Engine/Transmission (1994 - 1998) Should I bump my timing?

[Got Smoke?]

I've read a lot about timing the past couple of weeks on here, and even a little in the TDR magazine(I think).



I've been running thoughts through my mind of whether or not I should have the timing bumped on my truck. As far as BOMBing goes I'm stock.



Talked with Cummnzpowr (Greg) for a good 15 minutes about the whole subject. He seemed to think I should go for it and set it at 16 degree's, but my search of the 12 valve engine forum show's 15. 5 degree's to be the magic number.



Just wondering if this would be a good thing to do to my stock truck. It wouldn't really do much other than probably run a little bit better right?



Thoughts/Comments/Suggestions?

 

[Joseph Donnelly]

15. 5 is the number I posted a good while ago for fuel mileage, etc. but the best setting depends on your use of the truck. Come to the TDR nats in Columbus IN and I'll fill you in.

 

[CumminsPower98]

You will for sure want to bump your timing ahead some. My truck was at 13. 25º and I managed to get it just a hair over 15º the first time around and my mileage went up about 1. 5 to 2 mpg! Well just today I decided to try to fab a way to hold my pump from turning so as to make setting the timing easier and bump it on up to 16º since that's where I set my cousin's truck and it seems to run well there. Well my pump holding method worked and I was able to get 16º right on the dot and now time will tell as to how it does. I feel I might have gained a very small amount of upper end power as I felt my clutch slipping in 5th today and never have before this. SBC here I come, except I can't afford that, hmmmmm



Mark

 

[bighammer]

OK Cumminspower, I'm curious about your method. I haven't tried to set mine yet, so I'm not familiar with the problem yet. I would like to hear your solution, though.



Thanks

 

[CumminsPower98]

Well I will try to explain how I held the pump from turning when pulling the gear off. The P7100 has a setup on the driver side toward the rear made to hold the pump at factory spec. when installing it on an engine with the engine at TDC. There is a cap and sealing washer that can be threaded out and inside is a device with a fork on one end. This little pin/fork can be installed either direction. When installed with the fork end toward the pump it engages with a screwdriver like rod that sticks out when the pump is at the factory spec. timing. After the pump has been installed this pin is turned around and just rides in there. Well since I wanted my timing more advanced beyond 13. 5º I was not able to use this pin to hold the pump because the rod is toward the bottom of the hole in the side of the pump. So I just took a 7/16" bolt and cut it to the right length and installed it in place of the other device and VERY lightly tightened the cap which put a little pressure on the rod protruding from the pump shaft. Well I'm not very good with words and with no pictures this is probably clear as mud. I hope this helps a little. Some pumps move when the gear is pulled and others don't. So far I have done two that moved and one that didn't. I wish someone would come up with a better way to hold the pump though. To me this is the hardest part of the job.



Mark

 

[T. Baker]

The way I did mine was to lock the pump with the factory pin, loosen the gear, then pull the TDC timing pin, then put a magnetic degree wheel on the crank and back up the crank about 10 deg. , and then move it forward to 1. 5 deg. , before where it was and lock up the pump gear and remove the pin. Now my timing is at 15 deg. No special tools.

 

[Joseph Donnelly]

Using the timing blade on the side of the pump is not recommended. It is easy to bend, and expensive to fix.

 

[CumminsPower98]

Thanks for the heads up Joe. I'm sure mine is OK because I was very careful but from now on I will probably not do that again. I'm just frustrated that there is not an easier way.

 

[Greg W]

Timing change

Last week I had my timing checked. The factory setting was at 11. 5 and it was supposed to be 12. 5. I had it set at 15. 5 btdc and it has cleared up my white smoke on startup, the loping miss at about 1500 rpm when cold. The low end power is awesome compared to the sluggish slow spool up that it had before. I think that my mpg has gone up slightly even though I can't keep my foot out of it. The egt is slightly lower. It even sounds a little different. I had to back off my plate some more because since the timing change my torque converter has been slipping slightly. I should have advanced the timing about 7 years and 245,000 miles ago because the performance is incredibly different.