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Project: The New CDD Shop Truck
- Thread starter Thewespaul
- Start date
IDIBRONCO
IDIBRONCO
I guess you found the problems.
Haha yep, that’s where the compression went!
So just to recap, a few months back I had a customer fly in from out of state to meet about an upcoming build. Met at the airport and picked him up in the shop truck with a full bottle to get lunch. After lunch we took a trip to Mexico before stopping by the shop to check out my little facility and some of the projects. Well on the .71 jet (300 shot) it didn’t seem to have as much steam as it did on one pull, so stopped and pulled the jet out as a loud c7 corvette went by. Caught up to the corvette at a light and we gave it the beans. Truck was out on them till 4th where the unhappy synchros made for a slow shift and the nitrous was on for a second with the engine not under load. Nitrous backfires through the intake and pops an intercooler boot off. Pulled over and fixed the intercooler and finished the day at the shop.
Well next day truck acted like the batteries were low for a few revolutions then fired right up. Idled pretty rough, and I pulled the oil fill off and noticed a lot of blowby. Did a bit more digging and found the back injectors were hanging open. Pulled the truck apart and brought all the injectors up 200 psi and replaced one nozzle which didn’t want to clean up. Got them in the truck and it idled a lot better with less blowby, but still more than it did. Kept driving and working the truck as I do use this as a daily driver and for picking up parts and projects. This happened back in March, and I haven’t ran nitrous through it since because I knew something was hurt. Blowby kept getting worse, and it started only starting on 5 cylinders until it warmed up then it would catch. I did a compression test in April and found 7,8,5 had no compression. Kept driving it because I’ve been swamped and haven’t had a spare idit to drop in, but kept my eyes out for one.
Eventually it got where one cylinder never caught even after warming up completely. I knew it was on borrowed time so I started looking for any suitable replacement. That’s when I stumbled on this 1983 f250 2wd t19 Diesel for sale for $650 in Sweetwater Texas. Owner said it had a 88 7.3 and zf5 swapped in it, just needed to be wired up to run.
I loaded up the flatbed and went to pick it up in the shop truck. Got there and it was a 7.3, but still has a t19 in it. Got the truck for $450 and brought it home. I had been looking for a truck to build as a dedicated race truck, so I could make the shop truck more streetable but I wanted a c6 for it. I have a customer that needed his diesel swapped old ford wired up, and knew he had a good c6 that came out of the truck so I worked out a time with him last week to come out and get that job done and pick up the trans.
Well that was the nail in the coffin, I had to drive to Galveston and got stuck in Houston deadlock traffic. Engine was over 240 for hours just creeping up the interstate chugging on five cylinders and smoking out the highway with blowby. Got there and back without issue just taking a few stops under passes to let the engine cool off occasionally, but the idi brought me back home without a hitch. I pulled the 7.3 out of the race truck this past weekend and I’ve got it prepped to swap into the shop truck. Couldn’t stop myself from cleaning up the paint on the race truck first, absolutely love how this truck looks, but gonna be even meaner with a roll cage and slicks
Started the shop truck the other day and drove it into the shop to be torn apart. Engine never refused to start even with pistons that looked like this.
I think there’s a few things that caused this to happen, one being the obvious nitrous backfire spiking the cylinder pressure. Next are the 3M injectors, I will spill the beans and say these were set at 500 psi pop pressure when I had the injectors hang open. That lets a ton of fuel in but also really widens the injection duration, which means the injector opens a lot earlier and closes a lot later. I tried to offset that by increasing my delivery valve setting on the pump which is basically the pressure relief valve that the plungers have to overcome to send fuel into the injection lines. Well with this stock being as clapped out as it is, I didn’t have much room to adjust this without running into hot start issues even with such a low pop pressure. That left me with a ton of injection duration which meant even higher cylinder pressures. That compounded with the backfire butted the compression rings together, and broke the piston. At least that’s my working theory.
Overall I couldn’t be pleased more on the performance of this poor junkyard idit I saved from the crushers a year ago. The engine has paid for itself many times over with part testing and selling customers on projects with some wild joyrides, and of course being an idi it never let me down or stranded me on the side of the road. Onto version two for the shop truck!
So just to recap, a few months back I had a customer fly in from out of state to meet about an upcoming build. Met at the airport and picked him up in the shop truck with a full bottle to get lunch. After lunch we took a trip to Mexico before stopping by the shop to check out my little facility and some of the projects. Well on the .71 jet (300 shot) it didn’t seem to have as much steam as it did on one pull, so stopped and pulled the jet out as a loud c7 corvette went by. Caught up to the corvette at a light and we gave it the beans. Truck was out on them till 4th where the unhappy synchros made for a slow shift and the nitrous was on for a second with the engine not under load. Nitrous backfires through the intake and pops an intercooler boot off. Pulled over and fixed the intercooler and finished the day at the shop.
Well next day truck acted like the batteries were low for a few revolutions then fired right up. Idled pretty rough, and I pulled the oil fill off and noticed a lot of blowby. Did a bit more digging and found the back injectors were hanging open. Pulled the truck apart and brought all the injectors up 200 psi and replaced one nozzle which didn’t want to clean up. Got them in the truck and it idled a lot better with less blowby, but still more than it did. Kept driving and working the truck as I do use this as a daily driver and for picking up parts and projects. This happened back in March, and I haven’t ran nitrous through it since because I knew something was hurt. Blowby kept getting worse, and it started only starting on 5 cylinders until it warmed up then it would catch. I did a compression test in April and found 7,8,5 had no compression. Kept driving it because I’ve been swamped and haven’t had a spare idit to drop in, but kept my eyes out for one.
