have a case backhoe that has been dusted , intake hose fell off air cleaner . hard starting if will start at all .upon diagnosis found #1 cyl. only 175 psi other 3 are 325 psi . gonna rebuild anything to watch for ,am I going right direction ?
Could be as simple as a valve and or valve seat problem. Any blow-by coming out the oil fill hole with it open and the engine running. That would indicate a serious problem with broken piston rings or a piston. Depends on how much of a rebuild you are doing.
No noticeable blowby it’s extremely hard to start and very black carbon smoke not white already change turbo it had bearing failing and extreme signs of dirt no pieces missing
B3.9 & B5.9 Engines Group 14 Engine Testing Page 14-22 " NOTE; Due to variables such as starter and battery conditions that effect engine cranking speed, it is difficult to establish an absolute value for compression pressure ; however the following values can be used as guidelines: New Engine (cranking speed @ 250 rpm) 2412kPa (350 PSI) Used Engine (cranking speed @ 250 rpm) 2068 kPa ( 300 psi) It is recommended that the compression pressure be checked on all cylinders and then compared to specification. ALL cylinders MUST be within 650kPa ( 100 psi) of each other" I don't know the authenticity of this info, but this is kinda what I was thinking. I'd expect a dusted engine to be more uniformly low, how could one cylinder get all the dust? Do a leak down pressure test on your bad cylinder and check where the air is leaking, crankcase, intake, exhaust? Then check the valve clearance, then pull the head and see what you can see.
I agree with all cylinders should be more equal will do little further inspecting on Tuesday when back at it the only thing confusing me is the smoke out of exhaust when cranking black heavy smoke fills shop very quickly ?not usual unburnt white smoke you usually see thanks to all advice so far happy new year to all
If this engine has an after cooler, I have seen the cooler get stopped up when dirt is ingested. That will cause your black smoke. Don't over look the intake valves when doing the rebulid, they will often be extremely worn and sharp from the abrasion.
Just curious did the hose fall off the intake manifold side of the air cleaner ? What is the condition of the air filters ? A badly plugged air filter could cause a hose to collapse and deprive the engine of air. Heavy black smoke ---->does the turbo-charger spin freely ? Did you get the head reconditioned ? If the heavy black smoke condition is still there after the overhaul it is time to have the fuel injectors pop-tested. I would do it as part of the overhaul. If they are good then the Injection pump may need servicing. Here is a link to what may or not be your engines service/ maintenance manual. http://stephensonequipment.com/wp-c...2/LeeBoy-Cummins-B3.9-B5.9-Engine-Manuals.pdf