by Sherwood Heggen
Boat restoration is more than replacing frames and planks and putting on the shiny
varnish. No boat is worth its varnish if it doesnt have a well- tuned engine with proper compression and oil pressure.
Recently, I began the condition evaluation of the original K95 engine for my 1938 Chris Craft. I had run the engine on a test stand and found that it started fine and seemed to run smoothly. My concern came when I did a simple compression check. The compression gauge told me the engine cylinders ranged in compression from 70 to 100 psi. Not good when all the cylinders should have 110-120 psi for acceptable power. So, what does the low compression mean? Unfortunately, nothing good. It can mean any or all of the following: worn or stuck piston rings, scratched cylinders, mis-adjusted or worn valves, leaky head gasket, and anything that can allow air to escape when it is not supposed to. There, I think that covers everything.
The most frequent maintenance concern on these old engines seems to be worn, leaky valves. But, how can you be sure its valves and not piston/cylinder problems? First, disconnect the coil wire, remove all of the spark plugs and check and record compression of all of the cylinders with the compression gauge. Then, wet the cylinders with a couple of squirts of motor oil using an oil can with a flexible neck to aim oil at the cylinders through the spark plug hole. Turn the engine over a couple times with the plugs out to help distribute the oil on the cylinder walls. Then check and record the compression of each cylinder again. Did the compression go up? How much? A little or a lot? If it went up a little, it is likely the valves are out of adjustment or need grinding. If it went up a lot, it is likely the rings are worn, broken, or stuck. Either way, there is not much than can be done without some tear down. The head must be removed to grind valves and the pistons must be removed to do any ring/piston/cylinder work. To get the pistons out, it is necessary to remove the oil pan to remove the rod caps which hold the connecting rods to the crankshaft. To remove the oil pan, you need to remove the engine from the boat. There generally is no easy way to make things right once you get this deep into the engine.
How about oil pressure? Did you notice when the engine was running last summer that the oil pressure was a little low, like maybe down to around 10-15 psi at full throttle. Did you notice the oil pressure drops a lot from a cold to hot running condition? The engines main and rod bearings maybe ready to head South and you dont want that to happen. Even though the engine seems to be running fine with low oil pressure, you could eventually do a lot of damage to everything spinning around down there at high rpms. There is no substitute for mechanical soundness to make the engine run properly.
I was hopeful that only the valves were worn on my K95 because compression did not go up when oil was used to wet the cylinders. To do the valves I removed the head. Once inside, I noticed the valves, when open, could be moved laterally a significant amount. Oh no! Worn valve guides! The cylinders looked nice and shiny but that isnt necessarily a good thing. The cylinders should have a cross-hatch pattern which helps retain a film of oil for good lubrication and compression. So now, I am worried. A closer look showed vertical scratches in the cylinders allowing additional compression loss. The only way to fix that is to remove the pistons to hone or bore the cylinders. This will call for at least new rings if not new pistons and rings. I removed the pistons by removing the rod caps at the crankshaft and pushing the piston out the top of the block. Yikes! More trouble! The bearings on the rods were visibly worn through to the copper shell. It was reasonable to assume the worst and I removed the main bearing caps also for inspection. Double yikes! More big trouble! The main bearings were breaking up! I could actually remove pieces of the bearing from the bearing shell! The crank also was marked by the bad bearings. All this from an engine I assumed would need a valve job! It is obvious this engine will need a major overhaul and is currently in the machine shop for just that.
Hopefully, this gives you some insight with regard to the engine in your boat or restoration project. Do the whole project, and you will have more fun on the water. Here are some happier thoughts on boat restoration.
Lets see what your fellow BSLOLers are doing with their projects.
Fred Boss – 1957 Century Resorter 16 – Fred has had the boat upside down and repair and replacement is now done. The topsides are varnished and upholstery is in. Engine installation is next. Should be in the water by Summer 1998.
Ray Ellis – 1942 Century Sea Maid 17 – This is a major rebuild of a pattern boat. The boat was badly rotted and most of it has been replaced except for a couple of side frames. Varnishing is nearly complete and the Gray Marine engine is being rebuilt. Maybe in the water Summer 1998.
Mark Schaefer – 196X Lyman I/O 21 – The midships steambent frames and planks are rotted and are being replaced. Will be ready for ice out in the spring.
Denis Smith – 1963 Century Resorter 18 – Total keel up restoration.Also, Mid-fifties Tonka Craft O/B 15 – Currently in his shop to receive repair and restoration.
Jim Aamodt – 1929 Hacker Craft 26 w/ Kermath Sea Wolf 225 hp 678 ci engine – Hull is structurally sound. Jim needed to replace only one board on the transom. Power will be a Kermath Sea Wolf 225 hp 678 ci displacement engine. This boat was found in New York in 1969 by Bill Morgan who purchased it. It remained his personal boat until 1984 when it was purchased by a Mr Kavan. Jim bought the boat about a year ago and has had to do mostly cosmetic work plus go through the engine which he is doing himself.
Roger Fox – 1948 Chris Craft Deluxe Runabout w/131hpKBL – Rogers Deluxe has had deck and transom work done plus new stain and varnish and new upholstery. The engine is in good running condition with rebuilt carbs. New wiring is next. Should be ready to add water hopefully in 1998.
John Pole – 1930 Chris Craft Upswept Deck 26 – In process of a total restoration.John has rebuilt the bottom. He has replaced frames and did a semi-traditional bottom with diagonal strips of 14 plywood edge-glued with 3M 5200. A membrane of Cuprinol treated muslin was bedded in Petit bedding compound cut with boiled linseed oil. All of the bottom boards are new lumber. Sides and deck will be Honduras. Engine will a 454 with a Velvet Drive 1-1.
Jeff Stebbins – Chris Craft Sportsman 22 – Hercules M – Jeff is planning this restoration for the near future. Boat is a whitesided hull in real fine structural condition. Project will be a cosmetic restoration including new upholstery.
Bob Clark – Chris Craft U-18 – Hercules KL – A full restoration from the keel up is planned. The bottom was started by the previous owner using epoxy encapsulated luan plywood for inner planking. Bobs thoughts are to remove this and do a soft bottom with 3M 5200.
Great projects, guys! How about the rest of you?. There are more boats out there waitng for someone. Go getem!
An encouragement to those looking for an interesting, perhaps less costly, project. Consider a lapstrake or whiteside (often cedar planked) boat. The benefit of these boats is that the top sides are easy to maintain. If a dock scratches the side, merely fill the scratch and paint over it. Also, their lower perceived value makes them a good deal. If it is an inboard, you still get the same sweet rumble. If it is an outboard, a 16 or 18 footer can be ultra-roomy for the family or outing stuff. Either way, you will like the charm of the mahogany deck which is all you can see when youre in it anyway.
DONT DESTROY IT – RESTORE IT!