I would rebuild this engine if: 1. you have a sense that the boat has been well maintained, namely the engine zinc has been routinely replaced. Yanmar added a small amount of nickel (or was it chromium?) to the cast iron for their marine blocks, this and the zincs, were seen as equally effective solution as fresh water cooling. The old raw water cooled Volvo’s Universalls and Farrymans didn’t do that, so they rusted out and replacement customers created the demand on Yanmar for fresh water cooling. The little 1GM10 they’re still selling today is the same basic raw water design. 2. Take off the exhaust mixing elbow and inspect it, and the head. The only major flaw with that engine is welds cracking from heat stress in the elbow spraying seawater back into the head. The mix of hot exhaust and seawater is super corrosive and ruins the head.
Keep in mind -If you have a dripless shaft seal, the engine could be removed and re-installed for rebuild without haul out. -You could swap pressure switch for a guage and see if you are still getting good oil pressure. If so the main bearings will likely be fine, which will reduce re-build cost considerably. -It’s a model still supported by yanmar for almost all parts. -If your still concerned about internal corrosion, remove the housing on the front of the block that holds the thermostat and have a look. Similairly the housing that holds the zinc on the rear of the head can be removed and the internal condition of the head can be seen. The problem with re-powering is you’re over capitalizing the boat. Ok if you’re fairly sure your’re keeping it for the long haul. What’s the boat worth? In 4 or 5 years, there will be little if any difference in the value of the boat between rebuilt and new-ish engine. I looked carefully into buying a boat that needed a re-power. The mechanics only take these jobs on as a cost plus basis. They quoted me an average of 40 hours labour for the job, this varies due to the accessibility around the engines, work to adapt the mounting etc. Ancillary costs include haul-out of the boat, a week in the yard, crane fees to take out old, crane to put the new in 1 or 2 days later, possibly need new shaft, possible new prop, taxes…. It worked out a Yanmar 3YM30 could reasonably add up to $25K installed. A rebuild including oversized pistons, rings, a valve grind, new injector tips, and a new mixing elbow will result in an engine with lots of life, and cost less than ½ of new. Eric On Wed, Sep 27, 2017 at 2:33 PM, DON JONSSON via CnC-List < cnc-list@cnc-list.com> wrote: > Hi > > I continue to try and understand what is wrong with my engine without > paying more good money. And I have started looking for a new motor. > > First the problem. The engine recently started to leak a fair amount of > oil and to start poorly. We spent a lot of time trying to find exactly > where the leak was from and I had thought it was the head gasket. The > local mechanic, Charles at Gartside, said he really didn't think it would > be the head gasket as he had never seen an oil leak from one. We cleaned > the engine with brake cleaner, got some florescent tracing dye, put it in > the engine and let it run for an extended period. Although we some some > oil leak never saw the florescence with a black light. > > Regardless we decided it must be coming from the intake manifold. Of > course the leak is where it is almost impossible to get to but where the > leak occurs there aren't too many options. The intake manifold can get too > much oil in it if there is blowback increasing air pressure in the valve > and rocker arm cover. So, while the engine was running I pulled off the > breather hose which runs from the cover to the manifold. And there was > pressure and there was oil which blew all over. > > Now for the first question. Everything I read says this is a result of a > worn engine - rings, cylinder walls, etc. which leaks air into the > crankcase building up pressure. Has anyone ever seen a different reason > for this? I had a compression test done about 8 months ago and all was > fine then. But that was then. My take is a 37 year old raw water cooled > engine is not worth that kind of repair, albeit it only has 2,000 hours on > it. > > Second question. I'm currently looking at a Yanmar and a Beta engine. > Any comments? The Beta is cheaper. Also they sell a 25 HP which seems > about right for the boat. Both appear too wide to get in on my C&C 34. > Anyone have experience with this? > > Thanks > Don Jonsson > C&C 34 > Victoria > > > > Sent from my iPad > _______________________________________________ > > The bills have started coming in for the year 2018 and have gone up > again. October will be our fund raising month. Please consider sending a > small contribution to help keep this list running. Use PayPal to send > contribution -- https://www.paypal.me/stumurray > > All contributions are greatly appreciated! >
_______________________________________________ The bills have started coming in for the year 2018 and have gone up again. October will be our fund raising month. Please consider sending a small contribution to help keep this list running. Use PayPal to send contribution -- https://www.paypal.me/stumurray All contributions are greatly appreciated!
