Swollen Cylinders Leaking Water

[scski]

Bought this 96 Challenger last weekend, first ride since water test before buying, yesterday I found a leak at the exhaust gasket at the rear of the hull. Noticed the bilge water was hot, and today I found the likely leak.

It seems the exhaust was overheated before, I found the water regulator spring broken (fixed this before taking it out.) Pipe has been off and painted, and new hoses to waterbox and muffler.

Where the pipe runs parallel to the jugs, both cylinders have swollen and the oring is bulging out in a 3/4-1" section, photo attached. Looks like this would be where the hot water was coming from.

This is bumming me out, I either need two jugs or just get a rebuilt.

Any input?

 

[BMANN06]

Awesome Avatar pic!!

Looks to me like you need jugs. Possibly caused from overheating but more likely from poor winterization. Poke around on ebay for a couple jugs I've see them up there all the time.

 

[scski]

Thanks, my wife took that while I was replacing the injection lines.

I was thinking it was an overheat issue since it wasn't cracked, and it was swollen at the center on both jugs where there is less water.

Anyway, would there be any major issues aside from extra water in the bilge if I ran it like this through the season and fixed it this winter? Is it possible it could leak enough to overheat? (could depend on the alarm, I'd make sure it's working properly)

Also, if I were to buy two used jugs, can I switch my original sleeves from old to new (used) ones? Or should I just get jugs with good sleeves and have them honed?

 

[Dr Honda]

That's from not being winterized. If water is left in the jugs... when it freezes, it breaks the cyl's. I bet if you pull the head, you will see that the cyl is also cracked. Fortunately... that's superficial, and can be tapped back into place, and welded.

 

[BMANN06]

I wouldn't run it like that ... just because you'll likely end up with bigger problems but that's my opionion. Yah you would probably need to bring your old cylinders and new ones to a machine shop and have them determine the best route to get proper sizing. Even if you need to go +1 size on rings they're right there. But you may get a response for a 2stroke expert ... there's tons of 2stroke pros on this site.

 

[Dr Honda]

Thanks, my wife took that while I was replacing the injection lines.

I was thinking it was an overheat issue since it wasn't cracked, and it was swollen at the center on both jugs where there is less water.

Anyway, would there be any major issues aside from extra water in the bilge if I ran it like this through the season and fixed it this winter? Is it possible it could leak enough to overheat? (could depend on the alarm, I'd make sure it's working properly)

Also, if I were to buy two used jugs, can I switch my original sleeves from old to new (used) ones? Or should I just get jugs with good sleeves and have them honed?

It would cost more to remove and re-install your sleeves into a different set of cyl's than it would be worth.

But, as I said... those can be fixed.

 

[scski]

It would cost more to remove and re-install your sleeves into a different set of cyl's than it would be worth.

But, as I said... those can be fixed.

Well that is good news, thanks Doc.

Not had to have this type of work done before, should I look for a machine shop that does head work or just a good welding shop?

Do you think it would be detrimental to run it like this?

 

[scski]

I think I'll just go ahead and fix this now, I hate operating anything that's not right.

Looks like to get the cylinders off I just need to pull the head and cover, and exhaust manifold and then the cylinder bolts?

I have an exhaust manifold bolt that is stuck about 1/4" from flush. I tried tightening and loosening this before going out the first time, and 200 lbs of my weight (primarily just trying to loosen after I found it was more than snug) couldn't budge it with a regular allen wrench. It didn't leak so I wasn't going to mess with it. The top of the allen head was already starting to strip where someone else tried with a standard size hex. I was able to get a solid grab by tapping the wrench in.

I think an impact wrench will have the best chance of getting this thing out without completely stripping it, any other ideas?

 

[Dr Honda]

Any one with a TIG welder should be able to fix it for you.

The head comes off easy, and it's just O-rings for the gasket. Then pop off the exhaust, and remove the cyl bolts. When you take them off... look at the base gasket. There will be some punch marks in it. (prob 4 or 5) That's the thickness of that gasket. You want to replace it with the same size.

