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Re: Pushrod Falls Out of Rocker [Re: fast68plymouth] #2856210
12/06/20 07:40 PM
12/06/20 07:40 PM
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UPPER MICHIGAN, MARQUETTE COUN...
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NITROUSN Offline
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UPPER MICHIGAN, MARQUETTE COUN...
Quote

I didn't put this motor together either. So far I've been into it for a blown head gasket, worn bronze cam gear and this.


Also make sure the push rods do not rub the block. Ran into this years back with stage 6 heads and larger push rods. Had to clearance the block in several area's due to rubbing and deflection on the push rods. Just something to look for.

Re: Pushrod Falls Out of Rocker [Re: fast68plymouth] #2856257
12/06/20 09:17 PM
12/06/20 09:17 PM
Joined: Jan 2005
Posts: 4,406
Michigan
MarkZ Offline OP
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Originally Posted by fast68plymouth
Imo, what you’re measuring on the adjuster is meaningless.
Different valve tip heights, and camshaft base circle diameter will impact where the adjusters are.

Just curious.......How sure are you those are Comp lifters?

I haven’t seen any Comp HR lifters for a BB Mopar in quite a while, but I don’t recall them having the skirted wheel.
Of course..... they may have made revisions or changed vendors over the years.
( Edit - I looked through some pics on line. It appears they have had shrouded/skirted wheels for quite a while..... see pic, BB and SB )

Nonetheless........ if you adjust them like I suggested in my first post, I think you’ll find the problem goes away.

Yes, that may require different length pushrods.

Btw, what I see....... looking at your measurements is...... the “left” rockers have the long measurement, and the “right” have the short measurement.

Though....One thing you could check now is...... how far from being bottomed out does your current preload put the plunger?
What you have for total plunger travel would also be interesting to know.


The entire motor was assembled by a shop. I provided the block, rotating kit, heads, pan and intake - the shop sourced everything else. I'm going off of what the shop wrote up in the receipts.

I'll reassemble it all and do exactly what you recommended. May be a while waiting for a warmer day in which to work, but I'll post my findings back this thread. Thank you very much for taking the time to help me with this.


1987 Fifth Avenue - 512/518/D60
Re: Pushrod Falls Out of Rocker [Re: NITROUSN] #2856523
12/07/20 01:14 PM
12/07/20 01:14 PM
Joined: Dec 2006
Posts: 2,107
Byron, NY
W.I.N. Racing Offline
top fuel
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top fuel

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Posts: 2,107
Byron, NY
Originally Posted by NITROUSN
Quote

I didn't put this motor together either. So far I've been into it for a blown head gasket, worn bronze cam gear and this.


Also make sure the push rods do not rub the block. Ran into this years back with stage 6 heads and larger push rods. Had to clearance the block in several area's due to rubbing and deflection on the push rods. Just something to look for.

As a side note...I will allow the push rod to rub as a dampening technique. But it can not alter the trajectory of the rod...now back to your regularly scheduled thread.


'01 P1500, Blown/Inj BAE,/Veney ,Bruno/CS2,Dana 60
'01 Dodge 3500 S Cummins Auto, Fresh air kit, 4" Exhaust,
'05 Dodge Magnum R/T - Too Much to list
'60 Willys CJ5
'01 International LPX - Project,DT466, Allison
'64 Plymouth Valiant, Inj 528 Hemi, 2spd
Re: Pushrod Falls Out of Rocker [Re: W.I.N. Racing] #2901368
03/21/21 03:42 PM
03/21/21 03:42 PM
Joined: Jan 2005
Posts: 4,406
Michigan
MarkZ Offline OP
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I finally got back out into the garage to continue working on this thing. Got parts and while giving everything one last look over before assembly I discovered the bushes on the offending rocker had worked their way to one side. I don't know if this the cause of the pushrod coming out from under the rocker, or if it was what happened after the fact. Either way I've got another rocker on order now too. Should have looked over the parts with a better eye last time I was out there.

20210321_153015.jpg

1987 Fifth Avenue - 512/518/D60
Re: Pushrod Falls Out of Rocker [Re: MarkZ] #2901392
03/21/21 05:27 PM
03/21/21 05:27 PM
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USA
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I see multiple issues here, but the pushrod popping out is simply a lifter bleeding down. As CSK mentioned, you can run the pushrod .020" off the bottom of the lifter, and it will eliminate that problem.

That could open up another can of worms though. If the motor goes into valve float, the lifter will do it's job and pump up. That will hold the valve open and if P2V clearance is tight, could bend valves. Looking at the sweep pattern on the valve tip, I'd say the geometry is pretty far off and instability is likely. Also, it appears the adjuster is out much further than it should be. The preferred setting is one turn out from seated in the rocker body, and no more than two turns. That's turns, not threads.

Something else that is misunderstood is that valve float does not limit rpm. The valve being off the seat when it is supposed to be closed is what limits rpm. If valve float did it, lift rule class racers that run lofting cam lobes couldn't turn any rpm due to the controlled valve float. A hydraulic lifter does not really get into valvetrain instability any earlier (or at least not much earlier) than a solid lifter. What it does do is hold the valve open when the lifter pumps up from float, which then holds the valve off the seat. A solid will go into float and jackhammer the valvetrain into oblivion, but won't stop revving until the instability is so severe that the lifter bounce causes the valve to bounce off the seat and rpms stop climbing. Either way, the instability is present and the valvetrain is not happy. The preload has nothing to do with rpm potential, and the only reason for a zero preload hydraulic lifter, with a heavy retaining clip, is to allow the engine to continue revving like a solid when valvetrain instability is present.

Do the best you can at getting the valvetrain stable, and you will improve rpm potential regardless which lifter style is used. I didn't say they would both be equal, but improved.


Mike Beachel

I didn't write the rules of math nor create the laws of physics, I am just bound by them.
Re: Pushrod Falls Out of Rocker [Re: MarkZ] #2901400
03/21/21 06:08 PM
03/21/21 06:08 PM
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New York
polyspheric Offline
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Adjuster length affects rocker ratio, but also changes the geometry triangle (lines connecting the roller axle, the shaft center, and the CL of the adjuster ball).


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Re: Pushrod Falls Out of Rocker [Re: polyspheric] #2901402
03/21/21 06:21 PM
03/21/21 06:21 PM
Joined: Jul 2013
Posts: 561
USA
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Originally Posted by polyspheric
Adjuster length affects rocker ratio, but also changes the geometry triangle (lines connecting the roller axle, the shaft center, and the CL of the adjuster ball).

Agreed, which is why I recommend not extending the adjuster any further than necessary. Especially considering the adjuster angles and placements are wrong on shelf rockers to begin with.


Mike Beachel

I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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