[dieseldave71]

I have a few core engines and I want to select one to rebuild. Which blocks are supposed to be the "good" ones and which should I stay away from?

 

[edzzed]

see any diamonds in the valley ????

 

[chrisk1500]

599 or as mentioned a 506 with diamonds in the valley....

 

[4doorTAHOE6.5TD]

506 in/from a 2000 truck or 2001 VAN Has 4 threaded bosses under the LH engine mount including the three the mount bolts to. A new 506 service bare block with a date code later than 2000 or 2001 would be OK, IMO. Not totally sure if the 506 is there though on the late service blocks..

 

[dieseldave71]

I don't see any diamonds on this one. I's a 506, though. What struck me as funny about it was that the main bolts are different. On the three center mains the outside bolt is smaller (second pic) compared to the 929 block in the third pic.

 

[dieseldave71]

Is the "D130" the date code? Maybe someone can help me ID this thing. I got it from a guy who deals in military surplus stuff. Supposedly it was from a military humvee, but who knows? For all I know, there may be no difference between a humvee engine and a run of the mill 6.5 anyway

 

[dieseldave71]

Probably help if attached the pics

 

[oil burner]

April, 13, 2000. If IIRC supposed to be GM's last attempt to correct the block problems before they quit production and International took over.

 

[dieseldave71]

Oil Burner, thanks for the ID. What's "IIRC"? Why are the three center outside main bolts smaller? Was this an attempt to address the block cracking issues? Don't the later blocks have piston cooling jets? I don't see any, maybe I'm just not looking hard enough... Ok, so this is a 2000 "506" block- is this a good thing or a bad thing? Should I go with this one or one of the 929's?

 

[Chicago TDP]

929 all the way. The 929 should not have the piston oil spray cooling which weekend the blocks.

The smaller main cap bolts were put in to reduce the amount of material removed when the holes got tapped.

My advice is use the 929 though. I have gone through 2 506 blocks in my truck, no good at all.

 

[Turbine Doc]

. What's "IIRC"?

web speak If I Remember Correctly

 

[irelandd]

929 all the way. The 929 should not have the piston oil spray cooling which weekend the blocks.

The smaller main cap bolts were put in to reduce the amount of material removed when the holes got tapped.

My advice is use the 929 though. I have gone through 2 506 blocks in my truck, no good at all.

*** My reman that I put in this weekend is a 506. My old block is a 929 . I can't afford the $ to change now back to the 929.

What were you doing when the 506's gave out? I am only asking so I can get some miles out of my re-man and make the best out of a bad situation.

Thanks.

 

[Turbine Doc]

Knowing C TDP he wasn't Driving Miss Daisy , as far as "bad block debate goes" a LOT of it IMO has to do with how it was/is driven, my bad year "oil sprayer" has held up it's end of the bargan. Monitor EGTs, get improved coolant flow and live within known "safe margins" of the 6.5 and it will hold up.

Now that I've just signed my engines death warrant, a 6.5 with 12-13 psi boost, < 950F post turbo EGT, some fuel tweaking with reflash is recipe that has worked for me, plenty speedy when not towing, reasonable grunt for towing. reasonable mpg with the 3:73 17-20 empty, 12-13 towing.

If running sustained higher boost than that, splays IMO would be way to make sure it stays together,

 

[irelandd]

Knowing C TDP he wasn't Driving Miss Daisy , as far as "bad block debate goes" a LOT of it IMO has to do with how it was/is driven, my bad year "oil sprayer" has held up it's end of the bargan. Monitor EGTs, get improved coolant flow and live within known "safe margins" of the 6.5 and it will hold up.

Now that I've just signed my engines death warrant, a 6.5 with 12-13 psi boost, < 950F post turbo EGT, some fuel tweaking with reflash is recipe that has worked for me, plenty speedy when not towing, reasonable grunt for towing. reasonable mpg with the 3:73 17-20 empty, 12-13 towing.

If running sustained higher boost than that, splays IMO would be way to make sure it stays together,

Thanks for the feedback. So to be on the safe side do you think I should stay less than 1k pre-turbo EGT? Also, I was going to have the timing set for -1.94 as recommended in the Heath e-tork instructions. Is there any more risk in changing the timing to this setting or should I set it less agressive?

 

[DavidPhillips]

Anybody know the difference between pre-turbo and post-turbo?

Seems like I saw 200F somewhere but that's doesn't seem right.

 

[electricucian]

My 98 GMC had I think a 565 block that didn't last but 86,000 miles.I rebuilt a 599 block and so far at 5000 miles it is doing fine.

 

[Turbine Doc]

Thanks for the feedback. So to be on the safe side do you think I should stay less than 1k pre-turbo EGT? Also, I was going to have the timing set for -1.94 as recommended in the Heath e-tork instructions. Is there any more risk in changing the timing to this setting or should I set it less agressive?

With pre turbo reading maybe set 1200-1250 as your limit on a healthy engine of known history, but there really is no reason to run sustained while towing that high IMO, I usually never top much over 800F unlesstowing up grade then I just slow down, say depending on load 70 fro 75mph, or 65 from 70mph, I make up for the grade on the back side of the hill TDC -1.5 is a good tow/performance setting

 

[Turbine Doc]

My 98 GMC had I think a 565 block that didn't last but 86,000 miles.I rebuilt a 599 block and so far at 5000 miles it is doing fine.

Were you 1st or 2nd owner of the 565 engine, and gauged or no gauges, I have a place in Troutville, Va. still and know a couple of hills in the Blueridge that I backed off from without gauges I would not have known I was entering areas of risk; even towing a empty 6x12 covered utility trailer. And when in cruise control boost hunting can be a bear on em as well

 

[THEFERMANATOR]

Something that I think needs to be brought up hear is that not ALL of the 506 blocks are junk. The latest and strongest block design that CHICAGO is running is a 506. But it is the 506 with the INTERNATIONAL emblem in the intake valley. It was the 97-early 99 506 blocks that had MOST of the problems.

 

[Chicago TDP]

Yea, slight correction here: When I had my original 506 block from 1998, I blew it to pieces but that is cause I worked and beat on my truck like a red headed step-child. It was never cooled down after a hard run, and I pulled some sick loads with it till it just snapped in the cold weather and went "klunk"!

My NEW 506 is a 2005 engine. It is a whole new animal. It is more like a block for a military tank then a block for a truck with it having 40 more pounds of material in it then the older 2000 and previous blocks. The mains are HUGE and the cylinder walls bulg into the lifter valleys.