Beware Exploding Trigger Wheels

[racebmw]

I had my race car (1969 BMW 2002) at the track this weekend for the first time with the Megajolt setup. It ran great. The engine pulled happily to 8000 RPM which it would not do with the MSD system. The car ran very well and went faster than it ever has.

However, I was exiting onto the front straight at about 8000 RPM when the engine went "BANG" and started misfiring and running on 2 cylinders. I thought I had blown it up. After getting towed in we check for holes in the block and finding none we started looking at the Megajolt setup. We were checking the VR sensor when we noticed a big piece of the trigger wheel was gone. The trigger wheel had failed after less than an hour of run time.

I was using the Ford F2LZ-12A227-BB trigger wheel adapted to the M10 crank hub. I found a link to Sean Hyland Motorsports where they sell a billet trigger wheel to "eliminate the risk of failure of your powdered metal trigger wheel". So it would appear the stock trigger wheels are prone to failure at high RPM.

Hopefully the billet wheel will solve the problem.

You can check out the billet wheel at www.seanhylandmotorsport.com. Enter trigger in the search box.

Jeff

[brentp]

I had a similar problem, but due to bad engineering on my part- I had adapted the metal ring from a 1.9L escort to an aluminum under-drive pulley. The clamping arrangement I used failed at 7600 RPM, and the timing wheel bounced around the engine compartment before exiting the bottom of the car!

Thankfully I had steel braided oil lines in the area; otherwise they would've been sliced through like butter. I too, thought I blew my engine!

Here's what I have now: