Older and newer Military Humvv 6.5 T/D

[Aftermath]

Does anyone know the differences between the older and newer Military 6.5? I know that the newer ones are Optimizer diamond 506, and I'm told this engine is 506 What are the differences in new and old, or are they basically the same. I have an opportunity to get a complete engine from an older military hummv to use in my 3500 P/U. Thanks in advance

[Robyn]

If the engine has the <> diamond cast into the valley then it is the newer casting that is made by Navistar for AMG

The 506 casting number started in the late 90's while GM was still building the engines.

The original 506, depending on when it was cast had issues.

1998 until AMG took over were prone to cracking the #8 cylinder near the top rear.

Along with this flaw, all the other issues with main web cracks were there too.

Early 506 blocks that had the large oil squirters in the main saddles were prone to cracking the main web through the oil squirt holes, which would spread to the cylinder wall and eventually cause a coolant leak.


The only way to tell what engine it is, is to look at the Julian date cast into the back flange on the block.

Now all this said, not every engine from the various years in question will fail, but these did have a higher risk of failure.

The blocks with the Diamond <> cast in are of better quality.

Blocks with a julian date of XX XX H or later such as J,K,L etc (I not used) are AMG blocks and have the updated metalurgy and internal dimensional changes.

OPTIMIZER 6500 was AMG's designation for the new upgraded package.

The heads also saw major upgrades too.

Aside from what you can't really see, the only difference starting in 97 IIRC was that the bell housing bolts changed from 3/8"-16 thread to a metric bolt.
There was also an additional oil port added to the valley area.

All of the engines will swap in and about and everything will bolt up just fine.

The Mil engines had mechanical IP and the fuel injector lines and injectors are designed for such.

If you want to use a DS4 pump then you need to use the injector lines and injectors for the electronic setup.

The injectors are pretty much the same, just the pop pressure on the ones used with the DS are higher pop.

The lines have a different fitting on the IP end.

The other difference is the intake manifold and heads are different.
The intake bolts on the HMMWV are 60 degrees from the head instead of 90 degrees like pickup heads (Vans use the 60 degree set up too)

Heads will interchange

Good luck


Robyn

[Aftermath]

Wow Robyn, thanks for the info. Thanks alot of information. My question is this; if this engine is the older version and not the optimizer 6500, is it worth buying for $750 and rebuilding if it only needs rings, bearings, gaskets etc? This is a complete engine minus turbo. It does have the DS4 pump. I siezed my engine warming it up a few weeks ago and need a solution/direction to go in. Thanks for all the help!

[Dvldog8793]

Howdy
If it has a DS4, I would be questioning whether it came from a hummer.
IMHO....I would not pay for an older 506 without giving it a REAL good check over first. Or go into it with some sort of warranty.

[Aftermath]

After listening to the recording, I think he called the Injection pump a DB2 pump

[trbankii]

I picked up a confirmed Optimizer for rebuild about a year and a half ago for $350 from Government Liquidation. Like you say - complete engine minus turbo. So I’d say that’s a bit steep for something that isn’t even an Optimizer and needing work.

[Aftermath]

trbankii,
Do you know of a website or location for the government liquidation? Process for bidding /buying etc.? I'm in Georgia. Thanks

[trbankii]

Go to http://www.govliquidation.com/ and click on “Locations” at the top. Of course, you’ll have to see what is available in your area and likely wait for something to come up.

It looks like there are currently twelve active sites in Georgia, but I didn’t see any Optimizers. I did find some bare blocks in Oklahoma - LINK (http://www.govliquidation.com/auction/search?cmd=results&fromsearch=true&words=8%20cylinder%20diesel&location=OK&sort_column=lot_number&ascending=1&_per_page=30)

[Robyn]

$750 is too much for an engine that you can't hear run and check things like oil pressure, coolant level and warm the thing up and listen for odd noises.

The 6.5 is a good engine, but sadly they can hide a big basket full of non repairable issues.

Used Mil stuff are for sale for a reason, and not just because they like swapping them out.

Some older engine did get replaced with newer ones for various non serious reasons (Upgrades)

My opinion on used 6.5 that I can't hear run and examine well is that it's a $200 gamble MAX

Been through many of these beasts and found enough sadness and heartbreak to fill a mental ward.

I would advise staying away from the used mil stuff unless you can get it for little to nothing.

The last batch of mil stuff I was involved with was a disaster.

We were looking for a good block and crank.

The guy had about 300 of these engine in the metal shipping cans, and was using the shipping cans to build some really cool outdoor fireplaces for patios.

The engines were scrap iron to him and we sorted through a dozen or more, ripping them down and sifting through the carnage.

Cracked main webs
Cracked and badly eroded decks
Broken cranks
Cracked cylinders

And on and on it went.

After a full day in the guys warehouse getting filthy dirty ripping these thing apart we gave up.

