Trailered home a 1989 F350 dump truck that looks great on the outside, but the 7.3 IDI is something else

crazydane

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As I was cleaning up and re-arranging engine parts to prepare to start tearing down the original '89 engine, I moved the heads and the pre-cups fell out of them. I was a bit surprised as I figured they would have been in there pretty snug. Not a big deal since I won't be using these pre-ups anyway, but figured I'd share.

Here they are:

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While #5 is definitely the worse, several of the others have worn/enlarged openings as well.

Here's the backside of one of them:

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They all have at least some cracks, but none of them extend beyond the fire ring.

I got the good '92 block transferred to my lift table so that I can use the stand for the '89 engine:

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The fingers on my 1,200 lbs. stand are not long enough to reach the bottom bellhousing threads, so with this large engine, I'm forced to leave the starter plate, or whatever its called, on:

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It makes for quite an unbalanced mass when rotating the engine around, but I've managed so far without flipping the stand. :)

I've been supporting the engine with 4x4 blocks until I get the heads off before just letting the engine hang on the stand, and even then, it tilts forward. Definitely the heaviest block I have dealt with to date!

One other little tidbit, that little barrel that goes on top of the #1 injector was missing completely from the '89 engine I returned (it was on #2 on the original engine). On the '92 engine, it was on #1 like it was supposed to. Someone cross threaded the fuel line on the '92 one unfortunately:

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I suspect the threads can be straightened, but since the '89 one is good, I'll use it. Don't know if anyone is looking for one of these guys. If so, let me know and its yours.
 
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crazydane

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Tore the original '89 block the rest of the way down. Here's the #8 piston that caused the damage to the cylinder wall:

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Not sure what would have caused the failing but afterwards, the wrist pin walked out and started scraping the bore:

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I have not found the clip yet that supposedly went on the one side of the piston. Could it be that whoever rebuild this engine last forgot to put it on?

When I first pulled the pan, I found this:

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I think its the spring from the rear seal. Won't know for sure until I pull the old one.

Also, on #8, I'm 99% sure it was sleeved at some point:

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So maybe this block would be salvageable by putting in a new sleeve?

Also, the rod bearing are all Clevite STD size. Haven't popped the main caps yet, but I suspect those will the STD as well.

When I pushed out the pistons, the rings cleared the ridge easily, but the skirts got hung up at the ridge and took some effort to get out.
 
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crazydane

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I'll see if the machine shop would be willing to trade working on my '92 block in exchange for the '89 block. Doesn't hurt to ask and I can throw them both on the truck to take down there next week if he's will to at least look at it before deciding.

While I haven't put the micrometer on the .020 over pistons from the '89 block yet, my gut tells me they have some taper to them with the skirts being wider than the tops. So I'm thinking I won't be using any of those in the '92 block.

So I think my plan at this point is to take the '92 block to the machine shop, have him hone the bores and if #5 is too far out of spec after doing that, bore it .010 over and get fresh piston for that hole. Especially if he's willing to trade labor cost of the '89 block.
 

The_Josh_Bear

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I was going to suggest replacing that pop-tester gauge anyway since it's about 4x the scale we need. If you can find one for 2500psi that's ideal, 3k may be more accessible. That way you can get the resolution to get each injector within 50psi, which is ideal.
So I was late to the party on that one but that's the mod I would do to that tester.

Keep up the good work! Love the progress and pictures. It's fun to follow along and see your thoughts.
 

crazydane

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Great idea about just getting a gauge with the proper range. The Amazon reseller is giving me a hard time about getting a replacement. They want to see a video of me pumping and the gauge not moving. Already sent off all the injectors this morning are cores, so that's not going to happen for a while, so I'll probably just get a new gauge and be done with it.

Dropped the block of at the diesel machine shop this morning:

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He said he can bore #5 .010 over, but that the engine will no longer be balanced since a .010 piston weigh more than a STD one. He suggested that if I go that route, use a gram scale and drill out some aluminum on the .010 piston until it weigh the same as the other ones.

He did agree the ridges are not bad, but they are not even across the circumference on several of the cylinders. Cleaning up the ridges can be time consuming and a hone won't get rid of them. Anyway, he's going to check out the block and let me know his recommendation.

