03-02-2011, 07:00 PM #1
Pump rebuild questions / Crank replacement questions
2 Big questions of which will help me decide what to do this spring. Last year i rebuilt my jet drive, but since i didnt have a set of calipers calibrated correctly i set the first bearing (the one that sits flush against the flange on the inboard side of the driveshaft) by eye. The shop manual calls for i believe .91" +/- .004" from the driveshaft lip. But instead i set the bearing on the wear marks on the driveshaft from the old bearings I.D. The rest doesnt need to be measured. The thing is i cant garentee that i set the bearing within spec, it works just fine with 50 hours on it but do you guys think as preventative maintence i should take it back apart and do it the "RIGHT" way with a new set of bearings (measure it) or just say F it and leave it? Im sure its damn close to the spec but it doubt within .004"... Usually im pretty anal but it was the last few weeks of the season and i didnt have calibrated calipers at home that day so i said forget it and slapped it together.
Second question is about the crank, its seen 2 topend rebuilds, and 210 hours. Last time i had it apart it was all "In spec" per the references in the book, so i didnt bother replacing it. The small end deflection was close to being out of spec though. So, i got plenty of time to rebuild it all before summer and i have to pull the motor for some other work anyway. How long has everybody used there factory cranks for? And were yours still in spec when you decided to replace them? Also im pretty certain ill use an sbt crank (i know all the hate on them) but the fact is ive used there parts in both my skis that i beat on hard and neither EVER broke down due to sbt part failure... In fact neither broke down at all besides a sheared powervalve. But if anybody has some real input on why not to use an sbt 1 year warentey crank id like to hear it aswell.
Thanks for all the input, and does anybody want some diy guides on how to check out a crankshaft for wear? (it requires some calibrated instruments though)
03-02-2011, 07:19 PM #2
You can get brand new OEM cranks online for under $600. Thats just about $100 more for OEM and NEW not an SBT rebuild. I personally would spend the extra money because I would hate to find out an SBT crank that doesn't meet OEM requirements blew up my newly rebuilt engine.
03-02-2011, 07:53 PM #3
Q#1 you are fine with the pump bearing it pulls itself together when you torque the nut.
Q#2 I am a big fan of OEM new crank only.
03-02-2011, 11:53 PM #4
Simple and to the point! Thats what i like to hear, yeah ill just keep an eye on the pump for the seals to start failing again this summer. Im going to have to price a new one out i suppose since im saving money on a pump rebuild again, but lets speak hypothetically.... If i pull it apart and measure all the indicated tolerances on the crank and its still in factory spec... would anybody here replace it anyway at 210 hours? How many hours does everybody else "get" out of there cranks?
03-03-2011, 07:19 AM #5
- Join Date
- Oct 2006
i replaced my oem crank @ 200 hours ( 200 very hard hours) and only because i had a new t&w oem on the floor, i figured why not since i was rebuilding the top end and was going to throw ported cases in as well, so i just did the whole lot while i was in there....incidentally, my old crank got sold to someone who sold it to someone else who had a bad crank and its been going ever since, that was 18 months to 2 yrs ago so my old one would have closer to 3-400 hours on it now.
sbt and hot rod cranks are shit, avoid them if you can and stick to OEM.
03-03-2011, 10:08 AM #6
I typically like to use oem where possible, but sbt never sold me anything bad yet... however i never used there cranks and for such a critical part of the motor i am also leaning twoards oem. Just like to stir the water up sometimes damn thats alot of hours though!!
03-03-2011, 10:57 PM #7
Also, how do i know what type of prop i have? Its solas with a blue tip on a 2001 gp1200r, but i bought the ski used so i have no idea what prop pitch it is or brand. And further more whats a good pitch for a stock motor (besides flame arrestors and jetting)
03-03-2011, 11:08 PM #8
03-03-2011, 11:10 PM #9
If the ski has motor mods... (timing, milled heads, ported, bored), or it's in your future, go OEM for the extra cash. Otherwise if you are stock and want to stay that way, I say an SBT crank, it'd do probably as many hours as the current crank.
Atlantic is good to deal with, everything has been cheaper there, that I've found....
I think they use OEM cranks, and since it's "premium" I think it includes weisco pistons and not the other brand they sell... WSM, I forgot.
03-13-2011, 10:16 AM #10
oem crank is great.... boats.net is where I got mine. true and welded it myself. no problems.
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