Hyd Lifter Failure

[GreenMachine]

When I fired up my newly rebuilt engine (440), it would backfire through the carb about once per second. This started almost immediately after first starting it. I continued to run it for a few minutes troubleshooting, hoping it was something simple. I found the #2 exhaust lifter with the puck turned sideways and the pushrod wedged and bottomed in the lifter. The rocker arm adjuster was backed most of the way out too. There was no damage to the pushrod or rocker arm.

I'm 99% positive I had the adjuster tightened and adjusted correctly, and didn't notice anything unusual with the lifter beforehand. My method of adjusting the valves is to use a go/no go gauge (.040 wire) between the lifter plunger and the keeper.

I didn't take any pictures of how I found it, but the pic shows what it looked like. Just imagine it in the lifter bore with the pushrod wedged in it.

I've already installed another lifter and buttoned everything up. I'll probably fire it up and finish the cam break-in in a day or 2. I'm wondering how this happened and if my new lifter or any other lifter might do the same thing.

[PRH]

The rocker arm adjuster was backed most of the way out too.

IMO, this is where the problem started.

[69wannabe]

I had this problem after I went with a different cam in my 440. The push rod's I was running were borderline but still worked ok and after the cam change they were to short. Actually my adjuster was way down but it goes both ways. The adjuster should be kinda mid way's between all the way out and all the way down. What kind of rocker's are you running?? The comp rockers should be adjusted one turn from zero lash with the valve closed and that will give it the 0.40 to 0.60 that the hydraulic lifter should have on a mopar lifter.  Could have just been a bad lifter too. Hope it does good on the second try!!!

[GreenMachine]

I have the Mancini adjustable rocker arms. The adjustment was midway, I cut my own pushrods. I must have left that adjuster loose, that's the only way I can see this happening. Once it got loose enough, the oil pressure popped the puck out and got wedged between the pushrod.

[PRH]

I really don't think that's how the sequence of events unfolded.

More like....... Adjuster backs off, pushrod is bouncing all around the lifter, and at one point it "steps on" the wire retaining ring, which becomes unseated, then......since there is plenty of slop in the adjustement, the cup pops out, the pushrods steps on it over on one side, flips it sideways...... And you end up where you did.

I've seen similar results happen when there is severe float/lifter pump up in under sprung hyd cam racing applications.
It usually starts with the wire retaining rings half way out of the lifters..... Or laying in the valley(or oil pan, or in the now seized oil pump).