Why does ring locating pin fall out?

[Thunder101]

asked Jack from Carl's what he did to keep the relocated pins in place, and he gave me that goofy smile, and then told me. Pretty ingenious, and this is why the big bores Carl's uses don't have pin relocation issues

ok and the secret is in the pudding ???

 

[blindman]

im guessing gapless

 

[Redsledhead]

used a friends 03 800 HO and had the piston ring fail tore up the cyclinder . could this have happened because he was running 85 oct, gas instead of 91 as it states on gas cap? could this be caused by not deto right? Any insite would help. The motor had 1300 miles on it now I am rebuilding the motor it had factory pistons in it at the time .

 

[danno123]

I would like to know Jack's secret!!

 

[Throttle Junkie]

This happened to me it is not a Brand issue it is caused from Deto, and or exsesive heat, overheating or lean condtions, time and time again, it eventually works it out of the piston. Mine let go with no warning and it also wasn;t up to full tem yet either

Bingo, it's not a secret. Detonation is what makes them go away..period.

 

[LRD]

Here is some good pic of "toroidal combustion chamber" for those that haven't seen them before, boy would I love to have some cylinders with all the ports that TSS motor has and the ignition system!!

http://www.twostrokeshop.com/two_stroke_shop_engines.htm#headinserts

Good Luck

 

[waterford]

Deto Fix

I went through this with an after market head, (deto & pin issues). I increased the squish band at the tight end, was .048/.050" opened it to .070/.072" took care of the problem but I had to take a "gram or two" out of the clutch to maintain target RPM's. Sounds like I had the same head as the earlier post. Per Daly at Dyno Port the Chuckaroo head is the ticket. Daly WAS a firm believer in the top hat design before. Does anybody out there know what is different about the Chuckaroo head that reduces "power fade" as compaired to the other heads out there? Bohn feel free to jump in.

 

[rab]

ttt

 

[Mcx Nytro]

Different types. One was Wiseco and I cannot remember to other but it was aftermarket. I guess my quesiton is more "what would cause the pins to fall out?"

I'm thinking Detonation a small amount, so it does not really show on the piston face.

without reading any further, yes it is detonation. Wiseco is esp bad for this problem,I bought the Genesis motor from .....guess who???? A TOTAL POS mainly because of the wiseco pistons....Just one of thousands upon thousands of opinions about wiseco and .............you know who

 

[Thunder101]

2300 miles on my spi/spx pistons,day 3 of my trip and it ended with a bang . OEM only for me after this. !! Stock Tcat 1000

 

[polaris_dave]

my pin was pushed in and resulted in the replacement of cylinders and piston on my 800R. ~1800km

completely stock, 91 octane shell fuel (no ethanol). How would have have detonation? Running br9es vs. br9ecs??

When I was doing bottom end work to my old XLT, I too noticed that one of my pins was pushed in and the ring was starting to get worn on the corners from rubbing on it.

Since I worked in an aerospace shop at the time, we pulled the old pin and replaced it with a slightly larger pin. The original hole was reamed to the appropriate size for a press fit. We also knearled the pin slightly and used red loctite. Never had a problem with that piston since.

Make sure your pin stock is hardened high carbon steel.

One other thing we did was make sure the pin was long enough to bottom out in the piston, which would prevent the pin from moving inward. I'm surprised that the original pin was not bottomed out. That's just poor design/quality.

 

[polaris_dave]

I went through this with an after market head, (deto & pin issues). I increased the squish band at the tight end, was .048/.050" opened it to .070/.072" took care of the problem but I had to take a "gram or two" out of the clutch to maintain target RPM's. Sounds like I had the same head as the earlier post. Per Daly at Dyno Port the Chuckaroo head is the ticket. Daly WAS a firm believer in the top hat design before. Does anybody out there know what is different about the Chuckaroo head that reduces "power fade" as compaired to the other heads out there? Bohn feel free to jump in.

For those experiencing Deto, you should consider Singh grooves. Google it.

 

[Rich07Dragon700]

Many years back my son's heavily mod (too large, too square exhaust port) 500cc single cylinder Suzuki Quad Ice Oval Racer would loose the very small, short (approx .050" Dia x.10" long) Wisco ring rotation stop pin after a few races. So after a few races I easily removed the small short Wisco ring rotation stop pin. Drilled out a new hole slightly off to the side, pressed in a much larger HARD pin from a blown stock Suzuki piston (approx .070" dia x .160" long) (I think it had a gnarled patch, tapered?), never lost another ring pin. Kept the 500cc Suzuki Quad's engine together, easily won the open mod Quad Ice Oval Point Champion Ship many, many years back.

Many stock 800cc Ski-doo engines with the hot single ring piston loose the ring rotation stop pin, often after after only 2000 miles. As this pin is one of the hottest parts on the single ring piston!

In 2007 the top mod engine builder had trouble with his 440cc Polaris Champ Oval Ice race engines blowing out at the piston ring stop pin, on his special single ring pistons, hot-est part on the piston.
He corrected the problem by installing STOCK 440cc Polaris two ring pistons into a 120+ HP 440cc mod Polaris engines.
Good Luck to the HOT single ring piston engine folks; Rich

 

[One]

I had 400 miles on new stock pistons and a pin backed out from getting too hot...y pipe bolts backed out on the PTO side and had oil/gas leaking, got too lean...check your bolts everyone! Lost a shock a week later from a bolt backing out of my a arm.

 

[LRD]

For those experiencing Deto, you should consider Singh grooves. Google it.

Thanks for mentioning these, I read about them in Popular Science years ago but no pics.

http://somender-singh.com/ Lots of info plus pics of different types of engines with the combustion chamber grooves

Cat dyno #'s http://somender-singh.com/content/view/83/37/

Good Luck

 

[djm]

I believe the way the boat guys are welding there ring anti rotation pins in, is by drilling the pin hole in from the top - vertical, with a blind hole, pressing the pin down below the top of the piston and alumium welding a spot over the top of the pin so it can't come back out. It has both a press fit and aluminum weld over the top of it. You set the hole up so the pin diameter sticks out as far as the normal original pin protruded into the groove. I believe cart racers do the same thing.

Knock on wood, I have been mixing 110 octane race fuel with my pump premium 50/50 ever since 2003 on my two cycle engines, both jet ski and snowmobile and have not failed another piston since that time. I have buckets of pistons from prior years. I don't run boost but typically run about 13 to 1 at 750 feet to 1200 ft (maybe 15 to 1 for some short hill climb drag races with straight 110) and 14.5 to 1 at 10,000/12,000 ft.

 

[Thunder101]

The quallity of the pin is very important, what came to me the other day
is what if you were to punch a burr above the pin ?? small sharp punch ??
you would want to practice on some F old pistons but has anyone done this
or think it would work ??

And some picture of a singh groved 2stroke head.

 

[maluchm]

boy would I love to have some cylinders with all the ports

Calvin Pollet Cylinders?

CP Industries