Hot Rods A catastrophic failure

So sorry to see this - as someone who has long yearned for an ardun flattie and then see this, it is truly a heartbreak .... I hope the heads are still usable .....

 

What rpm was it when it went south?

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Sorry to see that...I hope you get it figured out and can get that motor back in your car and on the road again.

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Man that's just horrible.
You must have felt sick when that left go.
My deepest condolences.

 

My money is on the rod bolts not torqued properly.
If you don't use a stretch gauge the bolts can loosen up.
And since I see bolts still in the caps that's my opinion .
Sorry
I hope the heads are still ok


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I never broke anything going slow....

 

… You must be of stout character; as a Full Race FH owner myself - it looks like you’ve already got one leg up on it, cus I’d be unable to even to talk about it yet.
hang-in there man, Ric

 

Damn...That's brilliant!

 

Man I feel your pain! Sorry about your motor almost same thing happened to myself this Tues not nearly as much invested in my motor but just put a blown 327 in my 34 3w for dirt drags which is tomorrow! And I decided to adjust valves 1 last time and put my new covers on. Well got that done and when I started it the damb thing blew all 5qts of oil out the tail pipes in about 3 mins! At least I have my ol trusty A bone to back me up! Good luck buddy!! Hope the Ardun stuff is ok usually it takes 3 flathead blocks to find a good one anyways lol!

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The heads, if damaged, should be able to be repaired. I have had quite a few heads welded up and repaired over the years. Sorry about the engine damage.

 

I realize the rod bolt pulled loose. Yes, there very well may have been a mistake in the assembly process. We can't change anything that has already happened. My advice was aimed at preventing future damage on a rebuild.

I've had two engines blow that I built myself. I suspect rod bolts in both. The naturally aspirated one ran hard for several thousand miles. The blown engine lasted six runs. I changed the setup. Now running a lot more boost with no problems.


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I started using only ARP hardware in my engines a while ago and follow their torque tables, use their lube, etc. One simple part can jeopardize the whole works.

 

Boost shouldn't put any more stress on the rod bolts because the crankshaft pushes on the rod. Pull on the rod bolts occurs when the piston has to change direction at the top of the exhaust stroke. With valve overlap, boost should make that easier as the boost tries to push the piston down. RPM is what stresses rod bolts as the change of direction happens much faster.

 

Beat me to it.

 

Lots of factors here, if the rod bolt wasn't torqued properly from the beginning I would imagine you would hear the rod knocking..

How much compression did the engine make?

Did you hear the rod knocking before the failure?

How about any detonation?

 

Forensic mechanics.
Sorry for your loss.

 

Motor is at MY engine man now. He is going to check everything left to try to find out what happened. the first thing I looked at was the oil presser and it was 40 lb. the next thing it let go. No bearing damage. It will be a while because he is real busy. Jim

 

The rod capscrews look like the first couple of threads are deformed. I suspect the blind holes in the (after market) rods weren't tapped deep enough and the capscrew bottomed, giving insufficient bolt stitch and an erroneous torque reading.

 

Ouch. My condolences deucendude, thanks for sharing your story!
Reminds me of the old proverb "For want of a nail, the battle was lost...."
I remember Tom Senter's "Ardun White Paper" series years ago in the old R&C. Reading that was really my first exposure to these conversions and what goes into them, and knowing even that little bit makes this very tough to see.
Interesting theories posted regarding the failure but I'm just curious: how could you guys who suggested causes based on the posted photos pull out any credible details from that oily mess?
I'm telling ya, my eyes ain't that good!
Will be interesting to see the results of the forensic research.

 

Years of experience doing autopsies on deceased Diesel engines in an engine R&D environment for an engine Oem.

 

in one of the oil pan pictures it looks like a 4"piece of the cam, if so it must have been really noisy. Sad.

 

I'll go on record to say the cam broke 1st. Nobody here can go back in time to review every part that went in it. Coulda been an old proven NOS "blower cam" from back in the day but wasn't up to Ardun use? Didn't like pushrods? Maybe a minor faux pas in valve train geometry added stress? And too, maybe the previous owner leaned on it really hard a time or 10 and it was just on the verge of boom when you got it. When I did race cars and the like with modified motors I told the owners to take their battery or watch me disconnect something so it wouldn't start. "Why dude? It's all good." Yeah right. I never wanted to be the 1st one to start an engine that just buzzed high RPM recently with no knowledge of it's quality. How would that be, a client's crank on my shop floor. No thanks. Although an ugly sight I think it's worth the forensics and rebuild. Still thinkin cam...

 

It all comes down to reverse-engineering a Picasso painting...

 

That has to suck big time....

 

A very big shame. How are the heads? Will you get a new block and start again?

 

At this point my builder wants to disassemble the ARDUN Himself to analyse it. Definitely will build a complete short block at least.

 

It did a good job - there is one of everything in the pan

 

Heard back from my engine builder. He said he took the rest of the rod bolts off with a speed wrench. I think we know what caused this! He is not slow just very busy and others are before me. It was toast for this summer anyway. Heads look to be all fine.

 

Thanks for an update, it is amazing it lasted as long as it did if all the rod bolts were that loose!

 

So he's going to cover it?