Detroit diesel 4-71 start up

docmirror · Sep 28, 2022

I've been given a early 60s grader with a 4-71 2 stroke Detroit engine. It spins ok with a bar on the U joint, and go all the way around. It's complete but hasn't run in 9 years.

I haven't brought back a DD before. I have a few specific questions.

1. Is it 12V starter or 24V? What cold crank amps does it take?
2. How much oil in the crankcase? We need new oil of course.
3. Will ether damage it to get started?

Any other things I need to sort out before cranking it? I will put in fresh fuel and filters.

Rexkramer · Sep 28, 2022

Need to pull the valve cover and make sure the rack is
free, if not itll rev to the moon till parts exit the sides!

Janicholson · Sep 28, 2022

Be sure to have (either) a functioning intake damper or free access to a easy to apply 1/2 inch thick plywood intake stopper a runaway engine is never a good
deal. They start easily ether is not recommended by me. Jim

docmirror · Sep 28, 2022

Yeah, will have a block off board handy.

I'll have to do some research on the 'rack'. I guess that's part of the inj system.

K Effective · Sep 28, 2022

go to Bus Grease Monkey on Youtube and watch a couple of the early bus revival videos. He's really clear on how to start a DD after years, and how to free the injection rack and even pull and test injectors. Most of the busses are inline 6 cylinders, but the 71 series are all alike.

rustred · Sep 28, 2022

we had them on the oil rigs years ago. they are 12 volt , it had the big cat battery on it. all the years i been around them things i hardly
seeen them start with out starting fluid. it no ether anyhow! fill the oil to the full mark and you will have your answer. as you will be
adding oil anyhow later. i hate them noisy things. but they take a lot of abuse. must be a small grader to only have the 4-71. lots had 6-
71's

wore out · Sep 28, 2022

(quoted from post at 20:41:03 09/28/22) we had them on the oil rigs years ago. they are 12 volt , it had the big cat battery on it. all the years i been around them things i hardly
seeen them start with out starting fluid. it no ether anyhow! fill the oil to the full mark and you will have your answer. as you will be
adding oil anyhow later. i hate them noisy things. but they take a lot of abuse. must be a small grader to only have the 4-71. lots had 6-
71's

They could have and battery voltage the OEM ordered.

You have to look at the tag on the starter or generator to be sure.

A friend has an old 3-71 on a genset and it's 24 Volt.

docmirror · Sep 28, 2022

(quoted from post at 20:41:03 09/28/22) we had them on the oil rigs years ago. they are 12 volt , it had the big cat battery on it. all the years i been around them things i hardly
seeen them start with out starting fluid. it no ether anyhow! fill the oil to the full mark and you will have your answer. as you will be
adding oil anyhow later. i hate them noisy things. but they take a lot of abuse. must be a small grader to only have the 4-71. lots had 6-
71's

model 99L, 24,000Lbs, 4 wheel drive and steer. Will be big enough for my jobs.

Traditional Farmer · Sep 29, 2022

Put in a battery and try it.I bought an AC HD14 dozer with a 6-71 years ago that had sat for over 5 years,put in a battery and it fired right up.

MarkB_MI · Sep 29, 2022

It may have been re-powered with the Detroit. I'm not sure about your grader, but the older Austin-Westerns had International engines. Probably 12 volts. As I recall, our 99H used a pair of six volt batteries behind the seat.

It will take several gallons of oil. It's been a long time since I did an oil change on a 4-71, but they take a lot.

I would be surprised if it starts WITHOUT ether. It was common for Detroits to have a port on the blower intake so you could squirt starting fluid directly into the intake.

Your biggest concern on startup will be a runaway. There should be flapper valve on the intake that will allow you to kill the motor if it takes off. The topic of preparing a Detroit for starting after it has sat has come up in the past and folks here recommend first taking off the valve cover and making sure the injectors aren't stuck before cranking.

I dunno if you can get parts for that old grader. Clark bought A-W, but they've been out of the grader business for years.

Rexkramer · Sep 29, 2022

The rack controls the amount of fuel the engine gets, it
defaults to wide open when the engine gets shut off. Now
if its stuck you cant force the rack because it will break.

If the rack is stuck then you will need to flush out each
injector and carefully work the plunger up and down on
top of the injector. Once the plunger is free the fuel rod
on the injector will move freely.

Dont over torque the fuel lines either, they can crack!
Detroit fuel systems are simple, this is all pretty easy to
do. As it was mentioned, Bus grease monkey on YouTube
has videos on this and will probably make more sense
seeing it than reading it

Billy Shafer · Sep 29, 2022

1 should say on the starter.

2 should say on the dipstick

3 DO NOT USE ETHER. Unless you know how. I have seen more than one.
Destroyed by that stuff.

Fritz Maurer · Sep 29, 2022

Sure, a board will work for a runaway, but the best
bet is a functional emergency shut-down, complete
with cable to the operator station; a runaway can
occur at any time during operation, not exclusively
from long periods of inactivity. A runaway is a scary
thing if you never witnessed one... you dont want to
be running around tripping over shitte in a panic
trying to clap that board on there... when you can
be in complete control of the situation with just two
fingers

BarnyardEngineering · Sep 29, 2022

(quoted from post at 04:37:29 09/29/22) 3 DO NOT USE ETHER. Unless you know how. I have seen more than one.
Destroyed by that stuff.

You mean buy a case and dump can after can into the intake until it pops off?

