Question About Starting A DD

[Sparky1]

Just happened to remember something I read in the owner's manual for that 55C I was on last week. It said to hold down the stop button while cranking the engine as to allow it to turn over several times before it starts. This was to clear the engine of fuel and water as I recall.

I've never done that with mine nor have I seen anyone else do it with their's. Am I missing something here?

 

[eze2bme]

I have always used that method for starting my 6-71N's ... summer and winter ... less smoke on start up and less "oil sheen" on water.

 

[Brian Degulis]

I've always done that it just makes sense to turn it a few times with the starter before allowing it to fire. If water has entered a cylinder from a cracked head or something else you have less chance of bending a rod.


Brian

 

[jlightonjr]

Yep this is the exact method (hold down the stop) we used in starting our 671 TI's oh and the sound they made... Heaven!!

 

[SKYCHENEY]

Shouldn't this be in the tech section, or aren't you allowed to post over there?

I'm just playin' whichya, Randy. Now that you need some technical advice, it's fun to take over your role as the jester.

 

[Bob Bradley]

I've always done the same thing, but my understanding is that it pre-heats the engine to make it start easier.

 

[GJH]

I use this technique too. I was told by my mechanic that it is not necessary if the block heaters have been on or the engine has been running (such as starting back up after a fueling); I still do it some if the heaters have been on.

 

[Sparky1]

I've always done that it just makes sense to turn it a few times with the starter before allowing it to fire. If water has entered a cylinder from a cracked head or something else you have less chance of bending a rod.


Brian

That's a good point, one I hadn't thought of. I'll use this technique from now on, but until I read that info in the owner's manual, I'd never heard of it. So how many revolutions should be turned before releasing the stop button?

Shouldn't this be in the tech section, or aren't you allowed to post over there?

I'm just playin' whichya, Randy. Now that you need some technical advice, it's fun to take over your role as the jester.

Sorry Sky, but per the instructions on this forum, the tech section is for Hatteras-specific dicussion. Detroit's are not Hatteras-specific, so I followed directions... as always.

As for you taking on the role of jester, until SeaEric labels you as such, you're just a wannabe.

 

[eze2bme]

Good point about rollover time. I roll mine over for five seconds (one thousand one, one thousand two, one thousand three, one thousand four, one thousand five) and then release the STOP button. Anyone else???

 

[Sparky1]

Sounds like a 5 second roll-over may be a bit hard on the batteries and starter, but I'm just thinking out loud here. One thing I did notice when I was running that 70 a while back was the Captain would always use the parallel switch when starting the engines. He claimed that would cause less wear on the batteries, but he didn't use the stop button starting technique.

You'd think DD would have incorporated a compression release into their engines for such things if this technique is one they recommend.

 

[StratPlan61]

I always use this method to start my DDs. I hold down the STOP button for 3 seconds max, this usually provides 2-5 revolutions depending on temps. No matter the block heaters have been on, always use the same procedure.

 

[Genesis]

Holding the STOP button won't hurt anything and might help.

If there's water in a cylinder it won't matter (much); MIGHT prevent a bent rod but I wouldn't take that bet.

If its COLD out then the parallel relay will help a lot, as Detroits are all rotational speed to get the heat necessary to light. The less voltage drop the better in that regard, and paralleling the batteries helps materially.

As a general rule I used the STOP button on the first start of the day, but generally not after that.

 

[Bob Bradley]

The parallel is a big help, but you need three hands to use it, hold the stop button, and press the start button simultaneously. I use my knee on the parallel switch.

 

[Sparky1]

My engine(s) never turned more than a second before they fired, and I've never used the parallel switch. I'm assuming naturals are more difficult to spin than turbo versions given their higher compression, but maybe not.

I'd play hell trying to hold the parallel switch along with the start and stop buttons, so I think I'll still skip that part. I'm not as limber as I used to be.

 

[MikeP]

I start from the eng room for the first start of the day and hold the governor solenoid rod in the "off" position for a count of "one thousand one" before releasing it. Engines start instatly, regardless of temp though they will hunt a bit if it's cold.

This procedure is in the DD start procedures and several guys who have been DD guys for 50+ years say this procedure was taught to them in the military.

As has been stated - can't hurt.

 

[Genesis]

Yep. My first start was always from the engine room as well.

I want to HEAR them roll over. The gimmick with holding the STOP lever is that once the engine is rolling at its cranking speed you let go - the purpose of pulling it is to allow the starter and rotational mass of the engine come to cranking speed BEFORE the rack slams to full-fuel and starts spraying diesel in there.

There is little value to holding the STOP beyond the point where normal cranking speed is achieved.

 

[spartonboat1]

Yep. My first start was always from the engine room as well.

I want to HEAR them roll over. The gimmick with holding the STOP lever is that once the engine is rolling at its cranking speed you let go - the purpose of pulling it is to allow the starter and rotational mass of the engine come to cranking speed BEFORE the rack slams to full-fuel and starts spraying diesel in there.

There is little value to holding the STOP beyond the point where normal cranking speed is achieved.

The above is a good explanation. But I always thought the pre-roll w/STOP was for oil pressure, after sitting. I do the STOP start, for 5-6 secs a couple times, until the oil pressure comes up, then release STOP and start. Also, it pre-heats the cyls, to help the first light-off.

 

[Brian Degulis]

That's a good point, one I hadn't thought of. I'll use this technique from now on, but until I read that info in the owner's manual, I'd never heard of it. So how many revolutions should be turned before releasing the stop button?


Sorry Sky, but per the instructions on this forum, the tech section is for Hatteras-specific dicussion. Detroit's are not Hatteras-specific, so I followed directions... as always.

As for you taking on the role of jester, until SeaEric labels you as such, you're just a wannabe.

Just a few I hold the stop probably just 2 to 5 seconds that's many revolutions at normall cranking speed. You can just release the stop and let it start. I roll the first one over and don't start it because I want to be able to hear the second one roll over. Then I release the stop let the second one start and go back and start the first.

Brian

 

[Genesis]

The above is a good explanation. But I always thought the pre-roll w/STOP was for oil pressure, after sitting. I do the STOP start, for 5-6 secs a couple times, until the oil pressure comes up, then release STOP and start. Also, it pre-heats the cyls, to help the first light-off.

Rolling it long enough to get oil pressure to the sender is going to take a while (the point where you'll see pressure.) The only time I do something like that is after I change a turbo (where it IS important to avoid a dry bearing start that can destroy the turbocharger.)

 

[34994]

I don't have a stop button. My dd must be old school.