Since the last blog the motor has had a lot of work done to it. Starting with striping parts off it to paint, when I removed the intake and exhaust manifolds I discovered abrasive sandblasting material inside the ports (not going into specifics of how it got there). Finding garnet inside the head meant the moment the motor is turned over and the valves open, in would fall garnet and the cylinder walls, rings and pistons would be damaged (being polite hehe). So off came the engine head and the project again got bigger, I was really disappointed to pull the head off a motor that’s only done just over 800 hours. Again disappointed when I found out a replacement Yanmar head gasket in Australia is between $160 and $300. I ordered an aftermarket gasket from Italy 35 Euros of the shelf, at the door in Australia a week later for under $70.00. And it was exactly the same as the original. In the end I learned another valuable skill; how to replace a head gasket which my car will soon need too.
I did have a lot of problems with removing the copper core out of the heat exchanger (a unit where fresh water engine heat is exchanged with cooler temperature see water) could see some metal damage from looking down inside the housing. Had an expert tell me the unit was junk (Yanmar total replacement cost $3000), a mechanic with a hydraulic press could not budge the core. After using phosphoric acid then hydrochloric acid to loosen up the calcification, the property owner where the boat is kept suggested using a simple car harmonic balancer pulley which incorporated two bolts to screw it in place and one bolt in the middle to crew down and drive the core out the other end. The metal damage turned out to be only on an aluminum shroud that directed the flow of water threw the cooling rods and hardly matters. If I had of listened to the expert who I only went to see in the first place to press out the copper core for cleaning, would have been out of pocket 3K. The heat exchanger job alone took two days.
Finally after a week’s work I had the motor painted, back together and fully serviced. Have a great video of starting the motor on a trolley in the workshop, it ran perfectly and as a Yanmar should, I was, am so proud to be its owner. Although I noticed a line of fluid stain on the ground at the very back of the gear box drive shaft coupling. I was recommended to replace the gear box output shaft seal before putting the motor back in the boat. This is one area where I failed to take advice. After I hid notice when chaining the gear box oil it looked contaminated and now know after sitting for so many years it was.
Putting the motor back in the yacht since the yachts is high of the ground was a mission when I failed to get the phone call a crane was available. I spent a few hours modifying an old engine lift which was going to sit on one side the yacht and an extended boom which ran over the engine room was supported on the other side with the front end loader. I would then hoist the motor with a pulley up to the boom and slide motor over to the engine room. Well was ready to put it all into practice when mystically the crane turned up (hmm I wonder). Anyway motor was back in the boat in under 10minutes, took much longer to dismantle the modified engine crane. Latter that day when I got down to the final stages of setting up the new engine mounts to align the motor I noticed fresh transmission oil at the back of the motor in the bilge.
That night I unscrewed the clutch housing and removed the gear box for the second time from the motor while it was suspended in the yacht. The next day took it to the local Statewide bearings dealer to get a new seal and ended up taking the gear box back to the work shop to open up and replace the front and rear seals as well as check the bearings for wear, damage or corrosion from moisture contamination after not being used for a few years. To cut a long story short I ended up dissembling the gear box and replacing all the bearing, races and seals. I thought one bearing on the end of the main gear shaft pulled strait off the end and damaged the bearing trying before I realized I would have to strip everything of the shaft, gears, clutches, springs ball bearings. It was extremely stress full and I thought I was well over my head, believing I would need to seek an experts to help. Then the bearing shop guys said I need to adjust the wafter slim metal shims for allowed play before putting it back together with a micro meter. The Yanmar service manual said put the shims back in and said nothing about allowed play so I did just that. Put it all back together and it worked a dream on the bench, double checked by the property owner for play or excessive tightness (he was equally surprised I had rebuilt a trannie) and he confirmed it looked good.
With motor back in it was finally time to put the engine room lid/helm/console floor back in after blasting and repainting it. I reinstalled the helm and engine controls, oh and off course fully rebuilt both of them since they have not been used for so long.
Well that’s enough for now, if you