6.5 Diesel Block Identification (moved from navistar thread)

[Busted]

I have a block with GM in the lifter valley and on the main caps, the 1255506 casting number on the bell flange, and 506 on the back of the block, but no Navistar diamond and no 506 in dots in the valley. For those who see a lot of chinese/AMG blocks, what do I most likely have?

It's crack-free, looks beefier with the thicker taller main bearing caps etc., just want to be sure before I pour a lot of money into a buildup . . . .

[john8662]

I have a block with GM in the lifter valley and on the main caps, the 1255506 casting number on the bell flange, and 506 on the back of the block, but no Navistar diamond and no 506 in dots in the valley. For those who see a lot of chinese/AMG blocks, what do I most likely have?


Sounds like an early 506 block. Look for the date code on the opposite mounting flange as you found the casting number. Post that and we can tell you what it is, if there isn't one, post a picture and I can tell if it's foreign.

J

[Busted]

The date code is C221

I also can't find oil spray nozzles, but then I'm not completely sure what I'm looking for . . .

[Busted]

Figured I'd post a couple pictures anyway for future reference/comparison.

http://i20.photobucket.com/albums/b222/Byronm/IMG_0264.jpg

http://i20.photobucket.com/albums/b222/Byronm/IMG_0262.jpg

http://i20.photobucket.com/albums/b222/Byronm/IMG_0248.jpg

[Robyn]

The early 506 blocks had large outer bolts (center mains) and no spray nozzles.

The spray nozzles are located in the main saddle of the block on both sides of center.

The center hole in the main saddle is the oil feed hole. The ones a little offset are the squirt holes.

The squirt holes have a little aluminum nozzle pressed into them and they aim up into the cylinder to help cool the piston crown.

The nozzles recieve oil all the time the engine is running.
The oil feed from the pump comes from the oil gallery to the mains via the cam and then feeds the goove in the upper main bearing. The groove has pressure oil all the time as does the squirt nozzles.

The 97 production 6.5's had the large outer bolts and the nozzles. These were one of the most failure prone blocks built.

In subsequent years the outer bolts were reduced to 10MM down from 12MM and the size of the oil squirt holes was reduced also.

The oil pump used on the squirt motors was of a larger displacement to handle the huge loss of oil volume from the squirts.

These pumps have a 1/2" (Approx) spacer in the middle of the pump between the pump body and the cover. The gears are longer too.

The squirt block pump can be used on a non squirt block but not the other way around.

Using the lower volume pump on a squirt block will cause a very low oil pressure condition at low speeds.

Cracks can't generally be seen well until the block is bare and clean.

Some cracks will start at the register fit where the caps sit in the block. Most though start on the inside of the outer bolts holes (center mains only) and progress outward and then down the web along the length of the hole.

Many of the cracks can't be seen easily even after the block is cleaned up.

The trick to finding these little animals is to heat the web around the outer holes with a propane torch.

You dont have to fry the thing but just get the web Hot to the touch in that area. Let sit a bit and any cracks will see any oily band show up as the oil cooks out.
As long as any cracks dont go beyond the depth of the hole, they can be repaired with the Lock and Stitch full torque inserts.

A crack that starts in the area of the register corner and progresses down the web pretty much dooms the block to becoming a door stop.

Also have a look see at the cylinder deck area especially in the area of cyl's 1 and 2

errosion around the fire ring contact area is common. If its not too bad it can be fixed handily by machining the deck .010" and using a OS Felpro gasket.

Before you rip the sucker all apart. Make sure how far above the deck the pistons come (both sides) stock is flush to.002" above.

If you find that the pistons are above the deck more than this Oh say .010 or ??? the block has been decked prior to you owning it.

Now Felpro makes a .010 thicker gasket. Cometic will make a thicker one if you need it.

If you find that you need to take .020 or so off the block, Cometic will custom make gaskets for you.

Ask me how I know this.

Always replace the cam bearings on these engines any time there is machine work done.
The cam bores have a groove behind them and there is a nice Hidding place for sahvings to get stuck. Then when you run the thing there is an issue. Game over.

