TR timing belt tension

if 'alignment' means 'degree the cams' - The search engine will yield many responses.

the tension is set via the spring pressure in the tensioners. - check the search engine and folks will be happy to answer more specific questions.

good luck,
Vincenzo

 

The BEST way is to use some kind of tensiometer. This is a device that measures the own frequency of the belt, much like tuning a string on an instrument.

 

Te testarossa has its own 'tensiometer'. With the tensioners clamp "loose" turn the engine over a few times and note where the belt tensioner is compressed the most. At the point of most compression clamp the belt tensioner down and job done. Then the simple job of re-installing the engine

 

Philwozza is correct. With new belts and tensioner bearings installed and the tensioner bolt slightly loose, watch the tensioner "float" while it's taking up the slack in the timing belt while you rotate the engine over by hand. At the point where the belt is the "tightest"...that is the point where the tensioner is at it's farthest travel pushing on the belt....then tighten down the bolt that goes through the tensioner bearing to lock it into place.

 

Yup, that is the way. Clean threads and a torque wrench ought to do it.

 

I never use locktite unless there is a loose bearing issue but I i am happy to learn from others.........

P

 

The torque is 100 Nm

 

I used a dial indicator to find the tensioners farthest point.....

Gizmo Me

 

Sorry to stir the hornet's nest here, but this seems backwards to me (if the belt's stiffness is greater than the spring's stiffness -- and I believe it is). If you clamp the tensioner bearing down when the tensioner mechanism is most compressed, then, the belt tension at that position will be a teeny bit higher because the spring load is slightly greater, but, at ever other position, the tension in the belt will be lower (because the tensioner can't move out). Conversely, if you clamp the tensioner bearing down when the tensioner mechanism is most extended, then, the belt tension at that position will be a teeny bit lower because of the spring load is slightly less, but, at ever other position, the tension in the belt will be higher (because the tensioner can't move inwards so the belt is stretched more). I.e.:

Clamp where tensioner is at max compression = lower average belt tension

Clamp where tensioner is at max extension = higher average belt tension

What's the reference for using the max compression position?

 

Same with me.. The way to go

P

 

Its what the manual says or at least my interpretation of it


P

 

I have to disagree -- the instruction at the top of page B49 of the TR WSM that says:

"Tighten screw 1 (fig. 50) when the idle [sic] is in its maximum stretch position"

should be translated as:

"Tighten screw 1 (fig. 50) when the tensioner pulley is in its most extended position"

JMO.

 

One must see..... The shop manual is so weird! I's like somebody had a thought, documented it, passed it on to a "supervisor" whom in turn presented it to a secretary that would transcribe it, then tech heads passed it on and then via lottery the info was placed in the manual.....I believe that the "slight" diffs between up & down are minimal. The paranoia runs deep here, & I am a subscriber.....except when it comes to door seals!!

I see dead people Me

 

Steve and Kerry are both correct here. But as Kerry says, the actual difference that the tensioner bearing "floats" back and forth as the motor is turned over is slight. Steve is right about the varying spring loads acting on the belt....but with such a small travel distance, the spring load delta over such a short distance is negligable. The tensioner is locked down at it's most extended position against the belt as witnessed - or measured - during engine rotation.

 

Should he be locking the cams in place before removing the belt?

 

Yes, there are several neat devices developed specifically to lock the cams in place.
Various self-made "locks" are often used as well.

 

Carguy I believe had a pix showing I think 2 plastic " wedges" that could, it look like, drawn together by threaded stock. Am I correct in that assumption Jeff?

Clamp Me

 

If you look back at some of my old threads from last year I believe I posted a set of photos describing the process, including the cam clamping.

P

 

is there a tool to lock the cams foR the TRs?? if there is were can one get it from?

 

There are professional tools available for locking the cams in place. Many have made their own, which usually consist of blocks or wedges that can be tightened against the cam sprockets. Some people remove a camshaft retainer cap and put a matchbook cover in there and re-tighten it down to hold the cams in place. No doubt a professional tool is best, but the home-made ones work too. You must exercise caution when wedging the cam sprockets in place, it does not take much force to hold things steady...same for using the retainer cap method - don't overtighten things!

 

Here is a picture of the clamp I made based on the thread that Phil posted. Do NOT use the sprocket-holding tool that has pins that wedhe in the gear teeth! The pins are knurled and will ruin your gear teeth!
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