FerranRico

If the pump was already installed and you take it out without locking the timing bolt, it's gonna revert to the zero point and you loose your timing advance. if you lock the timing nut before removial (take out the spacing plate and tighten the bolt [10mm socket], lower front of pump) then you can stay at TDC and reisntall if you're only gonna rotate a tooth.
I bench timed my pump by putting on a vise (clamp on the the rear plate, unlock the timing bolt) and placing the output shaft nut back on turned it clockwise with a ratchet watching the dial indicator until I got the reading that I wanted, then tightened the timing bolt. Then you can go back after you've achieved your timing, and reinstall at TDC. After that check the flywheel timing to ensure that it corresponds with the pump's.
My two cents...

FerranRico

Harmonic balancer.. I'm stuck on flywheel.

FerranRico

Dude.. them's some pretty involved contraptions you've made.., looks like open heart surgery utensils to me... isn't easier to just use the ol' coat hanger method?
BTW.. i tried looking for your "timing is everything" thread.., you sure do post a lot!!!.., approximately on what dates was the thread posted?

G1625S

Use the 'advanced' search option, then search 'timing is everything' and specify thread name. Ask it to look in the first gen section only. Awww heck, just click here

https://www.dieseltruckresource.com/...ghlight=timing

FerranRico

I'm a reading that thread.. and I'm getting lost on the DEEP of it.., I Am a Rocket Scientist .. But you guys have me licked in your pump internal's dsicussions...

G1625S

I pick that one up every now and again when I begin to THINK I know what I'm talking about. Still not exactly sure what the good pastor is getting at, but I may pick up the VE manual here over the long weekend...

G1625S

''Dude.. them's some pretty involved contraptions you've made.., looks like open heart surgery utensils to me... isn't easier to just use the ol' coat hanger method?''

For me, the dial indicator on the valve is the way to go. Since the dial indicator is moving on the same plane as the piston, I feel it's the most accurate method to finding true TDC. As for looking like surgery, it kinda is...plus, I've dropped valve keepers into the abyss before Is it overkill? Yup, but it was killing me not knowing, so I had to go through the process.


edit--as for the contraptions, I can't seem to locate my cool magnetic flexy-fits-all base for my dial indicator. Anybody seen it?

Bushy

The physical length of the mechanical timing piston is a solution to more advance (dynamic) as the RPM climbs.....you'd be surprised how much extra advance you can get by modifying the piston....yes, you need to pull the pump to do this and, yes, you'll need to tweak your static timing as well as your spool valve (which has a role in regulating the supply side pressures).

I really didn't mean to be this long in getting back to this topic...I kinda fell off the turnip truck there a while back and got "can't remember-nesia" sorta...

bob....

FerranRico

"I can't seem to locate my cool magnetic flexy-fits-all base for my dial indicator. Anybody seen it? "

If you have a dial metering indicator for Rack&Pinion depth setting maybe that same base may work?.. don't know.. that just popped into my head...

Alec

The flexy base that came with my dial indicator is not rigid enough. I kinda prefer the old rod and clamp type.

Tweaking the spool valve will change the timing advance curve, but can't you get the same effect just by tweaking the spring? Or am I missing something Bob?

FerranRico

Done did it.. set the advance at 1.50mm, it started right up, very little white smoke and none of the shudders that it had with the previous 3.0mm advance.
I set the TDC and just popped the pump out, then I bench timed it to 1.50, upon placing back in.. it happened to fall right on the pump and housing marks after bolting down.., so I'm a happy camper... as I can retard or advance it as needed..; ran it a little while to check for leaks.. none..
I ain't messing with it anymore.., being that I only use the ol' truck for hauling my Jeep about 4-6 times per year to Rock Crawling events.., I can live with the low mpg's which seem to plague me..
There's a trip to Moab, UT planned for the summer, the Scrambler CJ-8 Owners Assoc is having their yearly meeting there.., it's gonna be 3100 miles from Yorktown VA.. and will definitely be expensive to travel there.., at 10-12 mpg's.. and $2.90/gallon.. it's a daunting prospect at $300-400 each way..., something to consider if it's worthwhile..
Thanks for the advice postings ya'll..

mopar65pa

Wow lots of info here. I'm trying to decipher it all........ so I'm gonna write out what I "think" I have found out.

89-91 NON-I/C motor
Factory timing is @ 1.4mm
upgraded timing can be from 1.55-1.65mm all the way to 1.7mm with stock injectors.

91.5-93 I/C motors
factory set @ 1.25mmUpgraded timing can be set from 1.35-1.4mm with stock injectors.

I have a 90 NONI/C motor with an I/C crossflow rad that runs at 140-160* unloaded, 190* loaded up hill right now with a 1/4 turn on the fuel pin and the star wheel and smoke screw backed out as far as I feel it should be since there was no star wheel when I got the truck and the smoke screw was turned all the way in.

I have no clue "yet" what the timing is set at.I have a dial gauge and a barring tool and want to set this thing correctly for more MPGs. The power is there already and better then the 92 I/C my dad is running in stock form.

SO where do I set my timing at on a 90 non-I/C pump to get max power to MPG performance?

From what I have read it's between 1.55-1.60mm

I can't afford to run this thing getting 14mpg around town and 12mpg loaded down. I need to get this thing into the 18-20MPG range but 22mpg would be awesome!

Assistance would be very much appreciated.