Hello Everyone, I have a old military Pettibone lift that has Detroit 3-71 power. This machine has sat and I have just got it fired up. It started w/o hesitation! The problem I am having is that the rack that operates the fuel shut off appears to be stuck. The square box that is to the right hand side of the blower has a linkage connected to the rack that is stuck. From the rack a lever connects to another rack that starves fuel to each injector. At present I have to block off the intake to kill the engine. I talked to a diesel mechanic that has limited experience with Detroits and he advised me to post a couple of questions before digging into the cut-off part of the engine. If I un-bolt the rack I can determine which of the injector fuel racks in stuck. I'd appreciate any guidance as to how to proceed. Thanks, Tom
Yes you can remove the rack and check injector for stroke, do not back off of the screws on the rack that adjusts the injectors fuel racks (a lot of racks) You should be able to tell which injector is stuck.
I agree with stinkycat, do not tamper with the slotted screws at each injector control lever, not yet anyway. Remove the pin that connects the control rod from governor to the rack assembly. Remove the two machine screws on each end that mount the rack pivot brackets to top of head, lift entire rack assembly free from head. Now you can check the operation of the injector sliders.
You can tell without pulling anything off, just wiggle the injector racks with a screwdriver. Use a little wd40 free up the stuck ones. jr
Yes, you can do it that way, I just like to be able to move each injector slider fully while feeling for any sticky spots myself.
Just don't like to remove the rack tube myself, tends to throw everything off and have to start over again. Getting lazy I guess. jr
Well, throw everything off, maybe, just a bit, but as long as you don't loosen the slotted adjusting screws, it's not far off, only requires a little tweaking on adjusting screws to get things back in order.
Tom, Before you fool with injector linkage try pulling short lever on top of governor housing. Good luck Bob
Gentlemen, As you all know this forum is full of lots of very helpful people. All you which you are! I sprayed PB blaster on all three injector racks and with a vice grip gently rocked the rod/pipe back&forth. It took a little work but that was the fix. It is amazing how frozen it was! Letting this piece of rarely used equipment sit taught me a lesson..... start her every 6 months are so Thanks again guys! Maybe I can return the favor down the road! Best regards, Tom
Glad you got it sorted out TFPace. :drinkup BTW, what motor oil are you using in that Detroit. Those engines are very picky about the oil. Never use multi-grade, such as 15W/40, only use SAE 40. And the oil that meets the engine requirements the best is Delo 100 SAE 40. Delo 400 does not meet the specs, and Rotella SAE 40 is borderline within the specs.
Oil Honestly.... I haven't added any since I bought it I have owned this machines nearly 10 years and maybe have put 10 hours max on it. I would have grabbed the 15W/40 if it called for it. Thanks for the suggestion on Delo 100. O'Reilly's has it on sale. Thanks again, Tom
Hmmm...71 series, still one of the best ol motors ever built.... even an idiot like me can work on them....
The Detroit 2 cycle is a blast to run. I can't imagine not using ear protection with this engine. Growing up in North-Carolina, Franklin and Timberjack had a large market share in the log skidder industry. Both brands used Detroit power and you could always tell there was a Detroit in the woods by the un-mistakable growl of that engine. Sadly, those days are gone. When did Detroit stop building the 2-stroke diesel for land applications? On another topic... which forum would be best suited to ask a question or three about the Pettibone lift-truck this Detroit is powering? Thanks, Tom
Forklifts/Telehandlers? Maybe?
So how do you adjust if the rack is off.
How do you know the rack is out of adjustment? Adjusting the fuel rack is something you DO NOT want to do with out training it could cause an engine over speed and serious damage will result to the engine and or persons. There a Detroit Diesel mechanic or old EX US Navy engineman around with all the oil patch mechanics in the area someone should be able to show you how to run the rack. PS using the blower air shut off is not good.
Im glad you got the injectors freed up. Honestly I dont think PB Blaster did the trick, I think the vise grips on the rack broke the stuck injector loose. I would hope you worked the rack back and forth, to see if you feel any binding. Another trick, is to take a hammer and big punch and hit directly on top of the spring plunger, for the injector (about the size of a quarter) one time and try it I have run many 71 & 53 engines in the lat 40 years and they are tough engines, but very noisy I bought a Drott 40 a while back, with a 4-71. It hadnt been started in 8 years, I put a new set of batteries, a squirt of starting fluid and it turned over twice and started right up Good Luck, wear ear protectors
How far should the rack rotate? I feel mine is stuck closed
It is a fairly straight forward and complicated event to set a rack and governor on a Drip Troit, I did it for over twenty years and still grab a service manual to do it. Do yourself a favor if you intend to keep it running, buy a service manual.
As far as oil I have had several 453 in my skidders and definetly run sae 40 its needed to build the proper oil pressure I also put in some marvel mystery oil. I was told this by a retired detroit mechanic
Don't fiddle with any adjustments if you don't have a timing tool. You can remove the units (one at a time) and just hold it in your hand, push the rack in and out, sqirt some WD 40 in and jiggle. Sticking problems are generally caused by water in the fuel. I was called to a machine that had sat over a weekend and one unit was jammed as tight as. It had to be replaced.
You haven't lived until you've had a 6-71 injector rack stick near full fuel, which means they ALL are near full fuel, and since the governor can't cut her back, the revs just keep climbing...... Judicious use of high gear and the clutch prior to yanking the emergency stop got it done, but not before I lost a year off my life... Of course I've heard stories of 8V-71's running away first firing after install in a truck and the mechanics beating a hasty retreat, that must have been something to hear, before the rod bolts let go....
This past winter on a quite normal 10 degree F day I was starting my 4-71 in my old log processor. It did not start right up with the normal shot of ether as it normally does down to about -0. I gave it some more and nothing. After messing around for 15 minutes and hooking up jumper cables as the batteries were going down, I grabbed a different can of starting fluid. That 4-71 fired instantly and ran screamming wild. I have never heard a Detroit scream like it was. I was standing up on the engine platform and had nothing to choke it down with. Could not reach the emergency shutoff. It ran crazy for probably 20 to 30 seconds before slowing down. Seemed longer. When looking at the original can of starting fluid it was some crap diluted down for "safe with all fuel injected vehicles". It layed in the intake and did not burn until the engine started on the good stuff. How that engine held togather is beyond me. I was expecting a connecting rod to fly thru me. Word to the wise is to insure you got real starting fluid and not some crap that burns only after the engine is running.