Advancing the pump timing

[Phil Stuart]

What are the benefits? I have read of others advancing about 1/8 inch on the pump and was curious as to the plusses or minuses on doing this.

If it has a positive effect on fuel mileage or engine performance than I will do it on my 89 with VE pump.





Phil S

 

[pepecat]

I also have an '89 and I did the 1/8" advance... for a WHILE. I noticed a harder sound at idle, almost raspier with the straight pipe, better (more gasser like, faster)high rpm power and worse low end (diesel like) grunt. I also noticed higher boost at cruising speeds and WORSE economy. I prefer it back to stock. My 727 can't do much of anything with the added power up top, and I need to scrape every penny of fuel saving I can get with this daily driver.

I did it becasue I thought hte reduction in smoke it would give me and a more full burn of fuel would mean a more efficient , better running engine, I found otherwise as did others on hear I have read.

 

[MPalmer]

when i advanced the timing on mine it sounded more like a 24v than a 12v but i also saw lower egt's... boost was bout the same. and i think my fuel mileage went up a little+its alittle faster takin off at stop lights now ... it also runs smoother now so im happy with where its at.

 

[rlyons]

Unless you have a heavier foot after advancing the timing you will see better or at least as good fuel mileage as you had before. I get 20 MPG empty now as well as when my truck was bone stock. If I get carried away with the extra power I will see a slight decrease in fuel mileage but like I said if you run it as you did before the increase it will still get just as good mileage with a lot smoother running engine and especially if you run after market larger injectors.

 

[pepecat]

I agree that driving style has the most to do with MPG. On '89 - '90's we already have bigger injectors and advanced timing stock though right?

 

[BushWakr - RIP]

You guys with the ealier trucks need to look at the data plate and check the timing requirements... I believe they were already set to either 1. 35mm or 1. 40mm plunger lift... . in essence that means that, like the larger injectors that came on the early trucks, your timing is already more "advanced" than the later models...

This means you'll likely "hear" the difference in engine sound a bit more noticably than others do...



pb...

 

[Greenleaf]

Yep. It's true. Not ALL the 5. 9's are built equally. There was an informative article published about three years ago that delt with this very topic. Issue..... ????..... 39 or 40 it was.



It basically said the same thing Bob just said. Also it mentioned that, along with the IC and other "stuff" the 91. 5 models recieved, was a change in the head gasket material. Important when you boost the internal operating pressures.

 

[pepecat]

Also with the wax motor Ksb valve disconnected, we're running the advanced cold start timing all the time! When I got my truck the ksb solenoid was disconnected, not as a bomb or mod but because the connector was so weak it wouldn't stay on. So I just leave it off all the time now I don't like the idea of the wax motor anyway, it seems uneccesary especially in our trucks. I looked at the data plate on my truck and it reads 1. 40 mm ... How much advance does the wax motor ksb give anyway?

 

[JLEONARD]

Yes pepecat we are more advanced than the newer trucks... . well our timing is. And they say timing is everything.....

And yes the book says 1. 40 mm.



I decided to leave my timing as is because I get good mileage, good smileage, engine starts on the first pop, and doesn't smoke at idle (unless it's really cold out).



Jay

 

[pepecat]

I agree, I like the way it runs at 14. 0 as well...

 

[Phil Stuart]

Very good info guys! Is this wax motor in the KSB you speak of similar to the wax motors on gas engine sensors to control vacuum for the various emissions components? As the engine warms up the wax melts I guess and allows the switch to change position?



Phil

 

[pepecat]

yes! the non i/c '89 and '90 models have the wax motor ksb's... . problem is they only melt at 160 deg. . !

 

[Phil Stuart]

yes! the non i/c '89 and '90 models have the wax motor ksb's... . problem is they only melt at 160 deg. . !

Do you suggest I unhook mine?It seems to work OK and I can tell a difference in engine sound when it is on and when it cuts out.

Thank again,



Phil S

 

[pepecat]

well I would favor uhooking it for the advanced timing it would bring, however, you should judge for yourself... whichever makes it run better, cooler, and /or better mpg