Hey guys, I'm tinkerin on my old 68 crackerbox GMC, 3 injectors are stuck. I got them out and soaked em in 50/50 acetone and tranny fluid to no avail. any ideas besides new ones?
That's sweet ibc! What motor does the jimmy have in it? I thought I knew everywhere around here, but I must admit, don't know where Waxhaw is.
671 inline detroit Waxhaws' 30 miles south of Charlotte 9 miles Nrth of Lancaster SC
Most of the time when those injectors get stuck it is because water has run through them and sprung the rack. In my experience it also blows the tips off the injectors. You will need to take them to someone who can take them apart. I suspect they are ruined though.
Cool, wasn't thinking of the Charlotte area. In my opinion, the 6-71 is the best sounding Detroit made. Pulling a grade with one pegged on the governor...she's singing!
Very carefully disassemble them and place in clean diesel fuel do not touch lapped parts with your bare hands keep wet with fuel be sure to check the rack and the gear that rotates the plunger inside the barrel you should be able to remove the spring and clean the rust off. The stack can be lapped using a lapping block talcum power check the "O" ring and see its free.
As stated, you need to get some rebuilt injectors. I have seen them on eBay at a good price, not sure what quality you are getting. If you hadnt already took them out, I would suggest a trick that works sometimes, on engines that have set up a while, what the heck here goes. If you have injectors that are sticking or stuck (hopefully the engine didnt run away) the engine is running, take a drift pin, like a 3/8" x 8" extension and tap the injector plunger (the thing that goes up and down) keep tapping lightly most of the time, it will free itself. Word of caution, working on these babies " Have a pair of vise grips on the rack/tube" you can control the engine speed/rpms. Every Detroit mechanic working on 71 & 53 series will use the vise grips, it only takes one run away to remind you of this (and a clean pair of underwear) Good Luck, these are tough engine and will run forever, noisy and a bit smokey but they pull great Keep us posted I live in New Bern and Coastal Diesel, has good prices on Detroit aftermarket parts and they have rebuilt injectors. I have a friend of mine that has a good 6-71 that is still in a truck, if you know anyone that needs one of these jewels. I think he want $900 for it
update My dad got the injectors freed up today while I was at work, he's retired. I didn't know that about not touching them with your bare fingers. They look good, no rust and seem like there gonna work. I'm gonna stick em back in this week end. I'll post the results......maybe a video. Ed
I was talking about internal parts these are easy to rebuild
yeah, like these internal parts? I agree,they are easy. Getting the bushing out was the hardest part. My best e bay purchase has to be a Detroit service manual I bought 5 years ago. I have several detroits for future projects... (1) 4-53 (1) 6-71 (2) 3-53 I would love to find a 1-53 or 1-71 These motors are great!
ibc, good luck finding a 1-53 or 1-71 as they weren't made How are the plunger & barrel? JMO, I would put rebuilt injectors in rather than trying to clean them, unless you have the test equipment to make sure the spray pattern is correct and it won't dribble fuel.
Could a swore I saw one at the hcea show 08 in Pa (stationary)
http://www.youtube.com/watch?v=28jAdxeSyVM Here ya go, a 1-71 Tried to upload it but I guess I couldn't so just copy and paste or just search single cyl detroit.
The 1-71 has to be really rare,I've seen & worked on quite a few 2-71s on gen sets & welders, but never even heard of a 1-71. They aren't mentioned in service or parts manuals. I learned something new. I'll bet they are had to get parts for; such as gaskets,cam & crankshaft
Well according to the youtube posters' there where under 1000 made.
1-71 They did make a Detroit 1-71, I worked on one when I went to mechanic military school and 2 since then, of course that was 38 years ago. I have seen and had a 2-71. I have never heard of a 1-53 or even a 2-53, but Im thinking they did make a 2-53 These small engines were used for pump and generator appliciations, the exact, moving parts fits a 1-71 through a 6-71 as long as the blocks are the same. Good Luck
I knew a guy back in the late 70's that put a 2-53 in a pickup so they do exist. jr
youtube Search any one of those engines on you tube and you will be there for hours watching engines run. I know I am. Another good search is....."shifting an old mack"
2-53 were made & used in generators, welders, pumps & other applications. Cylinder kits, rods, bearings valve train, injectors & other small parts were common between all the inline engines in each series[53,71]. There have been quite a few 3-53s & 4-53s put in pickups over the years. The 3-53 is a little shy on power. The weight & noise is a factor also. ibc, did you get the truck running yet? How is the rest of the fuel system? My concern would be that with 3 stuck injectors that the others may go next when you fire it up. Good luck
No, I haven't. This truck was on it's way to the scrap yard when a buddy of mine called and asked if I wanted it , of course I did. it spent most of it's life hauling mission supplies out west, up north and in Alaska. It's sort of a hobby project (as I have many) that I am determined to put very little money in (I am in the residential concrete buisness, not too good right now) so thats why I'm cleaning them and puttin back in as is. I have had the truck running but it ran wide open of course and on only 3 cylinders, you should have seen us tryin to shut it down, I ended up disconnecting the fuel line. I'll put new filters in it and use a clean bucket of fuel before I start it again and have my vice grips on the rack rod. Did I mention that the truck sat for about 15 years, they used to start it every year up untill the last five. Here's a picture of us bringin it home. The other pictures are of airline generator I picked up last year with a great running 4-53. I plan to use that engine in a 1943 BE pull shovel.
I would love to see that old jimmy freshened up, I remember those trucks well. Back in the 70's, there was a bread company here in town that had that same truck and F model Macks in their fleet. And their jimmy's all had 6-71's.
ibc, when you install the fuel lines to the injectors put a drop of oil on the flared end between the flare & the nut, it helps to keep from cracking or twisting the line. Torque the injector hold down to 30 ft.lbs.& the fuel ines to12 ft.lbs. The 4-53 looks like it has a woodward hydraulic governor. The woodward is alot more responsive than a regular mechanical variable speed governor. you'll have to make some adjustments to it when you get it in the BE. I don't know what high Rpm on that gen set is as it probably a 400 Hertz gen set. If I can help, just let me know. Mike
It's a 400Hz Military generator set probably a USN unit used on Aircraft carriers, could be a Hobart
Thanks for the tips Mike. Yeah it's 400Hz used by Eastern airlines at the Charlotte airport in the late 80's. Theres a switch on it that changes from drive to gen and when you switch to gen you better have your earplugs in.
Running Well I took a little time today and put my injectors back in. I cleaned them with acetone, lapped all the sealing surfaces, installed a new seal, filters and gaskets. Put em back in and started it up.:drinkuphttp://www.youtube.com/watch?v=b6ZVNWIErOY
Good to here you got it running, I know of some old 6-71 parts and a rebuilt head. I also know of a few compound drives if you are into detroit stuff
Go to Boats & Harbors yellow sheet listings and you can get a complete engine for about $1000 or less only because they never really changed since WW2.I ran equipment with them , trucks and big boats .The only difference between a marine use and a road use is the heat exchanger on the front of the engine.Back in the day I would go to the truck shop for parts because it was cheaper now its the other way around its cheaper at the marine yellow sheets. http://www.boats-and-harbors.com/classifieds.cfm
http://www.boats-and-harbors.com/onlinePub.html This link is better