How often to run the engine in a Centurion?

[Lynn Eades]

Malcolm, I am not the guy to answer your questions, but will say this;
When rings stick in the ring grooves, the engine looses compression or pumps/ burns oil- smokes. It'll still run, and may come right with use. When the rings stick in the bore that's a disaster that usually ends in seizure, or at least engine damage. Two quite different results.

[David Herbert]

Malcolm,
I think your instincts are spot on. If there are no issues like leaking coolant and a vehicle is kept in a dry and reasonably warm environment (ie. not outside in the UK in winter) running it for a short time and not fully warmed up is likely to cause more problems than were there before. I would expect that the relative humidity in your part of the world in winter is very low so there should be no condensation in the cylinders or anywhere else to cause problems. Rings do not just stick spontaneously, there is always a reason, usually either carbon build up or corrosion.

David

[Perry Kitson]

As David stated above Malcolm, you are right on the money. Running ANY engine for short peroids of time is not good. Again, I am no Meteor expert, but the rules should still apply as to any other gasoline engine. Gas engines have a distinctive disadvavantage when compared to diesel engines. Gas "washes" down the cylinder walls constantly, removing precious lubricating oils. I would think that mothballing the engine for the winter storage time would be better than running the engine occasionally only to bring it up to temperature (where thermal expansion has done its work to bring the pistons to the correct operating clearance), and then shut it down after a short run. I did a simple mothballing on my carrier engine every fall, and never had a lick of trouble with stuck valves (a common flat head problem), pistons or rings in 21 years.

[Malcolm Towrie]

What did you do to mothball the engine, Perry?

We have some Meteor engines here in various states of disrepair. I don't know where we got them from. One had the heads removed so I pulled the cylinder block on each bank to see what condition the pistons and rings were in, as at that time we were considering rebuilding an engine. It took a lot of effort to get the blocks, or skirts as they are called in the manual, off. This was b cause, on each block, the rings on one piston had seized in the bore with corrosion. Also, the rings on almost every piston were rusted and stuck solid in the ring grooves. The tops of some of the pistons were pitted with corrosion. Obviously, water had got into the cylinders at some time. Despite that, there was no corrosion damage to any of the sleeve bores and just some very light scoring. I thought they must be hard chrome plated, but apparently they're not. Some exotic Rolls Royce material, I guess. The condition of this engine indicates smaller amounts of moisture will rust the rings into the grooves, and larger amounts will also seize the rings to the bore. Maybe the ring material RR used to match the very hard sleeve bores was prone to corrosion?

Anyway, I think we won't run the engine routinely during the winter, maybe just put some oil in the cylinders and crank the engine over occasionally.

I'll also search some vintage aircraft forums to see if the need to run the engine regularly is legitimate.


Malcolm

[Perry Kitson]

I picked up this method from some old timers in the antique car hobby. I would do an oil change in the fall before putting the machine away for the winter. Then, with the engine"cold", lightly pour 10W oil into the carb as it idled, until it produced a nice smoke cloud for a 5-10 seconds, then shutting down the engine while still adding oil. This gets the oil onto both intake and exhaust valve stems, as well as the top end of the cylinder. Doing this with a cold engine, at an idle, does not give complete combustion, so does not end up with an appreciable carbon build up, as well as having more clearance before things heat up. Of coarse, pulling the plugs and adding some oil to the cylinders is good as well, it does not get oil onto the valves, but this is not a big concern for overhead valve engines.

[45jim]

When we restored our Centurion in Calgary (now in Edmonton and still going strong) we asked the very question of our old hats. You see regular army vehicles sit a long time in open storage between exercises and on deployments the vehicles are left with a skeleton crew and often go untouched for 6 months or more. Our museum vehicles would be no different.

In fact, when the Strathconas had Centurions most were kept in Wainwright while Regiment was in Calgary (about 4 hours away). A team in Wainwright performed needed maintenance but the tanks mostly sat for 8 months a year!

In the museum, we found the old maintenance logs and they stated that tanks prior to storage were to be "prepared". This perpetration included full maintenance, oil changes and greasing or oiling of all moving parts. Engines (including the aux engine) were to be run until operating temperature was reached and if the tank was mobile, it was to be driven approximately 5 miles. After parking they were allowed to idle for 5 mins and then shut down. The next morning the plugs were removed and 3 teaspoons of 10wt oil was added to each cylinder and the engine spun to distribute the oil and plugs reinstalled. If the engine was not to be run for up to 1 year or more desicator plugs would be installed in the spark plug holes. I was told no one ever saw a desicator plug during their service.

[jdmcm]

Would installing a block heater be useful? When I had my trucking company it was common to "plug" trucks in after they had sat for extended periods, even in the milder BC weather. If a truck had major engine work such as in an in-frame rebuild or god forbid a full out of frame rebuild, that truck never got started during break in until it was plugged in for several hours, preferably overnight...the big Detroits, 12V-71's were fitted with aftermarket pre-lubers from Luberfiner, this allowed you to push a button and watch the oil pressure from in the cab reach a certain point before you tried starting...much like the Russian/Soviet era tanks...might be cheap insurance compared to rebuilding a meteor? Should be a pretty easy installation in a vehicle with an external oil tank, and I believe Malcolm said the main fuel tanks were not currently installed...should give you plenty of room