Re: Cause for early ring failure with 4.625" bore blower motor?
 

Lou, I hear you about the plug checking process. I pulled two plugs right after shutting down after a long WOT pass so the idle shouldn't cause inacurate readings.

Bob, the pistons are lateral ported (rather than vertical). Do you think that might affect the leak down numbers or early failure of the rings. It seems just the oil rings are going as I'm not getting any blow by to speak of. I don't have a measurement on how far down the top ring land is from the top of the piston but I emailed you a picture so you can see for yourself.

cuda, good to hear from you. I don't think I have a wash down problem in the boat but during the dyno session, the ignition wire had come loose and the dyno operator had a tough time starting it so he kept pumping the throttle while he turned it over. We then found the loose ignition wire. Do you think that one time could have thrashed the rings?

Thanks again guys.

Keith

Re: Cause for early ring failure with 4.625" bore blower motor?
 

Robbie, if you're looking to keep some heat out of the piston pistons, you might consider some ceramic / dry film & oil shedding coatings

Re: Cause for early ring failure with 4.625" bore blower motor?
 

CCP, the builder did have the tops of the pistons coated. Is that what you are talking about or are you referring to the sides and or bottoms of the pistons?

Re: Cause for early ring failure with 4.625" bore blower motor?
 

Robbie:

Yes,was the top of the piston silver or bright (reflrctive)?? The dry film on the sides is primarily there to reduce friction and prevent seize.

You may be interested in coating the bottom to shed oil (allows oil to cool it, but not cling to it, thu sreducing heat....

Re: Cause for early ring failure with 4.625" bore blower motor?
 

Robbieracer,
From the photo the pistons are CP/Pankl with thermal barrier on the crowns, no other coating, 10-12 lateral gas ports, accumulator grooves. Do you know if the rings were back-cut? How much did the gaps open up to prior to the last rebuild?
Chris,
Was the engine set up for a crankcase vacuum pump? How many inches @ idle & WOT?
Bob

Re: Cause for early ring failure with 4.625" bore blower motor?
 

ROBBIE I'M READING SOME ON YOUR THREAD AND I THINK THAT THE PROBLEM MAY BE AS SIMPLE AS THE FINISH YOU ARE USING IN THE CYLINDERS.THIS RING IS NOT VERY WIDELY USED AND SOME PEOPLE TRY TO RUN THE SAME CYL FINISH WE RUN THIS RING IN ALL OUR DRAG RACING NITROUS ENGINES AND I CAN TELL YOU THAT EVERY ENGINE THAT WE HAVE FRESHENED UP THAT HAS COME FROM ANOTHER SHOP SO FAR THE RINGS HAVE HAD ABNORMAL WEAR WE HAVE ENGINES WITH 600 RUNS WITH OVER 500HP IN SPRAY ALONE THAT LEAK DOWN NO MORE THAN 7-10 % WITH THAT SIZE BORE THAT RING IS NOT WHAT I WOULD USE FOR YOUR APPLICATION BUT I KNOW SINCE ITS THE LATEST AND GREATEST THING OUT THERE NOW MANY SHOPS ARE RUNNING THEM IF YOU'D LIKE CONTACT ME AT 1-305-884-5368 AND I CAN GIVE YOU THE STONE PART NUMBERS AND THE PROCEDURE WE USE SO YOU CAN COMPARE TO WHAT YOU HAD DONE. HOPE THIS SHINES A LIGHT FOR YOU SINCERELY LAZ MESA WWW.MESABALANCING.COMPS THE REASON THIS CAME TO MIND WAS BECAUSE WHEN THE FINISH IS NOT RIGHT THEY SEAL UP GOOD AT FIRST AND THEN THEY START TO GO AWAY QUICKLY

Re: Cause for early ring failure with 4.625" bore blower motor?
 

Bob,
Robbie engine builder is top notch. The pan is a wet sump with internal pump. I don't know wether he is running an external vac pump or not.

Chris

Re: Cause for early ring failure with 4.625" bore blower motor?
 

What do the cylinder walls look like? Does it have dark or shinny spots?