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Discussion Starter · #1 ·
Hi, I am a new member here, this being my first post. I have a 94 k2500 that had a 6.5 diesel originally. I pulled it out and swapped in a 6.2 red block. Unfortunately I dropped a valve shortly after swapping it in, and destroyed the number 8 piston, cylinder wall, head, and turbo. I’m hoping to build this next engine to last longer. My biggest concern is fuel economy, with decent power (enough to pull a 13,000lb skid steer with ease). My theory is that if I build this engine for say 600hp, and then turn the power down to between 250-300hp, I just might have an engine that will last many years. This engine is another crack free red block, cast on 3-2-81. I will be studding the engine both top and bottom end, cast rockers, high flow water pump, super 54 turbo for reduced drive pressure, balanced rotating assembly, fluidamper, hi-pop pressure injectors, with 6.2 heads and pre cups for fuel economy. I’m sure I’m missing something but I don’t have my list with me. The engine came with 20 over sealed power hyperutectic pistons. Anyway, after doing a little research on these pistons, I found that they don’t handle boost very well. This engine will probably not see more than about 15lbs of boost, but it’ll see enough boost to shatter these pistons according to what I’ve read. So my question is, where can I find stock high quality pistons for this build, and can you point out errors in my build? This is my first full out build, so any advice y’all can give is greatly appreciated. Again, although a little extra won’t hurt, this engine isn’t being built for power. My goal is extreme fuel economy, and engine reliability. Thanks in advance!
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Welcome to DieselPlace
(y)
 
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For pistons maybe Sealed Power. They are a REALLY good brand. But good luck trying to get over 10 PSI Boost. But any way you want Stock Pistons as in like NOS or Aftermarket? I know of some Stock NOS ones but extremely expensive... (over $2,000). Check this thread out also. Are 6.2 pistons safe for boost

A, 6.2 nor a 6.5 will never 350hp. I've seen them built "up to" 300 and even then only lasted a few months to 1 Year (Depending on how you Drive/Treat it). Both engines stock can easily tow 13k no problem... Just Slow!. A stock 6.2 was 0 to 60 in 22.1 Seconds. A friend of mine built a 300hp red block 6.2 for his swapped 1979 k10 but only made it until month 4 before blowing up and he had over $8,500 into the engine alone. You'll get maybe a max of 250-275.

either way I've never done one of these builds before. So I'm not sure what you are missing. Maybe my next 1982 red block i will. I have a Lead from a friend on a Very very rare ATS turbo kit. Sine Banks are Discontinued since 2019 and are Extremely hard to find now.
 
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Discussion Starter · #4 ·
82kbody thanks for your reply. I’m not really interested in power, I’m more interested in fuel economy. The turbo I’ll be going with has a 1:1 drive to boost ratio, while the GMx turbos have a 2:1 drive pressure to boost ratio. I believe it is the drive pressure that kills these engine’s. So another theory I have, is that with a lower drive pressure, I can safely add more boost, and at the same time keep the egts lower. I think that even the 12v Cummins would blow up if you tried to pull more than 250hp with 30lbs of drive pressure and 15lbs of boost. The only time my engine will see 15lbs of boost is when I’m setting the waste gate, after that I will be trying for fuel economy. The old 6.5 got a roughly a whopping 15mpg, and the 6.2 with the gm4 turbo was getting an average of 24.3 mpg. And that’s with 4:11 gears. I’m hoping to hit 30 mpg with this engine, through the different injector angles and pre cups of 6.2 heads, and a better turbo, intake, and exhaust. I have seen many 6.2s before I left Facebook that had well over 300hp. And the owners claimed that they had been driving those engines reliably for many years. I don’t think I would have a problem achieving high hp if that was my goal. And although I myself don’t know how to reach that kind of power, I know that others have done it. So I think that if I build the engine for higher hp, and only run 250, that it should last a long time. But I could be wrong. It’s happened before lol. Also, I just found out that stock 6.2 pistons are made of hyperutectic alloy. So there goes my idea of stock pistons. Maybe I can get the ones I have coated.
 