My advice is to look elsewhere for a civy 6.5 you can hear run.

As I mentioned before, the heads and intake are not the same as a civy truck.

I have no dog in this fight, and nothing to gain one way or another.

Just offering a lot of years of experience and hard work beating on broken 6.5 engines.

Good luck

Robyn

[96K3500]

Your makin me nervous about my military pull out. J.R.

[Robyn]

Just sayin what I have seen.

Years ago there were stories started about the military 6.2 and 6.5 engines
being pulled out and that most were pristine condition, and replaced for ???????


Bottom line is there were some 6.2 engines that were in fair shape and replaced with the (then new) 6.5

Most engines are pulled for a good reason.

If they have more than a simple to fix issue they will be yanked out and a fresh one dropped in.

Field motor pools generally do not get into major rebuilds.

Finding a good one is not impossible, but the vast majority of the take outs are pretty sad.

Also the rigs like HMMWV may have low physical miles on the rigs, but they can spend hours and hours idling. which is not the best for them.


When they are running, they usually are run hard, especially ones that are run in the desert in high heat.


I won't say that you will not get a decent piece of iron, but the chances are slim.

The newer iron made by AMG may have a better chance of being a worthwhile piece to rebuild.


Sorry about the bucket of cold water on the campfire, but a lot of junk iron having passed by my way has left a really nasty taste behind.

It is a lot of work to build a good 6.5 from the ground up, and one needs the best piece of iron to start with.

I tried scavenging through bone heaps to get good stuff, and it never ended well.

After spending a grand on one block and winding up back at square one really brought the ideas home to roost.

I hate to see anyone spend their hard earned $$$ and wind up with junk.

The 6.5 is not a hard engine to build, far from it, but there are just too many little FUBARS that you can not see from the outside, and that even many shops miss until its too late.

Once you have been burned a few times you tend to get real wary.

My last trip down six and a half lane was a tumultuous one.

Bought a "GOOD USED" block from a builders supply.

Checked it over, all seemed ok

This was a bare block

No cracks.

Bored it
Decked it .010"
Magged it
Checked the mainline for straight.
Tanked it
Started assembly

Found out very soon once the crank was in and the first two slugs were in that one deck had been cut before and not marked (Piston waaaaaay toooooo far out of the hole :eek:

Saved it with a special multi layer stainless head gasket on the one side.

BAD PLAN

The gasket failed in a year.

Started over
Found a very strange deal on a rough bored block with real odd julian date

Turned out to be an AMG block that was never supposed to be loose.

Bottom line

There were no dowels, soft plugs, oil galley plugs, oil pressure relief valves or anything in it.

Bored it and fit a std set of pistons.

Started assembly

Crank had ZERO clearance

Main line was .0025" undersize (clearance)

Started asking lotsa questions.

Finally found out that it was indeed an AMG that had been part of about 100 plus blocks that were involved in a mfg error in the computer that resulted in small mainline bore.

There were blocks that were complete all the way down to some that still needed several operations.

Mine just needed a finish bore.

I had the mainline opened up to spec.

Good to go

Stuffed in a new SCAT crank
Scared up a brand new set of AMG heads (Another screw up where A P400 was shipped with pickup heads and had been ordered for a civy H1 )

Bought the heads from the shop that did the swap.

This engine was a winner and has been running over a year now without issue.

The truck sat for nearly 4 years during the process of trying to make things right.

A lot of stories and BS that ended up costing way too much $$$$

Paid $500 for the AMG block and a few more $$$ to make it right.

$600 for the AMG heads
$350 for the Scat crank

Used the rods and pistons from the original build along with the bearings, cam, lifters etc.

There is just so many places to get fouled in one of these things.

Garbage in, garbage out :)

Ask many questions
Measure a lot
Don't assume anything
Don't trust anything or anyone that you have not verified.

Check it
Double check it
Check it again.

If it does not seem right, it damned well likely is not.

If the seller says it's good, be skeptical.

Good luck

[Dvldog8793]

Howdy
Speaking from experience....When I was working in Motortrans....we would typically send a vehicle to 3rd for an engine replacement when it showed low oil pressure, excessive oil consumption, did not pass an oil analysis, or had a known contamination or catastrophic failure. The engines were NEVER rebuilt. MAYBE head gaskets were replaced but that was the extent of it.

In my experience, the idea that we replaced engines because we were bored and needed something to do between killing bad guys is a MYTH!

When we started the switch to 6.5, the old 6.2 machines would be sent in for a reman and then it would be determined if it would be refitted or destroyed. Until recently, only a very small number of my USMC Hummers were ever released to the public due to some weird legislation.

The most common problem that I saw with engines was oil analysis failure. Most likely due to outside contamination(salt water:eek:) or head gasket.
When the engines were pulled, they would get stuck on a pallet and sold for scrap. Any number of things could happen to the blocks while waiting for the auction.
I agree with Robyn 110%....A military take out is a risky proposition unless you can somehow determine its viability before hand. Also she is right, about the idle time. The trucks that I used were 12 years old at the time and had very few miles but would be idled for HOURS every week.
Good luck!

