2020 Trailboss LT 5.3

[dustyd99]

Have a trailboss 5.3 lifter issue..it was misfiring on cylinder 3. Changed plugs, coil pack, and fuel injector..still misfiring and had that lifter tick..so I pulled that head and changed all lifters on that side. Installed all back and noticed i can only get the crank to turn by hand 180 clockwise and 180 counter clockwise? Why won't it spin numerous times like it should? I pulled the head back off and tried to spin it with head off and spark plugs out and still just stops both ways with hand cranking? I'm stumped. Never was timing or cover ever pulled off. Just head. Pls help

[Jsdirt]

I would double check the new lifters against the old. Could have the wrong part number in there.

 

If they are the same, then you're going to have to go over EVERYTHING again. Pushrod location and length, if the rockers were tightened correctly, etc.. I'm not familiar with anything this new, but knowing GM, there's probably something they left out of the manual that's mission critical that needs to be performed

 

I hate these engines built the past 20+ years since there are so many things engineered into them that can bite you in the ass and ruin your day. A-hole engineering, I call it. Nothing is intuitive anymore!

 

 

Edited August 6, 2024 by Jsdirt

[dustyd99]

yea its all the right parts..thanks for incite but where i pulled everything back off with the head being off again..and it still not spinning past 180 both ways is what im stumped about? whats locking it up-i didnt drop nothing in the motor that i know of? i didnt mess with the timing nor pull the other head off even. it should turn and turn at the crank now. i dont get it...with head off and spark plugs even pulled on the other head it shouldnt lock up? is there something the truck did to lock it up itself by ecm or theft....with these newer engines 2019+ who knows what chevy is doing to throw us off?!? does anyone know about this? i mean you will turn it around 180ish degrees at the crank and it just dead hammers stops! then you turn it back the other way and it dead hammers stops! i looked at torque converter bolts all are good! i took starter off and its not the culprit either...do i have to pull the oil pan or what? im lossed

[Jsdirt]

I've seen this happen in small engines, but it was a 350° - 355° rotation, with only 10° or less where it stopped dead. That was due to excessive carbon buildup on the piston. That was caused by running crap, stale fuel for many hours, then letting the equipment sit idle for years. The carbon would swell up on top of the piston (presumably from moisture and then lots of gasoline in an attempt to get it running again), enough so that the piston couldn't pass through top dead center. I actually have a picture of the carbon I peeled off a Tecumseh generator engine I'll attach ...

 

With a 180° rotation, if the problem wasn't there prior to starting the work, then it's something that was done during the repair.

 

There's no mechanical system that intentionally locks an engine -  I can just imagine the carnage with a system like that with the way quality control is these days! 

 

Oh yeah ... can't attach pics here for whatever reason. Only forum on the net that won't let me! Guess I'll have to link it:

 

https://postimg.cc/ppM8vFnZ

Edited August 7, 2024 by Jsdirt