Joey Mack Posted December 3, 2022 Share Posted December 3, 2022 the gear train on the front of an E-7 is pretty stout.. jumping time would have caused issues in all cyl's. and i would expect watery eye's on the mechanic that is standing in the raw fuel cloud trying to figure out what went wrong... just sayin' 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517017 Share on other sites More sharing options...
Onyx610 Posted December 3, 2022 Share Posted December 3, 2022 (edited) So v, what your saying is you think cylinder 1 is loading up? Or whatever cylinder it was. Edited December 3, 2022 by Onyx610 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517018 Share on other sites More sharing options...
Vmac3 Posted December 3, 2022 Share Posted December 3, 2022 5 minutes ago, Onyx610 said: So v, what your saying is you think cylinder 1 is loading up? Or whatever cylinder it was. 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. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517022 Share on other sites More sharing options...
Onyx610 Posted December 3, 2022 Share Posted December 3, 2022 (edited) 9 minutes ago, Vmac3 said: 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. Agreed, that pop is the compression coming out the intake and pushing whatever exhaust is left in the cylinder out through it. I’ve been thinking timing the whole time but I don’t know much about these and didn’t want to sound dumb, also I wasn’t sure how these could jump time. So honestly it’s coming down to an engine brake, injector, or something in the pump. Glad you’re back, I will watch the big dogs now. Edited December 3, 2022 by Onyx610 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517025 Share on other sites More sharing options...
Vmac3 Posted December 3, 2022 Share Posted December 3, 2022 Thanks. I appreciate this site. Lots of learning from others experiences. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517026 Share on other sites More sharing options...
Onyx610 Posted December 3, 2022 Share Posted December 3, 2022 2 minutes ago, Vmac3 said: Thanks. I appreciate this site. Lots of learning from others experiences. Honestly that’s the best part. Regardless of skill level we all have been there done something and learned something someone hasn’t. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517027 Share on other sites More sharing options...
Mark T Posted December 3, 2022 Share Posted December 3, 2022 Those engines , the cam gear isn't keyed. But if it did move a little everything else would be off too. Not just one cylinder. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517049 Share on other sites More sharing options...
ChallengeDave Posted December 3, 2022 Author Share Posted December 3, 2022 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. Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517057 Share on other sites More sharing options...
fjh Posted December 3, 2022 Share Posted December 3, 2022 2 hours ago, ChallengeDave said: 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. Just a long shot here ! The Jake depends on the action of another rocker! correct ? SO maybe the spool actuator stuck on cyl one and is not retracted enough this could explain it ! I don't remember if the actuator piston runs off an exhaust rocker or intake! Another thing I don't know how honest your machine shop guys are BUT! If the machine shop missfired on something I don't think there going to admit it! Your going to get this head back reassemble it and the engine will run just fine! AND We will never know what the issue is or was unless you find something on your end! We had a situation had heads rebuilt the guides failed with in weeks seized valves blabla These people did not admit to any wrong doing would not come to the table on another total engine job ! gos to say WE don't use these guys anymore ! Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517067 Share on other sites More sharing options...
doubleclutchinweasel Posted December 3, 2022 Share Posted December 3, 2022 Not uncommon to lose spring pressure after the valves and seats are re-cut. This one sure has my interest! 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/4/#findComment-517128 Share on other sites More sharing options...
mowerman Posted December 3, 2022 Share Posted December 3, 2022 did anyone think to just adjust the valves probably too late for that...bob Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517132 Share on other sites More sharing options...
Joey Mack Posted December 3, 2022 Share Posted December 3, 2022 Hey there Bob,, If you go back to the begining, he listed all that was done.. I'm still not sure what happened, as are a few others.. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517144 Share on other sites More sharing options...
mowerman Posted December 3, 2022 Share Posted December 3, 2022 ok thanks for that,,,and no i didnt read all of them,,,but im sure if its poofing air out...its probably beyond adjusting,,,bob Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517148 Share on other sites More sharing options...
mowerman Posted December 3, 2022 Share Posted December 3, 2022 im surprized you didnt add,,,nobodys asking you,,,,fatstuff.lol.bob Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517149 Share on other sites More sharing options...
Joey Mack Posted December 3, 2022 Share Posted December 3, 2022 never... I luv u... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517153 Share on other sites More sharing options...
mechohaulic Posted December 3, 2022 Share Posted December 3, 2022 I put my coffee and doughnut on the jake solenoid . ?? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517156 Share on other sites More sharing options...
Joey Mack Posted December 3, 2022 Share Posted December 3, 2022 I bet you are right.. Myself,,,, In my mind was questioning how the truck ran good for 20,000 + miles, and now this? A sticking celenoid could happen during that time frame. and I did ask about an overspeed on the engine, but since this doesnt have a VECU, he cant find that info... anyway,,, you need to be on this thread... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517164 Share on other sites More sharing options...
mechohaulic Posted December 3, 2022 Share Posted December 3, 2022 have seen/ heard engines try to run when a cyl is in exhaust mode from eng brake shorting out. this is before the computers ran the engine. Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517165 Share on other sites More sharing options...
Joey Mack Posted December 3, 2022 Share Posted December 3, 2022 yes sir... and the power leash engine brake in the ASET engines can do it when an oring fails under the celenoid.. Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517167 Share on other sites More sharing options...
mdixon Posted December 4, 2022 Share Posted December 4, 2022 2 hours ago, Joey Mack said: yes sir... and the power leash engine brake in the ASET engines can do it when an oring fails under the celenoid.. Wouldn't this hold an exhaust valve open though? He's spitting out the intake valves, that's the only thing that has me reluctant to think it's the engine brake. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517211 Share on other sites More sharing options...
Big R Posted December 4, 2022 Share Posted December 4, 2022 If one selenium failed would it not effect two cylinders? Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517244 Share on other sites More sharing options...
fjh Posted December 4, 2022 Share Posted December 4, 2022 8 hours ago, Big R said: If one selenium failed would it not effect two cylinders? Three! My self ! I'm tapped out ! Can't speculate anymore going to have to be patient an see what unfolds here we will all know next week once Dave gets the head back on and running! My prediction is it will run perfect and we will never get to the bottom of the issue! Hope I'm wrong! Hopefully Dave will find a smoking gun or the machine shop finds an issue and fesses up ! But don't count on it! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517250 Share on other sites More sharing options...
Mark T Posted December 4, 2022 Share Posted December 4, 2022 Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517253 Share on other sites More sharing options...
Mark T Posted December 4, 2022 Share Posted December 4, 2022 and in case you're kick'n it old school avoid some guess work Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517254 Share on other sites More sharing options...
Joey Mack Posted December 4, 2022 Share Posted December 4, 2022 ok,, I missed the part about blowing back through the intake, I just read back over the post.. and Mark is showing you pics of a great tool to own,, any chance you checked compression before digging deep? Just curious, and I am really out of ideas on this one.. Good luck to you. Keep in touch.. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/70801-cylinder-pressure-out-intake-port/page/4/#findComment-517261 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.