787 seized rebuild

[Britrick]

Finally got time to finish stripping down my 96XP engine the last couple of days. Both pistons were seized in the bores but eventually freed them off a few weeks ago and have been waiting to strip down the rest .
Seems water or damp has got in through the MAG end ,the stator and flywheel were very rusty and this seems to of reached the crank , rusting up the two bearings on the crank immediatly behind the flywheel housing .
Who thought it would be a good idea to attach the flywheel housing to the crankcase with silly little 10mm bolts ! the heads just snap off as soon as you look at them ! only managed to get 7 out of the 10 in one piece.
So im hoping as the rest of the crank looks nice clean and good condition i can simply replace these two bearings myself , i dont have a bearing puller yet so which type would be best to get , a 3 legged puller or the type that splits the bearing by clamping down between the two?
Are these two bearings readily available in the states ? minnietonke? any idea of the part number ? i may be able to cross referance it here in the UK with a bearing supplier.
Thanks.

 

[Minnetonka4me]

I would assume you will need someone with a heavy press and crank experience.

What happened is someone got water in the hull and it seeped past the seal into the housing. It stayed in there and built rust up on the crank. Then the seal failed when the rust ripped it apart and that water started heading into the motor.

If you ever think you have a good motor and see evidence of water getting in the mag housing...just do yourself a favor and pull the flywheel and replace the seal at the very least. I also buff up the crank and make sure it isnt pitted right on the seal area.

 

[Spimothy Leary]

3 legged puller.

and ps, if its not neglected, (and leaking) which it obviously was.. those bolts wouldn't have been an issue, that doesn't happen overnight.

 

[Britrick]

Yeah I reakon it got wet , then wouldn't start next season , and spent the next few years in the corner of somebody's garage .

 

[manolocross]

I would say to replace the entire crank with a new on or replace entire engine... Reliability is king when your out on water 5 miles from dock!!!!

 

[Britrick]

Unfortunately it's not that simple or cheap to replace here in the UK . A full crank rebuild is around £350 GBP approx 500 usd , a replacement engine would have to be shipped from the US at great cost , besides the rest of the crank is in nice clean condition with very little wear .
Water craft like this are only used a few hundred metres off shore around here , we have a very straight flat coastline ,any river inlets are no wake zones so no point going up them ,or in small private lakes .

 

[Robj]

I know things cost more in the UK, but if the engine was seized and had water in it, it needs a full rebuild. Unfortunately you sometimes have to pay to play and these things aren't cheap.

 

[Minnetonka4me]

yup nothing worse then spending time and money to just have it fail again from cutting corners.

 

[Britrick]

I know things cost more in the UK, but if the engine was seized and had water in it, it needs a full rebuild. Unfortunately you sometimes have to pay to play and these things aren't cheap.

Hi robj, but the crank and balance shafts are out , pistons are cleaned awaiting new rings , everything is completely stripped exept the carbs which are soaking to try and stop the screws chewing up . Rebuilds don't come any fuller do they ? Would you replace every single internal part even if they aren't damaged ?

 

[Minnetonka4me]

The crank is on another level...but I hear ya you cant replace everything.

You gotta find a local crank guy...Or maybe it would be cheaper to buy a cheap core from me, I'll buy a OEM rebuilt and give them the core, then ship you the crank...?

 

[Robj]

Rebuilds are complete which includes reman crank with new bearings, seals, and connecting rods. Jugs are bored and fitted with new pistons. I had a 787 with a holed piston, rather than trying to fix the top end I sent it in for rebuild. As far as replacing every single part no, but all the wear parts are replaced. I cannot tell the condition of a crank bearing by just spinning it, remember these things turn at 7000 rpm, so for me when they get old and an engine requires major repairs, I just get it rebuilt. Preventative maintenance. When it is play time I want my toys to be ready to go and reliable.

 

[Britrick]

Cheers Minnie that's an idea , I will bear it in mind but hopefully it won't come to that , I will see if I can find somebody who can press on the new bearings . I'm already drawing up a list of bits and pieces for you , for when I have some spare cash .
Rob , it's different strokes for different folks , I brought this as a non runner so that I could repair it , that's half the fun of it for me , learning new things , and being able to say "I did that" taking the engine out and swapping it for a reman would seem pointless to me and remove the fun from it , may as well go to a dealer and sign on the dotted line for a fancy new one . If i fail this time and it breaks down again well at least next time i strip it down i will have a bit more knowledge , and all those damn bolts will be easy to undo ! lol
Cheers .

 

[Robj]

Good luck, obviously you know more than those of us who chose to have their engines professionally remanufactured compared to a half azzed rebuild.

 

[kwiktsi]

I see absolutely nothing wrong with what Britrick is doing for the expected use of his machine. Of course you can inspect bearings to make sure they are smooth, crank seals- eh, not really but you can make sure they are at least still pliable, mic the remaining parts to make sure they are in spec and slap it back together. I know many people who just fix what's broke vs. a full overhaul and they have no problems whatsoever. If he were taking this thing out for 20 mile rides and such, hell yeah I'd want to make sure it is all as good as it could get, but for some close to shore bashing- I'd ride anything that ran .

 

[Minnetonka4me]

I can only imagine what it would cost to ship a motor to the UK...prob cheaper to again have me send a core somewhere.

 

[Robj]

You can do a repair, or a full engine rebuild. They are not the same in terms of cost and reliability. To suggest that having an engine sent out for reman is the same as getting the dealer to do it is ridiculous. There is alot more work to replacing the engine besides rebuilding the shortblock.
I compared the cost of doing the rebuild myself with all the parts and machining, to having a shop rebuild it with a full 2 year warranty. The difference did not warrant me to do the job. Many on this forum take this approach.

In the end, really all you are doing is replacing the rings, gaskets and maybe a few seals and bearings. This does not even come close to an engine rebuild. Which is my point, do it right now, or you will once those 16 year old crank bearings pack it in. You get what you pay for.

 

[Britrick]

Good luck, obviously you know more than those of us who chose to have their engines professionally remanufactured compared to a half azzed rebuild.

Charming , thanks for your input . Just because I like to do my own work and fix things myself doesn't mean it will be "half azzed" .
Have a nice day .

 

[Spimothy Leary]

Charming , thanks for your input . Just because I like to do my own work and fix things myself doesn't mean it will be "half azzed" .
Have a nice day .

i don't think he meant it that way. I thought robj was implying that some members don't have the skills/tools/confidence to do a rebuild on their own (myself included), so they chose to order a professional rebuild vs doing a poor job themselves.

 

[Robj]

Nope half azzed has nothing to do with doing your own work or not. It has to do with cutting corners to try and save a few $$. Like saying the motor was seized and had water in it but the crank is OK? No it is not, and at the very least it should be rebuilt by a shop with new bearings, seals and con rods. No one on this forum that I am aware of has the tools to do this. Re using pistons is also not a good idea, but did you measure them and the bore to make sure they are within spec?

Many on here choose to rebuild their own. If you want to see an example of how to do it right yourself, take a look at racerxxx's thread. New OEM crank and the works.

You may think I am being overly critical, I just like to fix things once the right way and be done with it. That is why my 787 is at the shop being rebuilt.