Crankshaft toothed timing pulley query

[SLR No.77]

I'm still in the process of rebuilding the vhpd engine I have strewn around the garage and I'm now at the point of having the crank assembly balanced. However, the new crankshaft timing pulley I have is looser on the crank than I'd like. When fitted to the crank but not tightened it will rotationally rock by about 1.5º (1mm). Surely this can't be right

I've dissembled/assembled the timing pulleys a few times on various K-Series engines and I've never felt that there was this level of movement. I've also fitted a narrow 1400 pulley to the crank as a comparison and although there is some movement, it is definately a lot less. There's no sign of damage to the end of the crank, just a small shiny area to each side of the face where the pulley locates where a previous pulley has contacted, but definately no damage or wear that would cause this amount of movement.

Obviously when the timing and belt pulleys are bolted up tight the movement will disappear, but it's not something I'm happy with. Is this wide tolerance normal? Any ideas?

 

Stu.

 

www.superse7ens.co.uk..........the rebuild 😬

 

 

[Rob Walker]

Stu,

 

The last one I did I ended up drilling the toothed crank pulley and inserting a steel dowel in place of the protruding cast keyway. The old boy that does my balancing had refused to balance the assembly with the backlash in the pulley`s

 

Rob

[SLR No.77]

Rob, do you mean the keyway that locates the 2 pulleys together? This part is solid with no issues. It's the 2 pulleys rocking together on the crank that are a problem.

 

Stu.

 

www.superse7ens.co.uk..........the rebuild 😬

 

 

[Kevsta]

Logic would say that this is not good because when you tighten up the nut you culd potentially retartd or advance the timing of the cam pulleys depending upon where you position it when you tighten it. I don't remember there being any movement in mine. It might be worth getting hold of another pulley to fit as it might be that the pulley has sustained some damage from a loose crank bolt in the past?

 

Actually...thinking about it...is the movement of the pulley on the crank or the crank pulley to alternator pulley? That would change the above...

[SLR No.77]

Movement is a brand new pulley on an undamaged crank

 

Stu.

 

www.superse7ens.co.uk..........the rebuild 😬

 

 

[Rob Walker]

Stu,

 

If its play onto the crank nose then shim this. If you do not have pukka shim you could cut up a thin steel drinks/beer can, or J&L industrial supplies can supply the proper stuff.

 

I have never seen a K crank toothed pulley that was a decent fit. In practise it will never move when correctly torqued but if your balancing then you will have to shim it up to do a half decent job.

 

Rob

[SLR No.77]

Thanks Rob, plenty of shim-steel at work so no problem

 

Stu.

 

www.superse7ens.co.uk..........the rebuild 😬