What could cause case sealant failure on almost new PV motor?

[JKMike]

I'm not expert by any means with engine diagnosis but it definitely looked to me like it got a little hot by the scuff marks on both intake and exhaust sides. The billet cylinders retain a bit more heat than the cast cylinders do so they need more water flow. I helped a friend put a trinity matrix together with a ss900 engine. We set up his cooling as follows and this is in the south with 90+ degree water temps. 2- 1/2 lines feed a manifold with 4 3/8 lines going out. 2 feed the top of the head and out of the exhaust manifold to pissers, one feeds the spray bar and the last feeds the stinger with a flow control and another pisser. This was with a powerfactor ran wet.

I think your probably right!

So when I first set up this motor I had 2 1/2" lines coming in. One going directly to the manifold and the second I split into 2 3/8 lines with one going to the 2nd fitting on the manifold and the other the pipe and then out a 3/8 pisser. Then I had 2 1/2" lines coming out of the head going to pissers. I'm going to go back to that configuration for sure.

I was hardly getting anything on the temp strips I had on the head or the one I had running horizontal at the top of the cylinder. So I ended up feeding the manifold with a single 1/2 line split to both fittings and changing out the 1/2 lines coming out the head for 3/8 lines going to pissers. And that brought the temps up to what I was used to seeing on my 735. But as I now know thats too hot for these motors. I never would have thought that these billet motors needed to run that much cooler and so I never asked the question of what temp I should be shooting for.

This one's on me. But hopefully my mistake will help someone else avoid running into this type of issue.

Also I don't know if it's just dumb luck or coincidence. But if my case sealant hadn't failed I would have never found this issue and it would have been a whole lot worse!!!

 

[Roseand]

Not your motor specifically necessarily, but Zack @php always told me you can never run a motor too cold, just gotta make sure you warm it up well first. Many of his motors run two pump lines directly into the head first(reverse cooling)

 

[DylanS]

I think your probably right!

So when I first set up this motor I had 2 1/2" lines coming in. One going directly to the manifold and the second I split into 2 3/8 lines with one going to the 2nd fitting on the manifold and the other the pipe and then out a 3/8 pisser. Then I had 2 1/2" lines coming out of the head going to pissers. I'm going to go back to that configuration for sure.

I was hardly getting anything on the temp strips I had on the head or the one I had running horizontal at the top of the cylinder. So I ended up feeding the manifold with a single 1/2 line split to both fittings and changing out the 1/2 lines coming out the head for 3/8 lines going to pissers. And that brought the temps up to what I was used to seeing on my 735. But as I now know thats too hot for these motors. I never would have thought that these billet motors needed to run that much cooler and so I never asked the question of what temp I should be shooting for.

This one's on me. But hopefully my mistake will help someone else avoid running into this type of issue.

Also I don't know if it's just dumb luck or coincidence. But if my case sealant hadn't failed I would have never found this issue and it would have been a whole lot worse!!!

These threads are the best, I’m sure someone will be searching for specs on your exact engine someday and come across this.
Some good information you posted.

 

[Sparkplug]

Right off the bat I saw a.engine ran cold and not warmed up right. I have the exact same on my dasa I'm redoing. It happens. Mayne not your scenario. But it's minimal damage.

Like I said. You can slap it back together and its gonna be fine.

Or spend 18-2500 bucks to have the same exact performance that you might do the same exact damage to.

Sent from my SM-G991U using Tapatalk

 

[Sparkplug]

How many commenting bore their own cylinders? Rebuild and true their own cranks? Have thousands of hours of actual tray time beating the snot out of engines of all kinds in surf, sand, river, and sky??

And how many have thousands of posts on xh20?

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[Myself]

A couple comments.......one, I would definately hone that cylinder. You can work a nice crosshatch back into that within a half thou. Two....I didn't see anybody else comment about the piston wash. You asked if it looks rich....I think it's a bit lean. Especially if that black on the left is soot......is it?

 

[Half flip95]

Be careful with these off-the-cuff piston clearance numbers. I was once told that a 90mm piston needs more room to grow than an 81mm piston. There's a formula they use to figure it out, but I don't know it.

 

[SXIPro]

Someday I want to be a two stroke engine genius and have 10,000 hours of actual tray time in the surf...oh really, really I do!! A man can dream......

 

[kevbo]

How many commenting bore their own cylinders? Rebuild and true their own cranks? Have thousands of hours of actual tray time beating the snot out of engines of all kinds in surf, sand, river, and sky??

And how many have thousands of posts on xh20?

Sent from my SM-G991U using Tapatalk

You could be that guy if you stay in the game for 30 years. Almost every jetski enthusiast today will be out of the sport fairly quickly.

 

[Quinc]

You could be that guy if you stay in the game for 30 years. Almost every jetski enthusiast today will be out of the sport fairly quickly.

Probably because of sites like this and youtube and now facebook groups. No one wants to be happy with a stock well running ski anymore. Has to be just like or better then everyone else's. =/

 

[DylanS]

Someday I want to be a two stroke engine genius and have 10,000 hours of actual tray time in the surf...oh really, really I do!! A man can dream......

Which stance would you be riding during the one million hours and would you be running a primer?

 

[WFO Speedracer]

screw all that what kind of oil and which handlebars and grips ?i

 

[DylanS]

screw all that what kind of oil and which handlebars and grips ?i

Let’s not get too crazy here…

 

[SXIPro]

Which stance would you be riding during the one million hours and would you be running a primer?

I’m sorry. I can’t answer to peasants like you until you have 37 bazillion hours riding surf. Did you hear me?? Surf!!!!!! And you can site the Mikuni rebuild manual word for word because you spent your life reading and rereading it while other guys were out getting laid.

 

[JKMike]

How many commenting bore their own cylinders? Rebuild and true their own cranks? Have thousands of hours of actual tray time beating the snot out of engines of all kinds in surf, sand, river, and sky??

And how many have thousands of posts on xh20?

Sent from my SM-G991U using Tapatalk

Well I can't say that I have ever bored and engine block before it can't be that much harder than machining a 1.625" bore all the way thru a 14" aluminum rod while holding a 0.0005" tolerance. lol To be fair that was on a lathe so not the same thing I know, but damn was it a pain in the ass!!!

In all seriousness though while I haven't done it before I would like to and have every intention of attempting it. Sure it might be little risky but ill probably buy a trash block to try it on first to mitigate some of the risk. And if I screw it up that's on me! But at least in my personal experience, I have yet to find someone who has the attention to detail I am looking for and probably for good reason. It just isn't profitable to shoot for perfection on every single job.

 

[JKMike]

A couple comments.......one, I would definately hone that cylinder. You can work a nice crosshatch back into that within a half thou. Two....I didn't see anybody else comment about the piston wash. You asked if it looks rich....I think it's a bit lean. Especially if that black on the left is soot......is it?

So that shiny spot one the left was just oil. I'm honestly not sure if its soot underneath or not. It didn't come off with brake cleaner and the other piston which I put in the ultrasonic cleaner looks about the same. It could have been running on the lean side though, especially if it was sucking air thru the cases. I can tell you that the Full Spec 50's Im running were set up by Phill Clemons who helped develop the XS1060 so at the very least my carbs should be damn close.

Does anyone have any recommendations for what grit I should be using to hone the cylinder?

 

[JetManiac]

Someday I want to be a two stroke engine genius and have 10,000 hours of actual tray time in the surf...oh really, really I do!! A man can dream......

Tray time in the sky...

 

[WFO Speedracer]

Well I can't say that I have ever bored and engine block before it can't be that much harder than machining a 1.625" bore all the way thru a 14" aluminum rod while holding a 0.0005" tolerance. lol To be fair that was on a lathe so not the same thing I know, but damn was it a pain in the ass!!!

In all seriousness though while I haven't done it before I would like to and have every intention of attempting it. Sure it might be little risky but ill probably buy a trash block to try it on first to mitigate some of the risk. And if I screw it up that's on me! But at least in my personal experience, I have yet to find someone who has the attention to detail I am looking for and probably for good reason. It just isn't profitable to shoot for perfection on every single job.

These are pretty much my thoughts, I have dozens of cylinders around here I can screw up with no issues, The guy that bores my cylinders had an accident and is in a wheelchair , he is going to let me work with him some on getting some of my cylinders bored so hopefully it is another skill I can pick up along the way.

 

[mthomps]

Hey guys quick question: i have 9,998.4 hours tray time but only 3.6 of those hours are sky try time. I'm thinking about boring my stock syphon to get better hook up. Should I send it to xscream so they can also chamfer my rideplate or should i buy a few thousand dollars in machining equipment and do it myself.

I run lime green odi grips by the way. I ride moaner style but would switch to pumper dumper if it means max thrust.

 

[DylanS]

Have you considered this method this before wasting money on an expensive setup??? The spoons will contour to the bore perfectly and you can glue finer sand on for a better end finish