Help on 1980 International Harvestor 684 with 3.9 diesel

[FoMoCo]

Hello everybody. I just bought a IH Farm Tractor model 684 knowing it had problems. The dealer that I bought it from said that the problem might be low compression. They had the Injection pump and injectors rebuilt, and the engine is hard to start when cold. You have to crank it and then it dies, restart it and then just let it idles for 30 minutes until warm and it runs just fine. It does blow bluish smoke (unbrunt fuel) when cold, but once it is warm the smoke goes away and seems to run just fine. It cranks over easy

My questions is, does that sound like low compression? FYI all cylinders seem to be firing evenly. It has a bosch injection system, and it looks like the fuel tank has issues, since they have 4 fuel filters hooked up.

Any ideas, before I spend a 1,000 rebuilding the engine? I was thinking about using Engine Restore to see if that makes a difference, if so time for a re-ring.

 

[IHcornbinder]

No one thew a compression gauge on it before rebuilding the whole IP and injectors? That is the first thing i would do before I put a penny in it.

 

[IHcornbinder]

If it is low on compression tho, i have used the "restore" product before in a very tired jeep motor. I brought the compression up almost 20psi on the front cylinder. To bad it couldnt fix the burnd valves in the others.

 

[RLDSL]

If it fires right up then dies, then gives you trouble restarting and smokes a bunch, you have one or more slobbering injectors . It fires right off from teh fuel leaked into the cyl while sitting , then it has lost prime so you have to fuss a bit to get to restart, then the slobbering injector will smoke once running.
Would advice pulling the injectors and having them tested.

If compression is questionable, strongly advise running a treatment of Auto RX to unstick the rings and get the compression back up. I've seen compression go from around 135 to over 400 on a couple of holes with that stuff. Old diesels commonly get rings packed up, regular cleaning should be considered a service item, but avoid fast flushes, they can knock large chunks loose and clog oil passeges and cause you to have to tear into your engine for repairs ( ask me how I know this