Short nose crank...telltale signs? *HELP NEEDED*

OMY005 · Postby **OMY005** » Mon Mar 05, 2007 9:32 am

Maybe you could take the front pulley off and have a look. If it looks like this it might be to late. :frown:

Andrew.

Boags · Postby **Boags** » Mon Mar 05, 2007 9:35 am

mickfred · Postby **mickfred** » Mon Mar 05, 2007 10:36 am

geesus, thats not nice.

bruce · Postby **bruce** » Mon Mar 05, 2007 11:19 am

What should a good one look like?

suzi · Postby **suzi** » Mon Mar 05, 2007 7:25 pm

[quote="Boags'MX5

Suzi, let your friend know that she needs to have a "dodgy day"...

Boags[/quote]

Will do Boags - I want to suss out these wingzz as well as get her car fixed so will suggest - watch this space.....

deez · Postby **deez** » Mon Mar 05, 2007 9:29 pm

Thanks for your replies.

Looks like I might need a dodgy day too in the near future :roll:

Dodgy day @ Sydney, anyone? :mrgreen:

Unlimited beer and pizza!!!

Beer not avail during dodgy, but after, of course :mrgreen:

Sean · Postby **Sean** » Mon Mar 19, 2007 12:34 pm

Just had a thought of an easy way to check for a worn shortnose, feel free to jump in and let me know if you agree or disagree with teh viability...

Remove sparkplug from cylinder number 1.

Sink a skewer stick or other similar long thin object down teh hole.

Use a socket to spin the engine through a few full 360 degree cycles..

Now to my way of thinking, the stick should raise highest out of teh engine when the crank marker (on the big pulley) moves past the part marked as T on the timing cover marks...

DO you get it?

Anyone else think thiswould be a quick and easy way to diagnose?

Juffa · Postby **Juffa** » Mon Mar 19, 2007 2:07 pm

Sean wrote:Just had a thought of an easy way to check for a worn shortnose, feel free to jump in and let me know if you agree or disagree with teh viability...

Remove sparkplug from cylinder number 1.

Sink a skewer stick or other similar long thin object down teh hole.

Use a socket to spin the engine through a few full 360 degree cycles..

Now to my way of thinking, the stick should raise highest out of teh engine when the crank marker (on the big pulley) moves past the part marked as T on the timing cover marks...

DO you get it?

Anyone else think thiswould be a quick and easy way to diagnose?

It would work if the timing was out so much that the highest point for the piston did not match with the timing marks. You would also have to take into account any variation due to timing adjustment, ie 10 or 14 degrees (or other). I suspect that there would be too much variation for this to be fully accurate?

J

JBT · Postby **JBT** » Mon Mar 19, 2007 2:45 pm

I think Sean's theory is good but you'd need a very good eye or a very stuffed crank or both. Ignition timing won't change the mechanical relationship between the crank and pistons, so TDC should = No 1 piston max height.

Sean · Postby **Sean** » Mon Mar 19, 2007 3:13 pm

JBT wrote:I think Sean's theory is good but you'd need a very good eye or a very stuffed crank or both. Ignition timing won't change the mechanical relationship between the crank and pistons, so TDC should = No 1 piston max height.

My dodgy test had a peg temporarily superglued to the cam cover and the skewer held in the peg's clasp, I put a mark on where the skewr was at the T mark, and then rotated the crank a few spins, the skewer didn't move up, so I am assuming I'm right

If the crank/keyway was buggered the line would move up

JBT · Postby **JBT** » Mon Mar 19, 2007 3:35 pm

Cunning idea with the peg Sean

sabretooth · Postby **sabretooth** » Mon Mar 19, 2007 3:47 pm

Juffa wrote:You would also have to take into account any variation due to timing adjustment, ie 10 or 14 degrees (or other). I suspect that there would be too much variation for this to be fully accurate?

J

Just one thing, you're confusing ignition timing with cam+crank timing, so you can rule that out.

Sean, I'm not sure how your way will work. How will the first rotation be any different to any other manual rotations of the crank? Does it work by expecting the crank to initially be in the worn part of the keyway, and therefore the piston not at 100% TDC?

I'd be inclined to:
a) look for pulley wobble with the engine turned on - red5's was incredibly pronounced - it was incredibly obvious that that sucker was on its way out. This pulley should have an absolute minimum of wobble.
b) totally theoretical, but see how much slop (free play) there is when rotating the crank forward and back with a ratchet. Don't do it enough to move the pistons - extra-worn keyways should mean that there will be a bit of play before the woodruff key "bites" on the crank.

JBT · Postby **JBT** » Mon Mar 19, 2007 4:06 pm

sabretooth wrote:Sean, I'm not sure how your way will work. How will the first rotation be any different to any other manual rotations of the crank? Does it work by expecting the crank to initially be in the worn part of the keyway, and therefore the piston not at 100% TDC?

The theory as I see it is set the sprocket (crank) to TDC. Note height of piston. Turn crank and see if piston rises. No rise = good, rise = bad because the crank/sprocket relationship has changed.

Agree that the number of rotations has no effect but I doubt you'd be able to feel or see any slop if trying to rotate the crank back and forth unless the sprocket was very loose and about ready to fall off.

Sean · Postby **Sean** » Mon Mar 19, 2007 4:09 pm

sabretooth wrote:Sean, I'm not sure how your way will work. How will the first rotation be any different to any other manual rotations of the crank? Does it work by expecting the crank to initially be in the worn part of the keyway, and therefore the piston not at 100% TDC?

YEs it assumes the key will always fall into the worn part of the keyway.

The first rotation will not be different, I just rotated a few times to be sure. Also give you a chance to stuff teh skewer back down through teh peg to retest

Yes I am king dodgy.

My soluion if I had a brone crank would eb to leave it , put a newmark on the pulley where TDC is NOW, and move teh cams a tootch to compensate.

I'll say again - Yes I am king dodgy.

Really though,m with an import 1.6 available for $500ish, I'd say agrand would get you out of it to buy and fit the new engine...

Why bother with shonky fixes.

Boags · Postby **Boags** » Mon Mar 19, 2007 7:16 pm

WARNING - DO NOT ATTACH A SOCKET TO THE PULLEY BOLT AND TURN THE ENGINE MANUALLY.

This *might* alter the torque on the crank bolt, and if it wasn't f*&ked before, it will be now.

The reading I did when I thought mine was kaput suggested that rotating the crank using that bolt was asking for trouble. I'm not sure how else you could do it though. :?:

Boags