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Yeah, i don't know much about building engines, I've only seen a handful of owners building them past 200hp. Even then most guys would rather just Find a P400 Optimizer 6.5 eng block which they used in the Humvee's and are rated at 250 HP & 550 torque rated. Stock Specs is about all i know. After 4 years of continuously researching parts and looking for NOS parts to building my 1982 red block to Factory correct specs, All i can say is it's A helluva lotta work.

This is the guy to GO:TO for building these engines. https://leroydiesel.com/products/p400-6-5-long-block/
 
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[QUOTE="82Kbody, post: 9938161

This is the guy to GO:TO for building these engines. https://leroydiesel.com/products/p400-6-5-long-block/
He seems to be a good man. He was very helpful when I called him. I believe I will be buying my head and main studs from Leroy.
[/QUOTE]
Rite.

I have not used him as of yet. I may in the future be buying one of his "Early" Braided Steel oil cooler line kits. Since i cannot find any good non-damaged/leaking originals. Especially NOS. haven't come across any. But would be a holy grail for sure. The early 6.2s from 1982-83? Used NPT Fittings on the cooler lines on the Engblock side. Maybe even up to 1984... I cannot remember. But i know the newer style are different.

Where in the U.S Are you from? Michigan for me. Maybe you know of someone with a Main eng wiring harness for a C code?
 

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Discussion Starter · #8 ·
He seems to be a good man. He was very helpful when I called him. I believe I will be buying my head and main studs from Leroy.
Rite.

I have not used him as of yet. I may in the future be buying one of his "Early" Braided Steel oil cooler line kits. Since i cannot find any good non-damaged/leaking originals. Especially NOS. haven't come across any. But would be a holy grail for sure. The early 6.2s from 1982-83? Used NPT Fittings on the cooler lines on the Engblock side. Maybe even up to 1984... I cannot remember. But i know the newer style are different.

Where in the U.S Are you from? Michigan for me. Maybe you know of someone with a Main eng wiring harness for a C code?
[/QUOTE]
I’m from Texas. I don’t know where to find a wiring harness for an 82 except on my personal pickup. I have used the steel braided oil cooler lines on my 94, and so far, have not had any issues. I have new factory replacement oil cooler lines on my 82 from O’rileys. You just have to get them to look under images until you find the one you are looking for. But they won’t have any idea what you are talking about. Also, I think you could have a new set made at a hydraulic repair shop.
 

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If I were building up another 6.2 I’d just stud the mains and maybe head studs from arp.On the other hand I’ve always had good success with the felpro and victor reinz tty head bolts as well.Many guys jack up the boost on these types of engines but it has its limitations like any production engine.Treat it right and dont push it too hard and it’ll treat you good in return.
 

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Coated pistons are not available/made for the 6.2's best you could do is contact Unique Diesel, they can get top quality pistons and if you want to lower the compression they also can provide machining services and ceramic coating as well...
 

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Rite.

I have not used him as of yet. I may in the future be buying one of his "Early" Braided Steel oil cooler line kits. Since i cannot find any good non-damaged/leaking originals. Especially NOS. haven't come across any. But would be a holy grail for sure. The early 6.2s from 1982-83? Used NPT Fittings on the cooler lines on the Engblock side. Maybe even up to 1984... I cannot remember. But i know the newer style are different.

Where in the U.S Are you from? Michigan for me. Maybe you know of someone with a Main eng wiring harness for a C code?
I’m from Texas. I don’t know where to find a wiring harness for an 82 except on my personal pickup. I have used the steel braided oil cooler lines on my 94, and so far, have not had any issues. I have new factory replacement oil cooler lines on my 82 from O’rileys. You just have to get them to look under images until you find the one you are looking for. But they won’t have any idea what you are talking about. Also, I think you could have a new set made at a hydraulic repair shop.
[/QUOTE]

Wanna sell the harness? lol. I have been looking high & low for a 1/2 ton 82-83 emissions harness. Little to no luck. Very hard to find. Either way as for the oil cooler lines. Yeah, a Hydraulic shop is the last resort. But i really would like to stick with OEM ones. As I am doing a Period Correct Factory Restoration. So everything has to be right for those years the truck was made.
 
