Worn keyway - advice needed please

florncakes · Apr 26, 2017

I'm replacing the timing belt on my defender, due to a previous mechanic not tightening up the nose bolt adequately! The rear keyway for the timing is fine, no concerns. The front keyway which drives the ancilliaries is wide as the last keyway fell out in service and was rattling around. Question is, armed with new keys, what would you recommend to fix the gap?
I've no wish to replace the crank (although money no object I would do), no wish to weld/file/grind a new keyway.
I can make / have got some 1mm steel sheet at work, and some loctite and superglue here.

Some figures - the rear keyway is 6.3mm wide and the new key is a good fit.
The front keyway is 6.4-6.5mm wide at the bottom, 7.5mm wide at the top... err!

[GALLERY=]

[/GALLERY]
Your thoughts and experiences would be appreciated please.

jamesmartin · Apr 26, 2017

florncakes said:
I'm replacing the timing belt on my defender, due to a previous mechanic not tightening up the nose bolt adequately! The rear keyway for the timing is fine, no concerns. The front keyway which drives the ancilliaries is wide as the last keyway fell out in service and was rattling around. Question is, armed with new keys, what would you recommend to fix the gap?
I've no wish to replace the crank (although money no object I would do), no wish to weld/file/grind a new keyway.
I can make / have got some 1mm steel sheet at work, and some loctite and superglue here.

Some figures - the rear keyway is 6.3mm wide and the new key is a good fit.
The front keyway is 6.4-6.5mm wide at the bottom, 7.5mm wide at the top... err!

[GALLERY=]View attachment 122233 [/GALLERY]
Your thoughts and experiences would be appreciated please.

some strong chemical metal for keyway and loctite the shaft were pulley sits

Saint.V8 · Apr 26, 2017

There have been reports of peeps drilling through the pulley at the keyway position and using long grubscrews into the keyway, it is only to hold the pulley in place for the drive belt, aslong as the timing sprocket is held firm, that is the critical part.

Also there was tales of a tool that could be used to drill into the crank at 90deg to the key way and the pulley bolted in similar fashion to the above...

Whilst it has been done and no doubt Goooooogle will show images of such, it is not something I would do or advocate. making a shim is a possibility and the best course of action, length of service life would be a question though.

neilly · Apr 26, 2017

Whichever way you fix it, i would suggest painting a marker to indicate the tightened position , then at least in the early days you can check easily with a mirror that the bolt is still in the original position.

I ould go with JM's solution and keep an eye on it, but use good quality chemical metal, not the cheap stuff obviously.

Cheers

florncakes · Apr 26, 2017

Thanks for your thoughts - certainly a few things I hadn't come across. Chemical metal is very expensive, especially the good stuff! I'd also like to get the thing out again when the time comes to replace the timing belt again.
Despite what I originally stated I'm contemplating cutting another keyway. It doesn't have to line up TDC as it's only holding the pulley on to the crank, no timing done as St V8 said. It should be like new, albeit at a different angle. Dremel discs of the right size available from a certain auction site too. Must make sure swarf doesn't disappear down into the crank case too, so plenty of shielding needed.

Saint.V8 · Apr 26, 2017

Don't forget, part of the pulley also sits over the key for the timing sprocket - if you realign the pulley you'll have to cut a new slot in the pulley too to align with the timing sprocket woodruf key.

florncakes · Apr 29, 2017

It lives!
Thank you to neilly, st v8 and jamesmartin for your suggestions, you helped loads, especially st v8s how-to-change-a-cam-belt.
In the end I ground out the keyway so it was straighter - even with the the bare nose crank I could have done with a dremel and flexi-extension. As it was I managed with a battery drill and moved the crank around to get best angle on the cut.
I made a custom woodruff key at work to fit the wider keyway, with a small shoulder that the crank pulley pushed back into the keyway should it ever move. A bit of fettling with a file to allow the crank pulley to fit on and it worked a treat. New key is held in with loctite as well. Crank pulley torqued up as much as my short extension would go before it sheared. Refitted the rad, added water and anti-freeze, started straight away, much quieter too!
Even better, Mrs Florncakes said she would never get in a landy - she stood on the brakes while I applied the torque to the crank bolt, ha ha!

