Engine rebuild on a '53 B-61T: END673

[Keith S]

I'm considering a complete rebuild of my END673. It's not the original engine.

Fuel injection:

• Needs new lines. Straight or pre-bent are sold as a pair - if someone is interested in a set.
• Injectors "look" OK for a quick (not expensive) rebuild.

Cylinder heads:

• Pulled the valve covers, it looks like a fairly recent valve job - or at least new spring!
• Found a broken flat-head phillips screw sitting there doing nothing - no idea.
• A lot of carbon buildup on the intake and exhaust ports.
• Slight sign of water on #4 intake valve
• Pulled both heads
  • Cylinder #4 shows pitted rust. It's not seized.
  • Some head studs had been removed/installed with vise grips - I've seen a lot worse, but.
  • Two different heads
  • Two different head gasket types
  • Two different rocker shaft mounting brackets - one was stepped, the other solid.

Haven't dropped the oil pan yet.

Thoughts on a complete rebuild?

Edited December 25, 2023 by Keith S

[Joey Mack]

I guess, after all the hard parts are checked for re-use, you can go for it..  Many engine parts are still available..  I have one in my shop, and between PAI, and finding spare parts here at BMT,  I have what I need to finish it..  I see you have 18 bolt heads..  I'm pretty sure the head gaskets are still available..   jojo

[mowerman]

Rod mains and wrist, pins , are an absolute must once you get it that far down that’s what I would do then if you’re going to go that far might as well do the cylinders kits good luck

[mowerman]

Let me rephrase check the tolerances,, especially wrist pin  free, free play from a photograph your cylinder. Walls appear to be in pretty good shape. 

[mowerman]

I plan on dropping my pan eventually just to check everything out Old engine I would rather be sure everything is OK And catch any issues before they turn into a major mountains

[Keith S]

Cylinder #4 is rust-pitted.

PAI has a lot of parts for the E6 with notes that include the END673. Except for the head gaskets, most pieces-parts "look" correct.

Are the major components for the END673 and the E6 comparable?

[mowerman]

Well, your guess is good as mine as far as I remember E6 is a 676 Oh sure Joey would know good luck… bob 

[Joey Mack]

Thanks Bob, but I too am not totaly sure..  I am weak when it comes to END(T) or E-6..  Too me they are all E-6's..  I believe the water pump is the same style, just need to know if you have a short shaft or long shaft. I have seen different styled intake manifolds, some with a round inlet and some with an oval inlets..  I'm sorry I dont know more.  I just so happens that I will be back in the shop after Christmas Vacation..  I have an ENDT 673 and an E-Tech on stands and just recieved parts last week.  If I come up with Ideas on the ENDT -673, I will post them here along with pictures..  Jojo

[mowerman]

I have heard of aftermarket overhaul parts, but haven’t heard anything solid on anything. I wouldn’t be surprised if they were the same overall parts but no I do not know. Fortunately, my engine runs well with great oil pressure and hopefully I don’t have to put anything in it that is impossible to find. I’ve had four days off and done almost nothing the entire time yesterday I didn’t even get dressed.

[Keith S]

Head gaskets seem to be the biggest issue. PAI only list 20-stud gaskets.

[Joey Mack]

    Keith S,,  If you can get a hold of this book, it has a ton of part numbers..  however, I did not see the # for 18 bolt head gaskets..  

[mowerman]

I’m sure Mike would have all the answers, but we hardly hear from him

[Vladislav]

I may be wrong (never dealt with END673 by my hands) but what I figured out from the forum Mack made a major step redoing 673 into Maxidyne family. Those were called ETAZ-675 or so and further on and I belive started calling E6 and EM6 at a certain time. The matter I mention that is Maxidyne engines got newer more massive crank shaft and rods with reinforcements in the block too. Those parts differ from END-673, 711 and other older engines. E6/EM6 have removable liners you can purchase from PAI or other suppliers and they have an edge circle over the top to press into steel firerings to seal against the heads. Heads have recesses corresponding the edges at each cylinder. What is important all those parts are avalible and if older 673 have different liners, bearings, gaskets etc the overhaul may be found troubleful.

What I have on my mind is checking out on purchasing some old EM6 and use it as a basis for overhaul. Those engines look very similar to 673 at the outside and the most mating spots are similar. I mean the oil pan, front cover, etc. Sure every spot should be checked out for that but in general both engines have plenty of similarities.

I don't declare it as the way to go. But a possible option. First it worth to check out possibility of purchasing parts for 673 and having the value you may look for alternatives. My guess is buying a complete engine for parts wouldn't be a big offset in cost from the cost of all new parts. And as long as your engine is already not original to the truck you don't loose truck's originality much.

