1981 5.7 diesel DX rebuild

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Old Nov 27, 2025 | 04:35 AM
  #161  
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Sure brings back memories- some good- some not so much... I love your thread- thanks for posting it- great job!
Old Nov 27, 2025 | 06:57 AM
  #162  
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Originally Posted by Greg Rogers
Sure brings back memories- some good- some not so much... I love your thread- thanks for posting it- great job!
Thank you Greg.👍I haven’t had anything catastrophic happen with these engines but only a blown head gasket before I started using arp head bolts.I’ve also found arp starter bolts are a must have for this engine.Before that at least one bolt would break probably due to vibration,etc.
Old Nov 27, 2025 | 07:00 AM
  #163  
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Yesterday I installed a couple new battery hold down brackets.
Old Nov 28, 2025 | 02:53 PM
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The shop called today saying the collar is ready.Heres a picture of what it looks like.There isn’t much to it but I’m going to use larger outside diameter flat washers so the collar/ring doesn’t decide to work loose and fall out.Its a tight fit though.I had the pulley off and the collar is pretty tight upon the balancer.

I also bench bled the master cylinder and it’s back on the truck.The pushrod under the dash is also connected now to the brake pedal.Tomorrow if I get a chance I hope to put the grille back in place and the optional hood latch cable and the various parts that came with it.Instead of opening the hood from the outside,a cable will be used inside the cab.



Last edited by dieselolds81; Nov 28, 2025 at 03:02 PM.
Old Nov 30, 2025 | 05:15 AM
  #165  
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The balancer and pulley are back on the engine after giving it another shot of duplicolor alpine green engine enamel.All torqued down and good to go.I’m looking forward in getting this truck road ready.Still have a few more things to do with it but it’s getting close to done.Its been off the road about 15yrs.

Last edited by dieselolds81; Nov 30, 2025 at 08:21 AM.
Old Dec 20, 2025 | 07:47 AM
  #166  
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This morning I put another belt tensioner on this engine from Napa as the previous new tensioner under the ultra power brand I installed was making a clacking noise not to mention fluttering back and forth.As of now there is no belt flop or any noise.The tensioner now is definitely much better.It most likely has a stronger spring




Old Dec 22, 2025 | 04:31 AM
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A couple days ago I purchased a o-ring/seal kit with updated governor cage to use in one of my nos injection pumps.I have a 3271 pump with no updated cage so I’d like to take that pump apart and install the updated cage so at least then I’ll have no more flex ring breakage to worry about.

Old Dec 22, 2025 | 05:31 AM
  #168  
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There are a few videos on YouTube about rebuilding a Roosamaster injection pump.

I bought a soft parts kit with the intent of rebuilding the injection pump from my spare 7.3l IDIT engine. I've never gotten around to it. If I ever do it I recommend disassembling, cleaning and reassembling everything in one day. You don't want to leave a disassembled IP sitting around. You might forget where parts go and you'd leave it susceptible to contamination.
Old Dec 22, 2025 | 10:06 AM
  #169  
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Originally Posted by Olds64
There are a few videos on YouTube about rebuilding a Roosamaster injection pump.

I bought a soft parts kit with the intent of rebuilding the injection pump from my spare 7.3l IDIT engine. I've never gotten around to it. If I ever do it I recommend disassembling, cleaning and reassembling everything in one day. You don't want to leave a disassembled IP sitting around. You might forget where parts go and you'd leave it susceptible to contamination.
Thats true.I’ve had quite a few of these pumps apart and reassembled them with no problems.I’ve had Deere 4 cylinder and case 188 pumps dismantled as well to install new flex rings among other things.You can certainly save a lot of money by doing these repairs yourself.

Today I made a stab at replacing the old fuel tank sending unit in favor of a updated version with the water in fuel sensor.The old fuel line hoses are gone now.I got rid of all that along the chassis.Tomorrow I hope to install the new hoses and get the water in fuel wiring started.The old sending unit has a paint gun screen upon it that my father installed many years ago.










Last edited by dieselolds81; Dec 22, 2025 at 10:09 AM.
Old Dec 22, 2025 | 11:55 AM
  #170  
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Are you going to run steel lines with rubber hose on the ends? I'm not sure what Oldsmobile did from the factory. My 86 Ford F250 came with nylon fuel lines from the factory. It's sort of a PITA to replace.
Old Dec 23, 2025 | 05:43 AM
  #171  
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I thought about doing that as my other two Chevy trucks have steel lines on the chassis but I’m just going to put rubber fuel line hose all the way through and secure it in place so it can’t chafe or rub on something.I have some blue and black Adele isolator clamps I can use to keep things neat and tidy along the way with some self tapping screws.

I also have a Delphi 6.5 diesel lift pump with 3/8 Barb AN fittings on the ends I’m thinking of using.


Last edited by dieselolds81; Dec 23, 2025 at 05:46 AM.
Old Dec 23, 2025 | 05:44 AM
  #172  
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Originally Posted by Olds64
Are you going to run steel lines with rubber hose on the ends? I'm not sure what Oldsmobile did from the factory. My 86 Ford F250 came with nylon fuel lines from the factory. It's sort of a PITA to replace.
I don’t think I’ve seen nylon fuel hose.Just the typical gasoline and diesel fuel rated hose.
Old Dec 23, 2025 | 07:52 AM
  #173  
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Nylon fuel line is what is used in modern cars. It requires special tools to fabricate. CUCVs and Deuce 1/2s used OE nylon fuel lines.

https://www.summitracing.com/parts/ops-nfk81025f

I suppose it's a good alternative if you don't want to bend steel lines and want something more durable than hose.
Old Dec 23, 2025 | 11:25 AM
  #174  
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Originally Posted by Olds64
Nylon fuel line is what is used in modern cars. It requires special tools to fabricate. CUCVs and Deuce 1/2s used OE nylon fuel lines.

https://www.summitracing.com/parts/ops-nfk81025f

I suppose it's a good alternative if you don't want to bend steel lines and want something more durable than hose.
I haven’t worked on many fords but now that you mention it I do remember seeing that sort of line on the frame upon a 99 F350 7.3 I once did a oil pan R&R upon.

I think this water in fuel harness will be a great feature when I finally have it all in place.The new fuel lines are installed along the chassis up to the sending unit.The wiring connector is in place at the sending unit.I just need to run the harness along the chassis now and into the cab.I also have some brass fittings to go from 3/8 Barb to 1/8 npt which is what the lift pump uses upon the frame.Right now it has 5/16 Barb to 1/8 npt but I’ll remove those current fittings and install the 3/8.




Last edited by dieselolds81; Dec 23, 2025 at 11:33 AM.
Old Dec 24, 2025 | 01:26 PM
  #175  
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Today the new fuel hoses and water in fuel wiring was installed along the chassis.The 3/8 Barb-1/8 npt fittings were installed into the electric lift pump under the truck so all went okay with that.Just a matter now of getting the wiring in place inside the truck in regard to the water in fuel option and that’ll be completed.I used some Adele isolator clamps to keep the fuel lines secure to the chassis.




Old May 1, 2026 | 04:49 PM
  #176  
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The engine is up and running.Sorry for the delay in posting this.I will post a video in a few minutes.
Old May 1, 2026 | 04:52 PM
  #177  
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Here’s the link.I haven’t driven it yet.Its just been idling in the garage but it’s close to being driven at this point.

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