Snipes dead engine!

[seadoosnipe]

1997 Challenger...

Well, I got the motor in the shop and broke it down today. I thought I was just going to replace gaskets and be able to put it back together. I've made a video that I hope to put into the forum, for all to watch. I've had a problem with Windows 7 crashing all my Ulead Video editing studio software, so I've been restoring the equipment (dumped Windows 7). So, I have several vids that I hope to soon get posted for all to see.

My problems...... It doesn't look like a simple gasket replacment. I may replace the motor. I"ve thought about doing an upper end but for the moment, don't know that conditions of the bearings. I"ll be splitting the casing and doing some measurements along with shaft deflection to see what kind of condition the bearing and crank is in.

With the motor being over 12 years old, the original motor, I might as well do a complete engine. I would hate to do an upper end, just to loose a bearing later.

I've attached pix of both pistons. They are scared pretty bad, like something got into them. But, I know that did not happen. It may be caused from a lack of oiling. It could as well happened before I bought the boat from the original owner almost 4 years ago. But, I thought I'd put the pix in for all to see.

Oh, the measurements of the MAG piston ranged from 81.42 upwards to 81.86. The cylinder measured 81.74 to 81.80. The PTO ranged from 81.61 upwards to 81.74 and the cylinder measured 81.57 to 81.68. Of course, 82.00 is standard size. I don't see me being able to bore this out to 82.00 because of the terrible wear.

 

[seadoosnipe]

Bummed....

Well, .... I'm kinda bummed because after surveying the damage, it appears my Challenger will be sitting under a tree till next year sometime.

I'm going to start putting some greenbacks back when I can, till I can come up with the bucks to repair it.

This is a thread I'll use and update as I pull the engine apart. I've thought about just buying cylinder sleeves and pistons but with the engine about 13 years old, it seems like I'd be doing a patch and fix, knowing that it's only a matter of time before crank bearings, rotary seals and connecting rods go out. So, I might as well do a full job.

Since I've opened the top end, I'm dying to split the casing. The biggest reason is the CB shaft. My old "sunken" 787 has been a great tool for learning but when I opened it, the oil ran out and I wasn't able to see how much was in it............

So, check back now and then, I'll post pix as I get them.......:cheers:

 

[robin savell lloyd]

[Since I've opened the top end, I'm dying to split the casing. The biggest reason is the CB shaft. My old "sunken" 787 has been a great tool for learning but when I opened it, the oil ran out and I wasn't able to see how much was in it............ The oil ran out before you opened it? You may have had to many beers and forgot. lol Look at the rust on the gears There must have been some sort of breach between the pto crankcase as it looks rusted as well but the rotory vale chamber looks as if it may have been sealed well. Maybe I can not see well as I am looking at photos. In person I am sure that I may still get it wrong lol:cheers: QUOTE=seadoosnipe;108667]Well, .... I'm kinda bummed because after surveying the damage, it appears my Challenger will be sitting under a tree till next year sometime.

I'm going to start putting some greenbacks back when I can, till I can come up with the bucks to repair it.

This is a thread I'll use and update as I pull the engine apart. I've thought about just buying cylinder sleeves and pistons but with the engine about 13 years old, it seems like I'd be doing a patch and fix, knowing that it's only a matter of time before crank bearings, rotary seals and connecting rods go out. So, I might as well do a full job.

Since I've opened the top end, I'm dying to split the casing. The biggest reason is the CB shaft. My old "sunken" 787 has been a great tool for learning but when I opened it, the oil ran out and I wasn't able to see how much was in it............

So, check back now and then, I'll post pix as I get them.......:cheers:[/QUOTE]

 

[seadoosnipe]

You so crazy.....

Man,..... It's sure great to have you back in....>:rofl:

I guess I should look that over before typing it....you'll catch me on all my typos cause I know you read very intently. We've got to hook up by phone again. It's been a while since we chatted.

Honestly, I don't remember exactly what it was that drained out. It was the first time I opened a 787 and I didn't really know there was anything in it.

I remember, it was kinda upside down, in my work table (you know, the kind that has these clamp like things, that wood workers ues). Anyway, when I finally got the casing bolts out enough, all the sudden, oil (water and all kinds of other stuff ran out of the cranck). I think the oil from the rotary might have drained out too.

