6.2 Safe EGTs

[Carrera911]

So I've been wanting to turn up the fuel to get a little more power out of this dog of a motor. I wanted to check my EGTs first so I installed a gauge with the probe 2 inches behind the passenger side flange where it meets the manifold. I've only gone on a short test drive but whilst flooring it from a stop on a very mild hill it read 1180 degrees at 55 mph. Once I got to cruising at 55 they came back down. I didn't expect to see over 1000 at stock power levels. All I have done is remove all of the slack in the throttle cable so full pedal actually gives full throttle. From what I've read 1100 is as high as you should go on these so I'm hesitant to turn it up 1/8 to 1/4 turn that's recommended. Any advice?

 

[ryanruck]

I've turned up the pump on mine and I've got my probe right behind the Y in the crossover pipe so I'm getting a reading off both cylinder banks. The amount of cooling in that short distance is negligible, in my opinion, especially since I've got the crossover wrapped.

I've hit 1200-1250 a few times briefly on hills before I've caught it and backed off. No ill effects yet.

Admittedly my pump is probably a touch high. I just haven't felt like monkeying with it.

 

[Bravojmc]

I've turned up the pump on mine and I've got my probe right behind the Y in the crossover pipe so I'm getting a reading off both cylinder banks. The amount of cooling in that short distance is negligible, in my opinion, especially since I've got the crossover wrapped.

I've hit 1200-1250 a few times briefly on hills before I've caught it and backed off. No ill effects yet.

Admittedly my pump is probably a touch high. I just haven't felt like monkeying with it.

When you turned it up did you feel a big difference.?

 

[3jacks]

Subscribing to follow this thread.

 

[ryanruck]

When you turned it up did you feel a big difference.?

Yeah, it was noticeable for sure. You can actually merge onto the highway relatively safely!

You do adjust it I'd say go no more than 1/4" turn or maybe a little past that. I'm higher than that and, like I said, could probably stand to back it off a little.

 

[SSGT WILLEY]

I know for a fact on my turbo'd tractors, every mechanic I have talked to, has told me over the last 30 years, anything above 1100 degree's on the pyrometer is flirting with disaster. You will need to add another part to your cooling system before you go higher. Make sure you are venting ok, a partially plugged fuel cap could cause a leaner/hotter condition. Fuel cools, it is overload that heats. See: TheDieselPage.com

 

[pmramsey]

The sound inside the cabin must be deafening as these engines scream for air much above 50mph with normal fuel settings.

 

[ryanruck]

The sound inside the cabin must be deafening as these engines scream for air much above 50mph with normal fuel settings.

WHAT???



It's not terrible with the top off, on par with any other open top vehicle. With the top on I've done some sound mitigation with Lizard Skin and some heavy rubber interior matting. Will be doing underbody insulation at some point and also why I'm installing a VIC-3.

 

[3jacks]

Yeah, it was noticeable for sure. You can actually merge onto the highway relatively safely!

You do adjust it I'd say go no more than 1/4" turn or maybe a little past that. I'm higher than that and, like I said, could probably stand to back it off a little.

Did you do any other mods (exhaust or air filter) and do you have much black smoke?

 

[ryanruck]

Did you do any other mods (exhaust or air filter) and do you have much black smoke?

Not really. Just deep fording snorkel (with intake elbow) and exhaust stack. And yeah, she smokes plenty when I get on it.

I did have it at about 1/6 turn before I really upped it and barely had any smoke but only a modest power increase.

 

[Carrera911]

How did you access the allen screw? I spent almost an hour yesterday trying to get at the access cover. I got two of the throttle bracket bolts off but I didn't have a long enough 15mm wrench to get off the one rearward facing bolt. Once you get that out of the way how do you remove the 1/4" screws on the cover? My only guess is an open end wrench but that'll be real slow going in that tight space.

 

[ryanruck]

How did you access the allen screw? I spent almost an hour yesterday trying to get at the access cover. I got two of the throttle bracket bolts off but I didn't have a long enough 15mm wrench to get off the one rearward facing bolt. Once you get that out of the way how do you remove the 1/4" screws on the cover? My only guess is an open end wrench but that'll be real slow going in that tight space.

Hope you don't mind but I'm just going to copypasta something I posted elsewhere about turning up the injector pump... It was written referencing the directions posted on Flash Offroad.

First, it mentions a small mirror. You'll definitely need one. Almost impossible to see the hole otherwise. Also, you would do very well to get one of those claw things like this:



You will drop parts into the engine valley and that is the fastest way to get them out.

