Jump to content
The mkiv Supra Owners Club

Aux belt jumped off crank pulley


Jellybean

Recommended Posts

Has the ribbed outer pulley come off the crank damper? So now the belt is running on the inner, smooth part? If so you should be able to drive it a short distance at low RPM. If the alternator light comes on it means the belt has come off altogether and it will overheat in next to no time as the water pump and fan are no longer turning.

 

Is there any function on this thing that does NOT have issues ;)

Link to comment
Share on other sites

Has the ribbed outer pulley come off the crank damper? So now the belt is running on the inner, smooth part? If so you should be able to drive it a short distance at low RPM. If the alternator light comes on it means the belt has come off altogether and it will overheat in next to no time as the water pump and fan are no longer turning.

 

Is there any function on this thing that does NOT have issues ;)

 

ribbed outer pulley is till intact, the belt is running on the inner, smooth part :)

 

She's 22 years old , had planned to do all this prior to putting her on the road not due to issues , just because of age

 

Will get there !

 

She still goes like a train ;) Good old Toyota 90's engineering

Link to comment
Share on other sites

You don't just tighten the pinion nut up tight, you slowly torque it a bit more and more measuring the bearing movement torque (preload) with a special low measurement torque wrench. If you have just torqued the pinion nut up bloody tight the pinion bearings are now almost certainly FUBAR..... :( It will need a new crush tube as well as new pinion bearings, and the pinion depth setting will probably need re-doing. Diff builds are treicky until you have done a few and got a feel for things.

Link to comment
Share on other sites

Trust me I had these discussions with my mechanic but he is confident in his ability , has done a few, he was measuring the bearing movement after each nip of the nut,

 

If anything she was well under torqued, within the threshold

 

Question you might want to ask is if I trust his ability, and in fairness to him, he has done right so far and he did race a supra for a few years ;

 

We will get there, we all learn from our experiences but thanks for all the advice ! Really appreciate it [emoji6]

Edited by Jellybean (see edit history)
Link to comment
Share on other sites

There's no real right or wrong torque, the nut is tightened and a tubular spacer is slowly crushed unti the space between two roler bearings is reduced such as the preload on them is measured by their drag. There must be a YouTube video of someone doing a pinion bearing preload torque, surely? I have to warn that I have seen some totally incorrect automotive advice there, so take care. if I see something I'll try and post a link. I have a horrible feeling he's done it wrong.... Over preloaded pinion bearings would certainly whine!!

 

EDIT: Here you go:

 

 

The preload for used bearings will be different to that recommended for new ones.

Edited by Chris Wilson (see edit history)
Link to comment
Share on other sites

Thanks Chris

 

Tim was also doing it with him, he builds custom offroad buggys etc Was just talking to him just there and he said she is definitely nowhere near the max 376 ft·lb

 

He reckons she needs to be nipped up a little bit more and go from there, his torque wrench only goes to a max of 280 ft·lb

 

If the bearings are FUBAR , we will replace and go again ;)

Link to comment
Share on other sites

He reckons she needs to be nipped up a little bit more and go from there, his torque wrench only goes to a max of 280 ft·lb

 

That's irrelevant, he doesn't even need a torque wrench to check the nut tightness, he needs a special inch / pound torque wrench to see how much friction is in the bearings, and adjusts the tightness on the pinion nut to achieve this. If he goes too far and the crush tube is "crushed too much" there's no going back, it needs a new tube and probably new bearings if it's been run, and the adjustment started again.

Link to comment
Share on other sites

http://www.toolstop.co.uk/norbar-13285-tti20-torque-wrench-1-4in-square-drive-adjustable-1-20-n.m-10-180-lb-p70033

 

Cheap and nasty, probably, but perhaps OK for the occasional user. A Stahlwille one is probably £250 plus these days. You can get creative and use physics; a fisherman's balance pulling exactly 12 inches along a breaker bar, with the diff positioned so the weight of the bar is not adding to the torque. IE, with the pinion nut pointing up to the ceiling, and pulling the breaker bar or whatever horizontally. We are talking very gentle effort here.

 

Can it be done by feel alone? Hell, yes, after you have done 50 or so ;)

Link to comment
Share on other sites

You can get creative and use physics; a fisherman's balance pulling exactly 12 inches along a breaker bar, with the diff positioned so the weight of the bar is not adding to the torque. IE, with the pinion nut pointing up to the ceiling, and pulling the breaker bar or whatever horizontally. We are talking very gentle effort here.

 

That was the method I used on my original crown wheel & pinion swap. I was hoping it was a recognised option to a suitable torque wrench!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.