'89 R3500 Crew Cab 2wd to 4wd conversion & beyond

[6872xtc]

So I'm new to this whole timing control and being able to set it where I want. What do you plan to set for idle, cruise, and WOT timing? Right now mine is 25/36/36. Seems like it much be all in by 2000 or not much higher. I only set the idle and WOT timing, the rest is default Sniper.

I would suggest that you try some different settings and see what it likes.
I don't remember how much compression it has, but the large bore of a big block will take a lot to get detonation. (At least this has been my experience around here)
I believe that it may take some time to get things where all is good due to the cam, compression ratio, elevation and the weight of the truck. I try to listen closely during acceleration while moving, such as coming out of a corner and also when you lay into it a fair amount from say, 20 mph.
My truck likes some timing, I thought there was something wrong at first. I think it has 44 total now, but yours may be different.

 

[skunked]

Your initial number seems high, I've always been around 14-20 degrees. Total timing could be up to 42, really depends on the application.

 

[mrk5]

I've always run high initial timing after researching it a lot back in my carburetor days. I usually set idle timing at 15° to 18° and then when you connect vacuum advance you pick up an additional 10°. I live at 5000ft and end up wheeling at 8000-12000ft so the elevation allows for some of that extra initial timing.

Even Moab is still up around 4000ft elevation. With the carb I could the difference in how the truck idled between home and Moab.

@6872xtc the compression is really low on this vintage 454, I believe a little less than 8:1. I was thinking I might get away with more timing because of that.

 

[nvrenuf]

@mrk5 fwiw the rubber mounts on the diesel rad brackets are centered. It's a "tab" for the shroud to screw to that's offset making them left / right.

 

[6872xtc]

I would wonder how much timing advance will actually benefit it....
Mine is just under 10:1, and I don't think that I ever heard it knock at WOT. It would once in a while when I had it up to 52* total, but only in the midrange RPM.
I just found that I liked it better all the way around when I backed it down, and now it doesn't have to have 91 octane ALL of the time. The A/C also played into it.

 

[mrk5]

@mrk5 fwiw the rubber mounts on the diesel rad brackets are centered. It's a "tab" for the shroud to screw to that's offset making them left / right.

View attachment 234008

Thanks! I may see if I can modify the brackets I have to work as well. Maybe I could extend them an inch.

 

[mrk5]

I would wonder how much timing advance will actually benefit it....
Mine is just under 10:1, and I don't think that I ever heard it knock at WOT. It would once in a while when I had it up to 52* total, but only in the midrange RPM.
I just found that I liked it better all the way around when I backed it down, and now it doesn't have to have 91 octane ALL of the time. The A/C also played into it.

Are you implying there may not be much to help such measly compression...

 

[6872xtc]

Nah, I just don't know how much is too much timing !!!!!


I guess if your little gear reduction starter won't crank it, then it's too much.....
Does that make me sound like a starter snob?????
Mine is a smaller version of the Cummins one, and I found out how to make it grunt..
.

 

[mrk5]

Actually the cool thing with the computer controlled timing is that I can set the start timing different from idle timing. So while I have 25 degrees idle timing, I have 15 degrees for starting.

Been doing some more reading about timing, and it sounds like I should up my cruise timing to about 50. I was thinking WOT and cruise would be the same timing but that's not the case. At cruise the centrifugal/mechanical will likely be all in (unless going slow) plus manifold vacuum will be strong so vacuum advance will be in as well. At WOT you're not getting any vacuum advance. So using the MSD I had in there as the reference my cruise timing was 15 initial + 21 mechanical + 10 vacuum = 46 total at cruise.

 

[70jimmy]

220 221 whatever it takes.

 

[mrk5]

I remember the first 4x4 I owned, an 86 short bed GMC, had a horrible knock problem. I think I'm afraid to ever hear that noise again so I'm too chicken to cut 'er loose.

I'm thinking I will give it try with 25° initial, 40° WOT, and 50° cruise.

 

[mrk5]

My power steering leak is the AN fitting for the reservoir feed. Wonder if it's a bad fitting or something got in there. It's good and snug.

 

[6872xtc]

Did you do the loosen and retighten trick?
Sometimes you can use a wrench to rock the fitting after loosening the "nut", then retighten.

Or there may be a small nick in the seal surface.

 

[mrk5]

I could try that. I do that with valves, haven't tried it on these fittings.

 

[mrk5]

Radiator #3 should be here tomorrow....

 

[sweetk30]

 

[mrk5]

I think we finally have a winner. A little damage in one area but I think it'll be fine.

Just a little smashed. I'll try filling it with water first before install to see if anything shows up.

 

[Truckman4life]

Radiators are such a pain with shipping companies. I've gotten medium duty ones in huge 4'x4' boxes that cost over $1,000 and they break them too.

 

[mrk5]

Yeah I was starting to feel I'd never get one that'd work.

 

[mrk5]

Got a good test drive and trail run in Sunday. The 454 runs great. Didn't have any problems with the Sniper on the trail; works just as good as the GM TBI did. Have to get use to having more oompf when I hit the accelerator. I'm worried now that I'll break sh!t if I do snow runs.

Definitely need to get the bigger radiator in. In the morning it was cooler and the operating temperature was manageable but still getting pretty warm by the time I was at the top of the climb. This is highway running at 40-45mph climbing about 20 miles from 5000ft to 8000ft. Didn't have a lick of trouble with engine temperature on the trail. The really cool thing is the 454 has enough grunt I can pull the climb in 3rd gear with the torque converter locked up so the trans stayed nice and cool.

On the drive home, the story was a little different. Obviously didn't have an issue in the mountains since it was all downhill. On the interstate going over 65mph the motor was slowly heating up. At around 210° I sucked it up and turned on the heater which dropped it down under 210°. I decided to leave the interstate and take the side roads since running the heater in 90° weather really brings the suck. Didn't have any trouble with engine temps on the interstate in the morning but it was also 20° cooler. Seems as though the radiator can drop the coolant temperature 120° at 75mph, so if it's 90° outside the truck will run 210°. When it was about 70°, the motor was about 190°. FYI, I have a 180° thermostat.

Here are some pictures a reward for reading through the text above. If you didn't read, you have to skip the pictures.

It was so nice and cool up there. Elevation was about 10,000ft at the big water crossing. In the afternoon we had cloud cover and rain so it was really nice and cool.