You would not have believed that motor, when I first opened it. It was full of muck. Like a silt from settling underwater for a couple years. I still can't get the MAG piston from the cylinder. I've beat on it, cut at it and took a torch to it. All I want is the bottom end........but, I'm in no hurry for it, so I'll get it one day.

You can bet, you will be the one I call on web cam to witness the seperation of my good motor, to see what we find inside it. Hey, ... What do we say to each other if it's empty, or full of water.... :rofl:

 

[robin savell lloyd]

You can bet, you will be the one I call on web cam to witness the seperation of my good motor, to see what we find inside it. Hey, ... What do we say to each other if it's empty, or full of water. I would say that it is typical depending on circumstances. But than again looking at the piston on the pto side and what apears to look like a blueing process I would say that it may look similar, I would think that it is going to look beter. Because there is not as much heat build up as with the combustion chambers and the pistons that travel up and down 14,000 times every minute at 7,000 rpms. I know it takes those kind of rpms to keep you smileing out there on the water. I have always wondered what would hapen to those pistons traveling at that rate if say the oil pump had some small problem and did not pump oil for 60 seconds :cheers:

Man,..... It's sure great to have you back in....>:rofl:

I guess I should look that over before typing it....you'll catch me on all my typos cause I know you read very intently. We've got to hook up by phone again. It's been a while since we chatted.

Honestly, I don't remember exactly what it was that drained out. It was the first time I opened a 787 and I didn't really know there was anything in it.

I remember, it was kinda upside down, in my work table (you know, the kind that has these clamp like things, that wood workers ues). Anyway, when I finally got the casing bolts out enough, all the sudden, oil (water and all kinds of other stuff ran out of the cranck). I think the oil from the rotary might have drained out too.

You would not have believed that motor, when I first opened it. It was full of muck. Like a silt from settling underwater for a couple years. I still can't get the MAG piston from the cylinder. I've beat on it, cut at it and took a torch to it. All I want is the bottom end........but, I'm in no hurry for it, so I'll get it one day.

You can bet, you will be the one I call on web cam to witness the seperation of my good motor, to see what we find inside it. Hey, ... What do we say to each other if it's empty, or full of water.... :rofl:

 

[seadooya]

Snipe, thanks again for the rectifier, also, curious to know, if you did compression test, prior to wrenching, or was your boat, dead in water, and this being the reason of tearing it down.

 

[robin savell lloyd]

Snipe, thanks again for the rectifier, also, curious to know, if you did compression test, prior to wrenching, or was your boat, dead in water, and this being the reason of tearing it down.

I am kind of curious myself on compression. The pistons look like they were geting some oil and rings look ok but photos can be deceiving at times.:cheers:

 

[robin savell lloyd]

Well, I got the motor in the shop and broke it down today. I thought I was just going to replace gaskets and be able to put it back together. I've made a video that I hope to put into the forum, for all to watch. I've had a problem with Windows 7 crashing all my Ulead Video editing studio software, so I've been restoring the equipment (dumped Windows 7). So, I have several vids that I hope to soon get posted for all to see.

My problems...... It doesn't look like a simple gasket replacment. I may replace the motor. I"ve thought about doing an upper end but for the moment, don't know that conditions of the bearings. I"ll be splitting the casing and doing some measurements along with shaft deflection to see what kind of condition the bearing and crank is in.

With the motor being over 12 years old, the original motor, I might as well do a complete engine. I would hate to do an upper end, just to loose a bearing later.

I've attached pix of both pistons. They are scared pretty bad, like something got into them. But, I know that did not happen. It may be caused from a lack of oiling. It could as well happened before I bought the boat from the original owner almost 4 years ago. But, I thought I'd put the pix in for all to see.

Oh, the measurements of the MAG piston ranged from 81.42 upwards to 81.86. The cylinder measured 81.74 to 81.80. The PTO ranged from 81.61 upwards to 81.74 and the cylinder measured 81.57 to 81.68. Of course, 82.00 is standard size. I don't see me being able to bore this out to 82.00 because of the terrible wear.

maybe I am understanding your numbers wrong but they apear to be press fit pistons.

 

[kustomkarl]

It looks like that Walmart quick silver oil did it's job all right...I think you either pay when you buy the good oil or pay later after a tear down...and lots of swear words.