So... to put it back together... you will need a new base gasket, and exhaust gaskets.

If you were closer... you could bring them to me to weld.

 

[scski]

I got this apart today, and sure enough, both cyls have horizontal cracks about halfway down. I'll be calling around for a welder in the morning.

A few questions:

1) Both pistons have some scoring on one side, the mag on the port/bottom and the pto on the starboard/top. Jugs are also scored to match on those sides. I can still see nice cross hatch honing otherwise. (photos attached)

The compression still read good at 145/150, I checked it again before pulling everything down.

Is this scoring normal, ok wear? Anything to worry about or deal with now? The tops of the pistons look good except for the carbon buildup, I figure just leave that alone.

2) Is there anything to look at or check for while I am able to peek into the crankcase?

3) Is the amount sand sitting in the water passages in the crankcase normal? Obviously I need to get it out, just use a vac and don't let any fall in the case? (Seems that might be difficult to do.)

Thanks

 

[Dr Honda]

Hummmmm. That piston is ugly. Wellllll....... if it was my engine... I would consider a top end. It won't take long to have a failure. It's normal to see a scuff in a straight line... normally from the edge of a ring... but that's a big part of the piston, and sleeve. Also... you can see the burnt/stuck part on the piston. What I'm looking at is actually a light seizure that didn't stick. It could have been from overheating, or the wrong oil. (The over heat could be leaking rings)


your Q's:

1) No... that's not normal wear. That's excessive.

2) Make sure all the bearings are smooth. Any gritty feeling, and it's time for a crank.

3) There is always sand in the Cyl's. Since they are off... just scrap it out with a screwdriver, and then wash them clean. The guy welding it will want them clean.

 

[scski]

Hmmm, for some reason the 6th photo didn't make it in my last post. It's the other piston and case with sand. This piston looks worse with carbon on it.

Are these water passages clogged with sand or is this just the bottom? I still should clean all this out right?

I believe the PO used tc-w3 oil. He said it was "premium 2 cycle from autozone" and it was the standard green/blue before I drained it. I misunderstood and thought he only owned it for a couple years and noticed the other day the title says he registered it in 98.

If I had realized it had TC-W3 for most of its life or seen the jugs problem, I wouldn't have bought it.

I'm hesitant to put in just a top end, especially since the wrong oil has likely been in it for 14 years. I'd like to just get an engine from SBT and move on. However, I just bought it, and have already spent $1k on the pump, driveline, bimini and other misc. broken or worn parts. Luckily the hull and seats are really good.

I can either get the jugs welded and put it back together, and hope to get through this season and maybe one more. (expecting too much?)

I could swing a top end right now, but a complete engine would really be pushing it.

Thoughts on this? How bad is TC-W3 on the crank?

 

[Dr Honda]

The TC-w3 isn't hard on the crank... but it's hard on the rotary valve, and the pistons. Now... the nasty blow-by that has cooked the cyl wall and piston skirts is hard on the crank.

If everything is in spec... you could get a season or 2 out of the engine... but it could pop the first time out.

That sand is just sitting on the bottom. Get a shop vac, and suck it out.

I guess if I was in your position... I would check the cyl, and pistons to make sure they are OK... get the jugs welded... and put it back together. (and keep your fingers crossed)

See the 6 holes in the base gasket?? Make sure you get the same thickness.

 

[scski]

Thanks, that's what I was leaning towards. I took the cyls to a welder yesterday since they need to be fixed regardless, as a good core or to keep.

Hopefully the clearance won't be out, I didn't check the cyls before I dropped them off. I thought the compression would be bad if the clearance was out.

 

[scski]

Well I got everything back together and took it out Sunday and it ran great. Runs better than before since I richened the HS screws up a bit, synced the carbs and set the idle.

Here's a pic of the welded jugs, not the prettiest welding work (I think my eyes bulged a bit when the welder first handed them back to me), and a bit overkill, but did the job.

We'll see how long she runs well.