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Discussion Starter · #12 ·
I’m from Texas. I don’t know where to find a wiring harness for an 82 except on my personal pickup. I have used the steel braided oil cooler lines on my 94, and so far, have not had any issues. I have new factory replacement oil cooler lines on my 82 from O’rileys. You just have to get them to look under images until you find the one you are looking for. But they won’t have any idea what you are talking about. Also, I think you could have a new set made at a hydraulic repair shop.
Wanna sell the harness? lol. I have been looking high & low for a 1/2 ton 82-83 emissions harness. Little to no luck. Very hard to find. Either way as for the oil cooler lines. Yeah, a Hydraulic shop is the last resort. But i really would like to stick with OEM ones. As I am doing a Period Correct Factory Restoration. So everything has to be right for those years the truck was made.
[/QUOTE]
No, I’m afraid mine wouldn’t work even if I wanted to sell it. The truck is a K30 emission exempt. It was my grandpa’s old company truck. My plan is to restore it to factory condition.
 

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Wanna sell the harness? lol. I have been looking high & low for a 1/2 ton 82-83 emissions harness. Little to no luck. Very hard to find. Either way as for the oil cooler lines. Yeah, a Hydraulic shop is the last resort. But i really would like to stick with OEM ones. As I am doing a Period Correct Factory Restoration. So everything has to be right for those years the truck was made.
No, I’m afraid mine wouldn’t work even if I wanted to sell it. The truck is a K30 emission exempt. It was my grandpa’s old company truck. My plan is to restore it to factory condition.
[/QUOTE]
Oh well. lol but that's pretty cool you want to restore it to factory a K30 diesel these days is getting up there with "holy grail" along side finding a K5 diesel, or a shortbox truck.
 
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I have seen many 6.2s before I left Facebook that had well over 300hp. And the owners claimed that they had been driving those engines reliably for many years.
They have dyno slips on all these 300hp engines :ROFLMAO:
They don't call it farcebook for nothing.
Key word in your post is "claimed"
 

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I think that even the 12v Cummins would blow up if you tried to pull more than 250hp with 30lbs of drive pressure and 15lbs of boost.
A Cummins 6bt would laugh at 30lbs. Compare the block, rods and pistons between the 2.
 

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Discussion Starter · #16 ·
They have dyno slips on all these 300hp engines :ROFLMAO:
They don't call it farcebook for nothing.
Key word in your post is "claimed"
There was one man in particular that I’m thinking of, I can’t remember his name, but I think he was pushing just over 500hp, and just over 900 ft/lbs of torque at the wheel. He also had a dyno sheet to prove it. But he didn’t do anything to the bottom end to strengthen it. So I’d imagine that it won’t last long.
 

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Anything but Silvolite for pistons! The OEM pistons are the best pistons in my opinion. They're built to the highest standards and they have a steel ringland where as most aftermarket pistons dont. That being said I ran 15+ psi on Silvolite's and would get a year plus out of them lol. As for MPG's, dont expect any better. Best I've ever heard of was my buddies 2wd burb that would pull 25.
 

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Discussion Starter · #18 ·
Anything but Silvolite for pistons! The OEM pistons are the best pistons in my opinion. They're built to the highest standards and they have a steel ringland where as most aftermarket pistons dont. That being said I ran 15+ psi on Silvolite's and would get a year plus out of them lol. As for MPG's, dont expect any better. Best I've ever heard of was my buddies 2wd burb that would pull 25.
I’m having a hard time finding oem pistons. I already have sealed power pistons. Are they any good? Currently I have 4 engines I’m trying to build. This is the only one I have pistons for though.
 

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Discussion Starter · #19 ·
I’m having a hard time finding oem pistons. I already have sealed power pistons. Are they any good? Currently I have 4 engines I’m trying to build. This is the only one I have pistons for though.
I know where I can get custom forged pistons. They’ll cost just over $1000 to have them made. But I’m afraid my pockets just aren’t that deep lol.
 

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There was one man in particular that I’m thinking of, I can’t remember his name, but I think he was pushing just over 500hp, and just over 900 ft/lbs of torque at the wheel. He also had a dyno sheet to prove it. But he didn’t do anything to the bottom end to strengthen it. So I’d imagine that it won’t last long.
Bill Heath ?



In the link below it lists a GEP and a $20k budget just to get to 300hp.


One thing I can't find is a dyno sheet.
If I was building a 500hp 6.2 and put it on a dyno I'd sure as hell would have a sheet and video. If I can't see it I can't believe it.
 
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