Just another 7.3 under the knife.

[MeTo]

At first I wasn't going to do an engine post. There is little interest in a tow pig engine build. But I do have some questions, so some advice/tips would be appreciated.

The engine:
The engine only has about 113,000 miles on it, but the previous owner’s son-in-law who drove it for his business was an idiot. My big hope is that there are no piston gland pieces and cylinder wall streaks???? It doesn’t use oil and sounds mechanically great, but compression is a tight 360 psi on the driver’s side and 340 psi on the passenger side. The oil pan RTV is weeping. I ran the VIN with Ford, they told me the original engine was warrantied in 2000 at 74,000 with a replacement Navistar long block and turbo. WTH! Ford would not give me any details based on customer privacy. In the end, I got a
97 F350 diesel 4x4 for ONE grand.

So, I'm not looking for more hp/torque. I just want to reseal (rings, gaskets & o-rings) and do some reliability mods. Hopefully the pistons are intact and there are no streaks on the cylinder walls?

On the do list:
It HAD a duel mass flywheel, I ordered a South Bend 144-50K.
I modified the bracket for a duel idler tensioner.
New water pump, hoses, thermostat housing and a ss support ring to reinforce the housing.
Fab a weld in dipstick tube flange, no leaks there.
Replace HPOP hoses.
Install a super duty dipstick; the handle is above the cac pipe.
Fab a valley drain tube.
No fan and clutch, electric, it only pulls a small camper.
Tack oil spouts.
Heads & block will go to the machinist, $$$; just for what I don't have the tools to do.

Questions:
Pilot bearing, what's my best option? Bronze?
Would a 2000 Navistar long block have Cat ELC compatible sealant on the injector cups?
More to come.

I will post picks if anything interesting turns up? Hopefully NOT!

 

[CJunkie]

Why are you worried about compression and cylinder walls/pistons? Compression sounds ok to me

Sent from my SM-J320V using Tapatalk

 

[psduser1]

340 is a bit low on the compression, given the mileage, but hard telling till you get it open. If the bored are reasonably round yet, hone it and re-ring. Bearings, etc. as well obviously.
Google "oilite bushing", should bring up plenty of options. Oil impregnated bronze bushings, no lubrication reccommended.
Readily available, once you have the dimensions for the input shaft and pilot bore.
Edit* could just run it for a bit, unless it's down on power, or hard to start, etc.

 

[MeTo]

1st, the oil pan is leaking. The camper is always splattered with black oil. 2nd, my engine's compression for only ~113,00 miles is not normal wear. Especially for one entire bank to be 20 psi lower than the other.

The local diesel guy thinks the Navistar remand long block that was warranted by Ford, has a defect? He has seen many and has stories to tell; his first is don't buy Jasper. His money is on the block, he thinks it has been bored and the dimensions are not right on both banks? He stated a 300,000 plus mile engine typically has compression in that range.

I'm 60 years old and want to put this right NOW. By the time this needs to be done again. My wife's second husband can dell with it.

 

[MeTo]

340 is a bit low on the compression, given the mileage, but hard telling till you get it open. If the bored are reasonably round yet, hone it and re-ring. Bearings, etc. as well obviously.
Google "oilite bushing", should bring up plenty of options. Oil impregnated bronze bushings, no lubrication reccommended.
Readily available, once you have the dimensions for the input shaft and pilot bore.
Edit* could just run it for a bit, unless it's down on power, or hard to start, etc.

Agreed.

1st, I'm going to check the cylinder walls for streaking and cross hatch? Then I will plastigauge the journals. I'm confident the bottom end is ok. Not needing to bore will be grand.

The diesel gut I talk to has seen the rings and piston gland pieces fall on the floor when the pistons are removed on some.

I have read about the bronze pilot bushing, but haven't found one for the 7.3. Next, I'm going to measure the shaft and bore and either find one on line or have one cut?

 

[MeTo]

I tried to check my remand Navistar engine serial number, it's been rubbed out. Maybe it came from Chicago? Has anyone seen anything like this? The remand long block was done by Ford under warranty.

Would Navistar remove the original Ford serial number and stamp theirs?

 

[superpsd]

Just my advice. I would find another used tested long block. Maybe even keep and eye out for a running rolled truck. Will be much cheaper than a rebuild.

 

[co04cobra]

At 340 to 360 on compression, IMO, I wouldn't touch the heads, reseal it and run another 200K+ miles.

And I have compression checked A LOT of 7.3s. There are zero reasons to be concerned with those numbers.

 

[MeTo]

Thanks for the replies.

My intent with this endeavor is not to waste money or time, we could be boondocking. My truck is not a DD, it just pulls our light converted aluminum cargo trailer, which I converted into a solar boondock camper. I have had it in Yellowknife (NW Territory), a lot of Crown land in Canada and each year it pulls the camper from WI to the SW Arizona desert and National Forests in the west in the summer. So, it gets a lot of miles in some very remote areas; often with no bars on the phone. Because of that and my wife takes the truck and pulls her camper with it too, I need to know for sure that it's as reliable as I can make it.

Ideally, if I don't fine anything menacing inside, I will rering, reseal new injector cups with Loctite 620 for Cat ELC compatibility, do some reliability mods, new hoses/belt, replace oil cooler cartridge/orings, new LPOP and reseal everything using the Ford gasket set.