The directions mention removing the throttle cable bracket mounted on the pump to access the cover plate you need to remove but, they don't mention what a pain it is getting to the 5/8" nut that holds it on at the bottom and how it is nearly impossible to get that nut back on. It is very tight confines and with the bracket's design, you can only take it off and put it on with the nut completely removed because of the slotted mounting hole on the bracket. I figured out if you open up the hole by removing the bottom part of the slot, you can leave the nut on the stud and just slide the bracket onto the stud. Here's a shot of the bottom of the bracket before I removed the small part at the bottom of the slotted hole:



Made reinstallation a lot easier.

The screws on the cover plate are 1/4" hex head. I found a regular wrench was the easiest way to get them off. The throttle on the pump is too close to get a socket in there and it is too inset in the valley to get a screw driver bit in there.

Once I got the cover off (tedious because of how little wrench movement you get), I stuck the small mirror into the valley and had a perfect view into it. I got very lucky and my adjustment screw was exposed without having to turn the engine any.

The directions mention a couple different sizes for the allen wrench you use to adjust the fuel but I can confirm it is 5/32. I found with my allen wrench that the short leg of it was too short to get to the screw and the long leg was too long to fit into the valley. Used a Dremel and trimmed the long leg down until I had clearance.



The directions mention turning the screw clockwise to increase the fuel. That would be clockwise if you were looking into the access hole directly, counterclockwise if you're looking into the mirror from the opposite side.

Because of the tight confines and how tight the screw is initially, it is really tough to turn with your fingers. I used a set of channel locks. Once it was freed up, it was a bit easier to fine tune.
​

So yeah, unless someone has a better recommendation, you'll have to use an open ended wrench on the access cover screws and it is slow and tedious. Partly why I haven't gone back and adjusted the pump further.

 

[Action]

If you are talking about the big nut (15mm?) that faces the windshield....use lots of extensions and push them through the valley from inside the cab. It will take 2 folks.
Or get an injection pump wrench.

 

[Carrera911]

I appreciate the help guys. I'll try to link up all my extensions and see if that'll reach. If not it'll take 30 minutes of cussing and cutting my knuckles while hunched over the engine bay. If all else fails I'll leave it as is and justify my laziness by telling myself it's better for the motor lol.


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[Carrera911]

Finally done

I greatly appreciate everyone's input. I took off my radio rack and dog house to try using the extensions to get that one rearward facing nut. I finally got it done by using a combination of all the 1/2 inch and 3/8 extensions I had as well as 1/2 to 3/8 adapters. I could only get a 12 point 3/8 drive 15mm socket on the nut and only enough to crack it loose. Thankfully it wasn't rusty and I managed to back it all the way off by poking it with a screwdriver. I got the small cover off with a 1/4 wrench and was able to finger loosen the screws. The little allen screw was stuck pretty well and took many tries with standard and needle nose vice grips. I was careful to take note of how the allen was twisted as it took many attempts at pulling it back out to adjust the vice grips. I decided to do 1/4 of a turn. I did not want to have to do this twice and I figured it would allow me say 125% throttle input that I could use at discretion if needed.

TEST DRIVE
I went on a 15 mile test drive and wow did this wake up this turtle. First thing I noticed after the extra get up and go is it finally smokes a little like a real diesel should. Not nearly as much as a modern tuned diesel but these old IDI diesels run hotter and don't have oil squirters to cool the pistons. It clears up a lot once warmed up and can only be really seen while flooring it through first gear. Before if you were running 30-40 up a slight grade I would have to drop into second and floor it to get any speed. Now at just about any speed I don't need to floor it or drop a gear to accelerate.

EGTs
I wouldn't recommend doing this much of a tune without an EGT gauge first. It is now very easy to exceed 1100 degrees where as before beating on it the most I saw was 1200. I tried a 0-60 run and had to back off half way through 2nd gear. If I stayed in it I probably could've done it in about 14 seconds. With letting off a little and trying not to exceed 1100 I did a low 20 second time. Pathetic I know but stock it was more like low 30s. The biggest improvement though was in part throttle acceleration at speed which made a HUGE difference. Also the cooling fan does run a little more often now while accelerating up hills but this expected as more power = more heat. But I also have much more power now and with having the fan on is much less noticeable of a power loss.

I remembered to get a pic this time of where I placed the EGT probe.
And I also cut the end out of the notch to make getting the throttle bracket back on WAY easier.

 

[Havok]

Subscribing....

 

[Action]

My turbo came from government with a probe in the downpipe. I have never hooked anything to it.