 

[seadoosnipe]

I am kind of curious myself on compression. The pistons look like they were geting some oil and rings look ok but photos can be deceiving at times.:cheers:

I was in a hurry when I miced the pistons and cylinder walls. I did not know they were over till I compared them to the specs in the manual. I also don't remember if I zero'd out my mic. It is the digital version that has to be zero'ed.

You are def right, the pix do not do justice to the actual gouging of the pistons. I tried to take the glare off.

I don't think anything got in the motor, I believe the main bearings are going bad, causing the gouging on the cyliners. I'll know further when I get down to the crank.

But, the engine is all original and the guy I bought it from used TCW oils for most of the time he had it. I changed over to the full synthetic oil (accepted by BRP as a suitable oil) after I got the motor. So, this scoring could have been like this for the several years I had it.

Compression? I did do a compression test. I had about 135 psi on both cylinders. Actually, 135 on PTO and 137 on MAG. But, on July 4th, at WOT, the engine would bog down and then, shut off. Wait for a minute or so, it would start back up and as long as I idled, it would run with no problem. Get into or close to mid range transition, no problem. The only problem was WOT, when the jet pumps cooling pressure is at it's greatest.

I have recorded the entire engine disassembly and you can see, on the MAG side, at the exhaust port on the lower side, a breach in the gasket that seperates the water and exhaust gases.

Robin, I"ll see if I can do depth readings on the gouges and take a better set of measurements on the cylinders. I was kinda bummed because I don't like any wear marks on my motor. But, for 12 years, I guess some could be expected.

I have to spilt the casing now to measure the main bearings. I wanted to just do the upper end, new pistons and cylinders but if I have a bad main bearing,.... I'm blowing into the wind.

The gouges in the Mag cylinder are the worse. I'd say they have to be about .02 to .04 at it's worse. They are a lot worse than the pix show.

It's a busy day today but send me your phone number again via PM and I'll give you a shout. I'd like your opinion about some of the stuff I'm seeing. Maybe I can just re-hone and get a few more seasons out of it. But, I'd like your opinion.......:cheers:

 

[robin savell lloyd]

Truthfully I can not make any judgement calls from those photos there is a gloss on them. I would have been very embarrassed for anyone to have watched me mic out the kubota diesel I just rebuilt. It was my first mic job that I had ever done and the only good thing I can say is that it is runing. Trust me if you Knew what mistakes I had made you would be laughing and I would never hear the end of It. at least I learned from those mistakes. :cheers:

 

[seadoosnipe]

Measurements...?

I just came back out to re-measure the pistons, since there seem to be some question to their dimensions.

I calibrated my micrometer and re-did the measurements.

All readings on the MAG and PTO pistons run between 81.56 and 81.78. The standard is 82.00. So, the tolerances of the pistons seem to be o.k. I'm not so sure what the differences should be between the wall thickness of the cylinder and the pistons. But, I may order the upper end rebuild, and take it to 82.25.

No Karl, ..... The oil has nothing to do with the simple scaring I'm seeing in the pistons.

Both are scared on the same side and leads me to believe the RAVE valves may have had something to do with it. I'm going to def investigate further.

I've had a great conversation with Robin Savell Lloyd and I think after our talk, I might take his advice and work it out from where I am now, instead of a remanufactured motor. I do know for a fact, this is the origninal engine. To have 13 years on a motor and just that small amount of scoring, I think in all, they motor looks great.

I will still be splitting the bottom end to inspect the CB shaft oil, seals and crank bearings, while performing deflection and other measurements to the lower end, to make sure I don't have to go any further with it.:cheers:

 

[Dennis]

Pistons

Yo SNIPE,
Those pistons have that "water has washed the oil off of me" look about them. Exhaust manifold gasket or exhaust pipe gasket leaking water into the cylinder? Is the little cylinder drain hose clogged up with debris?
DAWG

 

[seadoosnipe]

Yeah... It was plugged...

