pulley bolt

[Garry4466]

Just started stag up, then heard a rattle, then a bang stop car found 3 blades broke on fan with pulley bolt loose lucky did not damage radiator but I notice there some play in vi's fan mechanism how much play should there be also how to tighten pulley bolt with the car being automatic

[MikeParker]

You need a big stilson to grab the tubular spacer behind the fan and pulleys. It is a bad idea to put too much torque through the crankshaft (as you may be tempted on a manual car). It is a mystery to me why Leyland engineers chose to attach the fan and pulleys with such a huge bolt. My guess is that the large bolt and huge torque are required to clamp the timing chain sprockets. Others may know more?

[flying farmer]

Virtually no play if the bearings are good.
Best option for tightening the crank bolt with an auto is to use a stilson wrench on the back of the crank pulley, I use this on manual cars too

Neil

[flying farmer]

You need a big stilson to grab the tubular spacer behind the fan and pulleys. It is a bad idea to put too much torque through the crankshaft (as you may be tempted on a manual car). It is a mystery to me why Leyland engineers chose to attach the fan and pulleys with such a huge bolt. My guess is that the large bolt and huge torque are required to clamp the timing chain sprockets. Others may know more?

Big torque is needed due to the harmonic balancer on the front pulley (the outer part is rubber mounted)

Insufficient torque will allow the bolt to rattle loose (which is probably what has happened here), and the rattling will quickly chew up the keyways on the crank and pulley.

[Garry4466]

I've got torque drill I used for wheel nuts, but I was scared to use it on pulley bolt incase I sheared it off

[DJT]

When I went through the trauma of having to change the viscous coupling on my auto three times in a short space of time due to poor quality parts, I used a 24v SnapOn impact gun borrowed from my local garage. This rattled the bolt out and also tightened it up to the specified torque without having to lock the engine mechanically or use a Stillsons on the pulley shaft.

Use Loctite thread locker when fitting the bolt.

[Goldstar]

Don’t want to be that guy Dave but how do you know it’s the specified torque without a torque wrench? Not being ar$ey, genuinely curious

[DJT]

Don’t want to be that guy Dave but how do you know it’s the specified torque without a torque wrench? Not being ar$ey, genuinely curious

Understood. The wrench I borrowed had a max torque setting quite a bit higher to that specified in the book for the pulley bolt, so I didn't go all out with it; just used a bit of common sense. Perhaps I should not recommend it for tightening, but it was certainly excellent at removal. I see some of the current SnapOn guns have stupid power!

The last time I used it was May 2009 and the bolt was still tight when I stripped the engine in Feb 2022, 42,000 miles later. That is good enough for me. The book says 90-120 lbft, which is quite a large tolerance. When I rebuilt the engine last year I used a piece of angle iron wedged in the torque converter starter ring and a torque wrench. Backed up with Loctite, it should be fine for a while yet.

[Goldstar]

Fair play. I tend to do the same to be honest. Not had one come out yet.