Maybe taking all the bores to .020 over is the best path forward and then re-use the pistons from my original engine? But I'll definitely want to measure them first to make sure they don't have taper to them, as the skirts did seem wider when I pulled them out.
 
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Nero

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Machine shop may know more than me, but last I recall machine shops drilled out the wrist pin a little for balancing. But don't take what I say as gospel its just what I've seen done on other engines.
 

crazydane

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I took a closer look at both my oem STD pistons and the .020 Mahle ones and I don't know that I would want to be drilling into any of them.

I then looked at the cost of a set of rings, cheapest I could find was $187 (ENGINETECH from rockauto), and knowing that I would need at least one more piston anyway (ENGINETECH K1577 $50 from rockauto), I figured I might as spend another $163 and just get a full set of pistons and rings from rockauto @ $400. Unfortunately they don't have anything smaller than .030 (was hoping for .020), but I guess taking out an extra .010 from the already thin cylinder walls is not the end of the world.

Also, I measured one of the .020 pistons and it was 4.108 at the top and 4.125 at the skirt. No wonder they were hard to pull all the way out.

Only question I have is that they are destroked .010, which combined with my thicker Felpro head gaskets, means I'll likely loose a bit of compression. Do you guys think that would be an issue?
 
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crazydane

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After noodling it over and speaking to the shop, I'm going to have them order the pistons and rings for me that are .020 over. Here's the full quite for parts and labor:

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So labor total of just over 6 hours or $660 and the cost of the .020 pistons is better than what I found online. This way I'll have a really good foundation I think for putting this thing back together.

I also decided to get brand new injectors vs. rebuild ones. Also ordered a Spectre 42473 fuel pump block off plate along with a can of VHT SP137 engine enamel. Finally, since the previous owner had bypassed the stock fuel supply line due to an issue with delivery, I picked up this guy:

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I plan to drop both tanks and clean them out really good and blow out all the lines and start out with fresh fuel when it comes time to do the first start up. I'll of course also be putting in a new filter/water separator.

Any particular break-in oil you guys would recommend? And have a garden hose running fresh water through the radiator during that initial 10 minute run, or?
 

Old Goat

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That is great you are going the extra mile and doing the engine right, cutting corners can come back and bite you in the ....
Pay now or pay later.

If this truck isn`t going to see many miles as you said above, why not just go with one tank, and eliminate the FSV?
I went through my fuel system a few years back. Changed to the 38 Gallon rear tank, replaced both Fuel Senders and a new $50 FSV off E-bay.
Worked good few time I was flipping it to see if it worked.
Ran on the 38 majority of the time and figured my front as a back up. About a year or so later flipped the switch to see if it worked, and it stuck between tanks, now didn`t know what tank I was on.
I was pulling from rear and returning to the front till I had fuel leaking out of the front one.

After much fiddling around etc... the rear goes to the Engine and returns to the rear. Front tank I plumbed with an electric pump as a transfer to the rear tank.

Just throwing it out there, something to think about.

I can get 600 mile out of the rear tank. usually fill around 500 miles.
You being a 350 and geared lower would be different.


Goat
 
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crazydane

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Good point about bypassing one of the tanks. That said, I would like to take the truck back to stock as much as possible. Accurate Diesel gave me credit for 15 of the 16 injector cores I returned so that mostly covers the cost of FSV. I also decided to go with brand new injectors vs. rebuild.

Furthermore, I dropped all 4 heads off at the machine shop and told them to use the '89 heads, but if the valves in the '92 heads look better, use those when rebuilding the '89 heads. Just got a lot of other things going on, so I figured I'd go ahead and outsource redoing the heads to them along with the block.

This way, when I get back the block and heads, I know they will be ready to go!
 

crazydane

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Machine shop called me back this morning and said that all 4 heads were cracked and no good to use.

Any suggestions on where to pick up a good set of heads with cores?

Found this place:


$450 a head seems reasonable. Need to call them and find out about core charge.
 
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Nero

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Were the heads actually cracked, or were they seeing the cracking in the precups that is normal and don't know what to look for?
 

crazydane

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I believe they magnafluxed the castings themselves, but let me verify with them. Good point!

EDIT: Yeah, they magnafluxed the castings and that's when they found out.
 

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