Yo SNIPE,
Those pistons have that "water has washed the oil off of me" look about them. Exhaust manifold gasket or exhaust pipe gasket leaking water into the cylinder? Is the little cylinder drain hose clogged up with debris?
DAWG

Yeah, it was plugged. But last year, when was checking all my lines for blockage, the line drained freely. That was because, it was clogged at the calibrated fitting where it connects to the muffler. I may not even have known that had it not been for the fact I had to remove the exhaust system to get at that round rubber seal where the exhaust passes through the hull. When I popped off the hose, I was surprised on how much sand debris clogged it up.

Which brings me to the conclusion that it's been that way since I bought it. The guy who owned it before me, used in solely in salt water, from the beach. The debris looked like sand from a beach.

So, what do you think about the gouging marks? I re-calibrated my micrometer and was coming up with 81.54 thru upwards of 81.72's.... So, the pistons don't seem to be badly worn. The rings are in good shape and the cylinder walls look o.k. The gouging is only on the exhaust side. There is one area on the mag piston that is flat spotted, about the size of a silver dollar.

I'm thinking I'll get two pistons and just do the upper end. I have since cleaned out all the calibrated fittings and made sure, there was no blockage anywhere else.

Robin and I talked in depth today about it, he thinks the pistons might be o.k. with the measurement readings. What do you think? Would you like me to take some better close ups?........

By the way, I think I did mention it in one of my posts, ... The manifold gasket on the MAG cylinder was blown on the lower end. I actually had suspected that when it shut down on my last July, just from a look at the plugs...........:cheers:

 

[Dennis]

Pistons

Yeah, some better close ups would be nice (both sides of the piston). Your pistons do have alot of wear. A new factory piston measures 81.89 mm in a cylinder that is 82.00 mm. This means that a new 787 piston/cylinder wall clearance is .11 mm
If the cylinders look good I would hone them and then measure the bore. The size of the bore after honing is going to dictate if you can re-do the top end using a stock size piston or if you are going to have to bore.
DAWG

 

[robin savell lloyd]

Merry Christmas Everyone

{ Merry Christmas Everyone }I am a bit confused here I know that I like to play a litle dumb :stupid: some times Louis but I hope that people can see past it at times. I dont need any help in that area. What Did You mean By this? [Robin and I talked in depth today about it, he thinks the pistons might be o.k. with the measurement readings. What do you think?] I think those pistons are toast! What I did say is that there are people more qualified than me on this site that have repaired these engines for a living for a long time and when you have done something for such a long time you begin to get good at it as this is their job. I did say that Dennis is one of the people that would be more qualified then I. Now my point of view on this matter is that I would do as Dennis said so that I would know what over size pistons to buy as I would not reuse your old ones after looking at the photos and hearing from you of how bad the scoring is on them and the cylinders. I can not see any hope of this going back to standard pistons and being within specs without new sleeves but I have been wrong before. If you are going to let a machine shop hone or bore oversize for you I would take the cylinders to them before ordering pistons to be positive that you get the correct over size pistons that they would recomend.:cheers:

Yeah, it was plugged. But last year, when was checking all my lines for blockage, the line drained freely. That was because, it was clogged at the calibrated fitting where it connects to the muffler. I may not even have known that had it not been for the fact I had to remove the exhaust system to get at that round rubber seal where the exhaust passes through the hull. When I popped off the hose, I was surprised on how much sand debris clogged it up.

Which brings me to the conclusion that it's been that way since I bought it. The guy who owned it before me, used in solely in salt water, from the beach. The debris looked like sand from a beach.

So, what do you think about the gouging marks? I re-calibrated my micrometer and was coming up with 81.54 thru upwards of 81.72's.... So, the pistons don't seem to be badly worn. The rings are in good shape and the cylinder walls look o.k. The gouging is only on the exhaust side. There is one area on the mag piston that is flat spotted, about the size of a silver dollar.

I'm thinking I'll get two pistons and just do the upper end. I have since cleaned out all the calibrated fittings and made sure, there was no blockage anywhere else.

Robin and I talked in depth today about it, he thinks the pistons might be o.k. with the measurement readings. What do you think? Would you like me to take some better close ups?........

By the way, I think I did mention it in one of my posts, ... The manifold gasket on the MAG cylinder was blown on the lower end. I actually had suspected that when it shut down on my last July, just from a look at the plugs...........:cheers:

 

[dlowings]

I am kind of curious myself on compression. The pistons look like they were geting some oil and rings look ok but photos can be deceiving at times.:cheers:

I thought this was odd, that the pistons looked so bad, and that the rings looked to be in somewhat good shape..

