rock
07-26-2009, 10:01 AM
Last week Scott killed his 2.5. Friday we removed it from boat and began to dismantle. Pulled heads and found some minor scratches on piston and head. Cylinder looked great but motor would only turn about 320 degrees. Obviously something floating around in block but due to minimal damage in cylinder I figured it would be something minor. Upon further inspection we discover a rod bolt had backed out and knocked the bottom out of the cylinder next to it. Hole 4 lost rod and hole 3 lost bottom of cylinder. Crank was junk.
At first I decided it was time for a new block as this was the 3rd rebuild coming up. First time was bad ECU and second time was the rod bolt backing out. There has been a ton of porting work done to this motor and I changed my mind and decided to weld. Went to welding shop about 10:00 am and cut a piece af aluminum to fill hole and proceeded to weld. Could not get to bottom of cyl on cylinder side so I burnt it in from the crank side. Penetration caused patch to swell up by at least a 3/8" into the cylinder area so it would need to be machined. Ground down area on the crank side and used my Bridgeport with a boring bar to clean up bottom of cylinder. Turned out great and motor was back together by 5:00pm.
We will mount motor this morning and try it again. The motor hadn't even broke in when the rod bolt backed out so I re-used rings. Had a good crank and extra rod and bearings so everything needed was there. I have always been very particular about what I put in a motor and this one has everything in it used. Quite the exception to the norm. This one will probably run forever since I am betting it will grenade. Ya never know.
Rock
At first I decided it was time for a new block as this was the 3rd rebuild coming up. First time was bad ECU and second time was the rod bolt backing out. There has been a ton of porting work done to this motor and I changed my mind and decided to weld. Went to welding shop about 10:00 am and cut a piece af aluminum to fill hole and proceeded to weld. Could not get to bottom of cyl on cylinder side so I burnt it in from the crank side. Penetration caused patch to swell up by at least a 3/8" into the cylinder area so it would need to be machined. Ground down area on the crank side and used my Bridgeport with a boring bar to clean up bottom of cylinder. Turned out great and motor was back together by 5:00pm.
We will mount motor this morning and try it again. The motor hadn't even broke in when the rod bolt backed out so I re-used rings. Had a good crank and extra rod and bearings so everything needed was there. I have always been very particular about what I put in a motor and this one has everything in it used. Quite the exception to the norm. This one will probably run forever since I am betting it will grenade. Ya never know.
Rock