300 hp with no block problems?

[scottm]

Hi all, first post from AZ. I am about to close the deal on a 97 3500 4x4 with a used up 6.5 td. I have been reading on here for a couple weeks now, and I saw some posts about block cracking in the 300 hp range.. Can strength be improved with main studs? And what about these new blocks from Bostic Machine, sold on ebay?

http://www.ebay.com/itm/6-5-L-6-5L-Diesel-NEW-ENGINE-BLOCK-Updated-Improved-/160575369263?pt=Motors_Car_Truck_Parts_Accessories&hash=item256309b02f&vxp=mtr

scott

[scottm]

Here is a stud girdle kit from DSC to prevent web cracks, a lot cheaper than a whole block. Anyone try this?

http://www.dieselservices.com/html/product/auto-performance-parts/GM/gm_94-00/gm_94-00_special_products/stud_girdle_kit_10mm_97__up_6_p78.cfm

[scottm]

Here is a Scat crankshaft. Has anyone gone this far in a buildup?

http://www.ebay.com/itm/92-01-NEW-SCAT-6-5L-DIESEL-CRANKSHAFT-6-5-GM-TRUCKS-/220975969800?pt=Motors_Car_Truck_Parts_Accessories&hash=item337331b608&vxp=mtr

[Robyn]

Hello

The 6.5 can live fine in the 300 hp arena
The block cracking has been an issue from the gitgo and is not HP related

The girdles for the 6.5 are pretty much a waste of time IMHO

The only real solution is the newer AMG blocks.

NOW
A used block that's not cracked should likely stay that way.

Blocks made in the 97 to 99 time frame are not good choices as they have a higher incidence of failure.

The 599 casting is about the best block.

Hope this helps

Missy

[ronniejoe]

Splayed main caps are the only real solution.

[Robyn]

X2

Find a good block, then do the splayed caps, ohhhh yeah

And not all that spendy either, if you consider what you end up with.

The AMG blocks are great, butttttt pricey, as you can't normally buy bare blocks.

The issue with the GM 6.5 blocks takes on many faces.
The cracks are not caused by power levels, but are more the result of poor metalurgy, "green" castings (not color) :D lots of stress risers left over from machining, and the list goes on.

The fact that the 6.2/6.5 is a shallow skirt block is one of the biggest issues, and the design should have never been considered from the gitgo.

Look at the DMAX, it has a deep skirt with cross bolted mains. The thing is a beast.


Ron has done many of the splayed mains with great results.

Now, any and all improvements or mods to the old 6.5 blocks are IMHO just a bandaid to the list of deficits this design had.


I still love thee engines, but the facts speak for themselves.

Now that I have called some smack, if you look at the numbers of these engines that were installed in vehicles and the number of engines that ran 200,000 miles or more without trouble, you get a different picture of things

YES the design was a tad shakey, but lots of vehicles ran a buttload of miles.

I have personally been into many of these engines that had been running fine and found cracks in the center main webs. How long would these have hung in there ???? no way to know.

I have see blocks with 200 k plus on the clock that were perfect, with no cracks, and others with 50k that were junk.

I mentioned "green castings"
I have seen blocks with cracks at the main register that had opened up as though stretched, this is indicative of a casting thats moving.

OHHHHH

FYI, a green casting is one that has not been "cured" or has had all the stress removed.
This is done by heating then slowly cooling and or other means prior to machining.

The cracks at the registers that spread are a indicator of metal that is not done moving. many of these cracks can open up nearly 1/32"

The normal cracks found are in the outer main bolt holes at mains 2 3 4
these start at the part line and progress down through the center of the holes, with some reaching through to the cam bearing bore.

I spoke of stress risers. these are sharp rough edges that promote cracks to start. Every hole in the lower end of these engines are razor sharp.
Chamfering the holes lightly removes the stress riser.
The main web edges are also razor sharp, more bad ju ju

Lightly breaking all these edges is also needed to help stop cracking
The first thing you learn in engineering is to eliminate SHARP CORNERS.
Rounded corners and radii are the only way to keep cracks from starting.