 

[robin savell lloyd]

Maybe I should of used different words, what I meant was that the rings did not look broken. I have seen people use pistons that I would not use and they still had fair compression numbers with the new set of rings that they installed

I thought this was odd, that the pistons looked so bad, and that the rings looked to be in somewhat good shape..

 

[Dennis]

Long story made short

If it were my boat and I was planning to keep it for another 4 or 5 years I would do a complete rebuild. I would install a new HOT ROD"S crank.....buy a set of .020 in. oversize PRO X piston kits....have the cylinders bored and honed so that I had .0055 in. ..piston/cylinder wall clearance....replace the oil injection pump or go to premix. This is the 787 rebuild recipe that I have used for alot of years and have enjoyed alot of success with it.
DAWG

 

[seadoosnipe]

Conversation....

{ Merry Christmas Everyone }I am a bit confused here I know that I like to play a litle dumb :stupid: some times Louis but I hope that people can see past it at times. I dont need any help in that area. What Did You mean By this? [Robin and I talked in depth today about it, he thinks the pistons might be o.k. with the measurement readings. What do you think?] I think those pistons are toast! What I did say is that there are people more qualified than me on this site that have repaired these engines for a living for a long time and when you have done something for such a long time you begin to get good at it as this is their job. I did say that Dennis is one of the people that would be more qualified then I. Now my point of view on this matter is that I would do as Dennis said so that I would know what over size pistons to buy as I would not reuse your old ones after looking at the photos and hearing from you of how bad the scoring is on them and the cylinders. I can not see any hope of this going back to standard pistons and being within specs without new sleeves but I have been wrong before. If you are going to let a machine shop hone or bore oversize for you I would take the cylinders to them before ordering pistons to be positive that you get the correct over size pistons that they would recomend.:cheers:

I was actually referring to my Dyslexia on my initial measurements, that you caught me up on. If I measred 82.45....? that was larger than the standard cylinder bore. Then, I realized I hadn't calibrated my micrometer. Like you sometimes sayk it's the simple stuff we miss........LOL

I'm going to go over them one more time. But, I think I'll do the rebild, llike so many have suggested.........:cheers:

 

[seadoosnipe]

Dawg

I'm not sure what DAWG sees that I didn't. But, I'm waiting to see what you elaborate on. How you knew, by looking at the pix of the pistons that my water drain on the lower cylinder head was stopped up. Also, why are the pistons only scored on one side?

And like Dlowings spotted, why do the pistons look so bad but the rings are in great shape?

I saw someone with a confused emoticon,.... I think I should use it because I have not seen something like this before, unless it was caused by something entering the air intake, causing damage but this scoring is limited to that one side, equally to the dimension of the piston to both MAG and PTO.

Robin,.... I explained a bit on the above post about the "in depth".... I believe I was overjoyed to hook up with you again after such a long abscence of our conversations and debates, that it was great to have you weigh in on this issue.

It's kinda really funny because I'm usually the one in the forum to help all out, now it's me that needs the pointers in return. I love being a moderator with the forum but just because I hold that position, it does not make me some kind of super tech. Anyone with opinions or answers are very much welcome and will be well received by me.

I'm hoping bills86e, Dr Honda, and Chester way in and submit an opinion. I don't have the bucks to replace the motor but don't want to do the upper end if someone thinks I have an underlying problem that will only destroy the work I do to the top.........

So, with my first real issue in the forum with my own engine...... I'm open to all input. Thanks in advance you guys!....:cheers:

 

[seadoosnipe]

My Christmas!....

Wow.... I just had to add this to my thread. I got a bunch of stuff for Christmas but must admit, I got one set of tools that I will get more use out of than any other.

It's a set of pic's. They have so many uses I couldn't begin to tell you what all I use them for.

I'm attaching a pix......

 

[seadoosnipe]

Split casing...

Well, I got the casing split today... Yeah, it was Christmas, kids were driving me crazy with all their new noise makin toys that I ad to go outside to the shop.

I stripped the motor down and split the casing. First impression is that it looks good. I'll be pulling some measurements on it tomorrow.

