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Discussion Starter · #1 ·
Things that suck to find.

A tick under your left one (or the right)
A bee in your glove.
Dog turd in your shoe.
Eviction notice.
Your mate in bed with the pool man.
This on the Driven end of the rear cylinder Exhaust Cam and bearing journal, 3 months out of warranty!
Auto part Engine
Machine tool Machine Auto part Metal Steel
Auto part Machine tool Machine Tool accessory Gear

It appears as though when my fly wheel key was sheered, some bits were sent through the engine, or was missed during warranty repair to fix fly wheel.
This damage is clearly transference and right at the oil passage to this surface, pointing to that being the scenario.
I put in a call to my dealer whom was so far, helpful.
I was Asked for more pics to forward to Polaris.
At this Point I'm looking at align boring the head. Or replacement of it and bearing cap and cam.
cam is 60
Head is 750.

But hey, as I always say, "Chin up! And put it where it fits". so the Silver lining?
Never before in my life have I been glad it's winter time ....till now.;)
 

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I see... no bearing inserts. If there is enough machining space then line bore and use inserts. It is clearly damage from either lack of lubrication or debris from the prior failure. I would say that Polaris should be all over that warranty claim despite the time frame. We also have some small diesels that run the cams in an iron bore... but we also put in a proper bearing shell on the driven end to take the wear and extend the engine life.
 

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ouch....that sucks to say the least. Hopefully they will see it was their fault during previous repair and take care of it.......
 

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Get in touch with Big Daddy for some details on that new engine thing..........
 
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Discussion Starter · #8 ·
It does look a lot like the camshaft is without a bearing there. Does this mean that the Scout engines are running without any cam bearings? God forbid they are just making throw away engines and charging the prices they get.
Correct.
There is no Cam bearings.. but, I havnt seen anything with cam bearings in a looooong time. Cars included..
With today's alloys, this has been a successful design for most things..
Technically, all things right,, they wouldn't even make contact, they float on oil film.
Looking at the rest of the journals, one couldn't tell anything has ever rotated with in them.
It is repairable as one with out, Albeit, at a higher cost.
All in all, the design doesn't surprise, nor bother me, as it's common and successful in today's engines that typically out last yesterday's engines with cam bearings, by a large margin..
I'd venture to say, judging by how bad it damaged the hard steel cam, if this had a bearing, it would have spun in the journal, and still did journal/cam damage when the oil passage in bearing went out of line, and maybe even seized, doing more engine damage.. every design has its ups, and it's downs.
 

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Correct.
There is no Cam bearings.. but, I havnt seen anything with cam bearings in a looooong time. Cars included..
With today's alloys, this has been a successful design for most things..
Technically, all things right,, they wouldn't even make contact, they float on oil film.
Looking at the rest of the journals, one couldn't tell anything has ever rotated with in them.
It is repairable as one with out, Albeit, at a higher cost.
All in all, the design doesn't surprise, nor bother me, as it's common and successful in today's engines that typically out last yesterday's engines with cam bearings, by a large margin..
I'd venture to say, judging by how bad it damaged the hard steel cam, if this had a bearing, it would have spun in the journal, and still did journal/cam damage when the oil passage in bearing went out of line, and maybe even seized, doing more engine damage.. every design has its ups, and it's downs.
Did you find any of the chunks from previous repair... either in the top end or in sump or in your filter? I would be very suspect of the oil pump in a case like yours as well. That engine could easily have additional damaging debris lurking in some crevice or corner. Evidence of that debris could win your warranty claim if they demand proof. Cause and effect.
 

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Discussion Starter · #12 ·
Thanks for your reply. Yes a spun bearing would've done more harm. I wasn't aware this had become common practice. I'm just getting old and can't get my mind out of old school for some reason LOL.
Lol! I get ya! While I'm not old,, (yet) being more in the "classic" range,, I do straddle the line between the days an engine was toast at 100k, and today when 100k is just broken in.. lol!
Cheers!
 

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Discussion Starter · #13 ·
Did you find any of the chunks from previous repair... either in the top end or in sump or in your filter? I would be very suspect of the oil pump in a case like yours as well. That engine could easily have additional damaging debris lurking in some crevice or corner. Evidence of that debris could win your warranty claim if they demand proof. Cause and effect.
Agreed. More searching will be done.
I'll be saving the oil filter for such research.
At this Point, no other damage was found, nor debris.
 

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The "cam bearing or no bearing" question has multiple possible angles... I am aware that most of the Japanese (and other) OHC engines run their cams without any bearing shells. I just commented on one case where Lister/Petter experimented and found that a Teflon-coated drive-end bearing reduced problems with their cams seizing up. It may cost more to have bearing inserts installed and in extreme cases cannot save your butt - if there is a bunch of loose debris in the engine. I am an old VW engine builder and their old stuff all had replaceable bearing shells to very good effect. No camshaft bearing issues to speak of. The bearing shells are relatively soft surfaces and capable of sustaining considerable damage (and wear) without seizing or transferring that damage elsewhere.
 

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Discussion Starter · #15 ·
The "cam bearing or no bearing" question has multiple possible angles... I am aware that most of the Japanese (and other) OHC engines run the cams without any bearing shells. I just commented on one case where Lister/Petter experimented and found that a Teflon coated drive end bearing reduced problems with their cams. It may cost more to have bearing inserts installed and in extreme cases cannot save your butt if there is a bunch of loose debris in the engine. I am an old VW engine builder and their old stuff all had replaceable bearing shells to very good effect. No camshaft bearing issues to speak of. The bearing shells are relatively soft surfaces and capable of sustaining considerable damage (and wear) without seizing or transferring that damage elsewhere.
I do not disagree. As you said, many different angles..:cool:
 

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Discussion Starter · #16 ·
Will this have any impact on that offer you had to get the big bore done over the winter? Guessing that this is a warranty issue I am thinking you'd maybe be putting all of that off or just forgetting about it.
Disassembling for that very operation is the factor that lead to this discovery.
We are going ahead as planned, with our with out Polaris coming to plate for me..;)
 

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I believe that this is a prime example of just how crucial clean and continuous lubrication is on one of these modern engines. The cams run with somewhat less clearance than crankshaft bearings. Any metal to metal contact will result in immediate heating of that surface and those alloys (no matter how space-age they may be) will overheat, fail, and gall as in that hardened camshaft journal... never mind what it will do to aluminum.
 

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I wish you success in finding and eliminating the root cause of that failure... and getting your engine back to pristine operational status. I'm sure you will keep us posted on that progress!
 

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Lol! I get ya! While I'm not old,, (yet) being more in the "classic" range,, I do straddle the line between the days an engine was toast at 100k, and today when 100k is just broken in.. lol!
Cheers!
Did you just say you’re not old yet? And then say you’re from the Jurassic range? Wow 39 and down is young, but over that......
 
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