Those old beasts will take a LOT of abuse.

westga · Sep 29, 2022

Should be 3 gallons of oil. Delo 100 40w.
And just to make sure you know don't try
to stop a run away by putting a rag over
the intake. It will eat the rag. It may
have a knob on the governor that you can
pull to stop the engine. I would pull the
valve cover off and the air breather
before I tried to crank. With the valve
cover off it gives you another way to
control the run away by having a pair of
channel lock pliers ready to pull the
lever from the governor back to stop.

Centerplate · Sep 29, 2022

Have a good 4-71 here for sale. It is in a grader made by Clark/ Austin Western.

Southern Wis.

4wdtom · Sep 29, 2022

I have seen a wad of newspaper lit on fire and held at the air intake aid is starting.

johnlobb · Sep 29, 2022

Another vote to watch the Bus Grease Monkey. He explains how to start up long dormant 71 series Detroit Diesels in some of his earlier videos. He always has a set of vice grips on the rack, and works it back and forth to make sure it's free, and has a way to stop or block the air intake if it starts running away.

docmirror · Sep 29, 2022

Thanks for the info. I will sort out the emergency shut down before we put into service. For now, I'll have a block of wood ready.

Isn't there a fuel petcock can be shut off to the inj pump? I guess that would dry out the inj pump, and may not be good for it.

I watched some of the vids from Bus gas Monkey, and well, they aren't very detailed more than I already know. I did see him lube and stake one of the injector valves on top of the head, so if I have a stuck inj I will know how to clean, lube and unstick it.

Not sure, but I think the oil fill is 16qts or 4 gal. I'll get a 5 gal bucket of 40W Delo 100 and a new filter. Pretty sure I'll also be swapping out the hyd fluid and the trans juice as well. Gonna be several hundred just in fluids to get us going.

May work on it Mon or Tue and will take some pics along the way.

This post was edited by docmirror on 09/29/2022 at 11:25 am.

docmirror · Sep 29, 2022

I saw that vise grip on the rail bar to do the throttling. I think I'll have the valve cover off for the first start and check the rail and all the inj valves carefully. The throttle on a grader is a long way up from the actual engine, and it's governored of course.

MarkB_MI · Sep 29, 2022

> Isn't there a fuel petcock can be shut off to the inj pump? I guess that would dry out the inj pump, and may not be good for it.

It can take a long time to kill a runaway diesel by shutting off the fuel. And once it gets going, it's possible for the motor to run on oil that's blowing past the rings. The flapper on a GM diesel is there for good reason; make sure it works before you try to fire it up.

Keith True · Sep 29, 2022

When a hoover runs away the governor is no longer in play.When that rack is stuck,for whatever reason,the governor
no longer exists.That thing will wind up until it throws parts all over the yard.Make sure the emergency shutoff is
working easily,from the operators seat.And,don't use the emergency shutoff as a regular shutoff.It will suck the
seals out of the blower.

westga · Sep 29, 2022

I read one time that these engines held
about a gallon of oil per cyl. So a 471
would hold 4 gallons. Mine held 3 gallons.

You asked about a fuel shut off valve and
my 471 does have a valve that is closed
after shut down so that the fuel doesn't
drain back to the tank overnight. This
just prevents priming the fuel system
before every start up. You might want to
check for a valve before starting.

buickanddeere · Sep 29, 2022

A properly built 4-71 will make 175 HP without being over fueled .

Russ from MN · Sep 30, 2022

I would think a hair dryer or a heat gun would work better, you don't want the ash and CO2 getting sucked into the engine.

Fritz Maurer · Sep 30, 2022

Dont bother with the vise grips on the injector
control tube. It is not that robust for the job it has to
do. If an injector hangs up, the only way to stop the
engine is twist the tube, bend a lever or damage the
gears in the stuck injector... possibly all three.... and
still might not be able to move it far enough to stop
the engine. All this expensive damage that could
have been avoided if the emergency shut-down
worked.
To increase your chances of success, pre-lube the
injectors by removing all the cross-over lines and
shoot brake cleaner through the injector to remove
the gummy fuel and then pump fresh fuel through it
immediately to avoid flash rusting. It is important to
note the direction of flow ( as indicated by out
and in cast into the cylinder head) so as not to
flush the injector in the wrong direction; later or
rebuilt injectors had only one filter under the inlet
adapter. Therefore, flushing in the wrong direction
would put any dirt on the wrong side of the filter,
and would pass through the injector again when the
engine was started.

clevepreach · Oct 2, 2022

My brother ran a 6-71 (238 hp) in an old Emoryville for a few years. If the temp was below 60*F just make sure you have a couple of cans of ether to get it started. If it's not slobbering oil and fuel somewhere it's probably about ready to blow up. If you decide to run it just slam your fingers in the door or bang you knee against something real hard and get real good and mad at it and drive it like you stole it and it will work just fine. RPMs are your friend. The more, the better.

Detroit Diesel - the world's most efficient machine for turning fuel into noise.

docmirror · Oct 3, 2022

OK, I was down at the shop yesterday, and here's an update. So far, I haven't found any damper or shut off plate from the air cleaner, all the way to the blower. There is a flange, just above the blower intake where I expect a flapper, damper shut off to be, but it is not there. Maybe there was one before, but it's gone now.

I have a few other jobs to get to before trying to crank it, but I'll have a block of wood handy just in case when we get to that point.

Thanks for all the good suggestions. I'll clean and pre-charge the injectors before lighting it off. I have the detroit diesel operator manual, and the maint manual. They both warn against using Ether except when the injectors are fully primed and up to pressure. There is a discussion in the maint manual about a priming pump tool that hooks up to the fuel filter housing.

Detroit diesel 4-71 start up

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

New User

Well-known Member

Similar threads