Mack EM6-300 camshaft?

[CRHardie]

My neighbor has a 89 Mack DM with a EM6 It developed a skip so he removed the valve covers and cranked it over He noticed little movement and large lash on #4 exhaust rocker and called me The push tube is not bent so Im assumeing the cam is bad unless this engine has roller lifters Does anyone know? Ive rebuilt a couple E7s but not a EM6 Thanks for your help

 

[Wayne M.]

I'm a Mechanic for NYC Sanitation. We have over 2000 Mack E7 E-tech trucks. We are having chronic flat cam and cam related problems. It seems that at around 7000 hours, the fun begins. We have always kept some Mack's around though the years (tho not too many in the late '80's) and have never heard of internal engine problems before the E-tech.