Impeller to Wear Ring Gap

[Gordo]

I bought a new wear ring and new impeller for my 2010 Speedster as I had damaged the original hardware by sucking up rocks. Odd thing though , when I dry fit the impeller inside the wear ring with just those two parts sitting on a table, I measure a gap of 1.4 mm, really 2.8 mm at extreme but half is the centered impeller to wear ring gap. However the shop manual species a maximum wear limits of 0.35 mm gap. I am using brand new hardware and I already exceed wear limits by a factor of 3 ! Could it be that when the nylon wear ring is fitted into the pump housing it will reduce the ID significantly enough to give me the 0.35mm gap, I doubt this. Just wondering if others have noted their actual gap using feeler gauges, this could be new hardware or even your impeller gap to wear ring on your present jet boat. I suspect the manual has an error but I want to get maximum performance and since this gap seems to be critical to performance I am even considering 3D printing my own wear ring that gives me a tight as gap as possible.

 

[MacSeaDoo]

Is your speedster supercharged? I believe there are 2 different impellers/rings based on NA or SC

 

[Gordo]

It is not supercharged. I order the parts from the dealer . I will double check the part numbers. I also have on order a vernier (8") so I can verify all diameters. Thanks.

 

[Gordo]

Part numbers check out as per the shop manual and other cross reference info.
For my 2010 Speedster 155 hp, wear ring number is 267000419 (received) and the impeller number 204160350 (manual) received 267000968 ( equivalent to 204160350 based on internet cross ref checks).
I just received a 8" vernier caliper through amazon and took diameter measurements to double check the feeler gauge method. Impeller OD is 155.5 mm, wear ring ID is 157.9mm which yields a 1.2 mm radial gap. A bit less than I measured with the feeler gauge but still beyond the manual specification of 0.35mm. In many forums people say the gap should be the thickness of a dime. I measured a Canadian dime it is 1.24mm and a US dime is 1.44mm so based on the dime criteria I am good but based on the manual I am out of spec. I suspect those Engineers at Bombardier made another mistake, they probably wanted a 0.35mm gap but with part tolerances that was not a realistic goal. I run into this once in a while as I work as an Engineer for an aircraft engine manufacturer. What the engineer wants isn't always possible due to part manufacturing and cost limitations. Just for kicks I am going to 3D print a PETG wear seal with as tight a gap as possible to my impeller .I may install it if I find the OEM part does not perform as my original wear seal. I am still interested in hearing from people that have actually measured the gap with a feeler gauge, what do you measure ? I doubt you get 0.35mm (or .014"). Here is the call out from the manual.

 

[Gordo]

Just pulled my pump assembly from my Speedster. Pretty easy job, I am impressed with how accessible the fasteners are. The original wear ring with about 120 hours on the boat is gouged up by taking in rocks. I measured the ID of the wear ring while still in the pump housing ,it is 155.8 mm dia , just what I would expect to give me a nice 0 .15mm gap to the impeller. My boat did hit 78 km per hour on GPS with two people and perfect water prior to ingesting rocks. I am concerned that this new wear ring will give me a 1.2mm gap. Just maybe the ring gets compressed radially by 1mm when it is put in the housing. Does anybody have experience with this. If I install the ring I can't return it so I want to try to assure myself that this new wear ring will result in the gap to spec. I am cooling (in freezer) the housing presently, will pull the damaged wear ring let it warm up and measure it in in it's uninstalled condition.

 

[eliterrell]

Just pulled my pump assembly from my Speedster. Pretty easy job, I am impressed with how accessible the fasteners are. The original wear ring with about 120 hours on the boat is gouged up by taking in rocks. I measured the ID of the wear ring while still in the pump housing ,it is 155.8 mm dia , just what I would expect to give me a nice 0 .15mm gap to the impeller. My boat did hit 78 km per hour on GPS with two people and perfect water prior to ingesting rocks. I am concerned that this new wear ring will give me a 1.2mm gap. Just maybe the ring gets compressed radially by 1mm when it is put in the housing. Does anybody have experience with this. If I install the ring I can't return it so I want to try to assure myself that this new wear ring will result in the gap to spec. I am cooling (in freezer) the housing presently, will pull the damaged wear ring let it warm up and measure it in in it's uninstalled condition.

Just replaced the wear ring on my 95 SPi. (Assuming you freeze it to get it in) After the wear ring expands inside the pump housing it should lessen the gap by a significant amount. Mine had about a .5 mm gap when I was just testing it but one everything was in place I had to use a breaker bar to turn it over for the first time

 

[Gordo]

Just replaced the wear ring on my 95 SPi. (Assuming you freeze it to get it in) After the wear ring expands inside the pump housing it should lessen the gap by a significant amount. Mine had about a .5 mm gap when I was just testing it but one everything was in place I had to use a breaker bar to turn it over for the first time

Thanks good to know

 

[Gordo]

I removed the old wear ring and installed the new wear ring . I am pleased to report that the new ring is a good fit. I have about a 0.2 mm gap between the new impeller and the wear ring. I had to freeze the new wear ring and then still required a fair about of force to get it into the pump housing. I conclude that the nylon is in a lot of compression and this brings the parts to spec. So in summary it is not a good idea to check the parts just on the bench without the wear ring installed in the housing. The wear ring sees a fair amount of compression.

 

[N8ID]

You may find that once you install the wear ring that the impeller will not fit into the wear ring. I had this issue and I ended up speaking to the impeller expert. he explain that when the wear ring is installed there can be about an inch of it that is several mm Smaller) at least on the plastic ones.
he told me to take a dremel and shave a little off. while not feeling good about taking a grinder to my new wearring. I did it when I got about an inch down from the end of the wear ring the impeller dropped right in.
He also said not to worry if the clearance was tight or even if the impeller hit the wear ring a bit . The impeller would make it's groove in the wear ring and it would be tight.
I know this was not exactly what this thread was about

 

[MacSeaDoo]

Curious where people are getting their wear rings? From my understanding, you should never have to shave or modify a stock OEM wear ring.

 

[N8ID]

One reason I went ahead and did the grinding (which wasn’t much) was because it was at the end of the wear ring so the gap didn’t matter.
It was not an OEM wear ring either.