Engine rebuild questions

[Blzr6.2'83]

I currently have a 6.2 diesel that is very tired. I want to build a nice 6.2 or 6.5 that i will use for offroading and city driving. I want to make it as reliable as possible, but also want enough power to go faster than 75(my current top speed with 3.42 gearing and 32 inch tires :( ). I'm guessing it will have to be NA becasue I only have about 2000 to maybe 3000 dollars to do it with. I know i need a 599 block or AMG block. How far would this much money get me to reach my goal? I will have to buy a core block to build up becasue i need something to drive while i am building my engine. I also want to run biodiesel or WVO so will propane injection still work with it? I'm a newbie with diesels so will probably have a lot more questions.
THanks for all the help,
Kyle

[Blzr6.2'83]

I forgot to ask if a 6.5 has more of a chance to get a cracked block than a 6.2 and if the power gain is worth it if i make the switch?
Thanks again

[john8662]

Welcome to TDP!

Actually you have quite a few options. You're right in the dollar amount for building a N/A engine. Since you'll be finding another block you will want a 599 if you want a 6.5, there are other castings of the 6.5 that are similar like the 141 and 929 castings. These all are blocks that don't have oil jets drilled into the webs for cooling the pistons. The later 506 casting blocks did and are very prone to cracking even in non-turbo form, that is, except the latest AMG block.

The 6.2 block is probably going to be your best bet, they all carry the 660 casting number except the latest 92+ blocks that share the 599 casting with the 6.5, just were not bored out as much. The best block in the 6.2 is the '82 casting, it also shares the 660 casting but will have a date stamp of 81 on the rear passengers side of the engine and be painted chevy red/orange. This block does have a higher nickel content in the alloy and is less prone to main web cracks. I wouldn't think that you would have a hard time finding a core 6.2 block for the build, as everyone is looking for a 6.5.

I don't know that going to a 6.5 block is going to net you that much more power, but going to 6.5 heads and injection pump and injectors is the key to more power. I think the best thing you can do for "seat of the pants power" in your situation will be to change your gearing to 3.73 with those tires. You will also want to concentrate on opening up the exhaust and air intake system. There are many great resources of information right here on the forum. Just click on the "search" text above to the right of the chevy truck picture. Select 6.2L Diesel and search for items concerning power upgrades, to more power. The list for increasing the engine power is quite long, things like:

Amzoil air filter
Swanger Air System
Banks Power Pack exhaust
Upgraded "J" Series intake manifold

etc.

And yes propane will work with biodiesel, but is NOT recommended for a N/A engine, works best with additional air via a turbo.

And finally, for your reading enjoyment, you may consider purchasing some of the bound feature articles about the 6.2L here on TDP

The Diesel Page 6.2L Book

http://www.thedieselpage.com/62book.htm

and

The Diesel Page R&R Guide

http://www.thedieselpage.com/t&rguide.htm

[Blzr6.2'83]

If I plan on adding a turbo can i run lower compression pistons on an NA 6.2 until i can afford to add a turbo?

[Blzr6.2'83]

Thanks for the info I will do the power searches. I now have another question.
If I plan on adding a turbo can i run lower compression pistons on an NA 6.2 until i can afford to add a turbo?

[john8662]

Yes, you can run the lower compression ratio pistons of about 19:1 without being turbocharged. The problem is you will see a slight drop off in power N/A with a lower compression ratio. It all depends on what you're going with the engine, I think for your situation I'd stick with the factory C/R and add the turbo for the passing speed and geared up off roading.

Just a little advice on the lower C/R if you decide to go that route. The only vendor offering the 19:1 pistons is only offering them in stock bore. So if you have a block that needs to be bored (and most do) to say a .020 oversize then you'll have to find another piston.

A vender on here called The Diesel Depot can make you a set of lower compression pistons by shaving the piston and or adjusting the wrist pin height to lower the ratio.

I haven't tried the lower compression ratio pistons myself, but am going to implement them in a 6.5TD build. We'll see what the difference is soon enough. But mainly it's for being able to add lots of boost and make the engine a little/lot more durable.

[opto]

So if you want to build a highpower engine you would rather want a high nickel 6.2 casting rather than a 6.5? Even though the 6.5 has oilcooling of the pistons??

[john8662]

opto,

Yes an earlier 6.2 would stay together better than a later model 97+ block because it doesn't have the oil spray piston coolers. The previous 6.5 blocks would be good for a build though, like the '599, '929. '141 blocks, but most just prefer the 599 made from 92-94. The problem with the coolers in the later blocks st that to implement this additional machining to the bottom of the engine block was done. This machining took out some of the blocks metal in the main webbing area and gave the block one more place to crack. And they did crack, most of these blocks besides cracking in the normal area of the main webbing also cracked starting at the drilled hole in the block for the oil spray nozzle. Most that cracked at the nozzle area had the crack spread all the way up into the cylinder bore, leading to coolant entering the oil.

Thats why I recommend a block that didn't have this so called "improvement." But for a 6.2 build, the best 6.2 to knowledge would be the 82 block that was casted of the higher nickel content. 83+ blocks didn't get this as GM either incurred additional machining expenses due to the block being more rigid or thought it not to be necessary. It really wasn't necessary for most 6.2's because they were not turbocharged and made around 155hp in J series form. But if you're building a 6.5 to replace a 6.5 in a later model truck, the '599 casted 6.5TD is what you're after.

[opto]

Thanks John

I already have a 6.2 in my 1991 CK2500. It is starting to wear down I think. So I figured I would start building something to replace it with. It is my everyday truck so I don't want to make a rebuild of it. Truck has already been stuck in the garage cause I'm still waiting on my new tranny from fourthgear. (Not his fault I have to wait, shipping overseas takes some time)
My plan is to prepare a block then just move accessories to the new buildup.
In this case is it better to go for a 6.2 or a 6.5
Plus I want to build something with quite a lot of power but I can't afford all good stuff at once.

[john8662]

opto,

It's all what you have access to. Personally I think the 6.2 will work great if you install a turbo on it. Or, find a good 6.2 block and then bolt on some 6.5TD heads, then you'll basically have a 6.5. I'm at my wits end with one of my trucks. I've got a new GM shortblock 6.2 engine to put together (heads, cam, etc.) and install it into my 86. It's a 599 casting 6.2, last of the breed. I'm looking for a set of 6.5TD heads currently, which has proved to be difficult. Most of my local diesel shops sold all of their heads.

So you got a Fourth Gear tranny like what Dr. Lee did? I was wondering about them myself, I am considering installing a new transmission with the new engine. I'm still curious how that trans is working out for the Doc, as the first shot at the rebuild failed due to the replacement parts not being machined smooth (not the builders fault).

What did you end up paying for the transmission before shipping?

[opto]

OK John I see the point, the heads are the important thing when building an engine.

I think i paid $2200 with almost all heavy duty upgrades possible, this also included converter, a big transcooler and new TV-cable. I think I will recieve it thursday and I have to be offroading on friday night.

Has anybody tried converting heads or building new ones to do direct injection instead of the precombustion chambers?

[opto]

What would be a resonable price for a 6,2 block from 82 with crank and rods. Assuming it needs to be bored. Or pherhaps, a more or less complete engine thats neds to be rebuilt.

Will there be any complications converting such a block to beltdrive?