Dynamic timing, great idea!

[Arborigine]

Sometimes I second guess myself and wonder why i do things the hard way, and if its worth it. Today was one of those days. We had a bit of a storm here and on friday they closed the mountain pass over the Sierras on the highway where I live. Last night the Cal DOT website and phone info line both list it as open. So up the hill I went. 35 miles later I come to a closed gate. Now I have to backtrack.. I stopped in at home and re-checked the website, still showing open. I proceeded to got to Doug's (Genlightning) in Minden to set the timing on our trucks, but was wondering if it was worth the trouble as I had set the marks static on the new U-haul pump and it ran fine. I have no other 6.9 to compare it to, and know it is definitely weaker than my Dad's 91 Cummins/Dodge. Over the pass I go, making this a 350 mile day transecting the Sierras twice in snow. I discovered that according to the instrument my timing was at 0.1 degrees. We reset it to 6.8, close enough to seven. Coming home I found that there was a noticable increase in power, and a much better response when suddenly floored in 4th gear from cruising uphill 2500 RPM at both 8700 feet altitude and at 2000. The truck is much more enjoyable to drive in the hills and should even get better mileage, but it will be a few weeks before those numbers are in. Next I have to re-work the throttle to get that 1/4 inch of throw I am missing.
The trip was really worth it. Had a good time with Doug (genlightning) and meeting his lovely wife and enjoyed seeing the fine work he has done on his Chevord.
The moral, don't trust the factory marks if you have swapped pumps.
Thank you Doug, for the invitation.

 

[typ4]

Its is common knowledge that the marks are only good on the original pump. Once rebuilt/replaced it means nothing.

 

[GenLightening]

Good to hear that not only did you make it back over the hill, but the change made a noticable difference. And send some pics of those trailers you told Sonja and I about!

 

[9779scott]

I have been thinking about timing my truck as I had the pump off it a while back. It just does not sound right to me nor have the power it should. I have read alot of stuff from guys and they all have alittle different way of doing it. Being that you just did it and worked well for you what is the correct way of going about it?

 

[FORDF250HDXLT]

sounds like you timed it by the pulse method then.in which case,you could still have a little more potential from the engine.via this method 8.5 BTDC +/- 1 degree is the way to go.if you set it to 7 degree's BTDC she could still be a little retarded.
via that method,the cetane and elevation do not alter the timing settings as if setting via lumy/ATDC.
still,going from 0 (close enough lol) to 7 BTDC,she must have felt like twice the engine.

 

[rockbender]

Looking forward to your updates on fuel economy as well as cold start reports!

 

[hesutton]

Thanks for the post. Cool story and sounds like an adventure. It's always nice to get to meet other members, plus, your rigs is running much better for you now.

Heath

 

[Arborigine]

We used the Kent-Moore rental unit. How does the clamp around the injector pipe work? A of measure of inductance?
Today I drove it of the same mountain roads that I used to go to work last week, big difference. Places where I couldn't maintain 4th gear I can actually accelerate now. now on to the twenty or so more items on my list.
We have had three mornings now with temps around 30 degrees F, and i discovered all my glow plugs are dead. I plugged in the block heater for 1/2 hour and it fired up. Got plugs ordered.

 

[Arborigine]

I got paid today so i could fill my tanks at $4.25 per gallon.
Running on bad mountain roads, 1500 to 8750 Ft altitude, hubs locked always, and some 4 wheel drive, plus some 3rd gear driving. Based on one tank each,
Before 15.03 MPG
After 18.54 MPG
Thats about 23% improvement by just changing the timing from 0.1 to 6.8?
I also changed all gear oils to Swepco 201 today, doubt it will have any measurable change, but everything is quieter.
In a few weeks I will be coming down off the hill and driving about 1000 miles on flatland freeways, will be interesting to see what mileage I get.

 

[RLDSL]

I got paid today so i could fill my tanks at $4.25 per gallon.
Running on bad mountain roads, 1500 to 8750 Ft altitude, hubs locked always, and some 4 wheel drive, plus some 3rd gear driving. Based on one tank each,
Before 15.03 MPG
After 18.54 MPG
Thats about 23% improvement by just changing the timing from 0.1 to 6.8?
I also changed all gear oils to Swepco 201 today, doubt it will have any measurable change, but everything is quieter.
In a few weeks I will be coming down off the hill and driving about 1000 miles on flatland freeways, will be interesting to see what mileage I get.

No, you won't see any kind of fuel mileage increase with changing to a fresh dino gear oil, you just get fresh gear oil ( which It was probably due for ) if you want to see a mileage increase, you need to swap in a premium synthetic gear lube in your diffs and gear boxes, then you will get a mesurable increase

 

[Arborigine]

Swepco is what we were using in SCCA and Baja racing, and german auto shops 30 years ago. It will take a noisy BMW trans with sticky synchros and make it quiet and shift smooth. Expensive, but with a proven benefit and solid track record.
Lousy marketing, but great products.

 

[rockbender]

Those are some pretty amazing results! I can only hope my timing is off that much too.

To play devil's advocate, some of my best MPG tanks have been in 4wd at 45 mph but those were flat straight stretches and not mountain passes.