Crankshaft Key & Timing Gear update

[Yamaha V6]

Well, on Friday morning, the less-than-a-week-old key & gear let go. I had been racing Kirk's beater 92 the night before (successfully, I might add), with no problems. The car saw redline a couple of times easily. However, Friday morning on the way to work, I got the car up to 4500 at one point coming up the onramp & out to pass a slower Semi, & the car started bucking, popping & backfiring (obviously timing related). The tach was bouncing all over the place, and I had from 2000-2500 as reasonably well running - lower or higher & I had to fight to keep the car running.

I got the car up to the shop (car was running fine after shutting it down & restarting), but went through a TON of gas getting it there. Pulled it all apart, and sure enough, the gear was totally fragged, and the new key had broken in half. The crankshaft was pretty well messed up at the key recess too. So, knowing a THIRD key & timing gear were not going to happen, I prepped for an engine swap.

Kirk mentioned the possibility of welding the woodruff key in place, & grinding down the excess to let the gear & dampener slide on. It ended up costing me $100 for the guy to come out & weld it & clean it up, but worked fantastic... for about 5 minutes. CLACK CLACK CLACK CLACK!

Sooooo, looks like the car's retired, perhaps to be parted, or I may swap in a 3.2L I have coming to me. We'll see how things turn out. I just hate to put a new engine in it, knowing in 2 months she's being replaced anyway. I can't see frigging with a crank swap in the car (the 89's an easy engine & trans pull anyway), and if I'm pulling the engine, I may as well put the 3.2L in there. Ah, who knows. Anyway, just sharing my pain.

 

[jthomas68]

If you went about it the 1st time,would it have been possible to grind the slot a bit wider and add a steel shime,or even 2 key`s next to each other worst case?I`m just looking at options for others who can`t just swap in another motor easily.

 

[Yamaha V6]

Crank replacement would be the only other real option JT, I'd guess.

You'd have to get the timing gear lined up perfectly. Fall outside the EEC's ability to correct the timing pulse & it'd be even worse than being a fixed 1/2 degree off or something.

That's a guess, of course.

I'm also guessing that the welding issue was due to the different hardnesses of the crank & key, perhaps. Or, possibly, due to the amount of grinding we had to do to clear the gear & dampener, that there was very little added material holding it there & it broke off. I dunno yet.

PS - if you need anything, let me know.

 

[jthomas68]

I`m going to retorque mine come spring,just to be sure.Maybe it`s something we should all add to our maintenance schedule`s since yours ins`t the 1st one do go bad.
Btw,i`ll be seeing you in 2 weeks,your snow kept me away this weekend.