MDS at fault ?

[Jds9911]

Just had my 5.7 rebuilt. The engine builder did not upgrade the cam or lifters to non mds, at my disappointment. He did remove the solenoids and put in the plugs. Now, when the engine builds oil pressure it only runs on 4 cylinders. Any ideas I should discuss with the mechanic.

 

[Hemi395]

Yeah that sucks. You can't put MDS lifters in with the MDS solenoid block off plugs because it will do just that, run on 4 cylinders all the time. The MDS lifters use oil pressure to collapse for MDS mode and without the solenoids there controlling oil flow to the lifter bores, they will get full oil pressure all the time and stay collapsed.

Definitely bring it back to the mechanic because it will be a V4 until you get MDS solenoids installed.

 

[Burla]

He has to make it right, or file a small claims case asap. what a bummer

btw, how does it run on 4?

 

[crackerjack1957]

Not much of an engine builder.........LoL

 

[WY.Ram]

Not only will it be a V4 forever but a V4 destined to destroy itself. Without spring pressure, the MDS lifters will 'jump' off the cam after peak lift at higher rpm. I would not drive it if it were mine.

Definitely a bummer, going all the back in I projected as my worst possible outcome, well aside from catastrophic failure that is. I do lots to keep from having to. Good luck

 

[David_Jacobs]

Just had my 5.7 rebuilt. The engine builder did not upgrade the cam or lifters to non mds, at my disappointment. He did remove the solenoids and put in the plugs. Now, when the engine builds oil pressure it only runs on 4 cylinders. Any ideas I should discuss with the mechanic.

Yeah that sucks. You can't put MDS lifters in with the MDS solenoid block off plugs because it will do just that, run on 4 cylinders all the time. The MDS lifters use oil pressure to collapse for MDS mode and without the solenoids there controlling oil flow to the lifter bores, they will get full oil pressure all the time and stay collapsed.

Definitely bring it back to the mechanic because it will be a V4 until you get MDS solenoids installed.

If that’s truly the case I’d be very concerned about other areas of the build. I’m very surprised it’s not backfiring and throwing a code, as the solenoids are not there. I wouldn’t run it at all.

 

[StickyLifter]

I wouldn't drive it above about 2500rpms for sure. Add the MDS solenoids back in and it will work correctly.

 

[theclassic]

Update?

 

[DILLIGAF]

This is why you dont ever let anyone work on your truck ! What a ******* moron.