TurboDan
Registered User
I dropped my heads off at a machine shop. I'm thinking maybe I just take the block in and get it done too? Full rebuild possibly. I dunno, wish the project was going back together and not coming apart still 
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My '93 F-250 IDI Overhaul Thread
- Thread starter TurboDan
- Start date
IDIBRONCO
IDIBRONCO
I would say that it depends on what everything looks like. If your bearings are in good shape, I probably wouldn't do anything more than reseal the lower end. If there is more than just minimal wear on the bearings, it may be a good idea to put in new bearings. Of course the cam needs to come out to install new cam bearings. If you pull the crank to install new main bearings (not that you have to completely remove it to change them), then at that point, you may as well pull the pistons. If there's minimal wear in the cylinders and the pistons aren't damaged, then I would have the cylinders honed and rering it. If there's more wear than you feel comfortable with (or a lot of cylinder wear), then now would be the best time to go full Monty and have the cylinders bored and install new pistons and have everything fresh. When I overhauled my 7.3 three years back, I had to install new, decompressed pistons because the machine shop took too much material off of the heads and I would have had valves hitting pistons. I didn't go oversized on the pistons because there was minimal wear in the cylinders. If you do tear it down to a bare block, you may want to knock out the oil galley plugs on wither side of the camshaft. I tap those holes out to 1/4" NPT instead of trying to reuse the smooth plugs. If you do this, only tap in about 5 threads at the deepest. If you go deeper than that, you'll block of part or all of one of the oil gallies. I seal the plugs in with a good pipe dope (thread sealer). That's as much to hold the plugs in as it is to seal the threads. Of course, if you do tap the holes, you want to do it BEFORE you take the block to the machine shop to be cleaned up.
Big Bart
Tow&Slow
I feel it comes down to funds. If you feel cash rich then I would at least hone, re-ring, new bearings, have the camshaft checked for wear, oil cooler seals, and a new oil pump. Feeling even more cash rich have the machine shop do it so you can just slap it back together.
When you redo the heads, you will likely put some more pressure on the bottom end. So you could be pulling this all again in 10K, 20K, 30K ???? miles because your bottom end had some good wear and the higher pressures took a toll.
Do a full rebuild and you should be good for another 100k miles.
So it really comes down to
1) Minimal expense - Check a couple of bearings, do the heads, and move on. (Many have done this with good results.)
2) Medium expense - Hone and re-ring, do bearings if needed, new oil pump, and move on. (Build in some extra longevity.)
3) Big expense - Rebuild, bore, line bore, deck, heads, etc, etc, and move on! (Likely get another +100K out of your engine if you do not overheat it.)
When you redo the heads, you will likely put some more pressure on the bottom end. So you could be pulling this all again in 10K, 20K, 30K ???? miles because your bottom end had some good wear and the higher pressures took a toll.
Do a full rebuild and you should be good for another 100k miles.
So it really comes down to
1) Minimal expense - Check a couple of bearings, do the heads, and move on. (Many have done this with good results.)
2) Medium expense - Hone and re-ring, do bearings if needed, new oil pump, and move on. (Build in some extra longevity.)
3) Big expense - Rebuild, bore, line bore, deck, heads, etc, etc, and move on! (Likely get another +100K out of your engine if you do not overheat it.)
If the head surface is clean and strait tell the machine shop not to resurface. If they think a resurface is required, have them remove the minimum amount of material.
I had a set rebuilt and many areas were not in spec. They also milled too much off. F
Precups fitment is a pain after surfacing the heads too. They're made out of a super hard material so their bores have to be machined seperately from the head surface. If no surfacing is done that part is skipped
Oddly enough their is a spec for the length of cracks along the precup opening. That's good to check too. Cracks always form and small cracks are fine
www.oilburners.net
I had a set rebuilt and many areas were not in spec. They also milled too much off. F
Precups fitment is a pain after surfacing the heads too. They're made out of a super hard material so their bores have to be machined seperately from the head surface. If no surfacing is done that part is skipped
Oddly enough their is a spec for the length of cracks along the precup opening. That's good to check too. Cracks always form and small cracks are fine
6.9 Blowby...Rebuild or new rings?
Did you check how worn or out of round the cylinders were before assembling everything? Yes. I was lucky, it was still within spec.
www.oilburners.net
TurboDan
Registered User
I can't find my balancer puller, so I just ordered one along with a ridge reamer. Once they get here I'll pull the lower end apart, clean and measure. If the numbers check out I'll reassemble with fresh bearings and I'll do my best to get the insides cleaned out. Are there any common failure items inside, like do people normally replace timing gears? I know if it was a chain I'd do it for sure, but I'm not sure on the gear longevity. How about the oil pump? do those commonly wear? I did find some plastic pieces in the pan, some might have been small enough to fit in the sump. They were exhaust valve seals in their former life.
My machine shop is 3-6 months out on short block work, so I don't want to wait for that. I guess if something is way out when I inspect I'll have to find some second option. Hopefully things are just "worn" and not "trashed".
