5.7 KEM Engine Replacement

[Nozzle]

Hi Folks,
I have a 2003 Custom Weld Storm with a 5.7 liter KEM Small block coupled with an AT SD312. Recently took it out and lost power while out, fortunately I made it back to the dock, however couldnt get the engine to start and had to rope it on the trailer. It would crank but wouldnt fire. Marine mechanic did compression check, and cylinders and #3 held 0psi and #7 145 psi. Bore scope indicate cylinders has scoring in the cylinder walls. This engine has been a sure fire for so long and just love this craft, it really caught me by surprise. The Mechanic recommends a new motor. Does anyone have any suggestions for replacing the engine with a new engine, or get a new long block to swap over. Im in the Portland Oregon area, also looking for any recommendations for conducting the work.

Thanks in advance for any insight/recommendations.....and good and safe boating all.

 

[Neutron]

You might not find a lot of info here because not a very popular boat here. But its basically a gm 5.7l engine modified for marine applications. Like a volvo penta or mercury.
It would be beneficial to have someone tear it down to determine what caused the damage. Unless you are putting a complete engine that has the manifolds, intake, and fuel injectors. Otherwise replacement of just the block could result in the same problem

 

[Beachbummer]

Might just need the head, or even a single valve. Of course the issue is the cost to repair vs replace when you are already in for so much labor. Maybe with getting the valve cover off to check?

Best of luck.

 

[Neutron]

Might just need the head, or even a single valve. Of course the issue is the cost to repair vs replace when you are already in for so much labor. Maybe with getting the valve cover off to check?

Best of luck.

Did you read the op post? The cylinders show scoring, how is a head job going to fix that. He need complete motor work

 

[Beachbummer]

Did you read the op post? The cylinders show scoring, how is a head job going to fix that. He need complete motor work

Zero compression from a little scoring? How are the other cylinders?

New engine suggestion indicates no interest in repairing... Trust but verify.

I read the post but not talking all stated at face value

 

[FSH 210 Sport]

Hi Folks,
I have a 2003 Custom Weld Storm with a 5.7 liter KEM Small block coupled with an AT SD312. Recently took it out and lost power while out, fortunately I made it back to the dock, however couldnt get the engine to start and had to rope it on the trailer. It would crank but wouldnt fire. Marine mechanic did compression check, and cylinders and #3 held 0psi and #7 145 psi. Bore scope indicate cylinders has scoring in the cylinder walls. This engine has been a sure fire for so long and just love this craft, it really caught me by surprise. The Mechanic recommends a new motor. Does anyone have any suggestions for replacing the engine with a new engine, or get a new long block to swap over. Im in the Portland Oregon area, also looking for any recommendations for conducting the work.

Thanks in advance for any insight/recommendations.....and good and safe boating all.

I’m curious, how many hours do you have on the engine?

The quickest avenue for return to service would be a long block, but I’m with @Neutron, I’d be interested to know what caused the failure in cylinder #3. You said cylinder #7 had 145 psi, what were the rest of the cylinders ?

Maybe just talk to the manufacturer and see what they can do for you. Looks like your engine is no longer in production but they might be interested in knowing what happened to the engine and or have an outfit that will either go through the motor or can do the long or short block option.

KEM Equipment, Inc.

www.kemequipment.com

 

[Neutron]

Compression readings should be higher than 145 on a non turbo/supercharged 4 stroke. Would think 175+ range