Ignition timing issue

[Movin]

If I were to use JB I would use plenty so that it is in contact with all
mating surfaces, use a new key and follow above and save the good
stuff for last..

[95Compact]

Ok, here's what I'm going to try first (before JBW)...

I made new keystock out of Grade 3 steel bolt shank... I'm going to fit it to the entire length of the keyway - from the crescent machining of the crankshaft inboard all the way to the outboard end of the keyway in the pulley assy. This will not only double the contact area that I had before, but will also index the pulley correctly again.

I'll post another pic of the finished key before I install it.

Cheers

[Movin]

Dang, that looks pretty good for free hand !

[95Compact]

Hehe, thanks Movin! Thanks to my GF for getting me an 8" bench grinder for X-mas!

Well, so far, so good after a few miles on the road...

Got it back together, crank timing seems to be dead-on, ignition timing set correctly and near middle of disto adjustment range...

Here are some more pics of the key - note that I left the outer end of the key about .005" proud of the pulley surface, so that the crank bolt would apply pressure (since the key is tapered now).

[FestYboy]

not for nothing, but don't you think that grade 3 is a bit SOFT for Key stock?

[Jim Rockford]

That is what I was thinking, plus heating up with the bench grinder has taken any remaining temper out of the metal and the surface hardness is LONG gone.

[Movin]

Ok, crank pulley/gear assy out... wow!

I'll post some pics on a minute, the crank keyway is $%*ed (sorry, 'screwed'), but the 'gear' and main bolt are fine...

Hang tight

How hard do you want it ? The crank is made of pretty good stuff and its screwed up! The problem is bolt torque, it came loose in the past. The next problem is worn parts, they will loosen a properly torqued and loctited bolt.
If the keyway is a wedge fit it stands a better chance regardless of how hard it is. A little something extra to take up the play between the crank and the gear would do it for sure, loctite makes a great product for that as well, in a pinch JB can do the job.

Heck, they put aluminum keys on lawn mower blades and they hold for the life of the mower unless you mow rocks!!

[FestYboy]

what worries me is the compression that extended key will be under once the washer and bolt are torqued.

[Movin]

Yes, that depends on how accurate the .005 proud is, and how bad the keyway is, it could split the gear, but at this point and apparently not able to replace the bad parts he doesn't have anything to lose. That would be a hard car for me out here to drive, I would always be thinking about it while out of cell range knowing I might be in for an all day/night walk!! I would hit softer road, the engine would load up and I would pucker up thinking the little gear just slipped a little..

[95Compact]

Whats interesting is that the old key (or original, who knows) wore a divot into the underside of the head of the crank bolt... probably .015" deep or so - I don't think it had more than 3/8" of keyway overlap to hold on to. Is there supposed to be a washer under the head of the crank bolt? I thought about adding one...

Anyways, the taper/extension of the key was to remove any slop from the interface of the ID/OD of the gear and shaft. I figured as long as there was room for the gear to wiggle on the shaft, they'd find a way to loosen up the hardware...

Barring eliminating the slop with an extremely thin layer of JBweld - which I wasn't particularly fond of doing - I figured the tapered key would be fine, even though it throws the centering of the gear off by a bit. At least the parts are now joined in tension to some degree.

As far as the hardness of the key, I was originally going to use a HSS drill rod as the blank, but changed my mind. If I used such a hard material and things don't work out well, it would probably completely destroyed my crank shaft keyway...

I'll keep you guys updated if anything goes bad, I plan to put a few dozen miles on it tomorrow - and I will have my phone (and more importantly, tools) with me!

Yes, I know my .001"s I've repaired and calibrated thousands of surveying and optical tooling instruments for the past 13 years...

[95Compact]

Well, another 25 miles, inspection and re-registration down - no problems yet!

One thing I though of last night was to use some thin shim stock around the crank shaft - opposite the key - to re-concentrate the shaft in the pulley bore... If I can measure the space between the shaft and bore (at the keyway) and divide that dimension by 2, it would give me the thickness dimension for shim stock that would put it back to center...

Imagine a U shaped sleeve of shim wrapped around the whole shaft, EXCEPT where the key is (at the break at the top of the 'U'). The piece would be about 1" square before it was wrapped around the shaft and the pulley assy slipped on... Then, I would reinstall the tapered key in the keyway.

Just a thought, but no complaints as of yet with the last fix, so I'm not going to mess with it today