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How far is too far ????

Sheanster27

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Yes I have a block and a fully stock rolling assembly and stock 98 heads with no cracks that I want to port and open up and biger valves but idk if this will cause major cracking issues and cause leaks I want to put optimizer heads on but at 1200 per head I think stock heads opened up is worth a shot in my opinion idk what do you guys think and the block is going to get a girdle and as much reinforcement help as I can put into the block and bottom end maybe even concrete in the block 3/4 full so I can make it even stronger I will be running water injection to help cool combustion down even more hoping to squeeze winter cooler in with everything elts if I can make it all fit lol!!
 

93detroit

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Connecting rods will definitely become an issue at extreme levels of boost. There are people out there who can carve a set of 4340 rods for you that will hold anything the crank and block will, but like others have said- not cheap. Last I checked 3-4 years ago they were $400 per rod for my Massey 44 (much larger rod than a 6.5 has).
 

Sheanster27

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I was thinking or having a billet steel set made I know a guy with a cnc machine but that's as far as the idea has gone but the big issue I'm worried about is rolling mass and what about a custom machined set of billet pistons would it be worth the coin to get them made ??
 

Twisted Steel Performance

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A db2 is manual so no computer for me, and to date no one has shown a ds and computer can come close to manual pump numbers. With all your wants you need a budget of 25-30K.

And Will, it's closer than it was, sent a cam off for welding and grinding to specs a bit different , with a diesel cam gurus help...
 

Sheanster27

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A db2 is manual so no computer for me, and to date no one has shown a ds and computer can come close to manual pump numbers. With all your wants you need a budget of 25-30K.

And Will, it's closer than it was, sent a cam off for welding and grinding to specs a bit different , with a diesel cam gurus help...
I know it wont be cheap but I'm young and dont plan on having it done for a while yet time is not an issue nor is money over time one pice at a time is how this build is being built
 

Sheanster27

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As far as my budget I d ok nt think I will be any were near that number i was thinking like 10k about I own the block heads and I can do most of the major modifications to the block and heads myself and the rest I have a close friend that owns his own machine shop and has always giving me a great deal on work that I need done he is the one that owns the cnc so I can get basically any thing custom made from him we talked about a set of pistons awhile ago and he said as long as he has a cad file to follow he can make any piston I want I haven't brought up con rods to him yet but I dont see it being to big of an issue as long as I can get a cad file made up
 

Rockabillyrat

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I haven't seen anyone run an inline pump on a 6.5. Let alone 2 4 cylinder pumps. There is a guy running 2 8 cylinder DB2 on a pulling tractor. But you could get more fueling from an 8 cylinder p pump to be honest. The downside to any rotary pump is high rpm fueling because of its design. Two 4 cylinder rotary pumps wound be fun to try. They will be able to fuel better in high RPMs since they have twice the amout of crank degrees available on the charge cycle. And with .370 H&R options you could make ALOT of fuel.

Really depends on your goals. If your looking for 400hp on fuel alone a modified DB2 will handle that no problem. Hell the DS4831-6033 can get you into that 400hp range as well. Quadstar refers to it as the "beast" pump. It was originally built for the p400. But John figured out the tuning to make it work with the OBD2 GM pcm.

If your after 400+HP on fuel alone you have to look into a DB4, big bore DB2, or machine work on a DS4. Unfortunately parts for the DB4 are obsolete. 3 suppliers told me they couldn't get them. And the last place they had availability was Seattle. Thats R&D territory, my guess is Justin bought all the NOS parts up for his pumps. There are .330 8 cylinder head and rotors available. They never made anything bigger in the 8 cylinder pumps. But it is possible to swap a .370 4 cylinder rotor into a 8 cylinder head. You just have to get lucky to fine two that are close enough to work together since a H&R is a machined pair. Lastly my research shows you absolutely can get over 200cc out of a DS4 with machine work. If you want to take a crack at it send me a message. You will need to be able to do your own tuning to make it a reality tho.

Back to the rotating assembly, the scat crank is cast in C H I N A... I called and talked to them about it years ago. The p400 bottom end is the only upgrade available for the 6.5 platform. Not only is the crank forged, But the rods are redesign with a larger wrist pin. Having a billet set made would be a nice addition to the rotating assembly. But seems unjustified for the power levels this platform is capable of.

If you really want a serious girdle look in to powered by design's build from 00. I've been wanting to contact him and see what it would cost to build another one...
super6_5_011.jpg

http://www.poweredbyd.com/6-5L-Turbo-Diesel-Project.html
 

Will L.

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Have you read N8in8or’s build thread? If not, do it now. Like don’t finish reading my post- fo read it all, now.

The set of heads you have can be done to work. So either get them worked to run them or buy fully done p400 heads from Chris. There is no reason to do optimizer heads and be slightly better, maybe.


As to the rods being made- why spend $1500-2000 and run some non proven units when you can get the proven fracture split p400 rods?
 

