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I need help SW down again losing coolant 550 miles - *FIXED* fingers crossed


They (ARP) might consider the 1st pass so light that it isn't worth doing? IMO, 3 passes is better than 2 on something like this. Tightening head in 3 steps can't be bad.
I was given this spec by Alba Racing in California who originally worked with ARP to create this set of special studs (about 3 years ago). They always tighten in 3 passes.
BTW - 55 ft.lbs is very "nice and tight" if you've ever done one. It's way more clamp force than the stock head bolts which is why the head is sealed better.
 
???
Well, when I got them 3 years ago, that's what they told me.
I'm gonna stay with 3 passes.
 
FYI you wouldn’t really want to have all the bolts totally loose and bring the first bolts in the sequence right to 25ft/lbs imo.

A more gradual progression of tightening is always preferable, it’s just common sense.

If your really anal, technically the head should be re-torqued after a few heat cycles.
 
FYI you wouldn’t really want to have all the bolts totally loose and bring the first bolts in the sequence right to 25ft/lbs imo.

A more gradual progression of tightening is always preferable, it’s just common sense.

If your really anal, technically the head should be re-torqued after a few heat cycles.
Well, that would be nice but in these 998s, you'd have to remove the cams cuz some of the head bolts are under them. Great design, eh?
I'm sure everyone knows what it takes to get the cams out of these (assuming you leave the cam sprockets on)! Someone needs to invent a special tool/fixture to hold the cam sprockets in place with cam chain tight so a guy could unbolt the sprockets and take the cams out without having to loosen the chain (remove tensioner) and everything that entails. It's absolutely no fun. Then, we could re-shim if we wanted to without taking chain loose or off. A good project for some retired engineer/toolmaker. I'd be first in line to buy one.
 
Well, that would be nice but in these 998s, you'd have to remove the cams cuz some of the head bolts are under them. Great design, eh?
I'm sure everyone knows what it takes to get the cams out of these (assuming you leave the cam sprockets on)! Someone needs to invent a special tool/fixture to hold the cam sprockets in place with cam chain tight so a guy could unbolt the sprockets and take the cams out without having to loosen the chain (remove tensioner) and everything that entails. It's absolutely no fun. Then, we could re-shim if we wanted to without taking chain loose or off. A good project for some retired engineer/toolmaker. I'd be first in line to buy one.

I'm certain less than 1% know what it takes! Obviously the machine was not designed around this engine! I made a McGyver tool/holder to hold the sprocket in place while removing the exhaust cam after a blown belt and spitting out a shim and keeper on the center cylinder. Wasn't fun! a 14 hour nonstop project! I almost lost it as the tensioner did ratchet up one spot tighter! I was barley able to bolt the exhaust cam sprocket back up as the chain went real tight, it was close, had it gone one tighter the engine would have had to come out!

Putting the cam back into position was a bugger to say the least, but I was also able to confirm if the crank is rotated backwards even the slightest, the exhaust cam will skip a tooth, its not a myth! And was it a biotch to get it back in time! Had the chassis been cut to get the tensioner out, it would be a piece of cake.
 
KA you certainly know all about it I can tell. I had to take my head off twice. It's not exactly an afternoon project. It was obvious to me that whoever engineered this contraption didn't consider for one second how one was going to re-shim or remove head. Who the he&* put the cam chain tensioner below and behind the jackshaft where you cannot get at it unless you either cut a hole through bulkhead or raise the back of the engine (and all that entails). What a disaster. Fortunately, these 998s mechanically are pretty durable except when blowing belts sometimes and spitting out a shim. Fortunately seems like that's pretty rare even with blown belts for the most part.
I bet you know this but there is a company that sells an after-market manual cam chain tensioner for this thing. I asked the company how, exactly is a DIY guy supposed to change it, how will you adjust it once it's in, and adjust it in the future? I got crickets. I think they were thinking about the Yamaha YXZ1000R SxS that uses this 998 non-turbo. The cam chain tensioner can be taken out with a crescent wrench or vice grip.
 
Come on guys you know the answer too this one. These machines are meant to be thrown away before the engine ever needs servicing.
Keeping a snowmobile running for more than 10k miles isn’t profitable for the manufacturers. They would much rather have you buy a new machine. Heck if there wasn’t laws against not offering replacement parts for a minimum 7 years ........I’m not so sure they would have them.
 
Come on guys you know the answer too this one. These machines are meant to be thrown away before the engine ever needs servicing.
Keeping a snowmobile running for more than 10k miles isn’t profitable for the manufacturers. They would much rather have you buy a new machine. Heck if there wasn’t laws against not offering replacement parts for a minimum 7 years ........I’m not so sure they would have them.
Its been pretty common at least with the Vipers to find exhaust valves tight or tighter than spec in 8000mi. Mine was one. 5 ex valves out of spec. If a tool for ensuring tensioner doesnt click tighter is made I would pay alot of $ to have one. I do have access to full machine and Fab shop. Anyone with any ideas how to do it I can maybe get it done. Its so easy to get the valve cover off but if cam removal is needed holy cow what a job.
 
I'm certain less than 1% know what it takes! Obviously the machine was not designed around this engine! I made a McGyver tool/holder to hold the sprocket in place while removing the exhaust cam after a blown belt and spitting out a shim and keeper on the center cylinder. Wasn't fun! a 14 hour nonstop project! I almost lost it as the tensioner did ratchet up one spot tighter! I was barley able to bolt the exhaust cam sprocket back up as the chain went real tight, it was close, had it gone one tighter the engine would have had to come out!

Putting the cam back into position was a bugger to say the least, but I was also able to confirm if the crank is rotated backwards even the slightest, the exhaust cam will skip a tooth, its not a myth! And was it a biotch to get it back in time! Had the chassis been cut to get the tensioner out, it would be a piece of cake.
when I did my nytro, I wedged something down between the tension and slack end of the chain. worked perfect
 
?? If a 998 has been run anytime recently, the cam chain is really tight so there is no slack in chain at all. Need a tool that attaches to cam gears to hold them in place so one can remove cams to shim/re-shim or do other service work. It's a major job to remove and re-install cam chain tensioner on the 998!!!
 
?? If a 998 has been run anytime recently, the cam chain is really tight so there is no slack in chain at all. Need a tool that attaches to cam gears to hold them in place so one can remove cams to shim/re-shim or do other service work. It's a major job to remove and re-install cam chain tensioner on the 998!!!
as stated in my last post. assuming it is similar to nytro, I cut a wedge out of plastic to push down in between the chain loops right in the middle, pushing the tensioner back a hair. might even be able to leave sprockets on. it works, I did it... I tried the whole sprocket fixture idea, didn't work nearly as well, a real pain to roll engine over and get the opposite sprocket bolt. done as I said, you can mark the chain and sprockets, it wont move on the lower.
 
as stated in my last post. assuming it is similar to nytro, I cut a wedge out of plastic to push down in between the chain loops right in the middle, pushing the tensioner back a hair. might even be able to leave sprockets on. it works, I did it... I tried the whole sprocket fixture idea, didn't work nearly as well, a real pain to roll engine over and get the opposite sprocket bolt. done as I said, you can mark the chain and sprockets, it wont move on the lower.
I am liking this idea! Simple is always best. Thank you!
 


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