2001 Virage 700 Engine Vibration

[Bluedmax]

Ok that makes sense. Depending on how long the manifold was loose and leaking water, that cylinder could have been running hot and getting wet then. I'm hoping that's all it was.
But I also just realized I'm backwards with my cylinder identification. The scored / grooved cylinder was actually the front one and the rear is fine. I only mention this because the reason I pulled the original factory engine in the first place was because the front piston was completely damaged. Pieces of either ring or piston started smashing itself to pieces (see pic...). I'm not sure what would have caused that, but I'm a little concerned now that I've seen "issues" with the front piston on 2 different engines. Maybe these two situations are completely unrelated, but if there's another issue going on with the ski (cooling, oil, other??) I obviously want to correct it now before I get another replacement engine.

[Myself]

Running hot because of the water leak. The cooling water enters the engine from the exhaust manifold.

Also, water entering the cylinder washes away the lube and scores up the cylinder.

[casey67]

Running hot because of the water leak. The cooling water enters the engine from the exhaust manifold.

[Bluedmax]

Back again with another troubling find. I pulled the engine tonight and got it all stripped down to ship off. I took a quick peek through the intake ports and found the rear cylinder to have HEAVY grooves already worn into at least the bottom skirt of the piston. What the hell would have caused wear like this with only a few hours?? I attached a pic of the front piston also for reference, which looks fine.

[Bluedmax]

Yes I agree. I’ll just have to pay shipping to return this engine to them (their policy) which I’m guessing will prob be about $150-200. Of course I would prefer everything to have worked right the first time, but was nice to have the 1 year warranty “insurance”. I need to get it turned back around soon though, because the 1 year warranty still expires end of September, even with the replacement engine.

[casey67]

I called SBT. Of course they said that variance isn’t right and to send it back. They want to inspect the motor, make sure the replacement engine doesn’t have the same problem, then send out a new one. Guess I get to R&R the engine a second time

Yeah, but eliminates any question/doubts about water and rust. Big win in my book.

[Bluedmax]

I called SBT. Of course they said that variance isn’t right and to send it back. They want to inspect the motor, make sure the replacement engine doesn’t have the same problem, then send out a new one. Guess I get to R&R the engine a second time

[Myself]

That could be it. I know that as a part of assembly, you are supposed to install the exhaust manifold without gaskets installed before the the cylinder nuts are torqued to spec, so that everything is aligned perfectly.

This is how it should be done on ALL multi cylinder engines that have seperated jugs.

[Beernutz]

That could be it. I know that as a part of assembly, you are supposed to install the exhaust manifold without gaskets installed before the the cylinder nuts are torqued to spec, so that everything is aligned perfectly.

[Bluedmax]

No I haven’t checked that, but we’ve never sucked anything significant like a rope since new. Only a few twigs here and there, which have been easy cleared by using reverse. The ski also runs smoothly otherwise. I’ll check it if you think this is a contributing factor to the exhaust bolts snapping, but would need some guidance how to check.

When working on automotive engines through my years, I’ve always been told the importance of flat mating surfaces for manifolds. I have to think a 0.013 difference between the surfaces of the 2 jugs is not good and is contributing to the issue?

[Myself]

Have you checked the runout on the driveshaft? Somebody sucking a tube rope up WILL bend them sometimes. I had a customer a couple years back that had bent driveshafts on BOTH of their Seadoos.

[Bluedmax]

Casey 67 - We're lucky enough to have a dock on a river and keep the ski in the water for summer. So it's been in the water until today when I finally had a chance to pull it out. I fired it briefly on the trailer, but it HAS been in the water this whole time. Hopefully there's enough lubrication throughout the engine to keep rust away, but after you read below, it may not matter anyway.

I got the manifold / pipe assembly pulled tonight. There's a total of 6 bolts that hold the manifold on the cylinders, there's 3 bolts per cylinder, each set of 3 bolts has 1 long bolt and 2 shorter bolts. It was interesting to find that all 4 short bolts were snapped off and the 2 long bolts were intact. I would have thought the 2 long bolts would have had "more leverage" on them and snapped before the short ones, but that's besides the point and it is what it is.

So upon inspection with a straight edge, the surface of the actual pipe/manifold seems to be straight and flat (as I expected). The cylinders however are not perfectly aligned across each other. With a straight edge across the mating surface of both cylinders I was able to "rock" the straight edge back and forth across the two. I grabbed a feeler gauge to measure the gap and there appears to be about a 0.013 difference. Not a lot, but definitely doesn't sound good to me. I'm thinking it should be perfectly aligned and flat 0.000 or close to it right? Then of course I have 3 broken bolts that were sheared down into their threaded holes (one of the broken bolts had the shoulder exposed and I could back it out by hand).

So the big question is... is a difference of 0.013" between the cylinder mating surfaces "out of tolerance" and be cause for my issues?

[casey67]

If the engine was started on the trailer after exhaust was leaking, I don't think there is any damage. Most of it is pressure in exhaust-that would keep water out. And any water after shut off should be pushed out with the trailer start.
Typically leaks at the exhaust gaskets cause temp issues, before hard to diag running issues, then external leaks.

Rust is biggest issue with water inside engine. With a well lubed crankshaft, the oil displaces the water- IF there was any small amount.

Yeah, with machine work, you are paying for attention/time spent. The more repeat work you do (volume with very common engine parts/more profitable repairs) the more a company makes.
As you noticed finding anyone to deal with "Orphaned" brands is difficult.
I commend SBT for even trying,while even at a low cost. They really are the best available.

[Myself]

I build all my own at my shop. I DID however pull an SBT engine for a replacement for a customer last year. It was a 951 Di that was vibrating so bad it was loosening exhaust bolts within 10 minutes. These have a balance shaft and I'm certain it was out of time. Anyway, they sent a replacement which wouldn't fire up.......no air pressure out of the onboard air compressor......which is PART of the rebuild. I got the OK from their warranty dept to take the compressor head off instead of R&R another engine. Found valve disc had never been replaced. I had a good used one on hand and it's been running fine ever since. If a critical part like that is missed, do you really think they are checking clearances, chasing bolt holes, wire wheeling all the bolt threads, etc?????? NOPE!

[Bluedmax]

So you've had bad experiences with them? I tried finding some engine shops that would do the work, even asked the question originally on Greenhulk. Couldn't find anything, so opted for SBT. Other than this exhaust thing, the engine seems to run good and have the same power as stock. I purchased the engine on 9/29 and do have a 1 year warranty, so I still have a little time yet.