crank shaft timing keyway
Turbo Mini Forums

i am in the process of putting my timing gear onto my new build and i have two crank keyways to try, one from my standard metro turbo engine and one from a old 1380 engine but neither of these will fit my new crank they are both the same size and both too small for my crank they just fall out.Are there different size keyways?.

cheers pete

I am pretty sure (99.9) they are all the same, 998 to 1275.

Something must be worn, you must have a snug fit ot the timing gear will rattle about and cause failure..

JF.

thats what i was thinking, the crank is freshly machined though so dont think it would be that worn?

998 and 1275 of all flavours use exactly the same key.

Offset keyways are for camshafts though. They will fit in the cam slot

On 12th Nov, 2009 Paul S said:

I think Gary OS has taken over my role as the forum smart arse

right i have tried four different keys now one being new and they are still not going in tight! does anyone have any sugestions of what i can do? do i get a key machined to fit in the keyway and the timing gear? or locktight or something PLEASE HELP

What do you mean by "the crank is freshly machined" ???

Is it just a regrind (in which case the key slot will not have been touched but could have already been worn/damaged), or do you mean a billet crank (in which case it's been machined wrongly, or manufactured for a different key to standard).

Schrödinger's cat - so which one am I ???

thanks for reply, what i mean is its fresh from morspeed its had work done to it but i would have thought he would have checked the keyway for damage before doing the work?

Schrödinger's cat - so which one am I ???

i got the crank in an engine kit from someone else who never built the engine, i think it was his crank before he got it machined at morspeed,i think ill go for the stepped keyway option as a bodge is not an option

cheers pete

Anyway, when the pulley is torqued up, there will be noe "force" on the keyway. If it's so tight that you can time the camshaft up decently you should be OK.

so vegard are you saying if i lock tight it should be enough because the pullly stops it from moving when tight anyway?

I think that's what I'm saying in a slightly more eloqent way

I would make a new key up that is slightly thicker and just open the keyway up in the pulley to suit. If you have any play between the key and keyway over time the slot will become more of a 'V' and cause no end of trouble. Do it right once and forget about it.

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1/4mile in 13.2sec @ 111 terminal on 15psi

yep agreed and have it booked in for tommorrow

id just tack weld it in place, and use a vernier

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

I,m with Matty on this. My training was that all keys should be a snug fit in both components or fretting can occur.I understand the point about extra clamping pressure from the pulley bolt but would still feel happier with a good fitting key.Its a more elegant solution,anyway.

On 2nd Mar, 2009 Vegard said:

On 2nd Mar, 2009 matty said:
I would make a new key up that is slightly thicker and just open the keyway up in the pulley to suit. If you have any play between the key and keyway over time the slot will become more of a 'V' and cause no end of trouble. Do it right once and forget about it.

What on earth would cause it to wear?

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1/4mile in 13.2sec @ 111 terminal on 15psi

but is that machinery where the keyway provides the drive? in this application the drive (or transfer of torque) comes from the tight bolt, the keyway is simply there for location purpouses. if the bolt is correctly torqued, the woodruf key will never see any forces placed upon it.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Ah yeah I see what you mean! It should be ok in that case.

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1/4mile in 13.2sec @ 111 terminal on 15psi

It's all down to how bad the wear (looseness of the key) actually is....

As I said earlier, if it isn't too bad I'd use loctite 270 and make sure the sprocket is rotated anti-clockwise as far as possible before doing the bolt up (so the drive is against the key, not the loctite).

But without seeing it personally, it's hard to call....

Yes, the drive load (torque) is from the loading of the bolt, not the keyway..... unless the bolt is a bit loose or becomes loose.

It's really down to how well you build the engine.... and obviously someone didn't do it too well before or the keyway would never have ended up in this state....

Schrödinger's cat - so which one am I ???