Mack Technician

Get a Granite and avoid DM, unless you get a mid-to-pre 2003 DM. DM from those 04-07 usually have low-spec engines. Mostly 300-335 AMI HP. Maybe you will have better pickings, that’s just from my shopping experience. CV-713 will have a better package. You will regret buying a low HP AI or AMI.

It’s in this post, scroll up....

Did you go through the service bulletin I made reference to? Mack doesn’t suggest changing EUPs for the issue.

Test injectors, verify how many bad, replace all if a couple are bad. Also good time to reset overhead on engine, since rebuild, now that your broke in. You have a CCRS engine, they burn through injectors faster than previous vintages. The fuel bangs the tips in multiple hits instead of one burst. Unless something has changed.....and Mack shaped up.....??...Locally sourced injector tips were generally better than remack injectors. Replace all your injector lines, even though they are new, per instruction from Mack. Not sure if you’ve been watching the threads ahead of you.....but folks are still lighting those AC engines up. Your heat index is 98-102 and you engine is capable of taking it to 1,800 if a fuel line fractures. Especially if you sleeping in it, don’t tempt fate, hate to see a brother on the news. good luck!🍀 let us know what fixed it.

Still trying to find my Made in U.S.A. on our machine?

We had some guys who were chronic idlers and would idle the truck to cool it before shutting it off at the house. The slobber would climb up the stem of the exhaust valve, he would shut it off, plug it in, go to bed, temps would go sub-zero, slobber turned to adhesive bubble-gum-pus, bond the exhaust valves solidly to the guides and bend his push tubes upon start up cranking. At the dealership we had a winter law- No shutting off a customers truck (outside) that isn't at full operating temp.

Looks like unburned fuel slobber coming from exhaust manifold joint. Common with winter cold starts regardless of injector health or idling with bad injectors. Usually leaves two black pus spots on you EUP chrome cover. Are you adding oil to the engine? Does your bill include injectors, or did they reuse them? Slobber coming out of one manifold union joint or both? what are you boosting at when in a hard pull(PSI)?

AI Turbo and Injector Specs.pdf Power curve specs.... AI460.pdf AI427.pdf AI400.pdf AI375A.pdf AMI370.pdf AI350.pdf AMI335.pdf AMI300.pdf AI300A.pdf

Supplement.

FYI- injector numbers AC-427 uses 736GB421M2 AC-460 uses 736GB421M3 AI-427 uses 736GB419M3 AI-460 uses 736GB419M3 (same as 427)

Visual. Helps the torque effect. Looks tough when your chassis twists and lifts a steer tire off the ground.

I was doing a little reading on assault. She added just enough components to make it second degree by groping. The groping would be third or fourth usually, 4th a misdemeanor. BUT.......If she had a drink and one other person was used to carry out the act it becomes second. Huh, what a coincidence?

Taking the wife out for supper tonight to celebrate. Might take Ruth Ginsburg out with us. For the sake of chemistry we checked if Ted Kennedy is available to pick her up and take her safely home.

Pretty fair when you consider the price of a stock, sub-par, 300 series ( over $2K).

Your out of the XT era. Use what you got. Every engine generation of Mack has had Cheats until recently. Screws to turn, puff limiters to cripple, warranty seals to break, injectors to swap, manifolds to switch, turbos to manipulate, special austrailian smoke files, XT files, tuners, deletes, etc, etc, etc. You now know what yours is, on a platter, from OR Mack who just did it. Good Luck!

Looks like we have our blueprint and a good testimony!! Thanks ORMack. You willing to mention cost on turbo build?

I’ll check Monday if you want? My tune up manuals are in my box at work. When I get time, and if I have space allowance, I may scan and upload my AI charts to the main Thread.

Yup, it’s messed up to pull with a stock AI460, you either are balls to the walls or panicking at an intersection because the torque dropped out and your stalling ocause you grabbed a low hole. They are IMO the worst version (if left Un modified) since they are torque bipolar and naturally your hauling big because it is suppose to deliver. Do turbo, manifold and injectors at the same time or you won’t be satisfied. If you’ve had bad luck with your locally available aftermarket try K&S. I’m not making a dime recommending them and you’ll be paying half as much as Rochester. I talked to Mike last week when buying some injectors and he said I sent 10 BMT operators to him (scattered over the lower 48) with 10 for 10 being 100% satisfied. Modify the 370. I believe Mack Pro gave a complete list of injectors and turbo numbers for AI engines two threads ago, including your 370.

370 is a good one, but you will never have a Maxidyne oxbow in your torque curve without modification.

Every AI falls on it's face in the low hole. With AI the number differential just gets worse as the HP band increases. E-Tech 350 has 1250 Ftlbs of torque at 1,100 RPM AI-350 has 1050 Ftlbs of torque at 1,100 RPM E-tech 400 has 1350 ftlbs @ 1,100 RPM AI-400 has 930 Ftlbs @ 1,100 RPM E-tech Maxidyne 275HP has 1310 ftlbs @ 1,000 AI Maxidyne 300 HP has 775 ftlbs @ 1,000 RPM E-tech 460 has 1,450 Ftlbs @ 1,100 RPM AI-460 has 1,000 Ftlbs @ 1,100 RPM Don't think in terms of "I may be wrecking my low torque" since you already never had it...….Think in terms of "I have none with an AI engine, how am I going to get it". Top ends are not a disappointment, the bottom ends all are. My best guess is the emissions test required the low RPM to emit less and they could not get the scavenging to lower the combustion temps to stop NOX. In turn they reduced fuel delivery so the lugging, long dwell time, of combustion could not get so hot. The fuel mapping is the issue so you manipulate it back.

Pretty good overlap. I wouldn't guess, but the torque curve touch may indicate the rating for your clutch would have been o.k. ..IF...it wasn't for the fact your running AI-350 hardware. AI-350 is soft on torque, do some homework on your driveline to be sure your fit. I marked your Ftlbs./HP differential in the curves..... Mack 370.pdf