hdsbc
Active Member
So its been a long time that i have been chasing down this fuel issue and i am utterly stumped at this point. first I will give you the specs. threw my research I believe its a 1960 model year Cat 17A D7 Turbo.
I bought the machine about 3 years ago and love it since day one strong like bull and dumb like one too ( nothing electric controlled). last summer, I had a sudden engine nock and loss of power and blew the dip stick clean out of the machine. I immediately shut her down and investigated. turns out I lost fuel pressure to #2 cylinder, dead cylinder. apon digging deeper I noticed the front half of the engine filling up with anti- freeze, I suspect when #2 went dead the compression had to go somewhere and it blew the dipstick out of the machine and across the yard about 15 feet and destroying the head gasket seal. Ok so simple fix I thought.
All new head set all new gaskets everywhere tore it all down and solved that problem, re-lashed the valve train put in a new push rod and lifter because someone's jimmy rig fix from years ago in my opinion was Ludacris, did regular maintance rebuilt all the hydraulic cylinders up front with brand new rods and seals what not and then it was off to the fuel system to fix the misfire.
Now this is where my Delma is I am at a loss I have replaced the injector nozzle and body, the line has no kinks or obstructions, I put a brand new piston pump on #2 high pressure pumps spot, the yoke was in spec so didn't change it, took apart the whole fuel system no contamination in the passage ports in the filter assembly transfer pump primary filter and both secondary filters are brand new, drained the entire fuel tank cleaned it no rust or dirt. played flip flop between a known firing cylinders injectors pump and injectors the problem always stays ay #2.
So with all that I figured it has to be the cam shaft or lifter. so I follow the book bring #2 up to compression at TC bought a brand new micrometer for measuring depth, set the lifter up to spec of 1.733 " from deck to yoke that dose not solve the problem do the same test to #1 cylinder the values are equal. so then I measure the lift at full rise thinking the cam lobe is worn down, nope it is exactly the same amount to lift as #1 so then I do the measurement to see if at TC the lift is right for that duration on the lobe matches exactly to known working cylinder #1.
When the engine is running it defiantly has a loud fuel nock and if you crack the injector lines will its running #1,3,4 all affect the engine idle negatively obviously bc its a no fuel scenario but when you crack #2 it dose not react like its running on only 3 cylinders of power currently.
When you take the fuel lines off the Piston pump caps you can watch a steady fuel stream like a guizzer shooting up about 6 inches on #1,3,4 but #2 barely will squirt 3" and at the injector tip it will only dribble fuel barely no atomization.
so now i am grasping at straws I get an idea maybe the lifter spring is broken and it works fine at slow speeds with the micrometer but as the RPM increases at engine running I get a "Valve Float" scenario like racecars at High RPM. causing my problems, so tonight I took the cam and lifters out of #2 and #1 no ware no scrapes nothing then springs feel identical resistance rollers are smooth the parts look brand new.
So to sum it all up everything on that cylinders fuel system is either replaced or in spec the cam is fine the lifter looks good it has the right amount of lift and duration, the piston pump is brand new and if you swap in old one it dose not change the line is clear the injector tip and body is new. and I still have a dead cylinder.
What could it possibly be left to investigate?
I bought the machine about 3 years ago and love it since day one strong like bull and dumb like one too ( nothing electric controlled). last summer, I had a sudden engine nock and loss of power and blew the dip stick clean out of the machine. I immediately shut her down and investigated. turns out I lost fuel pressure to #2 cylinder, dead cylinder. apon digging deeper I noticed the front half of the engine filling up with anti- freeze, I suspect when #2 went dead the compression had to go somewhere and it blew the dipstick out of the machine and across the yard about 15 feet and destroying the head gasket seal. Ok so simple fix I thought.
All new head set all new gaskets everywhere tore it all down and solved that problem, re-lashed the valve train put in a new push rod and lifter because someone's jimmy rig fix from years ago in my opinion was Ludacris, did regular maintance rebuilt all the hydraulic cylinders up front with brand new rods and seals what not and then it was off to the fuel system to fix the misfire.
Now this is where my Delma is I am at a loss I have replaced the injector nozzle and body, the line has no kinks or obstructions, I put a brand new piston pump on #2 high pressure pumps spot, the yoke was in spec so didn't change it, took apart the whole fuel system no contamination in the passage ports in the filter assembly transfer pump primary filter and both secondary filters are brand new, drained the entire fuel tank cleaned it no rust or dirt. played flip flop between a known firing cylinders injectors pump and injectors the problem always stays ay #2.
So with all that I figured it has to be the cam shaft or lifter. so I follow the book bring #2 up to compression at TC bought a brand new micrometer for measuring depth, set the lifter up to spec of 1.733 " from deck to yoke that dose not solve the problem do the same test to #1 cylinder the values are equal. so then I measure the lift at full rise thinking the cam lobe is worn down, nope it is exactly the same amount to lift as #1 so then I do the measurement to see if at TC the lift is right for that duration on the lobe matches exactly to known working cylinder #1.
When the engine is running it defiantly has a loud fuel nock and if you crack the injector lines will its running #1,3,4 all affect the engine idle negatively obviously bc its a no fuel scenario but when you crack #2 it dose not react like its running on only 3 cylinders of power currently.
When you take the fuel lines off the Piston pump caps you can watch a steady fuel stream like a guizzer shooting up about 6 inches on #1,3,4 but #2 barely will squirt 3" and at the injector tip it will only dribble fuel barely no atomization.
so now i am grasping at straws I get an idea maybe the lifter spring is broken and it works fine at slow speeds with the micrometer but as the RPM increases at engine running I get a "Valve Float" scenario like racecars at High RPM. causing my problems, so tonight I took the cam and lifters out of #2 and #1 no ware no scrapes nothing then springs feel identical resistance rollers are smooth the parts look brand new.
So to sum it all up everything on that cylinders fuel system is either replaced or in spec the cam is fine the lifter looks good it has the right amount of lift and duration, the piston pump is brand new and if you swap in old one it dose not change the line is clear the injector tip and body is new. and I still have a dead cylinder.
What could it possibly be left to investigate?