I found it frustrating to use and I was never 100% confident the setting was right at least not any more than by the usual rule of thumb methods.

The tool will be made with the specific purpose to do one time accurate measurements.Those measurements will be used with a modern tool to get consistent results on any future engines and projects. Fiddling and redoing the setup five or ten times to get a feel of the deviation and the average tension will help rule out any inconsistencies with using the original tool. If the original tool proves to be very consistent when verified with a modern tool, we'll probably get to hear that as well.

[fingers99]

I think the reason you can't find it is because the sonic method is much later (at least, in automotive applications) than the "big weight on the end of a stick" method. Fiat recently switched, but the chance of them producing any figures for the twin cam are, well, nil.

I'm sure any figures you can produce would be warmly recieved, together with any advice on using a sonic guage.

[rossocorsa]

I'll check my pile of misc tools in case I have any of the weights seem to recall I saw one kicking about but I definitely don't have the arms that they fit on. I do have the Fiat tool for testing the early 8 valve belt tension (also covers some other 70s Fiat engines) and the tool to check the volumex supercharger belt tension, both are based on calibrated springs that are pushed against the belt to a specific deflection. whether they are still accurate after years of sitting on the shelf I really don't know.

[rossocorsa]

I found one weight including a knurled top piece but it has no part number on it

[WhizzMan]

I found one weight including a knurled top piece but it has no part number on it

A picture tells more than a thousand words. Maybe a member will recognize which weight it is? If you could measure the weight and dimensions (if applicable) as well, we will at least have some reference for the future.