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Awesome 
maxamillion2345
Franken-80
Have you studded your 4bt?
maxamillion2345
Franken-80
Have you studded your 4bt?
Some pics of the Family Hauler. One showing great clearance between the driveline and exhaust.
- Thread starter
- #2,127
Thanks Mr Jits for posting those. I was concerned about my front drive shaft hitting my exhaust that I built for the twins so I finally put on my old bump stops and needed to flex it to see. We found a rock that would work and it looks like I've got plenty of clearance and nothing to worry about. I may be able to shorten the bump from where it stands but at this point the front springs are inverting so I may just leave them to save the springs.
I've been playing with tuning turning screws and mashing the throttle. I've reduced timing to 16.5 and played with all the screws. The recent tune still needs work; I'm not there. I am still too smoky for my tastes although part throttle is cleaner than before. I've tightened my spring gate some more but I may need to step up to stiffer springs as my latest netted me:
Total PR: 2.97 at 29psi
Pri PR: 2.36 at 20 psi
Sec PR: 1.25 at 3.8psi
My Secondary is not doing enough and the EGTs are warmer than before. Glad the price of diesel came down so I can burn it through the engine testing my tunes.
I've been playing with tuning turning screws and mashing the throttle. I've reduced timing to 16.5 and played with all the screws. The recent tune still needs work; I'm not there. I am still too smoky for my tastes although part throttle is cleaner than before. I've tightened my spring gate some more but I may need to step up to stiffer springs as my latest netted me:
Total PR: 2.97 at 29psi
Pri PR: 2.36 at 20 psi
Sec PR: 1.25 at 3.8psi
My Secondary is not doing enough and the EGTs are warmer than before. Glad the price of diesel came down so I can burn it through the engine testing my tunes.
- Thread starter
- #2,128
Another round of tuning last night. Star wheel up another 1/2 turn, 1/2 turn tighter on my MBC on the signal line to the AFC, swapped out to a stiffer spring on my spring gate and set it in the center of its adjustment range, turned full power screw in 1/2 a turn more. Took it for a drive and I'm heading the right direction. Cleaned up some of the smoke and it's getting more fun. I'm going to need a second set of eyes pretty soon as I keep adding more fuel so I can pay attention to the road and the other can get readings.
Total PR: 3.38 = 35psi
Primary PR: 2.22 = 18psi
Secondary PR: 1.52 = 7.7psi
For the next round I'll do about the same setting 1/2 turn more on each respectively. I also plan to bump the timing back to 17 or 18. I found this post from another cummins forum that seems to sum up a bunch of research I've done about timing and bigger injectors on the VE pumps.
Total PR: 3.38 = 35psi
Primary PR: 2.22 = 18psi
Secondary PR: 1.52 = 7.7psi
For the next round I'll do about the same setting 1/2 turn more on each respectively. I also plan to bump the timing back to 17 or 18. I found this post from another cummins forum that seems to sum up a bunch of research I've done about timing and bigger injectors on the VE pumps.
The biggest thing that I have noticed with timing is (with the ve of course) we need a lot of timing in comparison to other Cummins engines. The main reason for this is to do with injection pressure.
We need a very large injector per cc of fuel compared to other pumps. The less we break the fuel up, the longer it takes to burn. OR the higher the cylinder pressures need to be to burn it. This is why we need more air and higher timing to make x power when compared to other trucks.
So, in short, the larger the injector orifice size.... the more timing one needs. Also, the longer the injection event..the more timing one needs.
That's a short gist of it. Timing sweep, case pressure, etc... all are the more advanced aspects and are more involved than just rotating the pump.
We need a very large injector per cc of fuel compared to other pumps. The less we break the fuel up, the longer it takes to burn. OR the higher the cylinder pressures need to be to burn it. This is why we need more air and higher timing to make x power when compared to other trucks.
So, in short, the larger the injector orifice size.... the more timing one needs. Also, the longer the injection event..the more timing one needs.
That's a short gist of it. Timing sweep, case pressure, etc... all are the more advanced aspects and are more involved than just rotating the pump.
Is he referring to VE pumps in that post?
- Joined
- Apr 4, 2006
- Threads
- 162
- Messages
- 4,044
- Location
- Hillsboro, OR
- Website
- www.cascadecruisers.com
Just did catching up on your rig Mike... Looks great man. Hope things are going well. Happy Holidays my friend!
- Joined
- Apr 4, 2006
- Threads
- 162
- Messages
- 4,044
- Location
- Hillsboro, OR
- Website
- www.cascadecruisers.com
Lol... already been through one set of tires. There is another cruiser in my future... just started looking around a bit. Not sure if I want to take on another project or buy one that is pretty much "done". I thinking about a fj40 or 45 this time around. I'd still like to steal Ken's green 45. 
Saw your target boost was high 40s low 50s. Without reading back 100 pages can you give us an update on your engine:
What RPM Spring r u using?
Stiffer valve springs?
Stock head components? Head bolts, gasket, etc
What two turbos, looks like one is a HE351?
Injectors?
Pump mods, current and future?
Thanks,
Been batting this idea around for awhile. I currently get low 30-31 max with me HE351.
What RPM Spring r u using?
