Advice on Ford 134 cid Engine: Use or Fix????

[300 Mag]

Late last year while blading snow my '57 ford 640 with 134 cid gas engine developed a antifreeze leak between the head/block on right rear of engine. Checked torque head bolts, none were loose. Engine has oil in antifeeze, but no antifreeze in oil. Oil is clear and checks exactly full, engine does not use oil, smoke, etc. When running at operating temp, oil pressure is solid 45-50 psi. Compression check showed the cylinder #1 @130 psi, #2 @130 psi, #3 @110 psi, and #4 @135psi, all checked at operating temp. When checked cold, all cylinders were the same as when warmed up, except #3 was only 90 psi. I put some motor oil in cylinder and repeated the test, compression came back up to 110 psi. (side note, about a year ago I replaced a push rod in cylinder #3, it was bent and had jumped out, leaving intake valve stuck open. Not sure if this makes a difference or not) Since initial leak, I have used it about 4 times for maybe 30 minutes total running, and the leak has not occured again.

I apologize this is so lengthy. I only use this tractor maybe 50 hours or so a year, blading snow and running brush hog, and some loader work. I do not know if I should pull the head to try and correct the problem, or use it until something gets worse. I bought a complete gasket set, and I know how to replace head gaskets and do moderate repair to engines. My concern is that if I tear into it and there is serious problems (cracked head or block) then I may spend more money trying to fix the engine than just replace it with another used unit. Compression check looks like lower end might need some attention???, but oil pressure looks pretty good. Complicating the decision, the clutch is probably due to be replaced, I have adjusted it as much as possible.

Any opinions/advice/etc would be appreciated. Do I run use it untill it quits or gets worse, or do I pull the head and go from there. I don't use it a whole lot, and therefore do not want to spend a lot of money on it. Thanks in advance!!!

 

[john_Bud]

When you pulled the spark plugs to check compression, were any of them especially clean? If there is antifreeze leaking into the combustion chamber, it will steam clean the spark plug.

If there is no sign of leakage into the cylinders, then I would be enclined to keep using it. Compression is a little low, but part of that can be due to cranking speed. Hard to tell from here. The one does look like it is lower, but not enough to cause you to expend time and effort.

Now, if you do have leakage, then you need to at least replace the gasket. Smart money is on also decking the head so the face is flat. That would be only 20-40 bucks.

I've had engines spring a leak, especially when very cold, then "magically" never leak again. That's is the exception! Normally it's a down hill trip.

jb

 

[RodinNS]

Is it pushing antifreeze out the rad overflow?
If it's not losing any oil then I'd suspect that it doesn't have any oil in the antifreeze. What I would suspect is that the head gasket is leaking a bit, perhaps only sometimes, and pushing the combustion gases into the cooling system. That will blacken the coolant like there was oil in the coolant.
You have ring issues on # 3 combined with either a valve or gasket issue around #3....
Personally, if I didn't want to spend money on the old thing and it wasn't pushing coolant all the time, I'd keep an eye on it and keep using it. I'd also consider that if it does have a head gasket issue it could get worse at any time, without notice, dump antifreeze into the base and wreck the bearings, pistons and sleeves in short order.
Those engine kits can be had for about 700 (mabey less) complete and then you need to do the valve work. That's extra... If you let the thing go and the coolant finds it's way south, plan on cutting what may otherwise be a good crank, so add some more.
So.... if it's pushing into the cooling system now, I'd deal with it as soon as possible. IF it seems OK, I'd keep using it and keep an eye on it. Make sure it has the correct pressure rad cap on it as well and that it is functioning properly.

Rod

 

[souNdguy]

I'd pop the top and drop in a head gasket.

Oil into the coolant is not nearly as bad as coolant into the oil. Coolant in the oil will eat things like crank/bearings.

You may be lucky and just getting combustion byproducts in the oil looking like oil.

On your cyl 3 that had the comp go from 90 back up.. that is indicative of rings.. not valves, since the wet test helped compression. Looking at all the other good numbers.. and that one not bad warm.. I think at least I'd do head gasket.. and at most.. i might puill that piston and re-ring it and then do the head gasket.

soundguy