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Discussion Starter #1
Folks,

In case there's any interest here's a quick update on the folks that traveled from the north to invade the south this past weekend. I drove down on Thurday, with my wife and daughter, expecting to meet up with Rabbie on the road to the south. I guess the only place Rabbie is slow is on Rt. 81 because we finally met up at the track. Rabbie drove down with the Chief. Kenny Cummings and Jordan Levit lived the lives of playboy racers, flying in to the track on Thurday evening. I had an exciting moment on the drive down when a 18 wheeler jackknifed in the rain right in front of me. Six lanes of bumper to bumper trafic in the rain and this guy hits the brakes and he looked like he was on ice. As he started sliding I'm getting ready to plow into him because I was towing my 26 ft. trailer and I couldn't slow too fast. He bounced off the side of the Jersey bearrier and slid directly across in front of me bouncing off of another 18 wheeler. I went for the gap where he came from and missed everything.

First let me say Rabbie is fast but Kenny Cummings is the Man. The guy rebuilt his Norton from the cases up, twice, this weekend. He had trouble with a base gasket blowing out and spent Friday evening rebuilding it the first time. Only to have it do the same thing on Saturday morning. Kenny spent the rest of the day rebuilding it for the second time. Only to get about two laps of racing in on Sunday before it crapped out once more. But never was a discouraging word heard.

Jordan wasn't having much luck at all all weekend either. His bike was giving him problems with setup. I don't think he finished a race over the weekend.

Rabbie cleaned up, winning the Sportsman 350 race on both Saturday and Sunday. Along with the Sidecar races again on both Saturday and Sunday.

I took a second in Formula 500 on both Saturday and Sunday. I had a terrible start in my Formula 250 race on Saturday and ended up with a second there as well. On Sunday's F-500 race I missed a shift coming out of the infield horseshoe and did some damage to my motor. Still not sure what's going on but I was told after the race that everytime I let off the throttle flames would come out of my right side pipe. I tried to do my F-250 race but did one lap and came in. Now I understand why people are reluctant to do the bump up class if it's scheduled before their primary class. So this turned out to be an expensive weekend for me. I'm hoping it just bent a valve and didn't hurt either the head or the pistons. But I won't know for sure until I tear it apart to get ready to try this all again at Road America.

Craig
 

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wow, congrats to rab. sorry t hear about the motor craig. i think you got it though. dont you run a limiter on that? ah...guess not with the pvl. hmmm....if i had anything that i thougth would help you out, id volunteer it. but unfortunately i dont.

and definitely thanks for the update.

jc
 

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Craig...sounds like a bent exhaust valve....couldn't be too bad or you'd drop that cylinder every time the rpms came down. Check those valve clearances before you do anything else....if you see one with and extra .020" you know where the problem is.
Luckily you run aftermarket pistons which have thick crowns...and SS valves which bend before they break.
Course....could be something in the PVL too.

You and I are in the same boat....a single missed shift can cost thousands....makes you feel like a real racer don't it?
JohnnyB
 

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Discussion Starter #4
I've gotten as far as being able to see that the piston on the right side came into contact with the spark plug. There was no gap at all. And there are some nice marks on the crown of the piston from hitting at least the plug. Stay tuned. I hope to be able to pull the motor tomorrow.

Craig
 

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Well that's not a good sign. I'm pretty sure the piston didn't move and I'm pretty sure the plug didn't move....so something else was bouncing around in there.
You didn't hear a bunch of banging noises? Wonder if it broke off a piece of valve...usually when you drop the whole valve head it makes a pretty big, noisy, expensive mess. And if something doesn't give it either locks up the rear wheel or bends a connecting rod...or both.
Hope it's not too bad.
JohnnyB
 

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Craig, glad you survived the tractor trailer incident... Don't forget we have a dual sport dirt ride on Sunday, No crashing allowed since we really want to hit a diner this Sunday.

Karl
 

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Craig, also glad you missed the 18 wheeler or 36 wheeler...sounds like two trucks were bouncing around on US81. I hate that interstate!

Pete

p.s., I usually don't fly my helicopter to races because it is a bitch to get clearance to land...so I am stuck driving the 2000 white Ford Taurus.
 

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Discussion Starter #9
My motor is at Pete Talabach's place now. The only thing we've found it that the piston hit the spark plug at one point. Still not sure how that's possible unless the crank is screwed up. But he thought he'd be able to get started on it today. I took some pictures but with the camera I've got you can't see anything wrong.

I did get to hear JD's bike on the dyno yesterday.

Craig
 

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Craig,
At high rpm you can get some rod stretch. Do your pistons have plug dimples in them? My pistons have notches to clear the plug electrode, you have to index the plugs to make sure the electrode is aligned with the notch to provide the proper clearance.
If the engine has decent plug to piston clearance I'd still bet it ingested something that got caught in there.
Those clearance are pretty freakin fixed, if you had say .040" between the piston and plug...and somehow that clearance was taken up...that can't be good...or very likely. Had to be something in there.
Giant piece of carbon or something off the piston or head? Chunk of epoxy from the intake manifold?
JohnnyB
 

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Discussion Starter #11
I have the same dimples in my pistons. And I index my plugs to make sure the electrode in aligned as well.

Wouldn't I see more damage if something that got ingested in there than just the spot where it appears the electrode came into contact with the piston? No other indications of damage other than a spot where the exhaust valve also appears to have contacted the piston. Very slight. I would have expected to see marks across the top of the piston if there were a foreign body in there. We did see the ability to have some slight rocking of the piston in a parallel to the piston pin direction. No up and down play in the rod.

Craig
 

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Yeah typically you would see other damage, except in the off chance some got sucked in, crushed quickly..spit out the exhaust.

How far apart is it? Rocking parallel to the pin isn't good...in general slop in that direction is about zero unless the pin, pin bosses or small end is going. But still...unless the piston as room to rock in the bore I can't imagine that taking up more than about .010" of clearance.

Wonder if the piston kissed the exhaust valve, broke a chunk of hard deposit off the bottom of the valve.

Weird.
JohnnyB
 

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please explain why you think the electrode came in contact with the piston. is there a ding in the piston or is it just a mark? Was the electrode flattened?
 

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Discussion Starter #15
Evil,

Sorry, just saw your question. There was a dig in the piston directly across from the spark plug. And the electrode of the plug was closed up.

Craig
 

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Discussion Starter #16
Picked up my motor this afternoon. It had just a single bench exhaust valve in it. It was able to be straightened out. The assumption is that the spark plug was probably too close to the piston to begine with. We cut a new relief in the piston for the plug and put it all back together. Runs like a champ. Made some adjustments to the timing and it now makes more power than it's made up to this point. Tried out my new Clever Dog Race shop megaphones and they also improve power output, along with just looking cool.
Craig
 

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Craig, email me with the details of what meg dimensions worked out for you.
Nothing like dyno tuning. Gave me a "formula" that pretty much just plain works on any 175 if a person is willing to buy the parts and adjust properly.
Did Pete have any suggestions for different megs to try?
JohnnyB
 
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