951DI counter balance seals

[68ragtop]

Just curious whats up with the CB seals on the 951DI. The seadoo oem rebuild seal kit came with two CB seals. The CB I removed had doubled up seals on the PTO/Air pump side of the shaft. So three seals total. In the parts look up they show three seals, but It doesn't appear I can order them separately. It would appear I got shorted one?

 

[racerxxx]

Bummer, there are some on Ebay. It's either an LYO or a TTO brand seal. Both are Taiwanese seals. I looked here, I don't have any or else I would have put one in the mail.

This is all I got

420930395 or 290930390(supersceeded by the 420930395)---I can not confirm that

http://www.lianyu.com.tw/en/products/index.php?func=detail&sid=&id=10


http://www.tto.com.tw/pages/main.htm


ANy of these numbers line up

 

[68ragtop]

Thanks Racer, I was a little surprised that it had two seals. At first I was thinking it was because of possible failure, But now I am guessing there are two of them to keep one seal from experiencing CB oil on one side, & injection oil on the other. Hence them being installed face to face. Another option would be to re-use one of the existing seals. While I am not an advocate of that, they appear to be oem seals & fit tight & are still soft. Looks like the counter balance was replaced recently in this engine. bearings were in great shape, even though I am replacing them anyway for added security to the crank investment...... Question is, is a lightly used oem seal better than an asian counterpart........ Hhhmmmm.

Edit: I did find an oem 420930395 on ebay, but my quick search shows its for a 98 carbed, Not sure if they are the same size or not? I can do some research later too..

 

[racerxxx]

Do the seals in your kit have any numbers molded into them, can you read them? If they're hard to read and you have a smartphone take a pic and then zoom in on it--I call that putting your good eyes on, LOL. The 787's have 2 seals stacked like the 951 at the counter balance end. I've seen a bunch of them on 787 get mushroomed closest to the weight, as long as yours aren't in bad shape I'd say just use one of the old ones unless you can confirm a new one. I wouldn't see why BRP would use different seals from the carbed to the DI's but who knows. Also a local bearings and seals house should be able to measure what you have and get you one.

 

[68ragtop]

here's one from the bag.

 

[68ragtop]

I finally opened my box of new parts for the RX project & noticed seadoo provides both CB bearings as sealed units. Planing on removing the seals on the PTO side & of course cleaning out the grease. Any idea why they ship like this? obsolete old part or supplier maybe? The other odd thing is, even though the bearings are the same & both are sealed, they are different manufactures. One is a SKF, the other is a NSK.

Thinking about using the SKF on the sealed PTO side & open up the NSK for the mag side. Do you guys have a preference? If I install them were they are designated according to the part number, that would them the other way around. Also, Repack the PTO bearing, or leave it as is? I have seen some of these with a very skimpy amount of grease, but don't expect to see that in a SKF.

Is there a chance seadoo wants both of these bearings sealed now & I should install them as provided?

Thoughts?

 

[68ragtop]

Still not sure on the bearings. I was thinking maybe the replacements are just the 951 carb bearings & I need to remove the seals from the air pump side that is exposed to injection oil, But after looking up the part numbers for the carb'd 951 engines, they do use the same part number for both bearings & both are sealed, but its a completely different part number. than either side of the 951DI bearings. so there goes that theory.

Why would seadoo be providing a sealed replacement bearing for the air pump side of the CB shaft? I guess I'll just remove the seals & clean out the grease if nothing else, but stuff like this drives me crazy.

 

[racerxxx]

Could they be doing it to keep crap out of the bearing if the air pump grenades?

Sent from my SGH-T889 using Tapatalk 2

 

[68ragtop]

Do they fail often? It sure would be in the right spot to collect the debris from it.

 

[- BiRkS_]

I know my 951 carbed had sealed bearings. The oil seals kept the CB oil in the center cavity for the meshing gears.

Not sure about the DI but I don't think they'd change to open bearings?

