MaxPF's 6.2 build

[MaxPF]

So, how much did that new crank cost? I've been looking in my garage and searching crank that was removed from the block that's under the worktable. So far no luck finding it. I remember it having one bad journal, so wouldn't been any good to use.

Well, I managed to get an NOS GM 6.5 crank for $300. A brand new AMG/GEP crank will set you back about $500-$600. These are the only ones I would buy. AMG is American General, the company that manufactures the HMMWV for the military. GEP is AMG's General Engine Products division, which manufactures brand new 6.5's for use in the HMMWV's, as well as replacement engines. If you buy a Goodwrench 6.5, you are getting a GEP engine. The blocks, heads, and cranks are cast by International Truck and Engine, the same folks who make the Powerstroke, DT466, etc. These cranks are every bit as good as the GM cranks were (the blocks and heads are far better - too bad you can' buy em as seperate pieces like you can the crank. The only way to get a GEP block and heads is to spring for a long block). Any other crank you find will be Chinese in origin. A guy over at the Diesel Page bought one (which was advertised as a forged crank, even though it was obviously cast), and it broke in shipping!!! The material looked like gray cast iron, not nodular iron. You could have dropped a GM crank from an airplane and it wouldn't have broken. Breaking a crank due to mishandling is impossible, unless the material is horribly substandard. You will see these often on Ebay. Unless it is advertised as a GM crank (or possibly GEP crank) and you can verify it (i.e. casting numbers), you can be certain it is Chinese. Scat also has a 6.5 crank in their catalog. It is supposedly a "cast steel", although Scat's cast steels are actually a nodular cast iron. I don't know what the casting quality is like, but I do know that it does NOT have rolled fillets. Rolled fillets nearly double the fatigue resistance of the crank, and they increase the amount of bending the crank can handle before it even begins to fatigue. Rolled fillets are a necessity on cast diesel cranks. They simply won't have a long lifetime otherwise.

Also that block has cracked webs. Don't remember how badly. But after reading this thread couple of times, I started to wonder that if I buy main stud kit and fab full main girdle, could I use that block? What I've heard, crack free blocks are hard to find in here.

Well, as a general rule if the block is cracked it is scrap iron. There has been a couple folks who had 6.5 blocks with cracks that didn't extend beyond the bottom of the outer main bolt holes. They stop-drilled the cracks and installed splayed main caps, and haven't had any problems even though they are bombed fairly well. Note that they did NOT use the outer main cap bolt holes -with the splayed caps you drill and tap new holes at an angle that extend under the pan rail. This is the strongest part of the block. While I believe they won't have any problems with their motors, their success hinges on making sure that they intercepted the bottom of the cracks with the stop-drill. Otherwise the crack could continue to spread. It is definitely not something to try unless you (or your machinist) really know what they are doing and are willing to live with the consequences if it fails.

Do you have a 6.5, or a 6.2? Most cracked blocks I have heard of are 6.5's, especially the 97-2000 blocks with the piston oil sprayers in the main webs. Earlier 6.2's have thinner main webs than the later ones. I would reccomend that you keep looking for a good buildable block. They're out there.

 

[MaxPF]

Good things come in small packages

Well, now I can take my crank assembly to the machine shop for balancing. I was waiting on the gear drive, since the crank gear is helpful to have. It doesn't affect the crank balance at all, but it does set the spacing for the damper on the snout, and that DOES affect the balance. I could've just thrown my old chain sprocket on there, but I didn't want to have to pull it off once it was installed.

Here's a pic of my small box of goodies:

 

[BKinzey]

Got back into reading this thread. Lots of great info, lots over my head

I wish I could do half the machining you are but $$$

Good find on the gear drive. I'm planning on going with a Fluidmaster but maybe I can scrape enough together to get both.

I'm very interested in the studs and stud girdle though. Would your 6.2 girdle work on a 6.5? After you get yours done would you give me a spec sheet on it?


