Help Needed: Continental F162 trouble...

[jbi]

Hey everybody, this is my first post here.

I have a couple of Lincoln welders I'm working on, one with an F162 and one with an F163. The 162 was supposedly rebuilt a year ago, so I'm trying to get it going first. I put a small amount of oil in the cylinders and cranked it until I had oil pressure, then started it. It's got a solid knock at idle, sounds like from one cylinder, and it's blowing blue smoke.

Compression readings from cylinder 1 to 4 are: 135, 140, 70, and 100. Engine oil pressure was between 15 and 20 psi at idle on the mech. gauge. I changed the oil and filter and started it again, with the same results. When I first pulled the plugs to put oil in the cyls, they were only black from running rich. Now they all have oil on them, and I don't think it's the small amount I put in the cyls. I've checked and cleaned them twice.

I know this engine has sat for 6 months at least. Are there any common parts that would have seized up in that time? What would be the best way to go about diagnosing the problem?

Thanks in advance for your help. No one near me has experience with flat-heads.

[Andrew Mackey]

Could be stuck rings, but if it only sat 6 months, I suspect that there may be mechanical problems with the rebuild, if indeed one was done. Try shorting out one plug wire at a time, as the engine is running. If the knock goes away, you will find the bad cylinder. It could ba a bad piston, bad wrist pin bushing, or bad bearings. The oil pressure sounds like it should be OK. Does it drop off when the engine gets hot? The only way to check the cylinders is to pull the head. If the walls are glazed shiny, then the engine was not overhauled properly. Even if new rings were installed, out of round or glazed cylinders will not seal properly. I have seen automotive engines with 30,000 miles on the engines, where the cross hatching from cylinder honing is still visible. If your cylinders were bored or honed, the hatching should still be visible. Look for piston to cylinder clearance. Excess clearance means piston slap, and possible piston damage. Check at TDC, middle bore and at BDC. Look for vertical scoring and or signs of scuffing. Running without an air filter, dusty conditions, or injesting stray items will cause scoring, poor fit or misassembly of internal parts will cause scuffing (wear over a large portion of the bore) damage. Before you pull the head, try this: Remove the carb and muffler. and remove the oil fill cap. Remove all the spark plugs as well. Turn the engine to TDC #1 cylinder -compression stroke, and apply air to the spark plug hole. If you have bad valves, you will hear air escaping from the intake or exhaust. If bad piston, rings or cylinder, you will hear it air escaping at the oil fill. Do this for all cylinders. Make sure that the engine is exactly at TDC compression, or the engine will turn with the air pressure. If you do not have an adapter to fit the plug hole, either a rubber tipped nozle or an adapter can be had from a good auto supply like NAPA.

With your #3 cylinder at only 70 PSI, it seems that there must be a mechanical problem, as that reading is well below the 10% average differential needed for good engine performance. The mean pressure between the top 3 cylinders is 125. A 10% differential would be 12.5. Even the #4 cylinder does not meet the standard, but the #3 cylinder is worrysome. If the leak down test (pressurizing the cylinders), shows valve leakage, then perhaps merely lapping in and clearancing the valves is the answer. HOWEVER, that will not fix the oil consumption, and if the air is escaping into the block, and in view of the knocking situation, I believe a tear down probably is nescessary. A quick question - does the engine smoke full time? Does it get worse? Decellerating (slowing), Accellerating - pulling load after it warms up?

Andrew

[jbi]

Andrew, thanks for the prompt and helpful reply. I will get back with you after further diagnosis.

In answer to your question, I don't know if the engine smokes after it's warmed up. I've been afraid to run it for that long because of the knocking. I'd always thought knocking meant a bearing ready to go, but I've printed the Continental overhaul manual and oil pressure is within spec, which makes me wonder whether it could be bearings.

Anyway, I'm headed out to the shop for further poking and prodding. Thanks again.