TBM big hub/cone in OEM 155

yamanube

This Is The Way
Staff member
Location
Mandalor
I wanted to do a super detailed how-to on this since I couldn't find one but got lazy with the pictures and bored with grinding so I will throw this out and answer questions to fill in the gaps.
At first glance it seemed like it would fit in easy but it took a significant amount of grinding, I'm not sure if modifying the TBM piece would have been easier but this is what I did.
I would suggest starting with the rear most piece first, it will slide in at least most of the way, running it in and out a few times will leave marks on the stator where it needs clearance. Basically, the veins seem slightly thicker than a 144 stator so a little bit needs ground on each inside corner. Also, the bosses for the three pump cone screws seem slightly larger so those need modified.
I learned the hard way and kept trying to get away with less grinding than I needed, grind a little, fit and grind some more, work slowly but don't stop until this piece slides in smoothly. If you try to work with slightly less than perfect, it will push everything out if alignment and you won't be able to get the other piece in.
See the pictures for the areas I modified. It is very apparent when to try to fit the hub into the stator. The black marks you see are from the anodized stator, it makes it pretty easy to see what still needs work.

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yamanube

This Is The Way
Staff member
Location
Mandalor
Once that piece slides in without obstruction, you need to modify the end shoulder directly adjacent the driveshaft threads (where the hub of the impeller sits). The 144 hub must be smaller, this needs worked down until the TBM piece can slide down over it. I am working with a hand grinder and didn't take any real measurements, if you had access to a lathe, this would be much easier.

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yamanube

This Is The Way
Staff member
Location
Mandalor
The inside corners of the veins seen in the last pic did not need to be modified (I don't think). I was misguided by trying to fit that piece in before really getting the other end properly fitted.
 

yamanube

This Is The Way
Staff member
Location
Mandalor
Full disclaimer:
I have no idea if this will work well in an OEM 155 stator.
I have never run a 155 in anything, and I do not intend on testing this setup without the TBM hub so I will have no analytical information on how it compares.
I plan on running a big hub Skat impeller, probably 6/12, being pushed by a ~760cc 5 mil stroker (stock cylinder) and PFP pipe, I will post my thoughts when I get the ski on the water this spring.
I do plan on testing the three different cones.
I purchased the TBM assembly used, for what I would consider a good price. This may not be a cost effective option if you don't source good deals on parts. There are members on here selling modified, big-hub OEM 155/160 stators that might be quite close in price.

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loictahiti

Site Supporter
It’s what I ve done, and will do a report .......but my english is soo bad to explain what you have to grind and do .
So I m gone in different way, for the stator, I choose to modify the R&D front part , need just to enlarge the center, hope you understand what I mean.....
Let me show you some pics , it’s better than poor english ahahahahaha

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