Lots to do and not much $$ to do it with

 

[MaxPF]

The main spacing on the 6.2 and 6.5's are identical. So yes, any girdle designed for one will fit on the other,

Speaking of which, here are some pics of the finished girdle installed on the block with ARP hardware.

In case you're wongering, the gray paste is ARP Assembly Lube, which is a molydisulfide based lube. It is needed to get the proper torque and preload. I had to angle the ends of the girdle to clear the pan. This worked fine on the back, but the front of the pan is going to need some substantial mods to clear the girdle and the studs. There is also interference with the dipstick and possibly with a couple indentations on the pan. These are all fixable, but it explains why DSG doesn't tie their girdle to the front and rear caps. It does look like the DSG girdle would interfere with the dipstick though...

 

[4x4_76]

I had to angle the ends of the girdle to clear the pan. This worked fine on the back, but the front of the pan is going to need some substantial mods to clear the girdle and the studs. There is also interference with the dipstick and possibly with a couple indentations on the pan. These are all fixable, but it explains why DSG doesn't tie their girdle to the front and rear caps. It does look like the DSG girdle would interfere with the dipstick though...

Those are just small problems, compared to benefit it gives. But damn, that girdle looks sweet!

One guy here in finland made same kind of girdle, only it wasn't that tall, it was only about 16-20 mm. Took just a little pounding to pan to fit it in front.

BTW, the block I was speaking earlier, it's junk. Middle web crakcs are going towards each other, so it would be a major waste of time to use that block.

 

[MaxPF]

Not much to tell right now. The block, crank, rods, pistons, damper, and flywheel are at the machine shop right now. It will probably be a couple of weeks before I see them again. Meanwhile, I will take the oil pan, valve covers, timing cover, intake manifold, and water crossover down to the shop tomorrow to have them cleaned in the jet washer. I have been cleaning the lifters and other parts in my spare time. I also got some valve guide inserts to sleeve the between-valve coolant passages in the heads. I just need to get use of my friend's Bridgeport mill, which has a paying job on it at the moment.

I am still trying to decide what color(s) I want to paint the motor. I've been thinking arrest-me-red for the block and heads, black on the tin and accessory brackets, and clear on the timing cover, intake, and water crossover. Anyone have any other (tasteful) suggestions?

 

[MaxPF]

A change in plans... again :-)

Here's the deal: I wanted to have the motor finished and swapped in before my elk hunt at the end of October. However, that isn't going to happen. There's just too much to do, I am changing jobs (much better pay, but initially I will be fairly busy), and I can't stand the thought of short-cutting things. So, my new target date is Christmas, and I am going to go full tilt. The bottom end is already set up quite well. All that is needed is to mod the oil pan. The top end is where things will get interesting. Besides all new parts (lifters, pushrods, valves, precups, seats, springs, retainers, etc) I am thinking of replacing the seriously lame stock shaft rocker setup with something a bit less primitive.

Here's what the later, most common stock shaft rocker setup for the 6.2 and 6.5's looks like:

These shaft rockers have a lot of friction, and if the little plastic button locating the rocker breaks off the rocker can slide over, push the retainer down, let the locks fall out, and drop a valve I'm thinking of replacing them with something trick.

What do you all think of a setup similar to this one:

Full roller rockers Can you say "low friction"?

 

[imiceman44]

Here's the deal: I wanted to have the motor finished and swapped in before my elk hunt at the end of October. However, that isn't going to happen. There's just too much to do, I am changing jobs (much better pay, but initially I will be fairly busy), and I can't stand the thought of short-cutting things. So, my new target date is Christmas, and I am going to go full tilt. The bottom end is already set up quite well. All that is needed is to mod the oil pan. The top end is where things will get interesting. Besides all new parts (lifters, pushrods, valves, precups, seats, springs, retainers, etc) I am thinking of replacing the seriously lame stock shaft rocker setup with something a bit less primitive.

