Thread: Rebuilding my 787 in my `97 XP
10-07-2009, 12:10 AM #1
Rebuilding my 787 in my `97 XP
OK, I finally found a decent, rebuildable block for my `97 XP. The motor donor is a `96 GSX. The block and crank out of the XP were shot. The previous owner got water in the crankcase and one of the rod bearings destroyed itself and took out the crankcase with it. The XP's hull is in great shape, thus wanting to put a new motor in it. Did I mention that I am trying to pull this off with a limited budget, ie. as cheap as possible. The GSX motor is in OK shape. When I bought it, it would turn over by hand to a certain point and bind up. I turned it over with the starter and got 110psi on the MAG and 115psi on the PTO. The binding was from some minor rust on the MAG cylinder wall and a stuck ring. Other than the small rust spot, the cylinders are in great shape. Oh, this block was an SBT rebuild. You know they pull the OEM serial number tag off and put thier own on? Anyway, here is my plan... I'm gonna have the cylinders honed (either do it myself with a Flex-Hone or have someone else do it), new piston rings with the original pistons, new piston pins and bearings and a complete gasket set. I know its kinda a cheap way out, but I really don't want to spend the money for a new motor or a full on rebuild. Also, the intake has some scratches on the rotary valve side. Does anyone know anything about resurfacing the intake? The crankcase side is good, but the intake size could use some help. I'll try to get pics up later so everyone can see what I'm working on.
10-07-2009, 12:13 AM #2
Oh, I've got a whole `96 GSX ski sitting in my garage that desperatly need parting out. If anyone needs anything off of it, let me know. I'll sell parts cheap just to get rid of them! I told my neighbor that we could make a duck hunting boat out of the empty hull!
10-07-2009, 01:02 AM #3
- Join Date
- Aug 2009
- Beaumont, Texas
10-07-2009, 06:02 AM #4
10-07-2009, 09:42 AM #5
- Join Date
- May 2008
- Elephant Butte New Mexico
after cleaning up the rusty jug, be sure to measure the ring end gap. you need to realy really really clean the jug with hot soapy water after you run any kind of hone thru it.
resurfacing the rotary valve surface requires specialized machines, meaure the clearance and hope for the best.
rebuilding on the cheap often has dissapointing results, I'd take a good hard look at the crank and big end bearing before investing time and money in a rebuild..what's the point if you only get 50 hours out of it?
10-07-2009, 09:43 AM #6
10-07-2009, 01:04 PM #7
A few pics...
I'm gonna take the intake/rotary valve cover to work tonight and have one of the machinists look at it. It needs something, but I don't think it will need milled down more than .005". The pics of the cylinders make them look worse than they are... I think a flex-hone would clean 'em up nice.
Does anyone have any advice on getting the PTO flywheel/coupler off? Does it just screw on or is it pressed on? I need to pull the one off of the XP's old crank and put it on the GSX crank.
10-07-2009, 02:04 PM #8
For just a rec engine, I think you can reuse everything. You can probably just run the rotary valve cover as is. I would check the valve to make sure there are no nicks in it that could catch.
Pass a hone through the cylinders and you are good to go.
10-07-2009, 05:00 PM #9
That's my plan... just reuse everything and put it back together. This isn't gonna be a racing engine or anything special. I'm gonna reuse the pistons that I took out but I am going to get new rings. I've got 2 intakes so I want to try to get at least one cleaned up enough to use. Anyone know where I can get a complete gasket set cheap? BTW, the PTO coupler, is it reverse thread or regular?
10-07-2009, 05:01 PM #10
I gotta get the coupler off of the GSX crank too. Does it come off the same way?
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