NOW
You will ask, why did GM not do these extra steps ??????????

EASY $$$$$$$$$$$$$$$$$$$$$$$$$$$ :eek:

Translated, you get Corporate bean counters.

I have spent over an hour going over a 6.5 block "Dehorning"
YES this could be automated, but the cost is the reason they don't

I COULD go on for another page of script on this, but you would likely get bored.

yesssss
Get a good block, do the prep work and make 300 hp and enjoy

There are some good how to threads in the tech forum here at TDP
written by myself and others that have chased our tails and beat our heads on the wall.

RJ has built some marvelous 6.5 engines that make gobs of reliable power, so it can be done.

Heat rejection is your next worry.

At high power levels, grtting rid of heat becomes a problem.

300 is the sweet spot for a reliable 6.5

Have fun

Missy

[john8662]

The girdle kit helps.

I wouldn't build one of these engines w/o a girdle or splayed caps, especially if you're going to push it performance wise.

[scottm]

Thanks everyone! Splayed caps are the hot tip.. This particular truck deal fell through, but I am still a fan of the 6.5. I get a thrill from making 'second-rate' parts work well. But now I wonder, why spend $4-5k on a built up 6.5 when I can buy a duramax off craigslist for $4k?

[Robyn]

At this date you have a good point.
With the prices of used DMAX rigs coming down as they have it would be far more $$$$$ effective to go with the DMAX


Missy

[ronniejoe]

Thanks everyone! Splayed caps are the hot tip.. This particular truck deal fell through, but I am still a fan of the 6.5. I get a thrill from making 'second-rate' parts work well. But now I wonder, why spend $4-5k on a built up 6.5 when I can buy a duramax off craigslist for $4k?

It depends on the truck and what your goals are. If you have a really nice older truck, you may come out ahead vs. fixing up a worn out Dmax. It's really a case-by-case basis and dependent upon your desires.

[Yukon6.2]

At this date you have a good point.
With the prices of used DMAX rigs coming down as they have it would be far more $$$$$ effective to go with the DMAX


Missy
For me i like the simplicity of the 6.5/mechanical injection
Dmax injector problems and the cost if you can't do it yourself scare me.I hate computers,mainly because i know nothing about them.
I keep hoping someone will come up with a mechanical injection kit for the Dmax,then i might slip one in a classic.
Thomas

[scottm]

Yukon I like the mechanical stuff too. Can it be swapped onto newer engines or is it better to find a 93-94 doner?

[Robyn]

On the 6.5 the 1992 93 mechanical injection system can be used on any year 6.5 butttttttt, you MUST use the FUEL LINES from the mechanical system.

DB2 pump
Matching lines
Injectors should be set to the DB2 pop pressures.

GOOD TO GO

[ronniejoe]

On the 6.5 the 1992 93 mechanical injection system can be used on any year 6.5 butttttttt, you MUST use the FUEL LINES from the mechanical system.

DB2 pump
Matching lines
Injectors should be set to the DB2 pop pressures.

GOOD TO GO

And you have to work out the transmission controls. There have been some who done this with success. Bobbie Martin used to sell an instruction book, I think.

[greatwhite]

If you're serious about building it, don't waste time trying to find a good GM block. They're few and far between.

Drop the cash on either an Optimizer 6500 or the ultimate solution: P400 casting.

I chassis dyno'd my daily driver 98 K2500 with an Optimizer 6500 at 271 RWHP (see sig).

Docile as a stocker every day to work....

[Robyn]

The traany issue when converting aan auto tranny rig does take some fiddling.

I have followed with interest a local fellow who has tried in vain to get the factory stuff to shift the 4l80 correctly with the mech IP
He finally went to a stand alone controller for the box and all is well.

There are several stand alone controllers for the 4L80E that work sweet.

NOW a stick is no problem.

Missy

[Robyn]

Yukon

I fully understand your concerns about computer controls.

THE FACT that the MIL Hummers do not use the electronic controls is surely a grand indicator of the picture.

I am a firm believer that the mechanical injection is a great way to go.