 

[racerxxx]

I'm just thinking logically. You have a piston sliding back and forth that is squirted with oil, at some point there are going to be fragments that collect--why punish your bearing with that? But then again, I'm a 787 guy, one sealed, one open--but for obvious reasons.

I can see the SBT "pic" of the DI CB has open bearings. And this has always been a big thing of mine with the aftermarket stuff. If there is an engineering change, they have no idea usually. Case in point with my Passat, VW increased the size of the oil filter yet if you go to the autoparts store they sell you the small original size filter. Now, It would also be nice if BRP would include an update to this item..... note with the bearing. Either way, the opposite end is sealed, why not both. Just measure the width of the old open bearing and the new seald one, sometimes the sealed bearings are wider. As far as SKF and NSK, both are quality bearings and I wouldn't think twice about it. Now it it said Nachi or something I would shy away.

 

[68ragtop]

Nice job on the picture! that is exactly the same shaft.

In the pict, You can also just see the double seal I spoke about in the O.P. (three total)
the two seals go face to face behind the open bearing. One side keeps out the injection oil, the other keeps in the CB oil.
There is an oil injection port in the case right inline wight the counter weight. So there is a lot of oil tossed around in that cavity unlike the carbed engine where they are dry.

I'll keep searching for answers, but I am leaning towards removing the bearing seals & cleaning out the grease. Unless I can find some revision that was made. this bearing probably sees as much or more oil than the crank bearings.

The part that is strange is each bearing is from a different supplier, but are identical spec wise.
BUT, the seadoo bags are labeled 2011 & 2013, so maybe the vendors have changed.

On the rebuilt oem crank, all the bearings are SKF just like the originals.

 

[Matt Braley]

Isn't Nachi the Best you can get Japanese OEM bearing?

 

[racerxxx]

Isn't Nachi the Best you can get Japanese OEM bearing?

Perhaps, but all the ones we used on our equipment at work lived a very short life. Possibly we were sold a lower line of bearings.

Sent from my SGH-T889 using Tapatalk 2

 

[68ragtop]

I think it might be a new flavor of Doritos....

 

[racerxxx]

What's even funnier is on the SBT pic you can see the blue Dykem that they put on the end of the shaft so they can see the scribe lines the put in when they press the counter weight off. The when they press it back on they can make sure it's aligned. You can even see the two scribed lines, LOL.

 

[68ragtop]

Not the easiest to get dead nuts again either. I punched a permanent line across the weights & shaft ends before pulling it apart. Hard to get it perfect again when your aligning a shaft 1" down the bore of the weight. I was impressed with how accurate they are originally assembled. before I took everything apart, I installed a degree wheel (I use for timing automotive camshafts) on the crank of the 951. Using a dial indicator I put the MAG piston at TDC & zero'd my degree wheel. Then I moved the indicator to the air pump piston. It was not close to the same, it was exactly the same! Not even 1/2 degree off. I'm going to check it again before final assembly to see if everything goes back together that well. Of course this is with a new crank shaft too, so I am uncertain how perfect that CB gear on the crank is installed. I would assume BRP has them perfect on the reman cranks tho.... we will see.....

 

[68ragtop]

Dropped the new "rebuilt" seadoo crank in to do some initial checking before putting the engine together. While the oem rebuilt crank looks nice, I have a couple of complaints. The first was the threads on the PTO side were full of rust & media cleaning beads. Had to run a tap through it & clean it out. Was surprised that was shipped with all that crap in there.

2nd & more importantly the CB gear is installed 2 degrees off center. How big of a deal is this? Should I leave it, knowing the balance shaft is off a couple degree's or should i take the CB shaft back apart & adjust the shaft to match the crank? I checked the CB shaft against the original crank & it is within 1/2 degree of dead knuts.

Splitting hairs? Or should they be perfect?

 

[racerxxx]

You sure the gear is movable, I think the 787 one is keyed and I would assume the same for the 951.

Bummer on the threads, all mine were mint.

