I saw a post some where about putting a newer 6.5L IP on a 6.2L to make HP increase. I've got an extra 6.2L IP. Can it be built like the newer 6.5L IP's?

Nope, the roller diameter in a 6.2 pump is .280 and the 6.5's diameter is .310, it won't flow the fuel that the 6.5 pump will.

A 6.2 pump, turned up to maximum output will work on a 6.5 NA without much problem. It just doesn't have the capacity for properly fueling a turbo 6.5. Unless, of course, you are only using it as a passenger car, not ever hauling anything, pulling steep grades, full throttle, etc. Hah! I know you guys!

That's the pump plunger diameter, right? Rollers are identical........

Camring is also specific to 6.5, and to get accurate delivery, the housing is beefed, similar to the 7.3 housing.

About '95, Stanadyne 6.2 pumps and rebuilds were built using the 6.5 housing, so see if you can find one of those.

Or, simply, get a late blue label 6.5 DB2-4911 equiv Inj Pump........

Thats afirmative, plunger diameter.

Keep in mind that over fueling a 6.2 isn't a good thing. The weak link on a 6.2 is the piston. The crowns aren't very thick and pistons are fairly easy to crack if you over fuel or advance timing too much. The OE pistons however are quite a bit better than aftermarket pistons. Pretty much all of this discussion applies to a turboed engine because a stock injection pump supplies plenty of fuel for a NA application.:eek:

All you need is light haze at full throttle - black smoke is high EGT's is danger, period.

Black smoke and towing\hauling is double danger.

The 6.2 Inj Pump can provide any danger level you desire - no need for a 6.5 IP.

ok... so High EGT's is danger... we all know that, but what is considered a High EGT? and where is it measured? Would it be 'practical' to turn up a 6.2 pump by watching the EGT? With a pryo, would it be safe? Does turning up the pump effect mileage at all? Just trying to add to the 'lowcost power improvements' is all...

Any time you burn more fuel, the fuel economy drops. Nothing is free, if it's advertised as free, it's probably just good advertising!

Tuning with the pyrometer is ok if you have a set of readings, before and after stuff. Make adjustments carefully, look for the "light haze".

The closer to the turbo, the higher the pyrometer readings. The farther down the pipe, the cooler the exhaust gasses get. The ideas is, wherever you measure the temp, do it consistently. Take "before and after mod" readings the same way every time. Do not get "hung up" on trying to attain a certain EGT. Tune for good performance with a light haze on heavy acceleration. Any increase in smoke is bad news for the engine.

.Black smoke is unburned Diesel fuel - a light oil.

Oil retains heat of exposure, which in this case was combustion temperature.

Black smoke is oil that was at combustion temperature, but not enough O2 to finish the combustion process, meaning that it is at very high temperature.

When combustion process is complete, only the heated gases, and associated residuals, exit the cylinder.

Gas is low density, unable to retain heat, so temperature drops rapidly, is easily dissipated.

Oil, at greater density, transfers more heat into the cylinder, piston, exhaust valve, port, head, etc.

The fresh cool incoming air charge on the next intake stroke cannot effectively reduce the much higher residual cylinder temperature.

High EGT seldom melts piston crowns – it does, however, cause the piston to expand beyond design limits, which then seizes in the cylinder(s), with cracked\broken piston(s) as result

Limit EGT to 1100-1200 deg in the manifold at the exhaust port, keeping close watch on Engine Coolant Temperature, for surviveability.

EGT changes rapidly, where ECT is slow to react and indicate.

If EGT is at 1100 deg, and ECT is steadily climbing, heading upwards from 220deg, it is time to ease off, imo.
This could be resulted merely from poor coolant system maintenance, but does require some driver reaction.

Some say they regularly run at 1200 to 1350, sustained, with no damage, but I choose to err on the safe side, and steady EGT with increasing coolant temperature is a good indicator.

Remember - EGT can increase much quicker than the gage can follow, so you have little safety margin over 1200deg.

