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!997 GTX Engine Water

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etemplet

etemplet

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I was hoping nothing much was wrong with the ski but C'est Lavie.... she is wounded badly. I have a couple of questions for the group. How does the engine get full of water? I did notice a lot of water in the exhaust pipe when I removed it. I have to laugh because these guys you purchase from are either liars or overly optimistic on the condition of the ski. The PTO rave valve stem was pulled out of the plastic piece, no spring, Yes I am sure it was running great before you sat it up. I found the Rave Valve spring under the engine LOL. PTO Cyinder is garbage, Mag Cylinder is good. Pretty amazing that the compression was still 130PSI on the PTO cylinder with 150psi on the Mag cylinder.

Question on the engine. I am assuming you guys would recommend a rebuild of the lower. I am a little apprehensive concerning this and am wondering if expense-wise if it would be cost effective just to purchase a good engine. I am a machinist by trade so the work won't be a problem. :) How big a pain is the rebuild of the bottom end ? I have not found a total engine rebuild package at any of the shops. I am more comfortable building the engine than I am purchasing a used/rebuilt engine. Any thoughts ??

Are both cylinders the same part number ? I want to keep the cylinder bores "stock".

With regard to parts, rave valves cylinders and such, are all 787s the same engine?

Also.... the engine full of water... would that be from towing or is there some other cause I need to be aware of. Any input would be appreciated.

Gene
 
First, an engine full of water is typically from either flipping the ski and getting water in the engine or running it on the hose and having the hose ON with the engine OFF.

There is no reason to keep the bore stock, just bore them to the next oversize and get the correct pistons. You will have to trim the RAVE valves so they don't hit the now larger pistons.

You will need a rebuilt crank and balancer. You can't rebuild the cranks yourself. I suggest OEM cranks.

You can get a complete engine on exchange with no fault warranty from SBT.
 
Thanks Mikidymac.... I would like to do the job myself. Do we have any people on the Forum that do cranks ?? Who is a good parts source for the bottom end parts?

Looks like the cylinders are oversize already. (3.272")
 
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If you rebuild your own crank, PLEASE PLEASE post how you do it. That's the only thing I don't trust myself to do, and that's because there are no good instructions on it. It's a lost art that's dying with the 2-stroke era. You have to press the webs apart to replace the rods, and while I have a press, I am scared to misalign it, or have it be unbalanced. Crankworks does good work rebuilding, but they're expensive if you want your crank balanced. They quoted me $600 for one. You can get a whole rebuilt motor from SBT or SES (or a number of others) for around $1k, that includes rebuilt crank and cylinders, but you have to ship out your old parts. As for the RAVE valves, you'll only have to shave them if you go beyond the second oversize (.50mm or more).
 
You don't just need a press to do the cranks, you need the correct fixtures, spacers, V-blocks and dial indicators as well as a lot of experience. It is not only an are but an expensive investment for all the tools.

I get OEM cranks from Pro caliber for less then $400, no clue why CrankWorks is so expensive.
Cylinder boring is $110 from Group K (both cylinders) top end kit is $300 bearings for balancer and rotary valve is $100. So to rebuild it yourself with good quality parts is about $900 but no warranty. SBT is questionable parts but a warranty.
 
Do the OEM cranks have a lubrication hole in the connecting rod for the wrist pin bearing? Are they NOS, or OE Reman? Do you know if they're balanced? I believe Crankworx takes and balances them, which is why they're so pricey.
 
The oem cranks are exactly what they seem. OEM bearings and rods. Lubrication holes and trued to OEM specs. They are remans but exactly the same parts and tolerances they left the factory with back in the day. In my opinion for the money you can’t do better.
 
The OEM didn't have a lubrication hole at the wrist pin, but all the aftermarket did. Probably doesn't make a difference, except I actually DID have a wrist pin bearing blow up on me once on my original SPX engine. It was the cageless type.
 
IDoSeaDoo said:
The OEM didn't have a lubrication hole at the wrist pin, but all the aftermarket did. Probably doesn't make a difference, except I actually DID have a wrist pin bearing blow up on me once on my original SPX engine. It was the cageless type.
Click to expand...

Whew... that musta been ugly !!
 
mikidymac said:
I know the lower rod has the hole and I am pretty sure the upper ones do too.
Click to expand...
My lower rod (big end) has slots. I will have more information to post when I get the case open. My Flywheel puller came in today. I tried pulling my old flywheel with a home made rig and heat with the engine in the ski but I could not get it to move. I put a good bit of pressure on it too. Hopefully the tool will do the trick. Any advice on it ?? Will I need heat ?
 
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Great news. :) I have a more than decent impact gun. LOL How difficult is the other end to remove?
 
Never use heat on the flywheel, you will ruin the magnets if you haven't already. With the correct puller and an impact it will pop off instantly.

For the rear pto you need a chain wrench and a lot of heat. Pull the head and place a block of wood in the rear cylinder and put the head back on to lock the crank. Some use rope but I have had it not work.
 
Looks like the crank came with the PTO so I won't need to remove it. The Crank I purchased looks really good so far. I will open the crank case early next week and see what it looks like in there :) and begin the process of cleaning and rebuilding.

Where is a good place to purchase the full gasket set? Bore is gonna be 1MM over.
 
Never reuse crank seals. You will have to remove the PTO to change the rear seal. Good luck with the crank out of the cases and the PTO attached.

I have used WSM complete gasket sets for 20 years without issue. Stay away from SBT and Wonderosa.

Make sure you trim the rave valves to clear the larger pistons.
 
mikidymac said:
Never reuse crank seals. You will have to remove the PTO to change the rear seal. Good luck with the crank out of the cases and the PTO attached.

I have used WSM complete gasket sets for 20 years without issue. Stay away from SBT and Wonderosa.

Make sure you trim the rave valves to clear the larger pistons.
Click to expand...

Thanks, I will go with WSM. Never done one previously but how is the PTO attached ?? Threaded or pressed on??
 
It’s threaded standard direction. The impossible part is holding the crank without damaging or twisting it when unscrewing the PTO. It’s typically done when it is in the engine and you can lock the rear cylinder with rope or a wood block.
 
I can see where securing the crank would be a problem when trying to remove the PTO thingy. :) I have no special wrench so I am going to machine a wrench that may help. I will assume the Thread is right hand on the PTO. Thanks so much for he input.
 
There used to be a special tool that installs after you remove starter and locks into teeth of flywheel. That was many years ago
 
You don’t want to lock the flywheel to remove the PTO as you can twist the crank out of true. That’s why you lock the rear cylinder so the crank can’t twist.

Yes the PTO is right hand threads.
 
I never had an issue using the special tool and a little heat on the pto. Sometimes even having a 6ft bar on the pto and no twisting of crankshaft.
 
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