Here's what the later, most common stock shaft rocker setup for the 6.2 and 6.5's looks like:

These shaft rockers have a lot of friction, and if the little plastic button locating the rocker breaks off the rocker can slide over, push the retainer down, let the locks fall out, and drop a valve I'm thinking of replacing them with something trick.

What do you all think of a setup similar to this one:

Full roller rockers Can you say "low friction"?

Uh.... Low friction.., yeah I guess I can say it.
That would be killer.
Is that on a 6.2 l diesel? or is it something you are hoping to find for the 6.2?

 

[MaxPF]

It is a 6.5 - same difference. The guy who built that motor made a custom setup using Jesel roller rockers. Now, Jesel's are a bit too pricey for me, but Comp Cams steel roller rockers fit the budget. I would use BBC rockers, which have virtually the same pushrod seat to valve actuator distance as the 6.2 rockers, and they accept 3/8" pushrods. The difference is that the ratio on a 6.2 rocker is 1.5, whereas the BBC rocker is 1.7. That will increase the valve lift from .420" to .476". Assuming the valves and pistons have enough clearance at overlap, it should work fine. I'll see when I get there.

Here's another pic of that same motor. This guy has done some trick machine work:

That's his idea of a girdle . It's probably way overkill, but it sure looks cool

 

[smalltruckbigcid]

Yeah that girdle is a little overkill unless he's gonna twist it real tight. But it looks damn good

You may want to check for coil bind and other interference if you go to the higher ratio rockers. Don't use aluminum rockers though, it would probably bite you on the butt for life expectency on them.

George
Your doing good work brother it just costs so damn much don't it.

 

[MaxPF]

Yeah that girdle is a little overkill unless he's gonna twist it real tight. But it looks damn good

You may want to check for coil bind and other interference if you go to the higher ratio rockers. Don't use aluminum rockers though, it would probably bite you on the butt for life expectency on them.

George
Your doing good work brother it just costs so damn much don't it.

Yup. that's why I specified steel rockers. As for springs - no problem. I'm replacing them with much larger springs that will accomodate over .600" lift.

Yeah, this thing is costing quite a bit. I decided that I didn't like the wear I saw on the lifters, so I bought 16 new Sealed Power roller lifters and 16 new pushrods. There went another $300 Still, I keep reminding myself that even with all these add-ons it is still cheaper than the 383 gasser I was thinking of building.

 

[Xtremegmc80]

i defentily am subscribing to this... cause my next engine for my 80 gmc is gonna be a diesel.. in a year or two.. LOOKING GOOD... im a newb to diesels....

 

[BKinzey]

Wow! This thread is getting into modifications

Who's engine is that? and where is that drool smiley?

So, with all the mods you are looking at why are you staying with the 6.2 and not making the jump to a 6.5?

 

[imiceman44]

Wow! This thread is getting into modifications

Who's engine is that? and where is that drool smiley?

So, with all the mods you are looking at why are you staying with the 6.2 and not making the jump to a 6.5?

I wanna ask the same question:
If you had the option like I do now with a 599 block that can be bored out to 6.5 would you go up or stay with 6.2 for reliablility?

 

[MaxPF]

I wanna ask the same question:
If you had the option like I do now with a 599 block that can be bored out to 6.5 would you go up or stay with 6.2 for reliablility?

Well, I don't see the extra 300cc's of displacement to be a big deal. Good 6.5 cores seem to be harder to find vs the 6.2. My motor was a seemingly rare 165HP version out of a one ton truck with 227k on the odo. Judging by the condition of the donor vehicle I would guess that it was run hard and put away wet for most of it's life. Yet, the block was crack free and, other than the #7 intake pushrod and some scoring on the crank and cam journals from the resulting debris, was in good shape internally.

Is the 6.2 a better block? I don't know. Mine has thicker main webs, which I believe were carried over to the 599 and later 6.5 blocks. It sure seems like you see less problems with 6.2 blocks, but that may simply be because they aren't under as much stress as a turboed 6.5. I bet GM could have solved the main web problems by simply making the outer bolt .300" longer. The stock bolt only engages .300" of thread (less than 3/8"!), which puts an enormous amount of stress on the hole. There is a reason the cracks start there and not on the more highly stressed inner holes that have less webbing on the sides.

