Timing thread

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Re: Timing thread

Postby spencerdiesel » Sun Jun 18, 2017 2:09 pm

Got the sp144 wrench while I was in school, bumped the pump about 3/32".

By far what stands out most to me is how much less pedal I have to use to maintain the same speed. Pretty much everything else was about like I thought: slight drop in eggs, slight increase in rattle, lose a little on the bottom and gain a little on the top. Curious to check mpg.
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 1 turn, timing bumped 3/32"
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Re: Timing thread

Postby spencerdiesel » Sun Sep 03, 2017 9:43 am

Looks like overall the old girl is averaging about .75 to 1 mpg better after the timing bump. Mind you a 3/32" probably only puts static timing at about what a stock non IC truck runs.
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 1 turn, timing bumped 3/32"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 901
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC

Re: Timing thread

Postby spencerdiesel » Sun Sep 03, 2017 9:49 am

At what point does excessive inlet pressure to the IP affect the base timing piston position? On an old thread, someone stated after about 7 psi inlet pressure, the timing piston would not return to the fully retarted position or something?

I'm sure altering case pressure remedies that?
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 1 turn, timing bumped 3/32"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 901
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: Timing thread

Postby BC847 » Sun Sep 03, 2017 6:08 pm

Seeing as the vane-pump of the IP takes the fuel-pressure up to what? 30, 40, 50psig at idle (I can't remember), the incoming fuel-pressure would need to be above that in theory.
David

1993 12mm VE Fueled W250 CC, Green
12.67 @ 103.35
Your basic farm truck ;)
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Re: Timing thread

Postby spencerdiesel » Sun Sep 03, 2017 6:51 pm

BC do you know about what point base timing is altered by inlet pressure?
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 1 turn, timing bumped 3/32"
Muffler delete
spencerdiesel
14mm rotor
 
Posts: 901
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: Timing thread

Postby BC847 » Mon Sep 04, 2017 9:21 am

No.
David

1993 12mm VE Fueled W250 CC, Green
12.67 @ 103.35
Your basic farm truck ;)
BC847
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Posts: 1930
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