[JoeH]

44 minutes ago, Vladislav said:

I may be wrong (never dealt with END673 by my hands) but what I figured out from the forum Mack made a major step redoing 673 into Maxidyne family. Those were called ETAZ-675 or so and further on and I belive started calling E6 and EM6 at a certain time. The matter I mention that is Maxidyne engines got newer more massive crank shaft and rods with reinforcements in the block too. Those parts differ from END-673, 711 and other older engines. E6/EM6 have removable liners you can purchase from PAI or other suppliers and they have an edge circle over the top to press into steel firerings to seal against the heads. Heads have recesses corresponding the edges at each cylinder. What is important all those parts are avalible and if older 673 have different liners, bearings, gaskets etc the overhaul may be found troubleful.

What I have on my mind is checking out on purchasing some old EM6 and use it as a basis for overhaul. Those engines look very similar to 673 at the outside and the most mating spots are similar. I mean the oil pan, front cover, etc. Sure every spot should be checked out for that but in general both engines have plenty of similarities.

I don't declare it as the way to go. But a possible option. First it worth to check out possibility of purchasing parts for 673 and having the value you may look for alternatives. My guess is buying a complete engine for parts wouldn't be a big offset in cost from the cost of all new parts. And as long as your engine is already not original to the truck you don't loose truck's originality much.

This block uses the same oil pan gasket as the E7.

I think there are incremental differences in the 673 block casting as more was demanded of it. Pistons and liners should be the same, the displacement never changed. Biggest question will be head gaskets, and replacement heads if these can't be rebuilt.

[Keith S]

I'm finding a lot of things look good until looking at the details:

• Cylinder head studs & nuts
  • My 673 uses 9/16-18 x 6.75"
  • PAI has the 6.75" length... but only in 5/8-18, nuts too.
• Pistons, liners and head gaskets
  • Pistons... maybe. If the 673 pin diameter is 2" and 15:1 or 17:1 compression
  • Liners - all seem to be for use with the Fire Ring heads & gaskets
  • Head gaskets - Only for 20 stud heads/block.
  • I found a set of 18 stud gaskets - $375.
• Fuel injection
  • Don't know if the injection tubes leak. Water got in #4 cylinder somehow?
  • PAI has replacement tubes, but do the fit?

It's easy to spend a lot of money before knowing what I need and what's available. It's hard to get dimensions of new parts.

I'd like to rebuild it just because I like this stuff. But not if I can't get the parts I need for a nice, quality rebuild of the engine and accessories.

Edited December 27, 2023 by Keith S

[Keith S]

But... It's probably cheaper than an electric conversion

Probably

[Joey Mack]

What is the condition of the studs, they can be re-used. You have 2 different stud diameters. 

[Joey Mack]

I know that one of the END's I took apart had one piece pistons that were longer with more rings. But I think I put updated 2 pc. pistons in...   I dont know why I am forgetting..  As you can see,,  for me the old pistons are good for pencil holders..  

[Keith S]

All the stud are 9/16-18 x 6.75". A few are little rust-pitted, and a few more show minor marks from using vise-grips.

I was able to easily remove the nuts on all but one of the eight studs that unscrewed from the block. I'm confident the studs will torque up.

[Joey Mack]

Here is a sample of the info in the book I posted for you..  If you need part numbers, i will do my best to post the info..  

[Joey Mack]

just curious, do you not have 4 or is it 8,,,   larger diameter studs at the ends of the heads?  

[mechohaulic]

most important part of engine rebuild whether combo of old studs  VS new is the retorque after ??hrs. never seemed so complicated back then;;quess goes back to common idea of things SO DAARN SIMPLER THEN . 

[mechohaulic]

2 hours ago, Joey Mack said:

I know that one of the END's I took apart had one piece pistons that were longer with more rings. But I think I put updated 2 pc. pistons in...   I dont know why I am forgetting..  As you can see,,  for me the old pistons are good for pencil holders..  

they may hold a lot of pencils today ;;but those one piecers  pushed a lot of horsepower back in the day. pencil holders are in government offices today. LOL just sayin.  now  jack daniels wait your turn to speak.

[Joey Mack]

there is a machine shop in Charlotte that said they could ceramic coat the old pistons for re-use..  we opted out, but I would love to see them installed and see it run, for a couple years..  

[mechohaulic]

this ceramic topic has me wondering also. have been reading these post of ceramic lifters.  of the many hopes I have before my final breath is to participate in an engine rebuild by new day standards to witness new technology