Saint.V8 · Apr 29, 2017

Glad you had success.

Query: You mention you torqued as far as you could go before the extension sheared - did you achieve the correct torque and then the additional 90deg? As this is pretty crucial.

I used a short extension too at first and managed to shear the end off that (I think it was in the How To) in the end I used a deeper socket directly onto the breaker bar drive.

Kwakerman · Apr 30, 2017

Saint.V8 said:
Glad you had success.

Query: You mention you torqued as far as you could go before the extension sheared - did you achieve the correct torque and then the additional 90deg? As this is pretty crucial.

I used a short extension too at first and managed to shear the end off that (I think it was in the How To) in the end I used a deeper socket directly onto the breaker bar drive.

That was the first thing that came in to my mind to.

florncakes · Apr 30, 2017

I'm in the market for a 27mm deep impact 1/2" drive socket - will go back and check when I have one. Thanks guys - that had crossed my mind but wasn't at the forefront when I tightened the bolt. Will loosen and redo with reapplied loctite.

Al2O3 · Apr 30, 2017

Saint.V8 said:
Glad you had success.

Query: You mention you torqued as far as you could go before the extension sheared - did you achieve the correct torque and then the additional 90deg? As this is pretty crucial.

I used a short extension too at first and managed to shear the end off that (I think it was in the How To) in the end I used a deeper socket directly onto the breaker bar drive.

Hmmm

@Saint.V8 I bought a 27mm socket LINKY, but it's not a deep one. Am I likely to shear an extension bar? Should I be buying a deeper socket in readiness? Cheers.
(sorry to jump in here)

Saint.V8 · Apr 30, 2017

Al2O3 said:
Hmmm @Saint.V8 I bought a 27mm socket LINKY, but it's not a deep one. Am I likely to shear an extension bar? Should I be buying a deeper socket in readiness? Cheers.
(sorry to jump in here)

The pulley holding tool I used was quite deep set - as it was made for the deeper 200Tdi pulley, as such a standard depth socket meant I had to use an extension......which was a standard one and not any great make, also, it has probably led a hard life and was on its last legs anyway.....that, and because of the torque required with it being on an extension means you aren't pulling directly in a circle, you are adding a twisting moment due to the extension anyway....so this didn't help.

If your pulley tool is shallower, you may get away with a standard socket directly on the end of the breaker bar.....maybe give it a check first, and take it from there.

I am a 'large' lad at 6'3" and the wrong side of 23 stone, and using a 2' breaker bar getting the final 90deg turn of the bolt makes me puff a little.....don't underestimate the torque required to do it properly!!

Al2O3 · Apr 30, 2017

Saint.V8 said:
The pulley holding tool I used was quite deep set - as it was made for the deeper 200Tdi pulley, as such a standard depth socket meant I had to use an extension......which was a standard one and not any great make, also, it has probably led a hard life and was on its last legs anyway.....that, and because of the torque required with it being on an extension means you aren't pulling directly in a circle, you are adding a twisting moment due to the extension anyway....so this didn't help.

If your pulley tool is shallower, you may get away with a standard socket directly on the end of the breaker bar.....maybe give it a check first, and take it from there.

I am a 'large' lad at 6'3" and the wrong side of 23 stone, and using a 2' breaker bar getting the final 90deg turn of the bolt makes me puff a little.....don't underestimate the torque required to do it properly!!

The socket worked loosening it. I'm using Aaron's pulley holding tool, which I reckon is not as deep as yours. So, hopefully, will be ok,
Being half your weight, I'm hoping the three foot breaker bar I've got gives me the extra mechanical advantage needed.

Worn keyway - advice needed please

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