What happens when ya run lean at WOT

[Joe Bob]

BAD pistons, BAD.....what Ingo and I found today....

[Por_sha911]

Oh heck. That is bad. Did you know you were running lean?

[Joe Bob]

Not MY motor....then, it is NOW.....I have another pistons and I am purchasing another.....dizzy was way TOO advanced.

[ischmitz]

This is Zeke's 914 2.0 motor we pulled today. It happened within a minute of running time. The car did not make it all around the track at Willow.....

[Joe Bob]

HEY INGO.....Post the NICE pics of the engine bay and stuff....

[Zeke]

Looks like a detonation problem for sure. I can't make any excuses for what I did. But. I'm still questioning the racing gas I bought (F&L 111 octane). So many times I have argued here about tolulene running hot. This gas smelled of tolulene big time. I really should have stopped right there before pouring it in the gas tank.

But the gas didn't ignite by itself. My bad.

[ischmitz]

Here are some shots of today's engine drop of the 914.




The underside of the engine bay is all covered in POR 15. Nice:



Boxed trailing arms



And the oil breather system

[Joe Bob]

Hey, ***** happens....that's why I went out and bought an old exhaust engine analyzer. Proffesional tuners get big bucks because the test equipment is BIG bucks.

Zeke read the plugs, saw what he believed was a good burn...the mains on the 44s are 160s....fat as hell. It went lean at WOT due to advanced spark....looks as if the dizzy may have moved.....it WAS loose.

So....ya fix it and move on. I am very impressed with the detail that Zeke did on the car....he!!, he did stuff that I would never think of doing. I never saw the car before I went down and bought it....but I knew his rep as being meticulous....when tearing it apart, I was in awe of the craftsmanship.....he put a LOT of work into the car.

NOW...I'm gonna do a sixer conversion on it.

The bulkhead mount and sheetmetal are on the way from Rich Johnson and a REAL 2.0 "S" motor is coimng from Glen Sager. It's a peaky little buzzy motor, but with the small bore, competitive....160 hp dyno'd.....

[Schrup]

Looks like a great project Mike. I'm impressed with the detail of Zeke's work. Should be a gaint killer on the track when your done. Looking forward to watching your progress.

[pwd72s]

Back in '69, PCA scuttlebut was that the then new "S" cars with MFI could do this...holes in pistons. I'm thinking that's why the MFI cars tend to run best "rich"...

[Grady Clay]

I agree; this failure is the result of high speed detonation. I would guess you will also find the top ring land collapsed as well. Post some images of the sides of the pistons also.

This detonation occurred in the center of the combustion chamber, like taking a big hammer to the center of a piston. Once the piston structure failed then that large tapered hole formed. This is from too low octane fuel and/or too much ignition advance. I would bet it was the combination of the two. Head and piston temperature influences it also but I don’t think this was an issue here because it happened so quickly, “It happened within a minute of running time.”

What do the other two pistons look like?
What do the small end of the rods look like?

Yes, the engine may have been on the lean side, but I don’t think that wasn’t the root cause of the problem. The fact that the tops of the pistons are clean isn’t a good indicator in this situation (no running time and major detonation.) Many issues like this have compounding of causes. Had the ignition timing been more conservative and the mixture slightly richer, then perhaps the too-low octane might have showed up at low RPM and starting from a stop to give a clue. Had the fuel octane been more than enough, the too much ignition advance might not have been a terminal problem.

Milt,
Where did the race fuel come from? Other than big deal tracks and events (say Daytona 24 or requires “spec” fuel), I prefer to use fuel from a manufacturer delivered in sealed drums with certified octane. The cost is about the same but with a little effort, I am sure of what I am using.
Take a sample of the fuel from the car and pay to have it tested. It’s not very expensive.

Mike,
Please e-mail me and permit me to advise you on your 4->6 track project. I think I can add 2c.

I’m sorry to see the destruction of any good engine. Careful diagnosis of any problem (yours or hopefully some one else’s) adds to your understanding of all the issues.

Best,
Grady
gradyclay@hotmail.com
former CP & GT-2 914-6 racer.

[Doug Zielke]

Nice holes, Mike!

[Mike Kast]

Hey Milt? Does this bring you closer or further from the 356?

[Zeke]

Originally posted by Grady Clay


......Had the fuel octane been more than enough, the too much ignition advance might not have been a terminal problem.

Milt,
Where did the race fuel come from? Other than big deal tracks and events (say Daytona 24 or requires “spec” fuel), I prefer to use fuel from a manufacturer delivered in sealed drums with certified octane. The cost is about the same but with a little effort, I am sure of what I am using.
Take a sample of the fuel from the car and pay to have it tested. It’s not very expensive.


gradyclay@hotmail.com
former CP & GT-2 914-6 racer.

F & L Racing fuel in a sealed 5 gallon can from an air cooled engine parts house. Octane rating of 111. Five gallons mixed with five gallons of Chevron 91 octane California style. While I appreciate the commnent about determining the cause of the failure and therefore helping others out in the future, I won't be testing the fuel. This chapter in my life is closed.

It has become apparent that the distributor was somewhat loose and got turned accidentally while searching for an unrelated electrical problem just before going out on the track. The cap was removed for inspection. As you might know, those caps are difficult to get the retaining springs back on. More than one set of hands tried, but this is alltogether my error.

There is a reason this happened. I believe in fate. I'm looking forward to what life is going to offer next.

[pwd72s]

Whatever life offers next Milt...I hope it's good stuff!