The Dmax has a good reputation, butttttttttt, this said, the cost of doing injectors is $$$$$$$$$$$$$$$ :eek:

Sadly the electronics that are installed in the consumer rigs are not even close to the stuff installed in the class 8 trucks.

But even the big ones fail from time to time

FACT, the micro processor is fragile, subject to failure due to various causes, and these almost never happen on a warm afternoon in the driveway at home.:(

I have nursed a couple failing mech inj trucks home when they were real sick.

Had a 93 6.5 that the IP had started eating itself and the truck was lucky to make 20 mph while pouring forth copious clouds of white smoke :eek:
but it got me home.

A few days later. a fresh 4911 IP and some new squirts, JOY AGAIN :D

RATTLE RATTLE RATTLE.

The electronics are way cool, WHEN THEY ARE WORKING.

Get some bad grounds, or a family of rodents that moved in, " Huston, WE HAVE A PROBLEM "

Ahhh yess

Missy

[jggiedeman]

You asked about a engine block from Bostic Motors. I did that same route - thought I would save some cash by getting an somewhat inexpensive block. They drop shipped mine from some warehouse on the west coast. It went back two days later. The camshaft gallery was full of shavings, the machinging for the spray nozzles hit the bottom of the bores. Bostic migh do all of the remaining clean up to the blocks but they didn't care enough to do mine. I figured if the original company would not completly clean the block before installing the cam bearings that it was not worth anything. I also bought their cylinder heads. Depth of valve install ranged from 0.030" to 0.041" for intake and 0.036" to 0.050" for exhaust. The pre-cups were also magnetic. Stick to a full long block from the HUMVEE company or quality original rebuilt USA Gen Motors products. My .02 cents worth

[Robyn]

I have seen some of the aftermarket blocks that were full of shavings.

The blocks the Clearwater Cyl Head sells seem to be fine.

I would yank the cam bearings and the galley plugs ( all of them) and completely wash the block out prior to assembly.

This should include the bypass valves.

I have seen a few of these blocks and other than one that was full of crap, they seem fine.

Without a boubt, the AMG engine is the best choice, they are in many cases more $$$$$$$$ than some folks can swing though.

Even a new GM block or other Reman bare block needs to be washed out completely and all passages checked for crud prior to assembly.

Missy

[scottm]

Hi all, I took a year off from thinking about diesel trucks, but now I have a 97 3500 dually, so the 6.5 questions are back. If my calculations are correct, a good engine would be an optimizer 6500 block, with a Scat or AMG crank, with new heads, and an A-Team turbo with reprogrammed EI by Walking J. I think I found heaven at SS Diesel supply - what do you think of the heads they sell? Apparently you can't buy a bare optimizer block, but I found rebuilt long blocks pretty cheap on US Engine. Any word on these long blocks?

Thanks in advance,

scott

http://usepinc.com/inc/sdetail/198/879

http://www.ssdieselsupply.com/c28_engines_heads_and_components.html

http://walkingjdesigns.myshopify.com/products/6-5l-diesel-turbo-charger-a-team

[Robyn]

The AMG block were never sold as a "BARE" block.

One exception was a batch of them that got loose several years back due to a machining error.

The exact numbers are unknown and those who do know are not talking.

I snagged one of these blocks that wound up in Portland and found the issues with it.

The heads you posted the add on are likely china castings, as are several offerings on the market.

I bought a set a few years ago from clearwater cyl head, and these seemed ok.

The real deal AMG heads are $1000 a pair to the door the last time I checked $$$$$


The best crank is the forged AMG crank.

I am hearing that the Scat cranks have broken in similar fashion to the GM cranks, so as far as building a bullet proof engine ??????

I am sceptical of anything that does not come from AMG directly.


There is just so much stuff on the market that comes with a variety of stories, that it's difficult to know what you are buying.

If the block does not have the Diamond cast into the valley and the late AMG date code, I would not touch it with a looooooong stick.


Good luck

Missy

[scottm]

Thanks Robyn. It is pretty discouraging to know that the regular production 6.5 blocks are so crappy. I think it's criminal that gm kept putting them out for years while knowing how bad they were.