Jtm454 Posted July 14, 2023 Share Posted July 14, 2023 Have a Mack e7 dropped a valve we pulled it apart found the piston beat up decided to overhaul, we also found the cylinder that dropped the valve had Chunked a lobe in the cam, we replaced the cam and cam bushings timed by the book, two reman heads from Mack put it all back together we have a misfire, and a uneven crank you can tell a cylinder is dead have rechecked rack adjustment several times unsure where to go from here but has a noticeable drop out when cranking reman Mack cylinder packs, im thinking may have a ring issue, not sure if I’m over looking something somewhere any help is appreciated thanks Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted July 14, 2023 Share Posted July 14, 2023 Did you crack a fuel line to find the dead cylinder? Did you do the valve adjustment by the book? 2 Quote Link to comment Share on other sites More sharing options...
fjh Posted July 14, 2023 Share Posted July 14, 2023 2 hours ago, Joey Mack said: Did you crack a fuel line to find the dead cylinder? Did you do the valve adjustment by the book? does the engine have an engine brake? 1 1 Quote Link to comment Share on other sites More sharing options...
Jtm454 Posted July 15, 2023 Author Share Posted July 15, 2023 We did do valve adjustments strictly by the book, and haven’t attempted cracking the fuel lines we just remove one wire per unit pump was hard to tell any difference at all, and yes the engine does have engine brakes Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted July 15, 2023 Share Posted July 15, 2023 what year is the engine, you posted E-7, but EUP's are in E-Techs, CCRS, and ASET.. Im glad you followed the book. engine brakes? 1 Quote Link to comment Share on other sites More sharing options...
Jtm454 Posted July 17, 2023 Author Share Posted July 17, 2023 On 7/15/2023 at 7:51 AM, Joey Mack said: what year is the engine, you posted E-7, but EUP's are in E-Techs, CCRS, and ASET.. Im glad you followed the book. engine brakes? The engine is a 2005 I was under the assumption it was an e tech, it does have engine brakes, I know a bad injector could cause a misfire but could it cause what seems to be a loss in compression?? This truck has been an absolute nightmare, it was taken apart by another mechanic that went awol after getting it apart so we had to piece this entire thing back together several pieces were mismatched and robbed to be used on other trucks, and from what we have now learned we believe an injector was taken from the parts pile and used in another truck that had a bad one so we are assuming we know we have at least one bad injector in there, I’ve purchased the compression testing tools so we will have it out anyways, Quote Link to comment Share on other sites More sharing options...
Jtm454 Posted July 17, 2023 Author Share Posted July 17, 2023 On 7/15/2023 at 7:51 AM, Joey Mack said: what year is the engine, you posted E-7, but EUP's are in E-Techs, CCRS, and ASET.. Im glad you followed the book. engine brakes? Sorry I missed the specifics on the engine I could get a serial number if needed any input appreciated it at least gives us some ideas Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted July 17, 2023 Share Posted July 17, 2023 ok, Are you new to this series engine.. The lifters in this engine have ceramic rollers, and can crack with light shock loads. for example: when you are installing the rocker shafts, and a push rod isnt lined up correctly and ''pop's'' into place.. that shock can crack a roller. A compression test is a good idea. can you drop the oil pan and inspect the cam shaft.. if a roller is broken, it will be in the pan when you drop it.. 1 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted July 17, 2023 Share Posted July 17, 2023 no need for the specs, I know what you have now. its either an AC or an AI engine.. what chassis is it? 1 Quote Link to comment Share on other sites More sharing options...
fjh Posted July 17, 2023 Share Posted July 17, 2023 If you have bad compression I think it would be smoking! Do you have blue white smoke or excessive blo by? if not go with the bad injector theory! 1 1 Quote Link to comment Share on other sites More sharing options...
Jtm454 Posted July 17, 2023 Author Share Posted July 17, 2023 4 hours ago, Joey Mack said: no need for the specs, I know what you have now. its either an AC or an AI engine.. what chassis is it? It is a cv713 chassis the cam and lifters have all been replaced Quote Link to comment Share on other sites More sharing options...
Jtm454 Posted July 17, 2023 Author Share Posted July 17, 2023 1 hour ago, fjh said: If you have bad compression I think it would be smoking! Do you have blue white smoke or excessive blo by? if not go with the bad injector theory! That’s the weird thing I have absolutely no blow by no weird noticeable smoke we didn’t run it for long after we noticed the issue due to obvious concerns Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted July 17, 2023 Share Posted July 17, 2023 Ok.. it's an ASET-I.. any chance you can post a short video so we can hear it.. 20 seconds should be enough.. Quote Link to comment Share on other sites More sharing options...
fjh Posted July 17, 2023 Share Posted July 17, 2023 (edited) Yup good thought Joe ! That said had this happen many times ! Shit got in the injector on installing of the line just my observation! AC engine particularly bad for this because of all the crap in the way !Replace the injector! Good to go! Cylinder not getting fuel! just sayin! Edited July 17, 2023 by fjh 1 Quote Link to comment Share on other sites More sharing options...
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