Stiffer valve springs?
Stock head components? Head bolts, gasket, etc
What two turbos, looks like one is a HE351?
Injectors?
Pump mods, current and future?
Thanks,
Been batting this idea around for awhile. I currently get low 30-31 max with me HE351.
1974fj, wow, I've read your build, and Boots' all the way through. You have both built awesome rigs, been through all sorts of tribulations and both pull through with flying colors when challenged. You should read the previous 100 pages. Boots has built and thoroughly documented an incredible wealth of information here. Cheers to you both!
My $.02.
Last edited:
- Thread starter
- #2,136
Thanks for the kind words Pacer.
As I've continued to tune I hit a wall this week and have been kicked down the ladder so to speak. Something happened and I'm trying to figure it out. Total boost is barely 20psi now.
I've done the following:
Had a bad batch of fuel so both my pre and main fuel filters have been replaced
Running injector cleaner and fuel conditioner in my current tank.
Started hunting for boost leaks: checked all boots and clamps, replaced boost line fittings on both gauges (found they were kinked) and on the intake manifold, lines themselves are still good.
Checked turbo wheels for contact and play, no contact and no excessive play but I question if they are spinning well enough.
Rebuilt Manual Boost Controller located in my AFC signal line: used a stiffer spring, wonder if this is too stiff, plan to take out the MBC and see if anything changes.
Returned pump settings to my last known good combination (I've been keeping a tuning journal) but the 35psi that setting produced did not come back.
I know I'll find the culprit eventually, hoping to go to a buddy today after work for some additional troubleshooting.
As I've continued to tune I hit a wall this week and have been kicked down the ladder so to speak. Something happened and I'm trying to figure it out. Total boost is barely 20psi now.
I've done the following:
Had a bad batch of fuel so both my pre and main fuel filters have been replaced
Running injector cleaner and fuel conditioner in my current tank.
Started hunting for boost leaks: checked all boots and clamps, replaced boost line fittings on both gauges (found they were kinked) and on the intake manifold, lines themselves are still good.
Checked turbo wheels for contact and play, no contact and no excessive play but I question if they are spinning well enough.
Rebuilt Manual Boost Controller located in my AFC signal line: used a stiffer spring, wonder if this is too stiff, plan to take out the MBC and see if anything changes.
Returned pump settings to my last known good combination (I've been keeping a tuning journal) but the 35psi that setting produced did not come back.
I know I'll find the culprit eventually, hoping to go to a buddy today after work for some additional troubleshooting.
Exhaust leak between the high and low pressure turbos?
Has your smoke out the tailpipe changed at all?
Has your smoke out the tailpipe changed at all?
- Thread starter
- #2,138
I have looked at the hotpipe but there are no black streaks around the gaskets and no apparent cracks. I am getting some exhaust leaking from the wastegate pivot arm on the secondary but as is it hit 35psi before. I would think it'd have to be a visual crack to loose 10psi immediately. Or a combination of leaks but the likelihood of a bunch of small leaks happening at the same time seems nil. I made minor tuning adjustments including turning in the full power screw 1/2 (my expectation was to get into the 40psi range doing that) but the results dropped it down to 25psi, and now I'm down to 20psi. The weird thing is the EGTs are in check and it's only doing moderate hazing out the pipe (no black clouds like popping an intake boot under boost).
My gut instinct is that it has to do with fueling somehow like something got clogged or worse broken in the IP. But it still runs well and idles well, no missing like a scattered injector but maybe those are clogged due to the bad fuel. I would think my filters would have stopped anything big that could do damage. It just feels like it runs out of umpf quickly. I wonder if my governor spring came off or broke and it's defueling quickly, I've just never heard of those breaking. I'd have to pull off the top to see that but nothing looks obvious on the surface. I still have that MBC to remove and test before I have to start digging deeper. I'll find it.
My gut instinct is that it has to do with fueling somehow like something got clogged or worse broken in the IP. But it still runs well and idles well, no missing like a scattered injector but maybe those are clogged due to the bad fuel. I would think my filters would have stopped anything big that could do damage. It just feels like it runs out of umpf quickly. I wonder if my governor spring came off or broke and it's defueling quickly, I've just never heard of those breaking. I'd have to pull off the top to see that but nothing looks obvious on the surface. I still have that MBC to remove and test before I have to start digging deeper. I'll find it.
If your governor spring came off / broke, then the truck would not start at all. I've experienced that myself.
Do you have a fuel supply pressure gauge?
Do you have any fuel dripping from the vent boot on the firewall side of the aneroid?
Do you have a fuel supply pressure gauge?
Do you have any fuel dripping from the vent boot on the firewall side of the aneroid?
- Thread starter
- #2,140
Good to know about the governor spring. I wasn't looking forward to popping the head off the IP just to check.
I don't have a fuel pressure gauge, that would be a good avenue to try next, to see if my lift pump is kicking the bucket.
I was just in the AFC and didn't notice any fuel in the bowl but I'll keep my eye on it.
I don't have a fuel pressure gauge, that would be a good avenue to try next, to see if my lift pump is kicking the bucket.
I was just in the AFC and didn't notice any fuel in the bowl but I'll keep my eye on it.