Timing thread

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Timing thread

Postby spencerdiesel » Thu Dec 03, 2015 7:10 am

I know it's been beat on before, but Im finding info all over the place that varies on pump rotation.

Is 1mm = to 1 degree as far as moving the pump? Some other forum was saying a tooth was 5 degrees, but I swear I know it's 10 degrees.

At what point does cruising mpg drop because of too much advance? From the boom occurring well before it's time and spiking cyl pressure etc
Sorry if there's a thread (or several) on this already.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby RCCUMMINS89 » Thu Dec 03, 2015 7:19 pm

1 tooth is 10 degrees. Roughly 1/8" of pump rotation equates to about 2-3 degrees of advance. 1mm of dial indicator being 10 degrees (1.25mm is about 12.5) is kind of close, but not exact.......as the 1.25 and 12.5 and 1.4 and 14 is kind of close, but I am pretty sure that going above that it starts getting off.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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Re: Timing thread

Postby spencerdiesel » Fri Dec 04, 2015 8:41 am

Thank ya. Think I saw a thread one time that mentioned some point after about 1.4mm, the correlation changed. Didn't know how much the 1/8 bump was. I guess to get 17 deg. static, one would only advance 1/8 for non IC pump, and maybe 3/16 for IC pump?

The spacer allows full travel of the piston right?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby spencerdiesel » Sat Jan 02, 2016 6:24 pm

Haven't measured total pump travel to the head or anything, but how many deg. advanced is it when pump is to the head?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby RCCUMMINS89 » Sat Jan 02, 2016 6:57 pm

All trucks are a little different. As in not all pumps are rotated the same from the factory.
89 RC on shortened 92 diesel frame - NV4500 w/dual disc/4.10s on 37s. - Self built pump, "hot screw", lots of timing, True high volume low pressure lift pump, 62fmw/68/.7gated, 77lpm SAC Inj., Studs/O-rings,- 423/1220 Mustang - 11/16/2013 http://www.TheHungryDiesel.com full line dealer, if you don't see it please ask.
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Re: Timing thread

Postby spencerdiesel » Sat Jan 02, 2016 7:53 pm

:shock: :shock: I did not know this.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby spencerdiesel » Thu Jan 07, 2016 7:36 pm

Besides low end grunt loss, why do some folks say to be careful on advancing a rig that sees a lot of towing?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby Deathrod » Sat Jan 09, 2016 4:17 am

Supposedly advancing the timing while lowers EGTs the heat is transfered more to the pistons. Add a bunch of weight to the equation then you have problems. Might also run into cylinder pressure issues as well. If im wrong feel free to correct me.
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Re: Timing thread

Postby spencerdiesel » Sat Jan 09, 2016 8:58 am

Had a feeling :cry: It'd all be a guessing game, but with small timing (spacer only) one may just knock 100 or so degrees off the 1250 standard?

Hold 1150 just to be safe?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby Remps » Sat Jan 09, 2016 12:41 pm

It depends on how much weight you are pulling, what size/pop pressure injectors, what trans, and sustained towing cruise rpm. Also somewhat personal preference and driving style. If it was a pee pump, I'd say (imo) 18* max for sustained pulling 1800 rpm, 19* for 1900, etc etc. Us VE'ers are a lot more casual with the timing than those pee pumpers, who seem to be scared to death of the number 20, god forbid without head studs. :lol:
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Re: Timing thread

Postby spencerdiesel » Sat Jan 09, 2016 8:33 pm

I like all the numbers 8) No, really I do like numbers.

I've been wondering, I believe non IC VE's are 14 deg rather than 12 for IC. So for an IC engine, 1250 sustained with just 2 degrees of advance would be ok?

Because 1250 sustained is ok with a non IC motor as well?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby fatty » Sat Jan 09, 2016 8:39 pm

Temp is temp. I don't think it really matters what your timing is at. How much can the temp drop from the piston to the probe 8 inches away when you're at 2k rpms?
91.5 w250
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Re: Timing thread

Postby spencerdiesel » Sat Jan 09, 2016 9:11 pm

More food for thought
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby spencerdiesel » Fri Apr 01, 2016 5:17 am

How many degrees does the KSB advance? What gets fried if its hotwired full time?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

Fuel: THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw bottomed @ 3 turns, timing bumped 3/16"
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Re: Timing thread

Postby PToombs » Fri Apr 01, 2016 5:39 pm

7 degrees on an IC pump. I don't know about getting fried, but I know because case pressure is way up the pump doesn't like it much. Lots of extra strain on the internals.
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