The boat owner and I originally planned to bring the engine down to a marina in Excelsior, MN for servicing. But later the owner felt Excelsior was too far away and sought out and found a local marine shop that did work on old Chris Craft motors. So "Plan A" was nixed and we went forward with "Plan B."
I went down to the local marine shop and discussed the proposed engine work and left feeling like we had a good plan with a competent marine mechanic. We waited a week and a half for an estimate from the shop. But, they failed to provide us with one even after I enquired two more times... no return phone call, no return email... I was puzzled by it. Figuring if a shop can't even provide an estimate as had been agreed to, then perhaps things wouldn't go well if we continued to pursue it. So we abandoned "Plan B" and went on to "Plan K"... me.
While I'm not a qualified mechanic, I do know enough about internal combustion engines to do my own mechanical work. It was just a generation ago (my generation) that you could tune up your own car in your driveway, with a just basic understanding of automotive mechanics and a set of basic automotive tools. I'm familiar with this specific engine, a 1964 flywheel-forward, standard rotation (rotates right), marine version of the classic 283 CI small block Chevy V8 as I had a 283 V8 in my first car, a 1967 Chevy Impala that I used to tinker with when I was a teenager. This is old-school GM technology... no computers here, just a good old fashioned Kettering Ignition System, using a coil, a set of contact points, a condenser, and a rotor underneath the distributor cap. It requires simple timing adjustments using a timing light along with gap and dwell adjustments of the contact points using a feeler gage and a dwell meter. So I made a cost saving proposal to the owner tasking me with the engine work, "Plan K", to which he accepted. It will be fun to work on this old technology engine again and it will also be a learning experience for me. It will also save the boat owner some money. The biggest challenge for me here will be to realign the engine with the stuffing box prop shaft during the reinstall, it needs to be a 0.003" spaced tolerance, otherwise the prop shaft will wobble and vibrate when under power.
So the plan now is for me to do a compression check and evaluate the results, pull the engine, do a complete tuneup involving replacement of the entire ignition system including upgrading the alternator to a higher amperage output to support today's boating electronics, replace all hoses, replace the alternator and water pump belts, replace the water pump impeller, adjust valve lash, degrease and paint, and then reinstall the engine back into the boat.
Last week I began by first performing a compression check on all cylinders. The results ranged from 85 PSI to 145 PSI... too great of a difference which concerned me that a rebuild may be required. I squirted some oil in the 85 PSI cylinder and retested. The compression came up some which is an indication that the piston rings are worn. The range ought not to vary more than 10%. I sought the advice of a friend whom is a very good mechanic. He agreed it varied too far and after l told him that the engine hadn't been run for three years he immediately suspected that the piston rings could be "stuck" and suggested I run the engine for an hour in an attempt to expand them and then retest the compression. I did so and he was right on as the compression came all the way up to 125 PSI. The engine ran good, sounded good and was cool to the touch indicating that water was circulating through the engine appropriately. The valves were a little noisy though and there was little bit too much white smoke coming from the exhaust. It's hard to say just how good it ran, without actually operating the boat on the water in order to get a feel for how good the power is. With that, we decided the compression may be good enough, and possibly could continue to improve after some more running time. So we decided to put off a rebuild project and will reconsider it after a season on the water.
However, while running the engine I noticed a very slight crack in a heavily rusted area of the port exhaust manifold from which teardrops of water were seeping though... not a good sign for the condition of the exhaust manifold. Worst case for a cracked exhaust manifold is water could leak into the engine block and cause catastrophic damage. In doing further research I learned that it is recommend that marine exhaust manifolds and risers used in fresh water ought to be replaced every ten years. However, some forum discussion I read indicates that this might be a little pessimistic... I guess a guy has to form his own opinion on this. This boat has been run only in fresh water and the manifolds on this engine seem to be original, thus 48 years old. Also, the white exhaust smoke I observed when running the engine is an indication that something may be amiss with the manifolds. So the owner decided to have me replace the exhaust manifolds too. Here are some references:
- Boat U.S. - Exhaust Manifolds
- Boat U.S. - Inspecting Exhaust Manifolds and Risers
- Ship Shape TV Episode on Exhaust Manifold & Riser Replacement on YouTube
- Boat Parts Info article on Replacing Marine Manifolds and Risers
So this week my project was to find and order parts and pull the engine out. I spent a lot of time on the internet researching parts for this engine. The original equipment manufacturer (OEM) of the ignition parts for this engine is Prestolite. I learned that Prestolite was originally Autolite and Mallory now owns Prestolite. I also learned that Sierra after-market marine parts are quite popular, but figured it was best to go OEM. So all the ignition parts I ordered are Mallory parts. I was able to find a source for a Prestolite Voltage regulator.
Later in the week I built a wooden engine stand out of old fence posts I had and scrap 2 x 4's. I built it in such a way to keep the engine at the same incline as when mounted in the boat, as well as allowing plenty of clearance for when I paint it.
Friday I pulled the engine. It went fairly smooth. I disconnected and clearly labeled all the electrical connections as well as drawing diagrams and took plenty of pictures so I have something to refer to when putting the engine back in. I disconnected the Paragon manual reverse gear from it's shifter bar. I could not remove the exhaust hose from the exhaust manifold elbows so I cut them off since they are going to be replaced anyway. I disconnected the water hoses from the water inlet as well as disconnecting the fuel line from the fuel pump, being sure to shut the fuel tank valve off first.
The only thing left to do before actually lifting the engine out of the boat was to unbolt the six bolts securing the engine to the engine stringers via the engine mounts. The front two mounts were secured with a single lag bolt for each mount which they both came out cleanly. The port side came out rust free and looks as good as new. The starboard side was all rusted up as it was screwed into the area of the engine stringer that had rotted which precipitated this whole engine removal project. The challenge was the rear four machine bolts. All of them were badly rusted and I could not budge them, nor could I get a lot of leverage on them with a long wrench as the surrounding space was too constrained. Based on the condition of these four bolts I would surmise that the engine most likely has never come out of the boat. I made the quick decision to just cut the engine stringers since the whole purpose of this project was to replace them. I used my newly erected boat gantry to lift the engine out and mount it on the engine stand.
Here's the sequence of pulling the engine. I used an engine leveler hung from a chain hoist to keep the engine balanced while lifting it. The engine weighs about 730 pounds. The engine leveler hooks to the chain hoist hook from its center point. From the bottom of the engine leveler hang two chains that are attached to the engine block. You can then adjust the leveler accordingly to keep it well balanced. The process went pretty smooth and essentially just involved hoisting it up as high as possible, pulling the boat out from underneath (the engine just cleared the transom when I pulled the boat out into the driveway), and then lowering the engine onto the stand.
These are the badly rusted rear engine mount machine bolts... two to each mount. I could not remove them from inside the boat, so I cut the engine stringers. Ordinarily this would not be an option, but as the whole intention of pulling the engine is to replace the engine stringers, I had the option of cutting them. Once the engine was out, I had enough room to use a breaker bar and to remove the nuts, but had to split the wood as the bolts were so badly rusted that the wood would not slide off from the bolts. Two bolts remain rusted to the mounts. I ground them flush with the bottom of the mount so I could set the engine on the stand for the time being. I sprayed the frozen bolts with PB penetrating oil and will let them soak for awhile and will try again later to spin them off with a breaker bar after they have soaked some.
The interior of the hull now void of the engine.... lots of working room in there now.