ChallengeDave Posted December 2, 2022 Author Share Posted December 2, 2022 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! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516833 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 20 minutes ago, ChallengeDave said: 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! Bro ! Check the valve set first If the valve set is correct and you got your 16/24 or close then maybe there is a burned valve! or a chunk out of the valve seat on that cyl! again I hardly believe its not an rebuilders error more of an parts malfunction! These rarely failed a lifter but anything is possible ! I have heard rumor's here on the site of sticky valve guides I have never run into in our area how ever Shit happens! It the valve set is off then the head will likely be coming off! Please keep us posted It helps everyone gain knowledge! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516834 Share on other sites More sharing options...
doubleclutchinweasel Posted December 2, 2022 Share Posted December 2, 2022 Like FJH says, valve seat seems likely. Also, I have seen sticky valve guide before. Or, even too loose of a valve guide can cause leakage around the seat. Any kind of build-up on the seat? Burned spot on valve seat or seating surface of valve itself? Bad valve spring? Crack in head around seat? Loose seat? L:ifter sticking in bore? Has to be something there letting compression back out through the intake. Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516835 Share on other sites More sharing options...
ChallengeDave Posted December 2, 2022 Author Share Posted December 2, 2022 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. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516839 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 30 minutes ago, ChallengeDave said: 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. ODD! Sounds like you have a good handle on this ! So did you inspect the push tubes ! Do we have a loose ball end? There may be a REMOTE possibility the lifter is sticking in the bore ! I Seen rockers stick before !Dri rocker syndrome! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516840 Share on other sites More sharing options...
br549 Posted December 2, 2022 Share Posted December 2, 2022 Swap #1 and #2 injectors and see if it goes to #2, If not pull delivery valve on the injection pump and swap #1 and #2 and see if it goes tp #2 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516842 Share on other sites More sharing options...
Mark T Posted December 2, 2022 Share Posted December 2, 2022 (edited) Shoulda done a leak down test on it before taking the head off. Ruled out any compression related ailments. Then go to fuel delivery. Edited December 2, 2022 by Mark T more information 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516843 Share on other sites More sharing options...
doubleclutchinweasel Posted December 2, 2022 Share Posted December 2, 2022 12 minutes ago, fjh said: ODD! Sounds like you have a good handle on this ! So did you inspect the push tubes ! Do we have a loose ball end? There may be a REMOTE possibility the lifter is sticking in the bore ! I Seen rockers stick before !Dri rocker syndrome! I forgot to mention sticking rockers. Good catch! Sounds like valve train may be okay. So, like they said above, fuel delivery next? Sure did sound like valve train, though. But, then again, I HAVE been wrong before! 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516847 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 19 minutes ago, doubleclutchinweasel said: I forgot to mention sticking rockers. Good catch! Sounds like valve train may be okay. So, like they said above, fuel delivery next? Sure did sound like valve train, though. But, then again, I HAVE been wrong before! The Bosch pump did have an issue that would cause an miss when the delivery valve washer on number 1 would crack ! but is sounds like something not sealing Or a stuck injector! but usually you get black exhaust smoke with that! not a pop back thru the intake! If you have a fuel shop near by have the injector tested! Either way keep us up to date! very interesting issue! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516849 Share on other sites More sharing options...
ChallengeDave Posted December 2, 2022 Author Share Posted December 2, 2022 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. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516854 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 I can see your all over this! and you probably already looked But Question? Does The intake yoke have a guide pin? is it intact! I know they did away with the guide pin on one or the other at one point! Mental block here! Have seen guide pins break as well! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516858 Share on other sites More sharing options...
ChallengeDave Posted December 2, 2022 Author Share Posted December 2, 2022 8 minutes ago, fjh said: I can see your all over this! and you probably already looked But Question? Does The intake yoke have a guide pin? is it intact! I know they did away with the guide pin on one or the other at one point! Mental block here! Have seen guide pins break as well! 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. Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516861 Share on other sites More sharing options...