Anyway, I guess my thinking is that you should build whatever good core you find. 6.2 or 6.5 doesn't matter. With your 599 block you have the option of either. Going to 6.5 gives you the option of using off-the-shelf hard anodized pistons. However, these blocks did occasionally have the #8 cracking problem. It was much more common in the later blocks, however.

http://flashoffroad.com/Diesel/No8Cyl/CrackedBlock.htm

Staying with a 6.2 bore gives you more material in the cylinder walls, which is a Good Thing.

BKinzey: That tricked out 6.5 belongs to a guy by the name of Andrew Ashwill. He contributes articles over at the Diesel Page from time to time.

 

[MaxPF]

Holy wow I can't believe the lengths you are going on this thing.........




.............but I can't help think to my self.....All of that time energy and money and it'll still be a 6.2 in the end

What else would it be

Don't get me wrong Im not knockin' it..............I just don't get it.

What don't you get? It's no different than building a tricked out gasser.

 

[BKinzey]

Looks like you have done a lot of thinking and consideration on your build. Most would jump to the 6.5 because it's there. Glad to hear your reasons for sticking with the 6.2. Did you consider the latest whizz-bang 6.5 block from AMG as well? I don't know what problems it addressed but lots of oohs & ahhs on it. You certainly know more than I.

Lifts, ratios, etc are over my head. So if your choice of rockers causes the valves to smack things what will be the solution?

If you are considering going with 18:1 pistons take a look at the Kennedy Diesel set. Sounded like a better result than just lopping the top off

 

[tRustyK5]

Holy wow I can't believe the lengths you are going on this thing.........




.............but I can't help think to my self.....All of that time energy and money and it'll still be a 6.2 in the end

Don't get me wrong Im not knockin' it..............I just don't get it.

I can't believe the lengths you've gone to with your Cummins...yet there you are.

All bullsh!t aside I'm getting tired of your thinly veiled sneering at the 6.2/6.5 and Max's build in specific. I'm pretty certain we all know about your uber Cummins, and cool as it may be, most of us also don't care. If any of us wanted to be another CTD clone hero we would have gone out and built one of those instead...

So, if you have anything constructive to add please feel free to do so. If all you have is derisive sneering in mind...

piss off.

Rene

 

[MaxPF]

Looks like you have done a lot of thinking and consideration on your build. Most would jump to the 6.5 because it's there. Glad to hear your reasons for sticking with the 6.2. Did you consider the latest whizz-bang 6.5 block from AMG as well? I don't know what problems it addressed but lots of oohs & ahhs on it. You certainly know more than I.

The AMG block is an excellent piece. The only problem is that they won't sell just the block. You have to buy a complete assembled long block. If I had $6500 to burn I would have bought one myself BTW, if you go to your local friendly GM guy and order a replacement 6.5 longblock, guess what you will get? That's right, a nice brand new AMG long block

Lifts, ratios, etc are over my head. So if your choice of rockers causes the valves to smack things what will be the solution?

I found out that Comp has 1.6 ratio stainless roller rockers for BBC apps, so I won't be forced to go with 1.7's. If the valves get too close (which I don't think will happen) I will simply machine some shallow valve reliefs in the pistons. The stock 1.5 rockers give .420" of valve lift, while the 1.6's will give .448 lift. At overlap where there is almost no lift the difference will be a couple thousandths at most, so I don't think it will be an issue.

If you are considering going with 18:1 pistons take a look at the Kennedy Diesel set. Sounded like a better result than just lopping the top off

I already have the pistons. My compression will probably end up a bit lower than stock due to the fact that they are .010" topped pistons.

 

[DEMON44]

fair enough. I deleted all my posts. sorry for the inconvenience.