Crank Pin Pitting

pjsrider

pjsrider

PJS VIPER RIDER
Location
Central Florida
This probably belongs in the old school section but here goes. Me and my dad are running pjs viper 7000 motors in our 550 skis. They are basically the same as a kawi 550 but with 750 rees on them.. We are running 185 psi compression and a good quality 2 stroke oil. These babies turn around 9400 to 9600 rpm. We are having problems with the crank pins getting pits on them where the rod bearings run. The rod and needles look fine, but the hardend layer on the pin just gives up. Will going to a full synthetic or semi synthetic oil possibly help this? Our boats do get water in the engine quite often and we have to pull the plugs and spin the motor over to get the water out. We always get them fired up right away and ride them for the rest of the day or at least an hour or so after they get water in them. Do ya'll experience any problems after you get water in your engines? If there is even a chance of water getting into the engine we pull the plugs and check, so its not like we are hitting the starter with the motor full of water and bending a rod. Any help would be great. We are runing about 32 to 1 oil ratio.

Jay
 
B

B-ROLL151

Your Crank Is Not Strong Enough For That Kind Of Hp And Rpms. How Long Do The Pins Last Before Pitting? Are You Replacing The Rods When These Pins Go Bad Or Are You Just Putting A New Pin In? I Have Seen Where Rods Will Become Out Of Round And Need To Be Replaced. Is The Pin That Goes Bad The Same One Everytime Or Do Both Go Bad Back And Forth?
 
pjsrider

pjsrider

PJS VIPER RIDER
Location
Central Florida
When we rebuild a crank we use new rods not the old ones. We got about 2 months out of the last one. Thats riding sat and sunday for about 4 hrs a day. We weld and true the cranks and they are within half a thou along the whole length of the crank. We are running toko rods and cranks we buy from gordon at pjs in california. Are there any other high performance rods out there that would be better? We just found out that hot rods have an extra needle in the bearing so we might give these a shot. Another company has some rods with larger cooling holes and more of them so maybe we just arent getting enough lubrcation in there. Thanks for the reply by the way.

Jay
 
pjsrider

pjsrider

PJS VIPER RIDER
Location
Central Florida
It is not the same pin every time.. they both show wear, but usually one is worse than the other. Our thrust washers have very little wear on them because the engines dont last long. We are going to try klotz for the next engine and see if it helps. I understand it has caster in it which has a stonger film strength. Is there another oil similar to klotz that is better or equal?

Thanks
Jay
 
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