1999 blocks were better...yes...no?

[Dave12]

I've got a line on a complete drop in motor (thanks Nick!) that came out of a wrecked 1999 3/4 ton with 167,000 kms (100,000 miles). The problem is the motor is out of the truck so I can't hear it run.

I think I read that by 99 they had made some improvements to the 506 casting. Is that correct? Is there anything I can look for that will tell me if it's a good 506 or a bad 506. I know that ideally it will have the double diamonds (international symbol) in the lifter valley. Will the 99s have that or is it one of those maybe yes, maybe no things.

Short of pulling the pan, which I don't think I'll be able to do, what should I be looking for/at on this engine?

Thanks,
Dave

 

[nvmtnlion]

If I remember correctly, late 1999/early 2000 was when the Navistar blocks started winding up in our trucks. Most of our fleet of our 1999 6.5s here at the county are Navs.

 

[Dave12]

That's possibly very good news. So it will have the double diamonds if it's a Navistar block. If it doesn't then it's likely old stock which is not so good.

Thanks,

Dave

 

[Ratman]

Dave, -that is very close to the year that my 506 block was.

Rumor has it that some of the castings that Navistar made during the transition (sometime in '99) did not have the Navistar logo cast in the valley, because they were still using the existing GM tooling for a while.

That is not to say that a non-diamond block is bad, because apparently the critical updates (cylinder wall and deck thickness to alleviate the infamous #7 & #8 cracks between the head bolt holes and cylinders) were made PRIOR to the Navistar logos being cast in the valley in '99.

Someone (can't remember who) had the '99 block castings narrowed down to the very month that the casting change (wall and deck thickness update) took place. I will try to see if I can find it.

Congrats on finding yourself a motor!

 

[Dave12]

Bill,

We're talking about the GM 6.5. Navistar took over production from GM sometime in 99 and apparently made considerable improvements to help the previous cracking problems.

Dave

 

[JiFaire]

Congrats on finding a new engine, Dave! Hard to pull that 5er with your 10-speed!

 

[teroma25]

Dave, I remember readin' that it had to be cast after nov./01 to be true amg block. I just don't remember where I read that?

 

[JiFaire]

Dave, I remember readin' that it had to be cast after nov./01 to be true amg block. I just don't remember where I read that?

Wherever you read it, it's true... International started production of the 506 Navistar clock in November 2001.