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Detroit Diesel Guru's Needed

Bergz22

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Joined
Apr 4, 2019
Messages
86
Location
Illinois
I have two 6-71's that I'm trying to get running on a tug. One is 1063-5100 and the other only says 6A48 700. The engines got water in the fuel system, and siezed the HV6 injectors that were in there. We had N55's on hand, along with the hold downs, bolts ect. I also had the newer style control arms for the individual injectors, (not breakaway) No matter which way I try to install them the little ball end won't fit into the injector lever when I line up the 1/4" bolts for the bracket. Do I need to buy new tubes? Thanks for any help.
 

Vetech63

Senior Member
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Aug 10, 2016
Messages
6,543
Location
Oklahoma
We had them on hand and that's what my boss wanted, so they didn't have to buy any.
The marine engines are heavy builds due to them being at 100% load all the time. The injectors, timing, oil rings, pistons and compression rings are all special application. You would be best to buy the OEM injectors as they are matched to the other items for maximum performance.
 

kshansen

Senior Member
Joined
Mar 11, 2012
Messages
11,273
Location
Central New York, USA
Occupation
Retired Mechanic in Stone Quarry
Been long time since I worked on a Detroit but aren't HV6 injectors from a two valve head engine? I tried looking up for info in an after market catalogue but not 100% sure what fits what but looks like there are 3 or 4 different injector control tubes.
 

Bergz22

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Joined
Apr 4, 2019
Messages
86
Location
Illinois
These are two valve heads. Im just trying to get it going. My company hates spending money.
 

1693TA

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Feb 27, 2010
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2,687
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Farmington IL
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FAA Radar Engineer, (Retired)
I'd take those unit injectors apart on a bench. Really not very complicated internally at all but index marks must be aligned. You may be able to free them up by clamping the body in a bench vise and gingerly apply upward pressure to the follower with a pry and dinging hammer. Most times the are free once busted loose from being compressed.
 
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kshansen

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Mar 11, 2012
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11,273
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Central New York, USA
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Retired Mechanic in Stone Quarry
All these suggestions are good.

One more thing if I remember right, it's been many years, is that the N injectors have fuel port that are staggered where the HV injectors are inline if you understand my terms. This would suggest that besides the problem of the arms not being lined up you would also be needing to replace half or maybe all the fuel lines under the VC!

And just remember that those two valve engines were ancient history in the 1970's. The fuel lines have probably be on and off many times and they will be prone to cracks in the flared ends.

So even if you do get the engines running from the water in fuel you will need to keep an eye out for fuel in oil!

Did find this:

Only $130.40 with no core charge. Have no idea if they are any good but sounds like this company might not care, just get it running.

I'm a little worried about where this "tug" is operating hope it's not near a bridge I might be driving across or a ship I might be riding on as it sounds like it could be a shady operation.
 

56wrench

Senior Member
Joined
Dec 4, 2016
Messages
2,214
Location
alberta
Those old detroits are finical enough without trying to mix and match parts that weren’t intended
 

8V71

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Joined
Aug 16, 2019
Messages
186
Location
Fresno CA
Being they didn’t want to spend the money, hopefully he took those old ones apart, and freed them up.
I learned the hard way before. Installed wrong injectors and wrong cam timing. It ran really strong until the pistons started melting
 

kshansen

Senior Member
Joined
Mar 11, 2012
Messages
11,273
Location
Central New York, USA
Occupation
Retired Mechanic in Stone Quarry
Being they didn’t want to spend the money, hopefully he took those old ones apart, and freed them up.
I learned the hard way before. Installed wrong injectors and wrong cam timing. It ran really strong until the pistons started melting
Some here might say that was a good thing!

I know I would have liked having the little 4-53 Kato genset that was one of the last Detroits I worked on before I retired sitting in my shed when power went out for 36 hours a couple weeks back. I would have loved it even more if the exhaust was pointing at my "problem" neighbors house!

The only problem is even running every electrical thing in my house at the same time might not have been enough load for that engine! I mean the little 19 HP Generac genset I do have carried most of the load without a problem, a 4-53 would be what about four times that? I know what a Detroit will do if not loaded enough!
 
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