BTW – melted piston crowns are most often resulted from defective injector spray patterns, where it is more of a squirted stream, as in a flame-thrower or blow-torch, rather than a spray.

That's my story, and I'm stickin' to it..............

Great Description gmctd.... very informative. Anyone have any idea what egt a stock 6.2 J motor would show without any 'messing'? just lookin to get an idea of what the base is. Would you recommend putting the probe right at the outlet of one cylinder?

On a NA engine, I would try to put the probe in a location that gathers the average of all the cylinders on one side of the engine. Always remember that this reading is just an average, hence the reason to err on the side of caution. I would run no hotter than 1100 degrees. I have seen some stock engines that wouldn't even hit 900 degrees at wot. I have seen some engines get better fuel economy with the fuel opened up because it allows driving with less pedal, which results in more mechanical advance from the injection pump. If you have a heavy right foot however, expect mileage to suffer. By the way, did you ever determine your axle ratio?

Unless someone in the military (or forrestry service) changed it, its 3.08....

now I am starting to wonder, should I just go with 3.73's? My first thought was the 4.10's because I have them, but thye are the heavy 3/4 axles... and I dunno if I need them for my application.

Any thoughts?

If you have a set of 3/4 ton axles on hand, just do it:grd: Your acceleration will be awesome. 3.08's suck for everything except flat driving. You tranny will like it better also. With the 4.10's I would opt for a tall tire. 35" tires and 4.10 gears are almost identical to 3.73's with 31" tires. Or if you have a set of 16" wheels, 255-85r16 tires are about 33.3" tall and work well with 4.10's.

I recently swapped in a set of 3/4 ton axles in my daughters blazer, with 4.10's and 35-12.50-16.5 tires and it is very quick off the line and runs very well in direct, but is a little doggy in OD but if driven with a light right foot, it will get 20 mpg. Fuel is also turned up 1/2 turn:D :D .

My only thought had been, I dont plan on running tires bigger than maybe 32, or 33's... plus the 3/4 axles I have need all new ball joints, ujoints, and the rear needs a new pinion bearing. I would also have to have the driveshaft rebuilt to accomodate the shorter wheelbase (as they are in a pickup now). I started considering all that, and thinking about how good shape the current axles (and tires) are in, and was thinking it might just be smarter to buy new gears to replace the 3.08's that are currently in it. If I am buying new gears anyway, there is no reason to settle for the 4.10's if the 3.73 would be better for what I need. it will be a daily driver 99% of the time. The heaviest tow that it will commonly see will be a jetski, lawn mower, military 3/4 ton geneartor trailer or snowmobile trailer. This sumemr, it might see towing a 32' boat, but I have intentions of selling that ASAP. Also, wont the heavier axles cause a slightly worse mileage? On the plus side of the other axles..... they have the rear disc conversion on them... (need blueprints??)

You could probably change gears in your 10 bolts for about 400.00 if all of your bearings are in good shape. If you decided to use the 3/4 ton stuff, all of the outers of your 10 bolt would interchange, knuckles spindles outer axle shaft and ujoints. As far as drive line goes, you could use an conversion ujoint with your existing driveline. If you 3/4 ton front end was also a 10 bolt then you could just swap the brakes and you would be set.:eek:

my 3/4 front is a 10bolt, but the ball joints are hosed in it... too many miles with 33 x 15.5 swampers on it... ;) I am pretty sure that my bearings in the 10 bolts are fine. I am mostly trying to decide at this point... 3.73 or 4.10... It will be sometime this summer before I can do anyway... gotta come up with the green stuff. I think I will prolly do the tranny first anyway.

Thank guys, lots of good info.

If you decide to go the 3/4 ton route, which in the end would be much more durable, you can swap the knuckles with ball joints, tie rod, spindles and bearings and axle shafts over to the 3/4 ton front end, with no cost at all or use the 3/4 ton front end and put ALL of the 1/2 ton parts on it and then just re- gear the rear end to match. Could be done real cheap!:rolleyes: