bad lifter collapsed

[grewvin1]

1986, 454, 7.5 engine. Backfire in exhaust manifold. pull left bank valve cover off exhaust rocker only moving 1/4 the travel distance of all the others. Valve springs good non broken portion of push rod showed travel mark as did all the others, this one showed it only moved small bit. if a collapsed valve can this be pumped up or is this a dead lifter and head needs to be pulled. oh ya lifter is at the bottom of the travel not stuck in the top end of travel.

 

[09TNRT]

Sounds like collapsed lifter, no way to make it pump back up though. Time to pull it apart and see exactly what's going on.

 

[kenny nunez]

If the push rod is only moving 1/4 of the others then it appears that the cam is worn.

 

[Scott Danforth]

I agree, sounds like cam lobe went phhllbbbtttt

if I was swapping a cam, I would be real tempted to go with retro-roller lifters and a roller cam vs keeping it flat tappet.

 

[harleyman1975]

Ditto go roller.

 

[09TNRT]

I must've been speed reading, I swear I thought it said 96 not 86 lol. I 3rd the roller set up.