DieselAmateur

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Regardless of what heads you go with, having Chris ceramic coat them is a no brainer in my opinion. He can get them ported for you too. Given how heat is the biggest issue in IDI heads, coating any & all parts to shed heat will only help when chasing power.

x2 on Nate's thread

Also look into fabricating something like Nate's custom exhaust manifolds, or look into folks running a Banks sidewinder passenger side turbo mannie and a van one on the driver side, routing the crossover under the front of the engine. Anything to help the engine breathe.

On that note, if chasing power why not twin turbos? Eliminates exhaust crossover issues altogether unless you're going to run a centermount unit.
 

WarWagon

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I understand this is not going to be cheap and as far as crank goes I was thinking going with a scar crank and injection set ups any one ever thought of putting 2 inline 4 injection pumps in a custom gear case and runing that then you would have all the fuel you could ever want and then some I want to make 400 plus hp but I also want it to live would 18:1 pistons be worth the money or do I just deck the pistons ten thousands and use stock also what do I do for BIG con rods I want it to turn 5000 rpm or better I know I'm crazy but go big or go game I want to me cummins guys wish they have a 6.5 diesel
Welcome to the asylum.

We will help you build a decent 6.5 engine. What is it going in and what are you going to do with it? Does it need to live longer than 1/4 mile?

Don't forget gapless rings and lots of valvetrain work. I would sell the nice weak GM cast krap you got and start with a new Optimizer or P400 if you can get one. Have Chris build and coat it for you. The cost to go through the used crack prone GM cast stuff, well, you may as well start with a new longblock. (Use your friends favors for something else that will last.)


5000 RPM? 🤪 Making Cummins owners want a GM Turd of a 1970's bean counter design light duty diesel engine with an abortion of a factory exhaust and asthma attack turbo? 🤪🤪🤪 You will see a big "C" logo on the straight jacket they use on you. 🤪🤪🤪 You will leave the asylum with a new Cummins diesel truck payment. :facepalm:

GM 6.5 owners worry about blowing the engine all to hell IF the damn starter doesn't bust the corner of the block off on attempted startup. Cummins owners worry about the clutch and/or transmission taking the punishment a Cummins can dish out. I have a FCA Warranty for the power level a 6.5TD may reach for a very short time. This is 385 HP @2800 RPM and 930 lb-ft @ 1700 RPM but more importantly it has the HP at the low RPM to back up the torque a 6.5 simply lacks. Go newer for 400 HP and 1000 lb-ft but risk a CP4 disaster.

Having blown several 6.2's 6.5's and a few 5.9's Cummins engines I will leave the HD vs. LD diesel comparison here. Respectfully it should make it clear what's too far. (My Not-Stock 2003 5.9 was over 425 HP and 900 lb-ft and limited by the slipping South Bend Clutch. The #1 rod and piston from it is on the left. )

DSCN6028.JPG
 

Sheanster27

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Welcome to the asylum.

We will help you build a decent 6.5 engine. What is it going in and what are you going to do with it? Does it need to live longer than 1/4 mile?

Don't forget gapless rings and lots of valvetrain work. I would sell the nice weak GM cast krap you got and start with a new Optimizer or P400 if you can get one. Have Chris build and coat it for you. The cost to go through the used crack prone GM cast stuff, well, you may as well start with a new longblock. (Use your friends favors for something else that will last.)


5000 RPM? 🤪 Making Cummins owners want a GM Turd of a 1970's bean counter design light duty diesel engine with an abortion of a factory exhaust and asthma attack turbo? 🤪🤪🤪 You will see a big "C" logo on the straight jacket they use on you. 🤪🤪🤪 You will leave the asylum with a new Cummins diesel truck payment. :facepalm:

GM 6.5 owners worry about blowing the engine all to hell IF the damn starter doesn't bust the corner of the block off on attempted startup. Cummins owners worry about the clutch and/or transmission taking the punishment a Cummins can dish out. I have a FCA Warranty for the power level a 6.5TD may reach for a very short time. This is 385 HP @2800 RPM and 930 lb-ft @ 1700 RPM but more importantly it has the HP at the low RPM to back up the torque a 6.5 simply lacks. Go newer for 400 HP and 1000 lb-ft but risk a CP4 disaster.

Having blown several 6.2's 6.5's and a few 5.9's Cummins engines I will leave the HD vs. LD diesel comparison here. Respectfully it should make it clear what's too far. (My Not-Stock 2003 5.9 was over 425 HP and 900 lb-ft and limited by the slipping South Bend Clutch. The #1 rod and piston from it is on the left. )

View attachment 62278
I like your thoughts but I have seem 6
5 out last cummins time and time again and what make the cummins better un stock form than a 6.5 they all have problems the Cummins is only better becuase of the aftermarket support other than that it would have just as bad of rep as the 6.5 diesel becuase the real reason the 6.5 has so many crack and heat issues is the compression cumming dosent run them numbers if they did they would all have the same problems what I'm saying is cu.mins is not superior to the Detroit in any way in my eyes not in stock form in stock for a 6.5 will crush a cummins all day and save you fuel and money in the process and as far as my use I just want to make cummins loves cry because let's be honest high performance is just trial and error to see what works amd lasts right ??? Cummins engins are not all they are talked up to be being in the industry imnin I see more problems with them that my old 6.5 diesels just my experience and opinion
 

Twisted Steel Performance

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I'll save ya some hassle as far as the thought of installing bigger valves in your heads, don't bother thinking about installing seats, the casting is too thin for seats, just have the right size seat cut in the iron, and be ready for cracking, every induction hardened head will crack at some point, with added boost so goes cylinder pressures, it's the nature of hardened cast iron.
 