Remove cam bearings, machine block, hot tank or wash, resinstall bearings.

Make sure the cam bearings are installed just like the originals with the oil delivery holes oriented the same.

The front bearing has a notch, it goes to the front.

Hope this stuff is useful

Have fun
Missy

[john8662]

You've got a 2001 block, just prior to the Navistar casting, in appearance.

It's has the later caps on it, with the slants from the top bolts down to the lower outer main bolts.

It's a GM block.

Proceed with tear down.

[Busted]

Cool, thanks for the input!! When I looked in the valley and saw no Navistar diamond I was worried that I got a foreign block . . .

[More Power]

The date code is C221

This is likely one of the last GM produced blocks. AM General's first re-designed (with Navistar's help) blocks appeared sometime in November of 2001, and had the new date code numbering system.

I'd be curious what cylinder heads this block had on it - i.e. whether small or large port pre-cups.

Jim

[Busted]

The heads have the small port pre-cups, with one square stamped into them.

[Robyn]

Thats interesting. The later engines usually have the diamond stamped cups which has a large (largest) port.

Unless the engine was an N/A model.

Robyn

[Busted]

Interesting--do you know if it's possible to purchase just the pre-cups from GM or anyone else?

[Robyn]

GM sells cup seperately

They are $$$$$$$$$$$$$$$$$$$$$$$$$

Std size is a GM # 10183926 @ $72.99 each list and $42.21 shop price

There is an Over sized cup too GM# 12550985

Not sure about the oversized ones. Possibly need a special tool to install.

As lonf as the cups dont fall out there fine.

One can lighty stake both side of the cups long the part line to retain them until the heads are installed.

Just a light dimple is all thats needed.

Personally I would scrounge through some used heads and fine a set of cups marked with the "T" and as long as they dont have nasty cracks they are fine.

The late 6.5 TD's had diamond stamped cups.

Small port for economy and large port for power.

6.2's had little tiny ports as compared to the 6.5 td's

You can find a "Sticky Post" in the 6.5/6.2 tech section on assembly tips
I posted a nice pix of the different cups clearly showing the markings.

Hope this helps

Missy

[ashbee37]

can you tell me what year this block is

[Robyn]

Can you post a better piccy with good contrast of that date code (Right side rear on the bell housing flange)

Run a wire brush over the area and clean it good first.

The one piccy is just too washed out to really tell much.

Is that 6.2 ?? I see in one piccy, the 700R4 TV cable bracket.


Let us know

Missy

[ashbee37]

thanks Robyn, its all the same motor, ex militry
here are a few more photos of number and casting marks in the vally under injector pump looks like two triangles faceing away from each other then an MN
if someone wants the cable they can have it just pay postage from oz, it is a kick down for the gearbox isnt it?
pump type is db2831-5209
the last letter looks to me to be a p but one of your other threads dosnt say anything about a p????????

[Robyn]

The double triangles or Diamond <> is the Navistar casting logo

This could be one of the last GM engines that was made before AMG took over fully.

Does this engine have the one piece rear main seal ???

The pictures are still just to fuzzy to see the Numbers in the Julian date

The last engines that were done by GM were cast at the Navistar Foundary.

The later ones that were all AMG had a juilian date that started with a Letter.

H was 2001
I was not used
J was 2002
K
L
M
and so on

The AMG Blocks are all date coded with a Letter followed by 00 00 numbers that represent the month and day.

H 01 20 or some such

The GM codes are different.

Your engine is most likely a 6.5 and not a 6.2

If it has a single piece rear main then its almost a sure bet that its a 6.5

Navistar, as far as I know never cast a 6.2 block.

Now some late 90 through 93 6.2 engines used the 599 casting numbered block and were built as 6.2 engines.

These engines share the same crank as the 6.5 engine.

The cable and bracket of this type were used on the 700R4 and are a TV cable, and controls the throttle pressure on the 700R tranny.

