Broken head?

[tpitt]

Dr. Lee,
Got my transmission changed, (my 87 sub) put the 400 back in it. Run it for a couple of days and one day my wife went to start it and it started extremely hard.
Got it started and am getting what appears to be a puff of steam out of the oil fill. Seems to be consistant with a piston firing. Runs rough, also . It is not pressurizing the radiator nor is there any water in the oil. The puff of steam? is not condensing on the oil fill tube.
Any ideas, before I start to pull it apart? Thanks, Terry

[CleviteKid]

Gee Terry, sorry to hear you are having problems. I would suggest two diagnostic tests to find the bad cylinder or cylinders - a compression check to see if that shows a bad cylinder, and if they are all the same, I would try a leak-down test with up to 1000 psi regulated compressed air or nitrogen, if you have access to same in a safe manner. The development engineers at the auto makers in Detroit use the leak-down test as the critical arbitrator of engine condition before deciding to tear into it.

If you have a leak into the crankcase, you should either get lots of soot fast if the cylinder is firing, or a rising level in the crankcase from the fuel dilution if the offending cylinder is too tired to fire.

As for hard starting - if only one cylinder was bad the others should still fire on the first or second revolution and get you going. You may have a more global problem like a clogged fuel filter or air filter, water in the fuel, several non-functioning glow plugs, or a weak injection pump. Don't tell the wife I suggested it, but topping off the tank with a little gasoline would lower the cetane level of your fuel and make the truck very hard to start ! ! !

I know some of the above does not apply to you, Terry, but I wanted to put in a more complete list for some of the newer readers.

Good luck solving this one,

Dr. Lee :cool:

[tpitt]

Dr. Lee,
Thanks for your sound advice, I failed to mention it has been running rough when warm for awhile. Also is a little difficult to start when first started. Glow plugs are fairly new # 60g's.

I haven't had time to really look at it yet. It may well be time to give Jamie a call. I do have a good running 6.2 out of a wreck I bought. I may just put that in for now.

If you ever consider running for governor in Ca. You certainally have my vote. :D :D :D
Terry