SPINPOSI

(Engine wise) Just looking for your opinion about the main difference between the two.

I'm relativly new to cummins and have few "friends" riping on me for buying a 1st gen motor

-Jason

G1625S

If you're limiting the discussion to just 12 valve engines, there aren't many differences worth noting, really. The early, non-intercooled first gens had larger injector bores which gave the head a greater tendancy to crack between the valve seats when compared to the 91.5-98 head. Beyond that, there's the obvious difference of the VE pump on the 1st gen truck vs. the p-pump on the 2nd gen truck. While the p-pump reigns supreme in the ultra-rediculous horsepower arena, there are more than a few VE-pumped trucks with 600+ horsepower at the rear wheels....

SPINPOSI

So what has anyone done to prevent the cracking?

Can a P pump be fitted in place of a VE?

Why does a 2nd gen sound so different and Louder than the 1st?

Begle1

In 1991.5 they went to a head with smaller injectors. That head doesn't crack, but those stock injectors can only support around 250 HP while the earlier stockers are good for 300 HP. However, all the aftermarket injectors are made to fit the later heads, so there's not much of a reason to stick with the earlier heads beyond that 50 extra horsepower.

A P-pump can be put on in place of a VE, but it's far from a bolt-on. The usual consensus is that it's cheaper to buy a BOMBed VE to bolt on, unless you're shooting for 800 HP.

G1625S

Are you talking 12v or 24v? The 24v is an entirely different beast and is quite noisy. The p-pumped 12v trucks are noisy only when the pump has been advanced past, say, 16*. The VE has some seriously cool dynamic advance built in, kinda like the mechanical advance on an old gasser distributor, so you can have your cake and eat it too...low rpm grunt and a bit of extra injection lead up top The VE really is a beauty of a pump.

SPINPOSI

So....to get over 300hp I need a new head and injectors

SPINPOSI

Just talking 12v only...

G1625S

I assume you have an early 1st gen engine?

G1625S

Before we go any further, what are your goals for this engine? There's not much these things won't do, sometimes you just have to be more creative to get there

SPINPOSI

1990 CTD, NV4500hd, 4x4, reg cab,stock as can be....

SPINPOSI

Well .....I plan to shoot for 400 hp range.

But want to learn as i go , not just throw all kinds of money at it all at once...

Begle1

You don't need a new head. You can put aftermarket injectors in the early heads with a special adapter, but you're going to be playing cheat the devil with cracks.

Or if you want to be da pusherman you can inject enough water and nitrous to get to 400 with stock injectors, but at that point you're going to need O-rings in the head anyways to hold onto the cylinder pressures.

My theory is that getting a new head is an excuse to get a ported, polished and O-ringed head while you're at it...

G1625S

400 HP for play, or for towing? I'm not sure what you're used to driving, but these old trucks are a different beast. You can usually at LEAST double the torque for a given horsepower. Wannadiesel, for instance, hasn't cracked 400 HP (yet) but he's knocking on the door of 900 ft/lbs of torque which is some seriously neck-snapping twist power...not to say that you shouldn't shoot high, but that 'push you back in the seat' feeling is only a couple screw twists away on that '90 of yours...

edit: 3rd gear in my truck (which is not all that fast, really) is downright un-nerving and a few seconds of 4th gear will accelerate the truck to speeds dodge never intended a power wagon to see

SPINPOSI

I'm used to driving a slightly bombed 2000 PSD 330hp

All I do is tow.

If I wanted to drag race I'd keep the PSD or go buy a mall chevy duramax...

SPINPOSI

The PSD was / is nice but.....its just not a Cummins