[technician117]

In all my time reading here I have never seen a report on timing guide replacement gone bad to engine failure, except for once but it was a two post thread with no details.
It has to be something you did wrong in assembly, but stuff happens so don't sweat it. I have sheared off a couple of water pumps in my time, first one OK but the second one after knowing the issue, no excuse. The extra work is always a good reward or punishment.

There have been a few threads. I recall one where they assembled it, checked timing 10 times but still bent valves on one or maybe both heads. I've also heard a couple stories on the Facebook group over the years. Mostly people just get nervous, for good reason I suppose based on the consequences.

Even worse, I know of at least 1-2 "built" engines that VAC Motorsports put together that had bent valves. This was years ago, but proves that even shops can screw up the timing on these.

I find that it's all about taking your time and rechecking each step as you go.

Maybe that guide bolt wasn't actually threaded in all the way?

 

[technician117]

Update: 4k miles, two track days, and an autocross in without issues!

Always glad to hear about successful outcomes. With this repair job, it pretty much works or doesn't

This isn't a "one up you", merely more data for future readers: I did my guides back in June. That was 13,000 miles and 3 HPDE's ago. Now I have to worry about rod bearings but never again chain guides on this engine before it's time for a full rebuild or replacement.