As many of you know I missed a shift earlier this year and blew up my 2.7L 6 at Buttonwillow. I'm currently building a new car with a 3.6. I sold my burned up motor to a raceshop and they tore down the engine. What they found was that I did not bend valves as suspected. I broke the rings on every cylinder due to incorrect head clearance.

My missed shift was going to do damage, but not this much if the machine shop I used had done the clearancing correctly. What is interesting is that on the last rebuild I did with this engine, I used a large, nationally know engine machine shop and thought I was safe.

Even if I didn't miss a shift, my engine was living on borrowed time. It appears the pistons and heads were touching. It kinda makes me lose faith in everyone I talk to in this business. I'm not a master mechanic, but the lack of of attention to detail I have run across over the past 2 years has been really disappointing. Maybe I'm just cursed.

Anyway...here's some pics of what happens when your P's hit the heads.

Bill P.

pic 2

pic 3

pic 4...OUCH

Yea it sucks when things go wrong. Especially when it comes from a place that is "bulletproof". But the truth is their not and poo happens anyway. I hope you share this info with that particular shop, if only to make them double check future work.
Cursed? Must be the white magic kind

Yep...I know stuff happens. And everyone that has used this machine shop has nothing but good things. The race shop is documenting everything they find and I will share it with them to just close the loop. A mistake was made.

But it's still a bummer....

oh well....now back to wondering if I'll ever get back on the track....

Bill P.

I don't get it. The pistons and heads were touching? How can they make a mistake like this? The only way to build and engine and set the compression ratio is to measure deck height and CC the heads. How can a shop measure all this and then set the engine up so that the pistons touch the heads? That's a huge f-up.

You sure it couldn't have been that the top ring gap was simply set too tight and the rings butted. The over-rev then fractured the butted rings? Just guessing.

Demick

Hi Demick,

I know. It sounds really weird. But the shop that I sold the engine to races ALOT. Everyone here knows them. And they can't believe it either. I told them who I had the machine work done with and it is the same place they use for alot of their work that they sub. The owner of the shop says he's never seen something like this before from that machine shop, but they measure everything and said that something was terribly wrong.

The good news is that I am splitting the cost of new pistons with them as they can get a really good discount considering I have the receipts and they do business with them. I received good money from the race shop for the engine with the thought that it was just a bent valve, not broken pistons.

Very strange....

Bill P.

Well if you are sure the machine shop is at fault - let us know who it is.

Ken

Bill, this is not directed at you and I know you are not this kind of person, but this is what happens when people get the Wal-Mart syndrome. When $ becomes the bottom line. Sounds like this engine was just an anomaly, but the fact is that businesses are having a harder and harder time catering to a market that demands low prices. If you give them what they want they rake you over the coals for crappy work. It's a fine line that very few people can successfully walk. Oh well. Rant over.

My thread is not meant to bash a business, only to show what happens with a clearancing issue. I trust the shop I sold the engine to, but everyone makes mistakes, so maybe the shop I sold the engine to measure wrong, mis-diagnosed the cause and effect, or the machine shop was wrong.

Both the race shop and engine builder are very well respected, so I'm not questioning their motives. And it is not their fault that I spun the motor to 9000 RPM with my missed shift. But there were other things going on with the motor that I did not "order" when I specified what I wanted.

At least the cams and crank are fine, so I'll only have to refund a portion of what I received.

I wish I had the talent and time to build motors. I've done SBC's and 4cyl Ford's, but never an air-cooled engine. And a race engine to boot. I was hoping to receive a 200 hour motor, but I may really have received a 30 hour motor.

I've tried my best to talk, listen and learn. So far I'm not batting very well with regards to reliability. The car has been quick, but not reliable. The new one will hopefully be reliable.

I'm with Brad, I want to sit around and shoot the shit in between runs and/or days. I don't want to constantly rebuild my car just to play. I'm hoping we can build a reliable, fun car this next time out.

But it's frustrating when you break your toys....

Bill P.

Yes it is.. sorry man.

:\


M

What kind of modification can be made to a "race" motor and still expect 200 hours?

Stock HP 200 Hours

25% 250 ?
50% 300 ?
75% 350 ?
100% 400 ?

Just a reality check..

I find it strange that if the pistons were hitting the heads, you couldn't hear it (your exhaust must be really loud).

Secondly, upon installation and turning the engine over by hand, there would have been resistance.

Now if the clearance was to tight and the rod stretch at rpm caused the impact - that I could believe.

I built my engines with 0.032" piston to head. At rpm (7800-8200), the pistons could just touch and knock the carbon off (or so was my theory).

I gots to say this.

If your machine shop did not give you what you ordered, and that gave you engine carnage, they at least owe you a new set of the correct parts. If it's a one in a million event, then they will be able to cost in their defect rate quite cheaply, since the cost of it will be divided by a million.

That's just how it is. If you go to a dealership and give them $40,000 for a Lexus, you would not take a Ford Focus because the runner picked out the wrong car. Admitted - that would be a little more obvious, but if you are in the machine shop business, accuracy has to be what it's about.

Now - if the wrong thing got ordered - that's a different problem.

I also think you or your builder should have checked the parts prior to fitment, but that's easy to say in retrospect, and a step that I probably would have skipped as well. In software as well as life - it's always good to check your inputs.

Regardless - sorry this happened - it's a big bummer. I'm sure you'll enjoy the 3.6 though.

with SLITS

looks like detonation damage to me...esp. pic 4