Thursday, July 12, 2007

Albin engine, Part 4 - New Valves

Mounted on a work table in John Dickerson’s shop, stripped of its intake/exhaust manifold, valve cover and cylinder head, it was obvious why the engine had no compression and wouldn’t run.

The exhaust valves for both cylinders didn’t go up and down like they should. They were up and they stayed up. The valve lifters were a little pitted, too.

If the valves don’t work right on a modern automobile engine, it is relatively simple and economical to remove the cylinder heads, which contain the valve mechanism, send them out to one of the many machine shops that specialize in that sort of work, and have them fixed.

However, while the valve mechanism on the Albin engine is much less complex than that of a modern automobile engine, there are no machine shops that specialize in that kind of work for that kind of engine.

In fact, in all of metropolitan Los Angeles, there is only one shop that will work on that engine. And that shop already had worked on this engine. Twice in two years it turns out. And the engine didn’t run.

John Dickerson doesn’t work on this kind of engine, either. Or any other kind of engine. He sends the engine work out to engine shops that specialize in whatever he needs done. Usually it involves extracting much greater horsepower from an engine than its manufacturer ever imagined.

John was doing me a huge favor by hosting me in his shop. I’m always quick to overestimate my abilities. So I had assured John that I would do all the work myself if he would let me use some space, some tools, and answer an occasional question. After all,
I once rebuilt a VW engine. Many, many years ago. And to prepare for this task I bought a book about rebuilding engines.

As it turned out, my questions were, in fact, incessant. The space requirements kept expanding. And I probably laid my hands on most of the tools in his shop. In the end, John patiently rebuilt my engine for me, while I convinced myself that I was assisting.

Several hours spent trying to free and clean up the stuck valves led to the conclusion that all four valves and their valve guides should be replaced. The valve lifters would be cleaned, polished in place with emery cloth and reused. This was a decision prompted by both practicality and fear.

Removing the valve lifters meant removing the camshaft which meant removing the front and rear engine cases, which meant removing the transmission. The danger of damaging a part that couldn’t be replaced loomed larger than the probable cost of all the extra gaskets and other parts that would be needed.

A micrometer check of the cylinders showed that they had not worn beyond as-new tolerances in the 39-year-life of this engine, and they were still round. Swedish iron is good iron. All they needed was a new set of piston rings to replace the new rings that had been installed at the engine shop when it last worked on this engine. Apparently, if new rings sit in cylinders for months without the engine being run, they lose their ability to properly break-in and seal the cylinder.

Most parts are readily available for Albin engines from AME Ship Equipment Co., in Miami, FL, which imports them from the Swedish manufacturer, Fors Marin. (See listing and link in sidebar.)

Relying on ground shipping rather than air, in about 10 days we had four new valves, valve guides, a set of piston rings, cylinder head gaskets, manifold gaskets, and the other parts and spares we needed. The cost was $583.00.

I was surprised to learn that both the valve guides and valves themselves were supplied longer than they would be after installation. John deftly drove the brittle iron valve guides into the cylinder block and then snapped off the ends at the proper distance with a chisel and a sharp hammer blow.

The valve stems had to be ground down precisely to the proper dimension for the required .008 and .010-inch clearances from the solid valve lifters. First he made a V-shaped tray for his grinder to hold the valve stems at exactly 90 degrees from the grinding surface. Then he ground each by hand, checking repeatedly as he neared the proper clearance to get exactly the right dimension.

I did assist. My job was to lap the valves to the valve seats with valve grinding compound so that they would make a good seal when closed. The seats were in good shape, and the seawater in the combustion chambers had not ruined them. Valve lapping is done with a suction cup on a round handle. The suction cup grips the head of the valve while the round handle is spun between the palms of the hands moving back and forth opposite each other. It takes awhile to mate the surfaces of the valve faces and the valve seats that way.

Eventually the engine was reassembled. John welded up a mounting stand for it, complete with fuel, water and battery connections and we did a test run. It started fine. It pumped cooling water fine. But the engine would not run smoothly no matter how we adjusted the carburetor.

The carburetor, with its prior JB Weld repairs, proved itself to be just what it looked like. Junk.

1 comment:

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