Mark T Posted December 2, 2022 Share Posted December 2, 2022 56 minutes ago, ChallengeDave said: 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. There's an adapter that goes in the injector hole and reaches in there then a piece that screws in the hold down hole with a pipe thread port in it. So you need to remove the injector to test Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516862 Share on other sites More sharing options...
Joey Mack Posted December 2, 2022 Share Posted December 2, 2022 I just went back to page 1 and read it 4 times.. with all that has been posted, I came up with 1 question.. did you check the rocker arms to see if they 'rock' smoothly? I know that E-7 push rods can be installed wrong, off to the side of the lifter. I was wondering if a rocker arm hung up in the valve open position, and the push rod jumped off the top of the lifter.. Im really 'Reaching' on this one.. Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516864 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 29 minutes ago, ChallengeDave said: 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. Debating on sending out the injectors and maybe the pump. but I'm not real convinced of that yet. By your description of the issue nor am I ! popping out the intake would have been a classic failed lifter or bent push tube on number 1 exhaust back in the day ! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516865 Share on other sites More sharing options...
Joey Mack Posted December 2, 2022 Share Posted December 2, 2022 I'm out of likes,. So. FJH, here it is... 👍 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516867 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 18 minutes ago, Joey Mack said: I just went back to page 1 and read it 4 times.. with all that has been posted, I came up with 1 question.. did you check the rocker arms to see if they 'rock' smoothly? I know that E-7 push rods can be installed wrong, off to the side of the lifter. I was wondering if a rocker arm hung up in the valve open position, and the push rod jumped off the top of the lifter.. Im really 'Reaching' on this one.. Jojo I guy would think if the rod or rocker deal happened there would be evidence that would show on that push tube! even a chunk off the side of a lifter! No likes here either buddy all done for the day! Consider your self permeant on my like list! 😂 ChallengeDave defiantly picked the right handle here! he is definitely up to the challenge Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516868 Share on other sites More sharing options...
ChallengeDave Posted December 2, 2022 Author Share Posted December 2, 2022 49 minutes ago, Joey Mack said: I just went back to page 1 and read it 4 times.. with all that has been posted, I came up with 1 question.. did you check the rocker arms to see if they 'rock' smoothly? I know that E-7 push rods can be installed wrong, off to the side of the lifter. I was wondering if a rocker arm hung up in the valve open position, and the push rod jumped off the top of the lifter.. Im really 'Reaching' on this one.. Jojo 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. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516874 Share on other sites More sharing options...
doubleclutchinweasel Posted December 2, 2022 Share Posted December 2, 2022 9 minutes ago, ChallengeDave said: 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. Keeping my fingers crossed for you! But, it sounds like you are more than capable of figuring this one out. Can't wait to hear what you ultimately find. Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516876 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 37 minutes ago, doubleclutchinweasel said: Keeping my fingers crossed for you! But, it sounds like you are more than capable of figuring this one out. Can't wait to hear what you ultimately find. Agreed ! you also can bring lots to the table! hangout bro! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516880 Share on other sites More sharing options...
Joey Mack Posted December 2, 2022 Share Posted December 2, 2022 (edited) Amen! DCW.. and FJH Edited December 2, 2022 by Joey Mack More content needed Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516881 Share on other sites More sharing options...
doubleclutchinweasel Posted December 2, 2022 Share Posted December 2, 2022 Curious to see how the lobes check on that cam. Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516886 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 2 hours ago, doubleclutchinweasel said: Curious to see how the lobes check on that cam. Yup agree might learn something ! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516918 Share on other sites More sharing options...
Mark T Posted December 2, 2022 Share Posted December 2, 2022 I remember years back a guy used to not pay attention to the injector washers (at the tip) Those engines made some odd noises. Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516928 Share on other sites More sharing options...
fjh Posted December 2, 2022 Share Posted December 2, 2022 5 minutes ago, Mark T said: I remember years back a guy used to not pay attention to the injector washers (at the tip) Those engines made some odd noises. Bro he proved he had a bad seal on a valve the question at this point is why and what caused it! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/2/#findComment-516936 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.