Wow! took long enough to finally get into the engine to complete the diagnostics. I've seen broken link bars on diesel engines that wipe out lifters and camshafts.

I look at yours and all I can say is I would prefer those vertical link bars to horizontal ones. Can't say how it failed though. A link bar would have had to fail first to cause the lifters to rotate and wipe out the cam. At max lift, is there still clearance in the link bars to prevent binding? You would figure if there wasn't enough then more than one would have failed.

I run Crower HIPO lifters in my engine. Not cheap but can easily survive in a race engine with a lot of valve spring pressure and over 0.800" lift in the cam. A billet camshaft and thick wall pushrods complete the package.

 

woah, I had no idea about this whole thread. Spent a bunch of time reading it and I am staying tuned and I do await your next course of action. I am no engine-master, so I will leave the engine tech to those fellas here who are smarter than me.

 

It HAS taken a while. But since this engine was assembled in the spring of 2016, I've had a torque converter let go (fall 16) then a new transmission and converter (spring 17). That ended up being a bit of a fiasco as all the good parts were installed in the wrong transmission case for an F-body (a long cross country story ) which kept me from racing but still let me thrash on the engine (just no slick tired launches as the transmission mount was a temporary DIY deal), then the misfire crept in (summer 18). I bought a house renovation project that same summer (there goes the time and money), moved in the following year but no longer had a garage. The car was in storage for the following year. Then COVID, then the Alberta economy took a nose dive (there's goes more money...). Which brings us to the present. Still no garage but I'm back to a place where I can focus some of my time on the car once again.
So, that's that.

As for the failure, while I'm no further into the engine than that picture shows, my best guess is failure from fatigue.
Valve train assembly is an area where I'm always paying a lot of attention to the details. Having been bit hard with poor geometry, I'm zeroed in on the clearances and angles. FWIW, this setup is nothing exotic but it's got pretty good parts. Or did anyway. Ferrea valves, COMP Bee-Hive 26918 springs and tool steel retainers, spot on installed heights with attention to coil bind, etc. .575" lift isn't too much of a stretch with the 1.6 rockers. Those are Crower stainless with a .050" back set trunnion. Without that backset, proper geometry is not possible. Trust me on that one.
But all of those parts are getting old. The lifters have 60 000 kms (36 000 miles). The rockers have 40k kms and the trunnions are noticeably worn. I posted a video on that a few years back. All in all, the engine has seen a lot of action. The shortblock was replaced (sold the original 350) and was refreshed (bearings, rings but no overbore) the same time as the new lifters. So that's worn out too. 60 000 kms on a chokeless carbed engine is hard on parts.

I'm no engine master either but I've learned what works and what doesn't. Broken lots of parts but have had very successful if not overwhelming results as well. One thing I've learned about my car habits is that I put on a lot of miles. Case in point, the RPM Air Gap intake I purchased new in the spring of 05 now has 175 000 kms on it (105 000 miles). And there have been very few miles accumulated since 2018.

As I was saying, I'm guessing the failure came down to old age. I can say that the new build with ported aftermarket Vortecs (255 cfm/175cc) and XR288 cam really brought the car to life. While the dyno simulations show peak HP at 6300-6500, it pulled like a freight train to 7000. Which I bounced off of a few times and most certainly led to the destruction posted. New parts have survived that same build direction for us many times so the foundations are solid. But much like the owner, as parts wear out, it's difficult to ask for the same performance and durability.

Going forward, I'm hoping to have the heads disassembled this week to determine that they didn't take an unnecessary beating (I trust they're still relatively fresh) and the rest of the engine out of the car in a couple of weeks (still no garage so I'm fighting the weather and less than ideal working conditions). Then I can examine what I have and decide what's next. I can't see anything less than a rebuilt shortblock but I'm leaning heavily towards a new 383. Cam and lifters for sure. Plus all of the other parts that have been along for the ride.

 

LOL. I haven't been to the track in years. With my health, I'll probably never get to race again. Sucks since Calgary doesn't have a track any more. Doing a round trip to Medicine Hat or Edmonton just makes for a very long day.

When I did race however, I always expected to break something. At the end of a race weekend, if I could drive the car back into the garage under it's own power and didn't need anything fixed for the next race, it was a good race weekend. I've replaced a lot of parts over the years due to breakage. I even broke 2 engines in one season.

 

I'm not far removed from that myself. Here's hoping your health recovers and you can get back to what you enjoy.

 

I can't get any younger and I use home oxygen even when at work to get me through the day just to keep my blood oxygen levels at manageable levels. Lungs just are not what they used to be.

 

I can relate on a similar level.
Took my first cortisone injections just the other day for a decades old hockey shoulder. The 7 months that intervened between when I re-injured it (in February taking out the garbage!) and got these shots and were not the most pleasant. I could barely manage pulling on a t-shirt let alone lifting a cylinder head out of the engine bay.
Good thing I know how to relax and decompress. As far as the car sort of thing goes, I always remind myself that it's just a hobby. One that I enjoy but I try to keep it in perspective. Which is something I never used to do.

Best of luck Alky. I hope there's some degree of recovery for you.

 

That's quite the failure!

Metal fatigue I would say - given the mileage (IE not a "defect" per-se) - and probably a poorly chosen alloy for the application - or the bars/rivets were not manufactured to the engineering specifications. Probably never know the exact answer without analysis.

And definitely throw all of them in the trash. Absolutely not worth the risk.

GD

 

Unexpected too. I knew the cam was done but hadn't anticipated that lifter failure. Still ran though and relatively well which is why I had no suspicions.
Sadly, yes, the rest are all junk. I'd still like to hear COMPs take on it. The other link bars and rivets look practically new. They are tool steel with a black oxide coating and that coating shows no signs of wear.

Here's the deal now though. I'm hesitant to buy any replacements in this COVID / post COVID manufacturing environment. There's plenty of evidence that supports the notion the some of the QC has slipped as companies are rushing to restock inventory. It's probably much worse with off shore facilities.
I've got a 6 month winter window I'm looking through now and other than getting the shortblock built in time for spring, the rest of parts can wait. Things should improve.

 

I figured two years on was about time to update further.



Further to that, one thing led to another, and not in the best order I should add, I ended up with an all forged 357 that fired up the 1st time last fall.
Lots of good parts. The only thing that carried over with the shortblock was the block itself and crank.
If the transmission hadn't ***** the bed, I'd have been racing and cruising a couple of months ago.
Anyway...stay tuned.

 

Ah,the self-aligning cam lobe. A less successful design than the self aligning rocker arm.

 

Much less successful.
And it doesn't do much for valve lift either.
The roller looks like a ball bearing.

 

Wow, I've not seen that before. Link bar failure?

 

As near as I could tell, yes.
Found the link in the oil pan along with a river. The other rivet stayed in the lifter valley.
Older lifters, although good parts as they COMP's tool steel short travel versions, and I guess near 7000 RPM didn't make for a good mix.
No other damage other than all of the metal that got pulled through the engine. It was due to come out anyway so I'm not too bummed about it. And a new cam was needed too as that spec wasn't quite right.
Now it's back together, broken in and ready to go. Once I get another transmission built that is.