160 hp mr-1 engine swap (with jet ski engine)

[okula225]

Have you guys swapped out the head bolts when opening up the crank cases?

 

[WREKS]

I have not and the heads have been removed 3 times on each engine to clean the cylinder water jackets. However, the engines have only 100 hours each on them and do not get a lot of hard use. I would also be cautious with the torque values when reassembling. They seem too high to me. Remember, the head is aluminum.

I spun one of the valve cover bolts trying to adhere to the torque value (8.7 ft-lbs). Luckily, that broken bolt could be extracted from the Exhaust camshaft cap which is not sold separately. Be deliberately slow and careful!

 

[okula225]

I have not and the heads have been removed 3 times on each engine to clean the cylinder water jackets. However, the engines have only 100 hours each on them and do not get a lot of hard use. I would also be cautious with the torque values when reassembling. They seem too high to me. Remember, the head is aluminum.

I spun one of the valve cover bolts trying to adhere to the torque value (8.7 ft-lbs). Luckily, that broken bolt could be extracted from the Exhaust camshaft cap which is not sold separately. Be deliberately slow and careful!

I was able to torque them to the 8.7 ft-lbs without any issues and then the 49 degrees as well without any issues. However, my father is skeptical about using the old bolts as tensile yield stress will have stretched bolts that could break or the amount of force applied isn't enough. For $55 in bolts i think its worth replacing, however the engine is ready to be dropped back in the boat after the rebuild.

 

[okula225]

Engine rebuild was completed and was able to test the boat this weekend. All went well. No codes or alarms. She purred like a kitten and oil looked good after about 15 minutes of driving. I eased her back in, didn't go above 5k rpms for the warm up portion. Just have to fix the leaking intermediate and she will be ready for spring. Thanks for everyone's support.

 

[WREKS]

@okula225 That was quite an accomplishment. Were you able to keep to the plan?

... have them polish the crankshaft journals as well as sidewalls and use new journal bearings that account for the polishing delta off the crank....

I wonder what caused that to happen?

 

[okula225]

So the story did change a bit. It started as using a donor ski and parting out my failed engine to recoup the $$$. Then upon disassembling the engine I found that it had spun a bearing, and opted to buy a new crank and bearings. In total, about 2 days worth of work in pulling, disassembling, reassembling and installing the engine. About 2 weeks in deciding what to do and another 2 weeks in waiting for parts and such. All in all, this was a great first engine teardown and rebuild for me. Lot of good knowledge and pride in this project.

If anyone in NJ needs an engine rebuilt let me know!

 

[jws123]

So the story did change a bit. It started as using a donor ski and parting out my failed engine to recoup the $$$. Then upon disassembling the engine I found that it had spun a bearing, and opted to buy a new crank and bearings. In total, about 2 days worth of work in pulling, disassembling, reassembling and installing the engine. About 2 weeks in deciding what to do and another 2 weeks in waiting for parts and such. All in all, this was a great first engine teardown and rebuild for me. Lot of good knowledge and pride in this project.

If anyone in NJ needs an engine rebuilt let me know!

Nice I just rebuilt of of my mr1 engines aswell pre simple engine not looking forward to first fire up will find out if she holds up or blows to bits lol.