I never checked mine with a degree wheel, just align the dots to the case and gears and good to go.

Sent from my SGH-T889 using Tapatalk 2

 

[Matt Braley]

It's not like these cranks are going back to the factory in Austria to be "factory rebuilt". BRP has to designate certain crank shops to do their work and supposedly meet oem standards. Your probably the only one checking so if the work is really off I think you should say so or at least make them explain it. Guys like me throw them in thinking I'm getting the best.

 

[68ragtop]

To be honest, What I initially even checked it for was to make sure I pressed the weights on the CB shaft correctly. with the DI engine, the air pump piston is at TDC at the same time the Mag side piston is. So, before I took the CB shaft apart I checked it with a degree wheel. Once I had it back together, I checked it again & verified I had the weights back were they were.

Then I dropped in the new crank & checked it to find the 2 degree difference on the gear placement. I am guessing this small amount makes little to no difference, & I am probably looking too closely. I do this for a hobby & pay waaaay to much attention to details. Sometimes details that ultimately don't matter & just hold up progress I guess....

 

[68ragtop]

You sure the gear is movable, I think the 787 one is keyed and I would assume the same for the 951.

Bummer on the threads, all mine were mint.

I never checked mine with a degree wheel, just align the dots to the case and gears and good to go.

Sent from my SGH-T889 using Tapatalk 2

No, I am not sure how the gear is installed. But was assuming its just pressed on because its different than the original crank. Really the only other thing I use the degree wheel for is to make sure the pistons are in phase.

Cleaning out the crank threads was no big deal. just surprised me with how clean & oil the crank came out of the box. I am guessing whoever builds them for BRP forgot to chase the threads on it before putting it together?

 

[racerxxx]

The engine in my XP had a new Reman OEM crank, it too had a different CB drive gear--NO INDEX MARK other than a blue dot. I'll say it was not 100%, could have been closer. BUT, the gear without a doubt is indexed with a woodruff key and I know the CB was dead nuts on so I put it together and it hasn't skipped a beat, zero vibes.

If you look at the CB weight, the U should be centered on the case half, you be the judge. The blue dot on the crank is dead on the case half. Other CB weights have a different size U that I have noticed.

You can just see the blue dot

 

[68ragtop]

The reman crank has a hash mark with a blue line to highlight it. So I am sure they indexed it. just not in the exact same spot as my original crank. The phasing of the crank between cylinders is dead on, so I am guessing the CB shaft being a few degrees out of phase doesn't cause any imbalance issues.

Seeing it's easy to push the weights off the CB shaft, I might as well rotate them 2 degrees to compensate just because I can & its the middle of winter here. . Probably completely unnecessary & whoever takes this engine apart in the future will think the CB was assembled wrong as the hash marks I made on the shaft ends will not be lined up anymore. But at least then I know everything is dead on.

The engine has only been assembled to measure things anyway, so its really no big deal to do it. Take way less time than I spend researching things.

BTW, I also decided to ditch those seals on the replacement CB bearing by the air pump. I couldn't find anything pointing to the original open bearings being know to fail anymore than the sealed ones on the other side. Only thing I could come up with is possible moisture contamination to the bearing caused from compressing air in that cavity? I would rather run something I know has been working for years, rather than something nobody has heard of. I really doubt seadoo cares $.02 about a bearing revision on a 11 year old ski. Probably has more to do with the bearing supplier having sealed bearings as a less expensive replacement......?

For the life of me I couldn't figure out how the injection oil gets returned to the oil tank from a drain in the bottom of the air pump section of the case & has to go uphill to get back to the oil tank. Then I realized the chamber is probably under a little bit of pressure from the air pump blow by? just a guess, not sure on that one......

 

[68ragtop]

Here's a picture from the parting line of the block. I have the crank at exactly 90 degree's from TDC/BTC the hash mark is at root of the tooth just above my straight edge. You can see how its up a couple degrees from where it should be. you can also see the dab of blue paint to the right.