Twisted Steel Performance

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I'm all for going where few have gone with these motors, heck I'm a leader in that line of thinking, so go for it, try it all and learn. Myself, i have a large amount in what was a never run crate p400, so if you can do half of what you stated you planed for the amount you think you'll be doing good.
 

WarWagon

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Don't let me discourage you from building your dream engine. I merely suggest you start with the best you can get and that's NOT the GM cast stuff. If you were building a daily driver with modest power maybe. For wanting to find out how far is too far and again what is the intended goal? Land speed record, 1/4 mile, hot rod? Hummer you want to keep original? Maybe you just want to know what is reasonable out of a stock GM cast block?

I will say for the money spent to wring power out of a 6.5 you could drop in ANY GM gas crate engine and buy the minor difference in gasoline with the pocket change. A Duramax is also a better choice in the quest for power. I will make the argument that a 6.5TD modified is a better engine than a LLY Duramax overheater.

Yes they all wear out, drop a valve, or otherwise die. I have had plenty of trouble with both. You waste your time to lecture me on how reliable the 6.2/6.5 isn't. Start at post #8. GM Bean Counters thumbed their nose at Detroit Diesel's recommendations like use a forged crankshaft and later had to offer a 100K warranty on the 6.5 to sell them because of the 6.2 reputation for breaking the damn crankshaft in a horrible scrap metal death. Timing chain with 0.8" slop allowed, glow plugs and controllers that loved to kill engines, the cooling problems GM never figured out. Then the PMD pain.

A GM 6.2/6.5 fails you remove and replace it because it cracked to death. Block mains, cylinders, heads, precups... cracked to scrap. Odds ain't on the side of rebuilding. A Cummins fails you generally rebuild it including dropping a sleeve in it. Understanding the risk of hot oily parts sticking out of the pavement and having to start over when you start building power...

Additional pain is finding good parts anymore. From worn out head and rotors on Injection Pumps, injectors now made elsewhere and not the same quality, knock off or other parts no longer made to the original spec...

Oh yeah, when you want to get crazy with a Cummins they also make Forged Steel pistons that just laugh at a stuck open injector rather than melt down like aluminum pistons do.




forged_steel.jpg




4500RPM and then this happens.

" We had just crossed 2200HP at 146psi when the 6.7L Cummins block simply couldn't handle the pressure and separated! We have done over 3000HP on this longblock setup so we feel like it was definitely a premature failure... "

At the end of they day with 2000+ HP to "play with" that a 6.5 might make for 1/4 mile you are simply not going to make Cummins owners want a 6.5. After hopping up my 2003 5.9 Cummins, well, I have towed things at speed a 6.5 engine wouldn't dream of with power at lower RPM's... Having a warranty (on my 2018 RAM Cummins) for the same power my 2003 was at is a different world where I am no longer my own "warranty station".
 
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Rockabillyrat

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That 6.7 splitting on the engine dyno was the reason behind D&J and Firepunk working together to develop the all billet cummins engine. Industrial Injection just split one the same way but on a chassis dyno. Engine literally came out of the truck. 3000hp is where the stock 6.7 block can't handle the massive amount of cylinder pressure. Firepunk already broke their 1/8 mile world record twice with the new billet engine. A 6.2/6.5 can't compare to any cummins engine. Not even in the same playing field.

FB_IMG_1602423930469.jpg

As far as building a 6.5 goes, it seems to me like there are alot of overkill builds going on. Earlier this year a completely stock p400 with a built DB2 and a 60mm turbo did 380hp to the wheels. Head work is completely unnecessary at the power levels this engine is capable of. The stock GEP heads support 400hp. And when you port heads, with bigger valves and higher ratio rockers. You increase top end flow, but kill your low end torque. Port velocity is just as important as flow. The secret to heads is the smallest port that flows the most. Especially on a turbo diesel engine. Port velocity drives the turbine and really increases low end turbo spool. Pair that with a twin scroll completely divided system and you can light off a big single like stock. In my opinion spend your money on the bottom end where is counts. Slap on some GEP or p400 heads, built DB2, and a 60-64mm turbo and send it. No need to go any farther on these engines unless your trying for 500+hp all out race engine.... and at that point you will need a inline pump so your going to be opening the wallet big time for that. Then I could see justifying head work because the rpm range your using the engine at will benefit from it
 
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