CB chamber?... I was kinda surprised to find the CB shaft in pretty good condition after 13 years and no fill plug to maintain that area. It had about 3/4 of an ounce of a thickened black oil inside. It appeared to be a standard motor oil but after that amount of time, there is no tellin what kind of oil was in it.

I've been recording most of this event and hope to post them on "youtube". The question is when?.... Just go so many pokers in the fire now, don't know whicih one is ready to use.........:rofl:

I'll get some stills put up as soon as possible. Keep checking back in..........:cheers:

 

[Dennis]

Piston damage

I asked about the possibility of a clogged cylinder drain fitting or hose because the pistons look like the oil has been washed off of the piston skirt on the exhaust side. When the cylinder drain is clogged it causes water to be trapped in the cylinder and exhaust manifold water passages after the engine is shut off. This trapped water can trickle into the cylinder via the exhaust port if the manifold gasket isn't sealing properly. Rarely will a engine come to rest with one of its cylinders at TDC after being shut down which means the pistons are usually somewhere in mid stroke when they come to rest. This means water entering the cylinder via exhaust port will come in contact with the exhaust side of the piston skirt and cylinder wall washing away the oil.
The damage is done when the engine is started again because the piston skirt and cylinder wall are "dry" and have to wait for the fuel/oil mixture to relubricate them. It doesn't take alot of dry piston skirt starts before piston damage occurs. This situation will cause a slow decrease in compression which would explain your 135 PSI reading. A 787 with average wear and tear will still read 150 PSI.
DAWG

 

[seadoosnipe]

Makes good sense....

I asked about the possibility of a clogged cylinder drain fitting or hose because the pistons look like the oil has been washed off of the piston skirt on the exhaust side. When the cylinder drain is clogged it causes water to be trapped in the cylinder and exhaust manifold water passages after the engine is shut off. This trapped water can trickle into the cylinder via the exhaust port if the manifold gasket isn't sealing properly. Rarely will a engine come to rest with one of its cylinders at TDC after being shut down which means the pistons are usually somewhere in mid stroke when they come to rest. This means water entering the cylinder via exhaust port will come in contact with the exhaust side of the piston skirt and cylinder wall washing away the oil.
The damage is done when the engine is started again because the piston skirt and cylinder wall are "dry" and have to wait for the fuel/oil mixture to relubricate them. It doesn't take alot of dry piston skirt starts before piston damage occurs. This situation will cause a slow decrease in compression which would explain your 135 PSI reading. A 787 with average wear and tear will still read 150 PSI.
DAWG

Makes good sense DAWG. Last year, I was running 145 and 148. I also checked all lines to see that they were clear, including the drain line off the cylinders. Only problem is, with that calibrated fitting all the way in the rear, behind the resonator, I pulled the line from the fitting to check it. It drained fine.

Well, when pulling the motor, I decided to pull both muffler and resonator. If you look at the parts page, you'll see that 90* calibrated elbow is part number 29 and is right up against the back of the rear part of the hull (transom). I had a heck of a time just putting it back on, using my mirror. I had no idea it was plugged, till I took those two pieces out because I needed to replace the rubber expansion boot that seals the exhaust pipe at the hull. So, I have no idea how long that elbow was plugged.

I split the casing tonight before coming to work. I had maybe 10 minutes to look the bottom end over before leaving for work. But, first impression of what I saw, looked pretty good. I will be doing a complete set of measurements on the bottom end because if what you say is my only problem, then I should be able to get away with a couple pistons and put it back together.

Now, one more thing. Those pix you saw of the pistons, on the connecting rods and motor, were wiped clean. When I took the cylinder heads off, there was oil all over the pistons. But, it was a blackish kind of oil and you could see water droplets were mixed with the oil. I figured it must have run out of the cylinders and tuned pipe when I was tearing it down.

The motor ran good this past year up to July. July the 4th to be exact. I was heading out to Mobile Bay when it died. We had been tubing all day. After letting the motor cool off for a few minutes, it started right back up. I drove it back to the dock and as long as I didn't try to go WOT, it ran fine.

Thanks for the input. After going over what you've theorized and what I've witnessed while removing the component parts of the motor, ... I'm pretty sure your onto something. I have some spare 787 upper end parts but I think I'm going to go with all new. I'll keep you up on the progress.:cheers: