Seriously...why would anyone fix a 4 stroke? (joking...kinda) Oil pump / intercooler

[Minnetonka4me]

Ok so I took on a project 04 RXP. Unit had major failure and went thru the cases. I had about $700 into the ski and its in really good shape. I let it sit last summer seeing if I could run into a good replacement engine with no luck. I was about to part it down when I ran into a SBT motor on ebay cheap. Still in package, warranty until May. I know I know....SBT...but at 1800 including shipping with no core I bit.

So I finally started getting into it and first things first....both oil pumps were chewed up. That is my first question....is any dings unacceptable? The covers also had gouges from one opening to the other...I would think thats worse than the actual pump, but Id like to hear the experts opinions on this. The SBT literature made it sound like one little ding is going to cause failure and I dont want this thing coming apart on a customer so I just bought them...but Id really like to hear from the experts.

The other thing I just tested was the intercooler. Leaked....the top plastic thing the nipples are on. So before I started researching it I took a hammer and tapped around the brass edge and...no more leak. seriously? Can I trust that??

I would have had to rebuild the SC too but luckily my brother thought he needed it and rebuilt it top to bottom so I didnt have to pay for that.

 

[Coastiejoe]

No doubt,, the 4-tec is much more labor and parts intrusive..

I have rebuilt other high RPM 4 strokes and in every case that the oil pump didn't look new, I replaced them. I am anal and just felt better about doing it. After investing nearly 2 grand, I was a chicken not to do it. I have had a few covers that were gouged a bit and could not get a replacement. I used a marine appoxy and filled the gouges. I was never happy to do so, but to this date, not a one has failed.

 

[Sportster-2001-951C-Stock]

In most cases I replace oil pumps and pickup even if they look good and worked fine b/c warranty requires, but in the case of overpriced and unobtainable antique or sloppy made offshore junk I've resurfaced them back to blueprint specs.

Are you willing to yank the motor back out if the oil pressure stinks, vs the cost of new pumps?

This example worked fine still despite the wear you can see but instead of simply resurfacing the soft aluminum it got a cast iron wear plate b/c it was available at a decent price. The downside of a wear plate in this case is 2x chance of gasket leakage, the upside of cast iron was durability.

I didn't realize the 4-tec has two oil pumps, thanks for that.

 

[red2blue]

There is a difference between fix and engine swap. There is a difference between a project and a flip.

 

[Minnetonka4me]

Yeah but I don't want to have a "flip" coming back to me. That's why I replaced them, but I wanted to know how important it is that it's absolutely perfect

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[racerxxx]

Nick, for lack of better terms, does the oil pump look like a star that rides in a round female star?

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[racerxxx]

OK Nick, I went and looked at the fiche, yes those surfaces have to be PERFECT. Any light scoring and gouging and the oil pressure is going to be either lower than it should be or fluctuate. 2 and 3 are the "stars" I was talking about. Guys who build performance car engines will blueprint the oil pump to get the maximum performance and reliability from them. By doin that they will tighten the tolerances from the impellers to the pump covers

This is a pump from a hydrostatic JD lawn tractor. My pop has a failure in his (this pic is not his) but it had the lightest of scuff marks and would not have enough pressure to push the tractor. If you look at this pic you can see this guy was wetsanding the surface, that is how nice is has to be. I wouldn't take a chance, it will come back to bite you.

 

[ricardo1]

You don't want any scoring whatsoever on a motor that revs that high, I have build 4 bangers, v6 and v8 and one thing I ALWAYS change is the oil pump. You don't want to risk it.( I know this is not a car but it is a motor).

 

[Minnetonka4me]

Now you guys got me worried...the surfaces on the housings have a few light scuffs on them...Im def not replacing those though they are a ridiculous amount of money. Ill snap some pix.

 

[Sportster-2001-951C-Stock]

This one was way too scored, some 400 grit wet sand paper in a figure 8 pattern turned out good.
The shim gasket chosen left about .001 clearance for the two gears.

Years ago we used to scrape our heads on the concrete sidewalk and that worked but our head gaskets were super think. MacDizzy shows us a better way, turns out that's how we do it now too:
http://www.macdizzy.com/1989bhopup.htm

 

[Steven Mace]

Man, on another 4 tec site this poor bloke has had some oild pressure problems with his 4 tec.. check out his oil filter and oil pump pictures.. Yes thats a crack through it..

 

[Sportster-2001-951C-Stock]

Yeah I agree, that gerotor type pump is definitely toast man. Never seen one cracked like that.

 

[ski-d00]

The surfaces of the oil pump star gear and star ring mating surfaces have to be perfectly smooth and clean. Minor nicks are fine as long as you polish you them out to be perfectly flat so that only a small divot is left behind. More importantly is the clearance during operation which the manual explains how to check. The housing plates on either side can not have scoring and circle shaped grooves, this will reduce your oil pressure. Also, while the secondary slave oil pump is important(shown above in the fiche), the driving force on the system itself is from the main oil pump in the pto housing and is critical for the system. Now, with all that said, I've tested oil pressure before taking apart some knocking 4-tecs that had perfect oil pressure and they turned out to have very marked up oil pumps. Surprising, yes, would I put them back together that way, no, but a testament to a robust design by SeaDoo as oil pump failure, in general, just doesn't happen unless something else makes it happen.

For the intercooler, they can be repaired just like a radiator by brazing or soldiering. I wouldn't trust just hammering back in place.

Why fix 4-tecs? Well, once you understand them, they really are not that complicated. More parts, more precision, more expensive, but they can be rebuilt at a reasonable cost. Buying complete motors is expensive but if you rebuild yourself it can be done much cheaper. The key is to know what parts are worth, what is good and bad that can be reused, and what to buy to replace instead of trying to repair what you have.

 

[Minnetonka4me]

The hammering I did was on the top... No place to solder there. I was the lip holding the plastic top in place, I assume a bit of water froze in that lip and pushed it out. If it did leak it would be all external anyways. It's solid internally.

I decided to replace the seals between the oil pump and the water pump and miserably failed. First one I went full retard and forgot the seal behind it, then the 2nd one I wasn't using the right socket as I pressed in the oil pump shaft and bent the top part of the seal. I think this time I'll be the dealer guys to use the special tool to install it.

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[Minnetonka4me]

And as far as fixing this one... Everything was wrecked... Cases, crank, cb, both oil pumps and now 3 pump seals. I think I did fairly good on the price of the replacement motor but overall the margin is minimal for the amount of work.

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