Cranking cold 671 Detriot

[loadera10]

My fellow Hexperts. With an outside temp of 40 degrees, what is the best way to start my 671 Detroit? At 50 degrees it takes about 3-4 good trys to get her started. Starts fine on warmer days. I do have a engine heater....

[gus]

I don't have a block heater, if I did the following would probably not be necessary.

If my 671 doesn't start on the first crank when the weather cools I know it is time for the ether.

Ether was meant to be used in this engine and there is a nice little cup on top of the air box to insert ether capsules. Since these are no longer available I just squirt a small amount into the cup and she fires right up no matter what the temp. If it doesn't fire right up you haven't used enough so do it again.

There may be a small amount of smoke at first but only if you didn't use enough ether. Experiment to find the correct amount. You can tell by the size of the cup that it doesn't take much.

The big difference in the DD 2-stroke and others is that ether is supposed to go directly into the air box, not the air intake. Also the ether is squirted in, then I walk around to the front and push the starter. It doesn't work as well if the engine is cranked too soon after inserting the ether.

There is no need to spray ether into the air intake while cranking as is done with 4-stroke diesels.

[Beatenbo]

I have used the old starting fluid can for 35 years and never a problem Some are pro some con. An old GM rep told me years ago to start from rear. Hold throttle stop close and turn a few rounds without dumping cold fuel in would allow cylinder to warm then release and fire up. I'm on my 10th Detroit. My two pence.

[zubzub]

Mine just has a screw in plug on the blower.   I spray 5 secounds in there, put the plug back, go up front, bus started at 30 deg., no problem.

[loadera10]

Hey, thanks for the info. Mine doesn't have the cup either. Just put a new engine in and don't want to hurt it.

[Dallas]

Depending on the condition of your engine, all that has been said before is correct.

My engine has unknown mileage, but I just rebuilt the head, so I know that much is in good shape.

My method of starting in cold weather down to about +20°F is to use the heat soak method. I crank it 3-5 turns, let it sit for a slow count of 10 then turn it over for 3 to 5 turns. Repeat up to 10 times, but it should start well before that point.

If it doesn't start for me before the 10th try, (it has always started by the 4th try), or the temp is too low, I squirt a good shot of ether into the airbox.

I've always been able to fire this engine without preheating down to about +5°F using these methods.

Good Luck,
IHTH

Dallas

[loadera10]

She has 1000 miles since installation. Just spent almost $16000.00 on new engine

[gus]

The cup is there to hold an ether capsule. It is really handy because it has a spring loaded cover, just lift and spray. The real advantage to the capsules was probably that the ether amount was completely controlled but experience shows the correct amount to use.

If your cup is missing I would recommend one of those brass ball drain valves that is fully open with 1/4 turn and is straight into the air box. That might even be better than the cup because it sure won't ever leak air from the air box but the cup lid spring might weaken.

[makemineatwostroke]

loadera, i would plug my heater in and do Dallas's method being your engine doesn't have enough time on it for the rings to even seat, it will start better with time

[prevost82]

I use the same method as Dallas, usually works by the third crack at any temp. I'm not FOND of hitting it with starting fluid.

Ron

[tekebird]

A 5 second shot of ether is was too much.

a non starting 6-71 that is heated up with a block heater is a good sign of internal wear.  Loss of compression or bad fuel.

ether is terribly bad for engines..and generally it will not cause an immediate failure but does stress stuff significantly.

only time I use it is if I have no 120v available for block heat

[TomC]

For those of you that don't want to use ether, try this method from the rear at the engine.  First turn on the power switch, then with your hand hold close the on/off lever at the governor.  While still holding the on/off lever closed, start cranking the engine.  Count to 5 then with the engine still cranking slowly open the on/off lever and the engine should start (should take maybe 10-15 seconds total cranking time).  This works in that when you turn off the injectors, you are also changing the timing.  The timing is retarded towards turn off which facilitates cold starts better.  It has worked for me many times.  Good Luck, TomC

[DavidInWilmNC]

Is a 671 more difficult to start than an 8V-71, or is it due to the low miles since rebuild?  Mine's definitely broken in (around 30,000 miles or so), but it'll start with the second push of the starter button.  It'll often start, down to the lower 30's, with one 5-7 second push of the starter button.  Of course, it sounds like crap for the first few seconds and smokes like hell 'til all 8 cylinders are firing (a matter of seconds), but then it settles down to that familiar sound that I've grown to love hearing!

David

[makemineatwostroke]

David, it takes 15 or 20 thousand miles to break in a new 71 series rebuild or less if you work it every day.No way would I use starting fluid on a new engine if anything happens while its under warranty the owner and the starting fluid are going to get the blame.FWIW

[zimtok]

If you put 16K into a new engine then a few bucks more to get a block heater would be the best way to go.

My block heater is connected to my generator/shore power, so I am never without power to heat the block up. On cold days all I need is about 1-2 hours of the block heater being on and it will start right up. I only use ether if I can't wait for the block to heat up, and then just a little in the cup and it starts right up.

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