The injectors are Alliant ACs with ~35,000 miles on them, they are good to go.

With some luck, I should know without ANY doubt, the engine is rock sold. I have already been through everything else in the drive train.

As for replacing the DMF/clutch, Corey (CNC Fab) talked me into the SB 144-50KHD, not the 144-50K. Of course a new throw out bearing, bronze pilot bushing (self cut), fork and ball stud. I'm thinking about attaching a small steel tube/zerk on the clutch fork to grease the ball stud from the outside? No rocket science anticipated?

In the end, reliability, not cheap is the objective.

 

[MeTo]

Well I got the heads off today. The pistons are 10 over and all look good from the top. There is NO crosshatch visible. I can feel a ridge on the top of the wall, but it's about a thousandth or two? The engine has ~104,000 miles on it.

For an engine I just wanted to run. I would break the glaze, hand fit the rings and run it. I'm not sure with this thing? What say you?

 

[MeTo]

This is what I found under some of the caps.

 

[MeTo]

A tow pig thread, will I be talking to myself?

I measured the cylinder bores; extremely close to 4.11 for 10 over bores.

I'm hoping I can just break the glaze and hand fit the rings myself?

Tomorrow I will drop it off at the local machinist and get his evaluation. I'm thinking line honing, grind the main/rod journals from 10 to 20 under, cook and magnaflux?

The heads look great. I'm going to give the valves a hand lap and new seals. Replace injector cups just reseal with Loctite 620 for Cat ELC. Not sure if I' going to have them cooked and magnafluxed? Should I do it for peace of mind and insurance?

 

[mandkole]

To Cobra's point and his experience, it's a lot of work to fluff/buff it. 350# even across all cyls is fine for an intermittent trailer puller. What did it leak down? For me, do a full machine rebuild or nothing.

You have some maintenance stuff that needs attention. Sealing the high pressure oil plumbing/injs and charge air plumbing would have gone a long way. However, with no cross hatching it's hard to imagine you have a 110k mile motor there, so who knows?

Best of luck and you'll certainly learn a few things along the way.

 

[Magnum PD]

Just polish the crank?

 

[MeTo]

Just polish the crank?

I questioned it to. It's a slang term the machinist uses for grinding a crank, "because everyone likes shinny".

 

[psduser1]

At 340 to 360 on compression, IMO, I wouldn't touch the heads, reseal it and run another 200K+ miles.

And I have compression checked A LOT of 7.3s. There are zero reasons to be concerned with those numbers.

This is definitely doable-just add fuel and air. Wa-la, power gets better! Definitely less expensive than a rebuild, and will probably last indefinitely, based on use.

To Cobra's point and his experience, it's a lot of work to fluff/buff it. 350# even across all cyls is fine for an intermittent trailer puller. What did it leak down? For me, do a full machine rebuild or nothing.

You have some maintenance stuff that needs attention. Sealing the high pressure oil plumbing/injs and charge air plumbing would have gone a long way. However, with no cross hatching it's hard to imagine you have a 110k mile motor there, so who knows?

Best of luck and you'll certainly learn a few things along the way.

No crosshatch says high boost/high mileage to me. A glaze-breaker and hone will extend service life, maybe enough for what you want.
An overbore and piston would be better, and at lower hp levels, a basic piston shouldn't add more than 1-1200$ for the machine work and piston. Youre buying rings already, and hopefully balancing the bottom end.
That will get you another 200k, easily, even the 400+ hp range, and probably a lot longer, based on use, lol.
By then the valves will have pulled themselves well into the heads.:thumbsup:

 

[Magnum PD]

I questioned it to. It's a slang term the machinist uses for grinding a crank, "because everyone likes shinny".

No, I was asking, is the crank within range of not having to machine it for under size bearings.

 

[MeTo]

All journals are 10 under and pistons are 10 over.

I checked the top compression ring end gap on number 1 and its at 39 thousandths. I'm wounding if standard rings were accidentally installed?

A little history:
When I purchased the truck, it had been sitting for a couple of years. The owner had retired and sold his little business. He had hired his son-in-law to drive it. When I checked it out, it had a slight miss on number1 and a oiled gauze filter. Upon closer inspection, the filter had about a 1/4" hole worn through the bottom side. I checked the intake and turbo fins and could see it got dusted. No surprise there. This truck lived on gravel roads in NC New Mexico. We talked about a price and had a few beers. In the end, I got a rust free 97 F350 4x4 diesel for $1000 and a hand shack I would haul something if he needed it? I haven't heard from him in 3 years. The miss was the number 1 injector, I replaced them with New Alliant ACs. I shored up the rest of the drive train and now I see I will be investing a little more than I had anticipated into the engine. I have no regrets. I'm just chugging away at make it as reliable as reasonably possible.

Oh, and school is in session!

 

[mandkole]

^^^ok, now I understand your reasoning, haha. It doesn't owe you anything and I like going to school on these old trucks too.. Keep up the thread, they're fun.

 

[dsberman94]

I’d rebuild the engine with machine work. You’ve got a clean old obs for dirt cheap that should last a lot longer. With a rebuilt engine that’s probably an $8000 truck where I’m at.