Help me make up my mind? Keep 6.2 block?

[Busted]

I've been reading all the 6.2 / 6.5 posts and discussions, and perhaps I'm missing the relevant threads, but . . . .

Truck in question is my 1982 CC DRW 6.2. I have an NV4500 to replace the TH400, diffs have 4.10 gears. Right now I can get a '93 6.5TD donor truck with 210,000MI for $800.

Some of you have done a 6.5 turbo on the 6.2; others the turbo and heads, sometimes an IP upgrade to the late model DB2. Still others just swap the entire engine out.

What are the advantages to retaining the 6.2 block? Max RPM is slightly higher, CR is barely higher than the 93 but that's a disadvantage with the turbo from what I'm reading. 6.5 block gives me a serpentine belt without any effort, not sure how relevant that is. I've never personally seen a 6.2 with problems other than poor maintenance, and I've seen good and bad 6.5's, some real lemons. I've also read that acquiring a good 6.5 block sometimes requires a bit of black magic, i.e. cross your fingers and Magnaflux. I also understand the differences between the pre-cups for different years of 6.2 and the 6.5s.

Anyway, I'd love to hear some specific, technical 'splanations from both 6.2 and 6.5 proponents as to why they prefer one engine over the other and why. Please do include details as to your objectives (power, mileage) and usage habits.

[Robyn]

Baisically the 6.2/6.5 are identical accept for the bore. The cranks, rods and most all other parts can be swapped at will between them.
The real early (82) engine had an extra water passsage in the heads and also the injector threads were coarse instead of fine.

The later 6.5's went to an oil spray piston cooling system and the oil pump has a tad larger displacement to compensate for the greater oil loss through the spray system.

The 6.2 has 101mm bore and the 6.5 has 103mm bore.
Cams are interchangeable as are the heads.

The small precups were used in the early C 6.2's and will produce some great mileage numbers with the right butt gears.

The turbo 6.5's use a precup with a much larger port to enhance power.

The 6.2 will run fine with a factory 6.5 turbo setup when used with an appropriate IP (Turned up J pump or 92-93 6.5 DB2)

I have even seen a 6.2 dropped in where a 6.5 had been and was running the DS4 electronics (needs the front case cover changed along with the ballancer and the addition of interuptor wheel to activate the crank sensor.)

The 6.5 TD has coated piston crowns and the 6.2 does not.

Real early 6.2's used cast rocker arms and the later ones and the 6.5's use stamped steel.

Your choices are pretty wide open.

The 6.2 blocks can break just as the 6.5's do.
I had a 1994 dated 6.2 block that had mainline cracks so its not just a 6.5 anomaly

The real late 6.2's have the one piece rear main setup just as the 6.5
(Early 599 blocks were cast for use with either engine size)

The serp drive setup can swap all the way through the 6.2/6.5 lineup
The parts will swap to any combination you want.
You can retain the rear vacuum pump/oil pump drive plus the pump on the serp setup or you can go to a simple Oil pump drive as was used on the later trucks. There are even units that have an electronic signal device in them too (late 6.2 stuff)

The only down side of the 6.5 turbo on a 6.2 in an early style truck is the routing of the exhaust can need lead to some creative plumbing.
(The old style A/C system will hit the turbo exhaust outlet so some folks have used a S10 series HVAC unit)

Its all been done many times over with the good old mix and match parts selection.

Good luck with your project.

Robyn

[Busted]

'Tis reassuring, indeed. The donor truck I'm eyeing is a '93, so it's the mechanical IP still. I'll probably do gaskets, head studs, new balancer, and girdles on the bottom end just to be safe, then drop her in. I'll be doing a custom exhaust anyway after that--straight pipes with dual 4" stacks behind the cab--so it shouldn't be a problem to modify things to fit as I go.

Any reccomendations for head gaskets? I've read about MLS gaskets for the Cummins--are they worth the cost, or is something else going to break long before they go? Favourite manufacturer?

[WRB Diesel]

Robyn,

With the 6.2 and the 6.5 being so similar besides bore size what allows the 6.5TD to have a higher heat tolerance, is it simply that the pistons are coated?

Thanks

[Busted]

picked up the parts truck on the weekend, got it for $600 :-). '93 mechanical 6.5TD with the 599 block, 2wd NV4500 in great shape (not sure what to do with that yet) and kept a few other parts such as the rad, rear diff., grill, and hydroboost/master cylinder setup. A buddy took one of the fenders as well. I think I got a good deal for the useable parts I took off :-). The 2wd NV will be swapped for a 4x4 NV4500 that I have already and bolted to my NP205 t-case, then the whole thing is going into my '82 to replace the 6.2 that is currently there. I will be fabricating a larger crossover pipe and downpipe to fit my truck, then building an open exhaust, splitting just past the downpipe to dual 4". Hopefully everything proceeds smoothly .. . .

[Busted]

starting to rip into the engine and looking for head studs--am I correct in my belief that the ARP stud kit sold for the 6.2 works for the 6.5 as well? Is it recommended, or is there a different route for studding the 6.5 heads?