My machine shop is 3-6 months out on short block work, so I don't want to wait for that. I guess if something is way out when I inspect I'll have to find some second option. Hopefully things are just "worn" and not "trashed".
IDIBRONCO
IDIBRONCO
There's not really any common failure items other than the bearings. You can pull a cover off of the oil pump and check the rotors inside for wear. I believe that you use a feeler gauge to check the clearances. As far as I know, people don't replace the gears without a good reason. I'm not even sure if there is any replacements for them.
jrollf
Full Access Member
On my 93, I installed a Redhead Gear, and a Borgeson Steering Shaft. I'm VERY happy with it, there is no noticable slop in the steering. After install, they alignment tech even mentioned he hadn't seen an F350 with tight steering like mine.
Downside, the Borgeson Steering Shaft is expensive.
1993 FORD F 250 Borgeson Universal 000981 Borgeson Universal Telescoping Steering Shafts | Summit Racing
Free Shipping - Borgeson Universal Telescoping Steering Shafts with qualifying orders of $109. Shop Steering Shafts at Summit Racing.
TurboDan
Registered User
ok, I got #5 cylinder out and there are deep scratches in the cylinder. I'll clean the piston and see if there is some visible damage, but it doesn't look good. I can catch a fingernail slightly on the scratches. Dang it.
TurboDan
Registered User
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Other cylinders have similar marks but not all of them do.
IDIBRONCO
IDIBRONCO
Have you done anything to the engine like this before? I mean pulling the pistons out. The deeper scratch on the left hand side of the cylinder (in the picture) looks like it was there when the cylinder was honed. There's some others that appear to be the same way, but I can't tell for sure. It looks like you've been running the engine with the scratches in that cylinder for some time.
Big Bart
Tow&Slow
Was there any symptoms prior? Oil burning/smoking out of exhaust, eating a lot of oil, low compression (Rough idle), ????? Did you find anything wrong like parts off the head are broken off, glow plug broken off, part of piston ring broken off?
It appears they do not run from top to bottom. If they ran to the top it would be more challenging as you would see lower compression, more blow by, and likely more oill burning.
You should measure the bore to see if the block has every been bored out. If yes its that challenge of the walls are thinner on a 7.3 and if the SCA's were not used cavitation could be a factor in boring. (Maybe just hone and deal with a little smoke or oil burn.) But if it has not been bored and you believe SCA's where maintained, I would go ahead and bore, new bearings, new pistons, and new rings. You came this far, so why not do it right. Perhaps another shop near or far can do the boring for you. As you know the heads are complex, so you want the right shop to do those. Also perhaps see if there are any cheap donor trucks/engines around. Perhaps you can use a different engine till you rebuild this one. Or use the block out of a donor engine if yours is maxed out.
Now with all that said, if you had no issues before, and the truck cannot be down. Hone, re-ring, do heads, and see how it goes. It is just so much work to pull a engine I hate to see you shortcut and have to do all again a couple years from now.
It appears they do not run from top to bottom. If they ran to the top it would be more challenging as you would see lower compression, more blow by, and likely more oill burning.
You should measure the bore to see if the block has every been bored out. If yes its that challenge of the walls are thinner on a 7.3 and if the SCA's were not used cavitation could be a factor in boring. (Maybe just hone and deal with a little smoke or oil burn.) But if it has not been bored and you believe SCA's where maintained, I would go ahead and bore, new bearings, new pistons, and new rings. You came this far, so why not do it right. Perhaps another shop near or far can do the boring for you. As you know the heads are complex, so you want the right shop to do those. Also perhaps see if there are any cheap donor trucks/engines around. Perhaps you can use a different engine till you rebuild this one. Or use the block out of a donor engine if yours is maxed out.
Now with all that said, if you had no issues before, and the truck cannot be down. Hone, re-ring, do heads, and see how it goes. It is just so much work to pull a engine I hate to see you shortcut and have to do all again a couple years from now.
TurboDan
Registered User
This is the first time I’ve had it apart. The pistons have some scuff marks above the top rings but the skirts all look pretty darn good for a 250k motor. Bearings show wear but not what I would call abnormal. Nothing obviously wrong with any journals on the crank. I didn’t drive the truck much and I don’t recall it using too much oil or any serious smoking. Glow plugs were all intact. It did have a crap load of oil leaking, the outside of the motor was covered with an insane amount of oil sludge. One head had an exhaust guide that was very very worn but the truck had no miss. I didn’t bother taking the other head apart when I realized the one needed to go to the machine shop - both heads ended up going to the shop. I’ll try and call a machine shop tomorrow to see what the turnaround time and costs would be for full on machine work on the block.
TurboDan
Registered User
Some pics
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You must be registered for see images attach
IDIBRONCO
IDIBRONCO
So are the cylinders standard? If they have been bored already, you don't want to bore them out farther. Our limit at the shop I used to work at was .020". If they wouldn't clean up at .020", they would be sleeved back to standard.
