No compression Challenger 1800

[danzr1]

I just picked up a 97 Challenger 1800 with no compression on the mag side of one of the 787 engines. I took the head off and snapped a few pics. I did notice a tiny chunk missing from the piston, can't really see it in the pic, but its on the exhaust side. It's quite loose, but not seized. The other cylinder had 150 PSI. Take a look at the pics let me know if you see anything obvious as to why this occurred. I was planning on rebuilding it myself if it is going to be just a top end. Also, there are noticeable scores along the wall of that cylinder, so definite rebore. I was thinking of just taking it in also, that way they can maybe identify the cause, leakdown test, etc. Should I put a new top end on the other side or just leave it? It has 150 psi.

Any diagnosis on just the look of it would be great.

This boat hasn't been used since last season if that means anything. The previous owner said the bad engine runs, but it didn't for me, didn't spend too much time trying.

Bad cylinder on top.chip missing is on top. Hard to see it.

Bad cylinder, chip on left.

Good cylinder

Head, bad cylinder on right.

 

[Dr Honda]

if there is a chunk out of the piston... the rings are probably cracked.

Also... Check the RAVE valve to make sure it didn't contact the piston.

 

[danzr1]

Well I got the cylinders off. The piston rings appear to be seized to the piston more so on the exhaust side where the chunk is missing,but not cracked. The RAVE seems okay, clearance looks fine. Then I noticed water in the bottom end....that can't be good. I'm assuming new engine at this point? Where would the water have come from? Weird thing is, all that water in there, and nothing seems rusted, is everything some type of alloy?

 

[Dr Honda]

if you towed the boat... or ran it on one engine... the water will get pushed in, via the cooling system.

But yes... call up SBT, and order a new engine. It's the fastest, and cheapest rout.

 

[danzr1]

Yeah, well then that is probably what happened. The previous owner mentioned it would work with one engine. SBT is only in the US right? It would be nice if I could find one in Canada.

 

[Dr Honda]

Yep... sorry. I didn't look at your location.

They will ship up to Canada... but you have to send your engine first... and then the shipping, and import duties add a lot to the price.

 

[danzr1]

I think I can get an engine at the dealer for $1200, usually with warranty but this dealer isn't certified to work on boats, so no warranty. Any special tools to put the engine in? Can I do it myself?

 

[Dr Honda]

It's not hard to do it yourself.

The only special tools you will need is an impeller tool (to remove your PTO) and an alignment tool. You may get lucky, and the new engine will fit the same, and your alignment will be OK... but it's more likely that you will need to check it.

 

[danzr1]

I think I know where the water came from....when I removed the top end, water poured out. I have been thinking, if water was in the bottom end for a year, there would be rust, but there was none. Also, the water seemed clean, no rust in it. I removed most of the water last night when removing the cylinders. Think I could just replace the bad piston, and get the cylinder rehoned?