[Robyn]

I am going to make a guess here that many of the ideas got started right after WWII and then Korea to a lesser extent.

I can remember when I was a kid, there was a place not far from here up in PDX called GI Joe's (later became a sporting good store) and these guys handled war surplus.

You could buy anything imaginable
Guns
All manner of camp supplies
Trucks
Jeeps in a box (Yes these did exist and Dad bought one. Took us a day to assemble it)
Tools
Ammo

These things were all new and were being sold off.

They had lines of Deuce and a half trucks, all new.
Generators
Trailers
Tires
Clothing, including boots, hats, all manner of stuff.

The trucks were unused and generally had only a few miles on them.

At that time, with a few phone calls you could arrange to buy a B-17 four engine aircraft that was ready to go.(No guns) :(


Much of the surplus materials were new in the box so to speak.

After the Korean conflict there was a lesser amount of stuff, but stuff none the less.

My Son in law and I recently bought some Army 6 x 6 trucks to fool with

1952 and two 1954 rigs.

The highest miler has 18000 on the clock.

Only the ravages of 60 plus years has had any effect on them.

Back in those years everything surplus (almost was sold off)

A lot of small GYPO logging companies outfitted themselves with Surplus Army trucks as did many farmers and ranchers.

The stuff was cheap and of top quality.


Today the myth lives on me thinks, and far too much junk is sold off to folks who still grasp the urban legends of a bygone era.


Yup "The Jeep in a box"

A wood crate with all the pieces.

Frame, body panels, axles, engine and everything needed except fuel and oil to make it go.

All we had to do was assemble it, fill the gear boxes, add fuel and go.

These were designed to be assembled in the field with ease and quickly.

I don't think there was a battery in the crate, but that was a long time ago.

We used that Jeep here for years.

I know at least 5 of the local small farms close by had a Deuce and a half or a Jeep or both or more.


There are many blogs online that degrade the truth about the JEEP IN A BOX
And some of the scams that ran for years were true, but, we had one, and bought it in Portland at GI Joe's.


Good luck with the mil surplus

[JeepSJ]

Where on the block would the <> be cast ?

[JeepSJ]

Go to http://www.govliquidation.com/ and click on “Locations” at the top. Of course, you’ll have to see what is available in your area and likely wait for something to come up.

It looks like there are currently twelve active sites in Georgia, but I didn’t see any Optimizers. I did find some bare blocks in Oklahoma - LINK (http://www.govliquidation.com/auction/search?cmd=results&fromsearch=true&words=8%20cylinder%20diesel&location=OK&sort_column=lot_number&ascending=1&_per_page=30)

Ugh. $450 shipping for 2 partial 506 "diamond" short blocks. But I can get them for $25. I could then probably Ebay one of them to recoup some of the money.

Decisions, decisions...

EDIT - still, way better than spending $1K on ebay, plus $250-400 shipping for a "who knows where it was cast" block with no identifying markings.

[JeepSJ]

Well, 2 mil surplus diamond blocks just showed up on our shipping dock today. Both still have cranks installed. Bores on both are clean showing lots of cross-hatch and no ridge (one doesn't even appear to have ever been run). Can't wait to get them home and torn down and over to the machine shop to get cleaned up and checked for cracks. I guess the fun starts now...

[Aftermath]

JeepSJ; If you decide to sell one, give me 1st opportunity. I could use another. Thanks

[JeepSJ]

JeepSJ; If you decide to sell one, give me 1st opportunity. I could use another. Thanks

Will do.

[JeepSJ]

Little more info on what I ended up with. One has a date code of R, which I believe translates into 2009. I can't make out the date code on the other. The R has the better bores, and the crank spins freely. I can't check the crank on the other, but it appears to be missing all the outer bolts on the main caps.

They have bosses and holes on the top at the rear of the valley, most likely for turbo. I'll need to research sealing those off. It is strange on what is there and what isn't. R has a cam and timing chain, the other doesn't. Both have the freeze plugs removed but still have the block heaters installed.

[trbankii]

Ugh. $450 shipping for 2 partial 506 "diamond" short blocks. But I can get them for $25.


Well, 2 mil surplus diamond blocks just showed up on our shipping dock today.

So you actually got them for the base bid? Or something above that?

The local ones have been going for at least $250 or so - sometimes quite a bit more.

[JeepSJ]

So you actually got them for the base bid? Or something above that?

The local ones have been going for at least $250 or so - sometimes quite a bit more.

I got them for $190 for the pair. Original shipping quote was $450, but the weight listed was a couple hundred pounds too high, so I got a $180 refund on the shipping. So I am $460 total to my door.