Eventually it got where one cylinder never caught even after warming up completely. I knew it was on borrowed time so I started looking for any suitable replacement. That’s when I stumbled on this 1983 f250 2wd t19 Diesel for sale for $650 in Sweetwater Texas. Owner said it had a 88 7.3 and zf5 swapped in it, just needed to be wired up to run.
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I loaded up the flatbed and went to pick it up in the shop truck. Got there and it was a 7.3, but still has a t19 in it. Got the truck for $450 and brought it home. I had been looking for a truck to build as a dedicated race truck, so I could make the shop truck more streetable but I wanted a c6 for it. I have a customer that needed his diesel swapped old ford wired up, and knew he had a good c6 that came out of the truck so I worked out a time with him last week to come out and get that job done and pick up the trans.
Well that was the nail in the coffin, I had to drive to Galveston and got stuck in Houston deadlock traffic. Engine was over 240 for hours just creeping up the interstate chugging on five cylinders and smoking out the highway with blowby. Got there and back without issue just taking a few stops under passes to let the engine cool off occasionally, but the idi brought me back home without a hitch. I pulled the 7.3 out of the race truck this past weekend and I’ve got it prepped to swap into the shop truck. Couldn’t stop myself from cleaning up the paint on the race truck first, absolutely love how this truck looks, but gonna be even meaner with a roll cage and slicks
You must be registered for see images attach
Started the shop truck the other day and drove it into the shop to be torn apart. Engine never refused to start even with pistons that looked like this.
I think there’s a few things that caused this to happen, one being the obvious nitrous backfire spiking the cylinder pressure. Next are the 3M injectors, I will spill the beans and say these were set at 500 psi pop pressure when I had the injectors hang open. That lets a ton of fuel in but also really widens the injection duration, which means the injector opens a lot earlier and closes a lot later. I tried to offset that by increasing my delivery valve setting on the pump which is basically the pressure relief valve that the plungers have to overcome to send fuel into the injection lines. Well with this stock being as clapped out as it is, I didn’t have much room to adjust this without running into hot start issues even with such a low pop pressure. That left me with a ton of injection duration which meant even higher cylinder pressures. That compounded with the backfire butted the compression rings together, and broke the piston. At least that’s my working theory.
Overall I couldn’t be pleased more on the performance of this poor junkyard idit I saved from the crushers a year ago. The engine has paid for itself many times over with part testing and selling customers on projects with some wild joyrides, and of course being an idi it never let me down or stranded me on the side of the road. Onto version two for the shop truck!
IDIBRONCO
IDIBRONCO
You forgot to add that that wasn't the only time for the nitrous backfires. It may not have been the first time either. I got to witness that back in January.
Yep, although that was just a small pop nothing like the last one. First happened in December 2018 when I went to the larger jets
F350camper
BOOST!
First off... I'm mad about the deal you got on that bullnose 
But seriously... I knew these things were tough but that's downright impressive! Yeah it's been getting worse but you managed to squeeze a couple MONTHS out of an engine that was "blown". That's pretty sick.
I'm very much looking forward to seeing your projects when I get there in July!!!
But seriously... I knew these things were tough but that's downright impressive! Yeah it's been getting worse but you managed to squeeze a couple MONTHS out of an engine that was "blown". That's pretty sick.
I'm very much looking forward to seeing your projects when I get there in July!!!
First off... I'm mad about the deal you got on that bullnose
But seriously... I knew these things were tough but that's downright impressive! Yeah it's been getting worse but you managed to squeeze a couple MONTHS out of an engine that was "blown". That's pretty sick.
I'm very much looking forward to seeing your projects when I get there in July!!!
I’m really impressed by this engine, besides the 20 thou ring ridge the bottom end is otherwise immaculate, with some sleeves and new pistons, crank will polish up and be used in the race truck.
I like to think we’re all winners. Most of the shrapnel was from the pistons, but the rings were gone too. Hard to say what gave out first!
Before the incident it didn’t go past 1200, but since then it was really down on power and got up to 1300 pulling some trucks up long hills.
Garbage_Mechan
Garbage Mechanic
Amazing how many turbo charged mechanical Diesel engines I have torn down in the last 40 years that were still getting the job done and looked like that. Usually only torn down due to excess oil consumption. Turbocharging covers up a lot once on boost.
Yeah the back pressure was pretty bad, I never got around to putting a drive pressure gauge but tiny turbo with a lot of nitrous making up for a lack of air to burn a lot of fuel, makes for a lot of air getting backed up into the cylinder, just because the exhaust can’t get past the turbine.
austin92
Full Access Member
I would literally kill for that bullnose. My grandpas truck that he left me is a red 83 f350. It’s in pretty good shape but that one of yours looks new. Mine had a 3.07 dana 61 with 28 spline axles shafts in it, something you might want to check out on yours.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
The_Josh_Bear
Full Access Member
What's your trick to get that paint so nice?!? Great find man! My pickup has always had that matte look and while I'm not much into looks, *some day* I'll have decent paint on her. But that looks great! Pretty amazing story of the engine...wild.
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