ChallengeDave

PAI does show a listing for an offset keyway pat no. EKY-3179, mack 54GC29. Does not show application for that keyway besides it being for the E7. Also to add, they only list one cam for the E7 non Etech.

Just checked impact and PAI to compare the two motors. The 350 I used as a core, used the same camshaft and keyway as the 427 I built it as. I used another truck we have that has the 427 for all the spec info for this build. So at this point I still need to double check cam timing for the heck of it, and pump timing. Also am going to see what its going to take to mount the larger CH intercooler. Currently, the machine shop is going through and rebuilding the heads again, this time replacing the intake valves as well. They seem to be eating a bunch of the cost for this as a sign of good faith.

So after further conversations with the machine shop, they came to the conclusion that this thing has been running hot. By that they mean the combustion temperature is too hot. I didn't get a report from my driver as far as high egt or boost issues. Ill double check timing to make sure thats not affecting anything. Seems a bit odd to me, dont know if i buy it. maybe one thing could be that this has the smaller charge air cooler on it. This is a 95 Ch that came with a 350. I dont know if the 427 came with a larger cooler. What do you guys think?

Alright guys, minor update that everyone has been waiting for. Machine shop got back to me yesterday and told me the intake valves were hammered. So they disassembled the rest and found that the guides and on the intake and exhaust valves on all three has considerable wear. I did not know this, but they only replaced the exhaust valves , not the intakes. According to them, they didn't need to be replaced, so i guess they just resurfaced the intake side. I do trust these guys for the most part. Been dealing with them for years and have never once have a problem. They are doing some more research and investigating on their end as far as the parts that are in these heads(remember, they were 350 cores). They were worried that maybe this engine was turned up quite a bit can caused the very fast wear. All i had done to it was spec it out to 427(vmac). I may be missing some more details on what they told me(I have the memory of a goldfish). Now I am working on pulling off the second head, because more then likely, its in a rough state as well. Been super busy between this, rebuilding a Liebherr engine, Cat axle rebuild, and running the shop. So its been a slow process figuring this one out. Ill feed you guys some more once I can. Thanks again everyone!

Hey all, thanks for chiming in. To add some info. Engine did this at idle cold, so I never felt the need to test drive since the issue was present. I thought as well about cam timing, but I would assume if that was the case, all other cylinders would present the same symptom. Didn't check the spring pressures on the head, since I don't have a method here to do that. That's what ill let the machine shop handle. I kept thinking of the jake as well. But while I had it at idle with the covers off, I couldn't at least visually see it partially activating. I did rebuild the jakes during the overhaul, didn't see anything unusual. Couldn't hurt to dig into them while I'm waiting I suppose.

I did and they do rock smoothly. The only thing that can be felt is if you rotate it past its "broken in" position, its like a very very slight stumble. I have felt that numerus times on other rocker shafts without issues. I know what you mean about the pushrod, I cant say I checked for that when I removed the rocker assemble and push rods as for a one of them jumping off the lifter. But I figured that would have been very obvious and there would have been witness marks had it done that. At this point I'm going to wait to see what the machine shop says about the head, and if its good, ill reinstall it and probably go back to square one. I cant thank you guys for all the help so far, I promise ill keep you guys in the loop when I figure this one out. I have been lurking on this site for too long and I'm happy that I finally made the jump and reached out to you guys. Without a doubt ill be sharing what knowledge I have here and help where I can. I have built up too much Mack knowledge to not share.

It does have a guide pin on the intake on this one. I believe they changed that on the Etech engines the the pinless floating yoke. Of course they are intact. I'm happy that this is no catastrophic failure anywhere on this so far, but i just wish this baby would just give me a sign. I just sent the head back to the machine shop and let them be sure its 100%, meanwhile ill measure up the cam lobes. Debating on sending out the injectors and maybe the pump. but I'm not real convinced of that yet. I get the feeling I missed something big at this point. Ill retrace my steps after some lunch, my stomach is calling.

You're not kidding when you say this is interesting! I did check the lifters for binding and they slide up and down in their bores great. Checked the rockers and they were getting great oil supply and rock freely with no excessive play. When I had it running, the exhaust was nice and clear, no smoke. The one odd thing i did notice during my initial inspection, with the valve covers off with it running, you could watch the valve bridge for the exhaust valves wiggle/rotate side to side as it went up and down(this does have jakes, fyi). There isn't any play or wear in the pin it rides on. These were rebuilt injectors, along with the injection pump (done by D&W diesel). Not assuming they are good since they are fresh, just stating info. I do wish i had a way to leakdown test this, been meaning to make or buy the proper tool for some time(Ill take recommendations). Ill continue digging.

I already pulled the cylinder head off last night. But before I did that I did check the valve set and they were spot on where I reset them after the head retorque after the initial run in. I pulled both valves out of the head and inspected them. Neither intake valves are burnt and the don't seem to bind in the guides at all. I spun them on a drill and they are both true. The seats seam to be intact. I reinstalled the valves and springs, then filled the intake port with break clean and it didn't come rushing out around the seats.

Alight guys, here we go. So fist back story. This engine I built started as a 350 core. Did my research and got all the necessary parts to upgrade it to a 427. Used a PAI engine kit. Cam was sent out and inspected with the lifters(had them polish the lifters). Heads were completely rebuilt and block decked, counter bored, and inspected. Did every step that anyone that knows these E7 engines would to give it a new and healthy life. For some background about me. Been a working foreman for our fleet for 10 years, we have about 30 macks(mostly grey engine, 2 red). I seen a lot and rebuilt a lot of these so far. I'm by no means an expert, but i have a good idea on what these old dogs need, and what makes them bark. So I got in this morning and first thing I did was drop the pan(yes, I also drained into a clean pan for inspection). No extra presents found in the oil or drain pan. Checked out the cam lobes and everything looked just the way they did when I installed it. Lifters also were intact and looked great! I'm still at a loss here, so im going to retrace my steps and keep closely inspecting everything. I'm going to try and see if i can measure the lift on the lobes incase i am missing something sneaky. Wish i had some juicy info for you guys, ill keep you posted! Thanks everyone!

Checked them earlier, they are all straight. Cant see as well as I thought I could from up top. Going to drop the pan in the AM. Going to sleep on this. Thanks everyone!

Out of frame, block, cam heads, everything got sent out. just working on turning it over now. I can see them from up top with the head off. Ill keep you just posted.

Well i cant say I looked to closely at the cam. Ill take a look at the lobes now if i can get a good look at them.

Hello all! Got an interesting one here on my hands. Have a 95 E7 427 Vmac1 that I did a complete out of frame on about 20k-25k miles ago. Truck has been running great and pulling even better. Driver brought to my attention that he heard a strange noise on the driver side of the motor. So when I put my ear onto the CAC pipe going into the intake, all I could hear was a popping/wooshing sound. Took the pipe off and it was even louder when I fired it back up. First thing i did was cut out each cylinder and found that it would quite up only a little on cylinder number 1 when you killed that injector. Pulled valve covers and checked for valve clearance on number 1, checked everything else out visually while I was in there. everything looked great so far. Pulled the forward intake manifold and confirmed noise was coming from number 1. upon startup, you could see a puff of smoke come from number 1s intake port. So my thought was that I must have had a intake valve problem, so I pulled the cylinder head and wouldn't you know, both valves seem to be seating just fine. No visible damage to the piston, no bent push rods. So now I'm stumped. I'm looking for ideas on what i may have missed, ill take any ideas you guys might have. Thanks!