Vmac3

I appreciate the compliments. These engines are only used to tear down and build up. If they dont follow instructions and I dont catch it, imagine the carnage that would happen if they ran it. This gives them good hands on experience and to give them some idea on what to expect in the real world. The biggest issue that I see is that they do not follow a process. They just what to rip and tear into to it.

They all run. We bug them so they have to follow troubleshooting steps, and explain their findings. We also bug a truck and they see what we did to bug it, such as a missing ecu fuse. They cant just pop in the fuse and say its fixed. They have to explain why it doesn't start using wiring diagrams and describe what pin at the ecu doesn't have voltage or sometimes ground (depending how we bug it). We start by explaining what the pointy end of a screw does to doing aftertreatment, starter, charging, sensor, transmission, driveline diagnostics. We have PTT and explain how it works (when it does work) all the features it has. We have 6, 10 and 13 speed transmissions that they disassemble and reassemble using Eatons procedures. They disassemble differentials and reassemble them using Eaton procedures. There is a lot of content starting with foundational content in the first semester to more advanced content in the second semester.

So some of you may already know. Im a teacher at a college in Toronto Ontario. The program that I teach in is sponsored by Mack/Volvo. The students sign up for 36 weeks and receive 3 levels of apprenticeship training. Here in Canada we have an apprenticeship that is government funded. They learn all aspects of a class 3-4-5-6-7-8 truck, from wheels and tires to exhaust aftertreatments systems to everything in between. Here is our lab where we have students perform certain things. If you look under the racking you will see that they was disassembled engines right down the bare block. We will study how they work, do measurements, talk about failure analysis and so on. Right now they are doing battery testing using hydrometers and multimeters. V

Thanks. I appreciate this site. Lots of learning from others experiences.

My first thought was timing. Why else would the intake spit out compression?? Then thinking he may have a fuel issue. Injector leaking or something. He has ruled out sticky rockers. Someone mentioned a delivery valve also.

I don't think it's a cam because the intake valve would have excessive lash and he would of noticed it. Also the intake would not open all the way because the lobe is worn out. I wonder if the injectors have too much forward leakage (dribbling).

True. I'm not sure what else. Someone mentioned engine brake possibly.

I read and reread the thread. If the cylinder pressure is coming out from the intake then you would think the obvious like a valve hanging open or something pushing down on it such as the engine brake. The only other thing I can think of right now is cam timing.

Cam timing??

Crankshaft Mains Step 1. 150 ±20 N•m (111 ±15 lb-ft) Step 2. Angle tighten 120° ±5° Crankshaft Main bolts are only to be reused 4 times. Connecting Rod Bearing Caps Step 1. 30 ±3 N•m (22 ±2 lb-ft) Step 2. Angle tighten 180° ±6° Connecting rod bolts are only to be reused 4 times. If you are reusing the connecting rod bolts, then a light coating of oil on the threads and under the bolt head are to be applied. If you are replacing the bolts with new ones, they are coated with phosphate and oil and they must be installed dry. The information above was taken out from the engine manual. If the bolts broke you may want to find the problem before reassembly. Also, those connecting rods are fractured rods, if they were de-torqued they will loose their strength. Those rod caps are an exact fit, if they move around the fracturing will not be the same and they can/will fail prematurely. V

Fuel diluting the engine oil? Is there a dent in the oil pan causing a restriction at the oil pump pickup? F is right, those aux shafts cause a lot of grief. Seen them where the gear slips on the shaft. Does the oil pump pickup have the correct o-ring between the pump. Is the pick up sitting correctly on the oil pump? Im grasping at straws aswell. V

Here are some documents that have part numbers that you are looking for. Dealer cant help?? IS it supply chain issues or is it lack of knowledge or caring? V Jake Brake Rebuild.pdf Tune up Kit Instruction.pdf

Very interesting read. "Unfortunately the main advantages of Marmon, i.e. prestigious character and manual production, turned out to be his greatest curse". Too bad.

To verify cam and crank corralation you need an oscilloscope. Another way is to remove both sensors and barr the engine over. The cam gear has two dots drilled into it. It's highly unlikely the cam gear would slip, otherwise we would be picking up engines pieces from the oil pan. Once the two dots are in view, check to see if the missing teeth on the flywheel line up with the crank sensor hole, if not rotate the engine again and line up the dots on the cam and recheck the crank. If they still don't line up then the ring gear has slipped. You will need a mirror and make room to view the cam. It's tight but it can be done. V

I think you would. It was a shot in the dark. Maybe a bad vibration damper. V

Is the auxiliary shaft walking back and forth?

Just wondering?? What year did Mack convert to diesel powered engines or were they always diesel?? I never really thought about that. V

Hi Guys, I believe the post was for an E-TECH not an E7 (Vmac1 or 2). No throttle response may be because of datalink faults. What model truck is it? Different models have different issues. Can you check for codes? V

It was really heart wrenching to see all the destruction it left behind and all the people it has affected. At the same time it was awesome to see everyone getting together and helping each other out. My thoughts and prayers to those affected in the U.S and eastern Canada. V

I think its a waste of time and money. Better to donate your time and money to someone who really needs it. We already know what the outcome is going to be. V

Did you put silicone on the timing gear plate before you put the cylinder head on? It can also be the cam position sensor o-ring that failed. When you put the upper timing cover back on, did you make sure that the cover is flat with the cylinder head? V

Yes sir. Thats the egr oil return line. V

Try isolating the short. First put in a circuit breaker so you are not replacing fuses while testing. Disconnect one thing at a time that the fuse supplied power too. I dont have any wiring diagrams to send you to help with. V

I also agree with the sentiment with others. Changing timing, injection metering, deleting these emission components and squeezing as much power as you can out of these engines that are not designed to do so will cause a lot of heart ache. A good example is the ASET AI engine, notice how the engine rpm ramps up slowly from idle compared to older E7 engines? You are not going to get all that power at once. Cylinder pressures climb gradually to increase longevity of these small bore engines and try to reduce exhaust emissions. If cylinder pressures peak to early in these engines, what will happen to that engine is anyone's guess. I wouldn't want to risk that, especially with the crazy cost of parts, the availability of them and then trying to find a knowledgeable wrench to work on it is going to compound the problem. Oh yah, cant forget the downtime also. V

If the turbo is closed then too much exhaust back pressure is building up and you don't have enough exhaust scavenging. That will cause the engine not to run smoothly. It will always be under load. I would remove the actuator and move the lever while the engine is running. If it clears up when the turbo is open then the issue can be with the tune or the turbo. I don't know, just a guy thinking out loud. V