23hp vanguard no/ weak spark

[lady bug]

I'm working on my friends engine . Its drive is a 23hp vanguard. I put the cpp cheatha camshaft and high riv kit in it. Also machined the heads 100k with the slim head gaskets It has run great for the last 5 days and stopped out of nowhere almost like someone threw a switch. I inspected everything. Great compression. Good fuel. This thing acts like the timing is off. Everything leads me back to the poor spark the engine now has decolped. dull white not a crisp blue white. I know in the past it was a poor ground that you left me too and wamo that was it. Then another time I lost good spark on the same engine and you pointed me to the diodes in the coil wires presto that fixed it. So I removed the cover on the engine flywheel is good and tight. I removed the coils wire wheeled where they mount to the block re gapped and cleaned the magnet on the flywheel. The spark didn't improve. Then I removed the diodes all together. Thinking if they were open they couldn't cross feed eachother. again the spark didn't change. On the initial crank it spark good about 2 times then falls off. Is it possible both could went bad at the exact same time. This engine did go from 3600 rpm. To about 5500. Thanks so much if you have any input.

[BIKERMIKEYBLACK]

Did you put an advance timing key in it if so it’s probably sheared ??

[lady bug]

I did thanks for sending me in that direction.
If it is sheared Which I have had in the past. What would be the fix to continue running an advance key. I put loctite on both the key and on the snub of the crank like I said that happens to me a few years ago. Thanks so much I never even thought that.

[TheNewGuy]

Make sure to rotate the flywheel against the key when installing.

[BIKERMIKEYBLACK]

You’re supposed to lap them in with valve grinding compound from flywheel to crank but personally I don’t like them because they are always shearing Right SLONOMO ?

[lady bug]

I have never laped them in. I could see how that would be helpful. I have installed them before so I was very much cautious to turn it against the key when installed. Used blue loctite on both flywheel and snout trying to pin it down the best I couldalong with proper torque on the flywheel nut. Thank guys I will pull it apart tomarrow and update you guys. If that is the case that it's broke any way with keeping these advance keys. Or there always problematic?

[TheNewGuy]

Three 18 hp's and one 23 hp ran the crap out of them, never sheared the timing advance key from CPP. Just my story.

[slonomo]

Originally Posted by BIKERMIKEYBLACK

You’re supposed to lap them in with valve grinding compound from flywheel to crank but personally I don’t like them because they are always shearing Right SLONOMO ?

You got that right. Every one I have used has sheared. I've used lapping compound, impacts, etc and so forth. They always shear and it's always a pain to take all the stuff off to remove the shroud and take off the flywheel. I don't use them anymore.

I've had 5 different big block engine versions in my cart, all 5 had timing keys, all 5 sheared. No idea why. Not saying they all will do it, just saying I've never had any luck at all, and that they do shear.

[lady bug]

I have had success with 18hp. Then an 18hp that sheared. Now I'm on to this 23hp that did it. I'm going to pull it and see if that's my culprit thanks guys

[lady bug]

I wonder if the high comp. Along with cam ect. Causes it to rev faster resulting in a sheered key. Flywheel is really heavy maybe rotating mass can't catch the quick climb of the rest of the engine?