Running without engine tins/fan

[andreic]

A week ago I picked up a 1.8L engine that is a bit of a mystery -- I know little about its health, other than that it spins freely and appears to have compression. It has been sitting for at least a year (possibly more), but there is no rust on it.

My plan is to test it, figure out if it is in good health, and if yes give it a complete do-over (cleaning, new seals all over, etc.) and install it in my car. I'm trying to figure out the order in which I will do things.

Here is what I did so far. I took off the tins, fan housing, and fan. I gave it a partial cleaning (it was incredibly dirty, now it is only somewhat dirty...). I drained the oil, put in a new oil filter, replaced the pushrod-tube seals (they were leaking badly) and did a valve adjustment. I plan to replace the points, rotor, and spark plugs with new ones. Then I want to install a pair of carbs I have in the basement, put on the exhaust and a transmission case and starter that I have, and try to start it.

I would like to test run it and perform a few basic tests on it before investing more time in cleaning it and the fan housing, engine tins (they'll need cleaning and repainting, etc.)

My question is if it would be OK to test run 5-10 minutes without installing the engine tins and the fan back on. I want to do this for two reasons -- one is to save time and work, the other in order to be able to see where else it may be leaking oil, so I can correct the problems. The outside air temperature would be in the 30's (I am in Wisconsin). Is there any risk of damaging the engine by doing this? All I want is to be able to check oil pressure, and warm it up enough to check compressions. So I don't plan to run it full power, just idle it most of the time, and maybe get it to 2000-3000 rpm for a few seconds. (I will do all this outside the garage, with the engine in open air, on a stand, not in the car.)

Any opinions?

Thanks a lot!
Andrei.

[Steam Driver]

In my opinion and experience with air-cooled engines, absolutely not. Definitely not ten minutes, and five would be pushing it. It needs some sort of airflow over the fins for sure. Maybe a couple of box fans would help, but I wouldn't do it myself.

Reinstall the tins and fan; it won't take that long. You don't need the tin that seals it into the engine compartment, just the engine shrouds. I have done this was VW's and 356's - tested them on the floor of the garage before lifting into the car, but NEVER without the fans and cooling shrouds.

[Dave at Pelican Parts]

One other caveat: Make sure you have a low-pressure carb-friendly fuel pump, not the stock high-pressure high-volume pump used for fuel injection. Overflowing the float bowls in the carburetors will not lead to good results.

--DD

[andreic]

Thanks for the comments. I decided to do what was suggested, and I'll install the engine tins before running it. I have ordered a low-pressure fuel pump as well, for the carbs.

Nevertheless, any suggestions on what else to check before the engine is running? The engine must have had tons of oil leaks (from how dirty it was). I replaced the pushrod tube seals, which were obviously leaking. The question is now whether to replace the other important seals (front main, rear main, oil cooler) before test running the engine, or should I first test run it?

On one hand I fear that I do all this work and find out the engine is junk, on the other I don't want to have to drain the oil again, etc. Can all the seals I mentioned above be replaced with the oil in the engine and the tins on?

Thanks,
Andrei.

[Dave at Pelican Parts]

The seals you mention can be replaced without draining the oil.

When you have the flywheel off, inspect all of the gallery plugs--the round "freeze plugs" that seal off the ends of the drilled oil galleries. You should pull the fan off (and maybe the fan shroud) and look at the oil gallery plugs up front as well. These are known to sometimes come loose after a zillion or so heat cycles. It is somewhat popular to goop over them with JB Weld if they're still tight, which usually keeps them in place. During a rebuild, some will remove the plugs and replace them with threaded pipe plugs.

It's somewhat hard to thread the holes without leaving chips in the oil system, so replacing the plugs is usually only done during a rebuild.

--DD

[URY914]

Even with the fan and tin in place you need to "feed" the fan with air. Use one of these to blow air toward the engine. You need A LOT of air moving across the heads. Cheap box fans won't get it done.

[Steam Driver]

"feed the fan?" Why is that required? They aren't "fed" when installed in the car. Quite the contrary, generally buried and out of any ram airflow.

[URY914]

You think a car with its engine running runs cooler or hotter when it is sitting still or driving down the road?

Ever see a car running on a dyno? Fans are placed in front of the engine.