Missy

[CedarGrove]

thanks Robyn, its all the same motor, ex militry
here are a few more photos of number and casting marks in the vally under injector pump looks like two triangles faceing away from each other then an MN
if someone wants the cable they can have it just pay postage from oz, it is a kick down for the gearbox isnt it?
pump type is db2831-5209
the last letter looks to me to be a p but one of your other threads dosnt say anything about a p????????

That is a GEP block, but I don't think it's a tv cable for a 700r4. This engine came out of a N/A Hummvee and I don't think they are rockin' the 700.

The letter might be an R (2008). They didn't use some letters that might be mistaken for another letter.

I have an engine just like yours and just finished rebuilding it this weekend. Ask me anything.

[Robyn]

Your right, the military never used the 700R4, they used the TH400 in most of the applications.

That bracket is a dead ringer for the 700R4 TV cable connection.

I just had one in my hand a couple hours ago.

It may be for another purpose, I have no clue as to what though.

I have had my hands on several Ex MIL 6.2/6.5 engines and they all had mechanical injection pumps and TH 400 trannies that used the vacuum valve on the IP to run the modulator.

That bracket is very freshly painted as compared to the stuff around it, making me wonder, if maybe the engine has been used in another application since being G I issue


Missy

[CedarGrove]

My engine came with the same bracket, so I'm sure it's a Humvee thing.

[argo]

It is my understanding that some TH-400 applications are running a cable operated modulator instead of the vacuum modulator we are familiar with. It bolts in place of the vacuum unit and it is operated with a 700-R4 type cable.

[CedarGrove]

I couldn't find the part in the humvee manuals, but I was able to identify it as part # 12339141 through kascar Bracket, Electrical Modulator Control

Bracket, Electrical Modulator Control,1993 and 1994 H1 and all HMMWV with Turbo 400 Transmission

[Robyn]

That makes perfect sense.

I had forgotten about the "NON vacuum" modulators on the MIL Hummers

[More Power]

Anyone have part numbers for the cable and modulator?

[CedarGrove]

Anyone have part numbers for the cable and modulator?

I don't know much about humvees and I know even less about transmissions but these are parts that I believe might be involved. Use these as a jumping off point only.

trans control module 5714645
connecting link 12339149
modulator 5596528
kick down switch 5572065

[ashbee37]

OK now you have identified that what is this on the side of pump

[More Power]

OK now you have identified that what is this on the side of pump

Is that the "kick-down" switch? I know that the VRV (vacuum regulator valve) used in the civilian app includes a KD switch in addition to the variable vacuum regulator.


trans control module 5714645
connecting link 12339149
modulator 5596528
kick down switch 5572065

Trans control module? That's what a computer is called for the Allison 1000. The TH400 is not computer controlled.

When I toured AMG's Mishawaka HMMWV plant in 2006, I learned that AMG used a separate TCM in the mil-spec HMMWV for the 4L80-E. Not sure what company provided it.

[argo]

The cable operated modulator is sometimes refered to (erroniously) as a module instead of as a modulator.

[Robyn]

That little unit has a wire harness coming out the opposite end from the little roller.

My bet is that its the kick down switch for the TH400.

The civy trucks have a little switch mounted under the dash that the arm on the throttle pedal activates.

I have never gotten real close and personal with a MIL Hummer, so I can't say for sure.

It makes sense that any and all important controls for the engine and tranny would be industrial quality and not the cheezy little plastic stuff that we see on the civy stuff.

If that is the kick down switch, the contacts would close at or near the WOT position.

There is likely two wires in the little harness. The kickdown Solenoid is a simple device thats either on or off.
Activating the switch would turn the solenoid on and cause the 3-2 downshift or 2-1 downshift depnding on road speed.

The cable device controls the throttle pressure which also controls line pressure in the tranny.

More throttle = more hydraulic pressure to the clutches etc.

The reason for the cable control would be simple, the HMMWV does not use a vacuum pump and it would also likely be considered a "weak link" in the system.
The cable is a pretty much "Bomb Proof" way to go.

Interesting goodies you have there.


Missy

[davidsicard]

I got code # M196 can any one help me for the year of this block Thanks