Mid cabin - 8.1 install
Posted: Fri Oct 23, 2020 8:52 am
They’re in, and I’ll have them running this weekend but unfortunately have to wait until the spring to actually run them and THEN get the correct props. For now, I have a punch list a mile long but chipping away.
The install and fit wasn’t too bad. The mounting brackets had to be relocated (back about 4”) and leveled. In order to figure all of that out, I decided to unbolt a transmission, bring it to the boat and use it as my guide. I started by installing a plastic bushing (had that made) in the shaft log which held it centered. Once that was locked in place, I used pieces of wood and shims under the transmission until the two coupler faces were roughly aligned. Once I had that determined, I was able to find the position of the mounting brackets. Basically, the transmission is dictating where the engine falls. I have the same thickness shims under the front mounts as the rear but will tweak that next.
Some quick highlights:
- my goal was (is) to have the engine mounts to be roughly at the 1/2 way point when the final adjustment is completed. I shot a little low on the mounting brackets knowing that I could shim “up” but not down.
- the best $30 I spent was getting a line drawing of the 8.1 blown up to a 2’x3’ poster and hung up under a hatch. I referred to that constantly as I was figuring out the mounting bracket locations.
- the factory width from mount to mount was closer to the “outside” of the Crusader spec so the trunnion overhang was always too far. To fix that, I added 3/4” aluminum stock behind one side of each bracket which narrowed the gap.
- In terms of overall fit, I had to trim about an 1” off sections on each hatch because they hit the top of the risers. I’m referring to the support sections on the outside edges only so not a big deal. I have about 2-3” of clearance over the aluminum plate on top of each engine.
- I beefed up the factory mounting backing plates in thickness and size. I’m referring to the square galvanized “washers” under the lock nuts. A couple of mine were basically rotted away and all were bowed over time. Fortunately, my stringers were rock solid but I used thinned epoxy to seal all of the bolt holes, then 4000 as I was reinstalling all of the hardware.
- something all mid cabin owners should check is the bonding connections on top of the tank. There are two 8g wires which are designed to dissipate static electricity from the deckplate/hose nozzle. I could tell they were corroded and of course the SS bolts were fused to the aluminum bracket so that was fruitless. I abandoned that location and instead used the section that sticks up on the face of each tank (it looks like they needed this to weld the tank and then it got roughly cut.... I have a pic).
Not only were the connections no good but I had to go back about 3’ on each side until I got to clean wire. On this point, I don’t have confidence that this wiring was doing anything at all. This would be a PIA to repair with the engines installed but possible. My new attachment points now are much more accessible.
I have more pics and will add to this post going forward.
Bob