smorse54 Posted March 29, 2011 Share Posted March 29, 2011 Hi, a friend just rebuilt a mechanical E7 350.This man is a fine mechanic who has an excellant reputation of being the best.He did an inchassis with piston and liner kits, rod and main brngs, pump and injectors and rebuilt heads. When the engine brake is turned on it works fine but when it is shut off one cylinder on no.1 head stays on until the oil pressure drops.He changed the dynatard solenoid, still did it. Thought maybe an exhaust hydraulic lifter was sticking,went thru and reset.Switched complete rocker from front to back, problem stays in front head. will do this when brake is manually applied with no electrical power, so not an electrical issue. Yes oil is at operating temp, truck driven several miles. Any ideas?Thanks,Steve Quote Link to comment https://www.bigmacktrucks.com/topic/18523-dynatard-trouble/ Share on other sites More sharing options...
theakerstwo Posted March 30, 2011 Share Posted March 30, 2011 Beats me but make sure and let us know when you find the problem. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/18523-dynatard-trouble/#findComment-75168 Share on other sites More sharing options...
Rob Posted March 30, 2011 Share Posted March 30, 2011 I have no experience with this engine but sounds like an oil bleed problem to me. Where is the oil bleed port when the solenoid is released? Is it possibly through the rocker shaft if there is one? How about galling of the pivot point(s) of the rocker arms? I can't remember which engine it was but the rocker shafts if installed incorrectly would not oil themselves and were short lived. Are the intake, and exhaust lifters the same? Any chance the lifter bores were honed oversize and a larger diameter lifter installed that is too large for the bore? I don't want to sound like an idiot although I fit the profile but with the problem remaining in the head, one needs to "drill down" to how the system operates to facilitate a repair.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/18523-dynatard-trouble/#findComment-75172 Share on other sites More sharing options...
smorse54 Posted March 30, 2011 Author Share Posted March 30, 2011 Hi, my friend tells me the oil bleeds briefly when dynatard is first applied from port at base of solenoid. Thought that was odd so checked another E7 that he was retorqing heads on, same thing. We thought oil bled when solenoid was released not applied. We wre looking for a diagram of oil flow in dynatard.couldn.t find one. I will check old service bullitens tomorrow for any info. This was a Mack pedigree reman that he rebuilt after only 160K miles.He used OEM parts including heads. Thanks, Steve Quote Link to comment https://www.bigmacktrucks.com/topic/18523-dynatard-trouble/#findComment-75178 Share on other sites More sharing options...
Packer Posted April 1, 2011 Share Posted April 1, 2011 Could it be that a piston in the dynatard is sticking?Was the Dynatard rebuilt?Silnoid routes oil through the passage ways and holds a small piston down.When the power is pulled off, (12 volt) the piston should move back (up) and all is well.Pull the one that is hanging up and check for scoring.A little bit of polishing is too much!Replace/rebuild and see if that wont fix it!Packer Quote Keep a clutchin' Link to comment https://www.bigmacktrucks.com/topic/18523-dynatard-trouble/#findComment-75264 Share on other sites More sharing options...
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