Bombing GM 6.2 Diesel

[Vaughn MacKenzie]

My buddy recently got a '82 Blazer with the 6. 2 and I am in the process of also buying a beater '82 Blazer with the same engine.



My buddy's rig runs pretty good, it accelerates as good as you'd expect a 6. 2 to run, but even at full throttle it doesn't make one bit of smoke. Once it made a miniscule puff when I was behind him and he hammered it to pass someone.



Can you turn up the pumps on these? Certainly you can add more fuel and actually make it smoke a little! The exhaust is pitiful, all the way from the super restrictive manifolds to the wussy 1. 75" plumbing for each bank. The clearance between the frame is so tight headers look to be out of the question, but has anyone heard of headers for these??



The general plans for BOMBing that I have for my rig is a mains girdle, turn up the fuel and upgrade the exhaust. For 160K miles and sitting 8 years it runs pretty good. The motor sounds tight and smooth, very little blowby. The owner retorqued the head bolts at 100,000 miles and hasn't had a lick of trouble with the engine since new, other than being hard to start after sitting awhile. He also defeated the EGR since it was almost new so that probably helped a lot.



Vaughn

 

[Vaughn MacKenzie]

I just found out Stans Headers builds headers for the 6. 2L diesel with 3" collectors . .

http://www.stans-headers.com/gm_headers.htm



Vaughn

 

[HoleshotHolset]

Yes, you can turn them up... but you have to be careful. They don't take kindly to too much fuel... with no turbo under the hood... it's easy to overfuel them.



There's an allen screw on the pump that you can crank up a bit... . I don't recall exactly where it is.



Matt

 

[Vaughn MacKenzie]

I am planning on a pyro, but I have no idea what is "OK" as far as EGTs on a non-turbo engine. The compression ratio is sky high on these but at least there is no added boost so cylinder temps and pressures won't be as high as on a Cummins TD. But I doubt there is piston cooling either.



I am checking into the mains girdle, I heard they aren't that expensive and are pretty easy to install and helps the bottom end significantly. Keeps from breaking mains, crank and the block. Replacing the timing chain with a quality double roller helps too from what I heard. . . keeps injection timing accurate (another reason 6. 2s blow out the bottom end, sloppy timing).



Vaughn

 

[HoleshotHolset]

"OK" EGT's on almost every diesel I have ever seen is the usual 1250°F (pre-turbo on turbo applications)...



Go beyond that for extended periods (few minutes... ) and you start to gamble with your pistons...



The 6. 2s don't have oil nozzles to spray the pistons... so they're at the mercy of combustion temperatures with little to help them out.



If anything, I'd concentrate on the head gasket more than anything else... . keep good glow plugs in it too. I've heard WAY too many stories of the tips breaking off and ruining engines.



Matt

 

[Ol'TrailDog]

I think probably the best way to bomb a GM 6. 2 involves a ammonium nitrate and diesel mix. :-laf

 

[Turbo Tim 1]

Originally posted by Ol'TrailDog

I think probably the best way to bomb a GM 6. 2 involves a ammonium nitrate and diesel mix. :-laf

Yup, I bet that gets a couple federal agents surfing the TDR!

 

[nickleinonen]

http://www.kennedydiesel.com has stuff for the 6. 2/6. 5 diesels. you could make a home brew propane injection [someone over on the forddieselforums made one for his n/a 6. 9] system. should help out. timing can also be advanced

 

[Vaughn MacKenzie]

Originally posted by Ol'TrailDog

I think probably the best way to bomb a GM 6. 2 involves a ammonium nitrate and diesel mix. :-laf

LMAO Traildog. . . that might be good for one quick pass down the 1320



Nickle I'll check out Kennedy website.



Holeshot I'll change out the glow plugs as a precaution, I have no idea how often they should be changed. I'll see how the headgasket does, the originals have held for 160,000 but by now it may not take much to blow one out.



Vaughn

 

[ProMac1K]

I think that should be a Roosa Master pump, not sure if it's a DB or DM. It should have a max fuel screw on the rotor. To get at that you take the governor cover off, take some of the linkage off, and turn the pump over till you see an allen head screw. Can't remember if there's one or two on that pump. Also I think there is a torque screw on the pump somewhere that can be adjusted. Maybe that's just the DB pumps. But better left well alone if you know what I mean, without a calibration machine. Like Matt said, they overfuel fairly easy. Another thing would be to advance the timing, like was mentioned earlier. I believe you can also put a turbo kit on it from a 6. 5, or maybe an aftermarket kit with a Schwitzer turbo or something like that. If you want, let me know what pump that is and I can tell you more on it.



Trever

 

[juicedcummins]

They are very easy to turn up. [from memory]



1 take the top off the pump

2 pull out the shut off soloid

3 use a light and look down into a little hole for an allen screw underneath where the shutoff was. In that hole you need to see an allen screw straight up. To make the screw staight up rotate the engine over by hand. [harmonic balancer -Johnson bar]. It takes 2 revs of the engine for 1 on pump.

4 Once you get it straight up get a 5/32 allen wrench [recommend t-handle]. \

5 turn the screw clockwise 1/8 of a turn. This is a baseline adjustment and will work ok for most depending on elevation.

6 reinstall all components.

7 check engine timing 5. 5/6deg before tdc worked well.



Disclaimer; This is all from memory so try @ own risk. Elevation and load will decrease the amount off fuel to be added.

 

[juicedcummins]

If you are going to change the timing chain you should check into a gear to gear set. Diesel services group out of Reigina Sask used to sell tons. They are a good set up with about 3deg cam advance built into the cam gear. [from memory]

 

[Vaughn MacKenzie]

Thanks Juice & TMaas. I was thinking a gear set would be the right way to do the timing chain.



Vaughn

 

[HoleshotHolset]

If/when you do the timing set... . it would be wise to swap in a new water pump as well. They're nowhere near as easy as a 6BT to change...



Matt

 

[J DeMaio]

They are not bad engines for what they are. I think you can get fairly decent power out of them. If it were mine I'd add a turbo. We have a 6. 2L HD in our 84 blazer and I love it. It has 2 1/4 inch pipes coming out the back from the manifolds with glasspacks. She will bellar. Sounds better than gassers. I've known quite a few people with these engines, they are a MUCH better design than the ole 5. &L heap. If it has the EGR I'd remove it. Fuel rate should be left to a shop. If you don't get that linkage hooked up correctly, she will run wide open. As far as EGT's go, I'd say no more than 1000*. Do as I say, not as I do I had a pyrometer that was in the pipe below the drivers side seat, and it would read 1600* on a hard pull I know it aint good. For turbo's I'd call banks or ATS. You should also join the diesel page.



John