Pushrod Falls Out of Rocker
#2849628
11/21/20 04:33 PM
11/21/20 04:33 PM
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Joined: Jan 2005
Posts: 4,452 Michigan
MarkZ
OP
Worthy
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OP
Worthy
Joined: Jan 2005
Posts: 4,452
Michigan
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Got a weird one. The pushrod on number eight intake fell out of the rocker arm today. Noticed it immediately when the motor fired up. Slight miss and mechanical ticking sound - hard to distinguish from the normal racket the roller lifters make.
Motor is a 400 based 512 with Comp Cams retrofit roller lifters and adjustable rockers.
This is the second time it has done it. Same hole as last time. Some of the photos show damage to the rocker, adjuster and scuffing on the pushrod end. Lash is set the same as the others. Inner and outer springs seem to be ok. Motor is three years old now with a few thousand street miles. Any ideas? I'm just fishing for advice before I pop the intake to inspect the lifters.
Thanks...
1987 Fifth Avenue - 512/518/D60
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Re: Pushrod Falls Out of Rocker
[Re: AndyF]
#2849723
11/21/20 08:27 PM
11/21/20 08:27 PM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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This is only if it’s a hyd roller.......
Too much to type for the long version......... Always happens right at start up?
I’ve had it happen here, and have talked to several others that have had the same thing happen.
The short answer is........try running more lifter preload.
From the point of where the plunger is preloaded to, to the plunger being bottomed out in the lifter...... has to be less distance than the depth of the adjuster screw cup in the rocker arm.
The adjuster cup is .120” deep. Set the lifter preload so it’s .090”-.100” from being bottomed out.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Pushrod Falls Out of Rocker
[Re: fast68plymouth]
#2850436
11/23/20 01:12 PM
11/23/20 01:12 PM
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Joined: Jan 2005
Posts: 4,452 Michigan
MarkZ
OP
Worthy
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OP
Worthy
Joined: Jan 2005
Posts: 4,452
Michigan
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Sorry, should have lead with this information. Yes, it is a hydraulic roller and the couple times this has happened was at startup. Motor always ran fine until parked and this only happened after it was allowed to sit overnight.
I'll give it a go with more preload then, .095" from the bottom.
I'm still going to pop the intake and inspect the lifter. While I'm in it I can use the opportunity to rephase the distributor gear and install the Holley distributor to allow for computer controlled timing.
Do you think the damage the underside of the rocker warrants replacement? I'm going to get a new adjuster screw anyways seeing as how it's beat up.
Thanks guys.
1987 Fifth Avenue - 512/518/D60
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Re: Pushrod Falls Out of Rocker
[Re: MarkZ]
#2850438
11/23/20 01:16 PM
11/23/20 01:16 PM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,514
So. Burlington, Vt.
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I wouldn’t worry about the rocker, but would replace the adjuster.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Pushrod Falls Out of Rocker
[Re: fast68plymouth]
#2850525
11/23/20 03:00 PM
11/23/20 03:00 PM
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Joined: Aug 2003
Posts: 43,315 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,315
Bend,OR USA
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I wouldn’t worry about the rocker, but would replace the adjuster. Been there done that, had to do it more than once Buy the good adjusters, not the cheapest ones you can find
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Pushrod Falls Out of Rocker
[Re: Cab_Burge]
#2850561
11/23/20 03:42 PM
11/23/20 03:42 PM
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Joined: Jan 2005
Posts: 2,540 Milwaukee WI
TRENDZ
master
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master
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
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I would add... Do a leakdown or at least a compression test. Looks like it ran with the pushrod real close to the fulcrum. That is a huge rocker ratio jump. Possible to bend a valve or squash a valve seal, etc.. Just as precaution, no likely damage. Best to be sure though.
"use it 'till it breaks, replace as needed"
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Re: Pushrod Falls Out of Rocker
[Re: topside]
#2850773
11/23/20 11:13 PM
11/23/20 11:13 PM
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Joined: May 2019
Posts: 714 Lake Villa Il
INTMD8
super stock
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super stock
Joined: May 2019
Posts: 714
Lake Villa Il
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How much preload are you currently running? And, how did you arrive at that?
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700
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Re: Pushrod Falls Out of Rocker
[Re: TRENDZ]
#2850777
11/23/20 11:33 PM
11/23/20 11:33 PM
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Joined: May 2019
Posts: 714 Lake Villa Il
INTMD8
super stock
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super stock
Joined: May 2019
Posts: 714
Lake Villa Il
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Looks like it ran with the pushrod real close to the fulcrum. That is a huge rocker ratio jump. Possible to bend a valve or squash a valve seal, etc.. Just as precaution, no likely damage. Best to be sure though. Good thinking, I thought the same, but also thought it lost a bunch of preload with no adjuster. Maybe the two to one ratio was made up for by a loss of .100+ length
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700
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Re: Pushrod Falls Out of Rocker
[Re: Rollo!]
#2851273
11/25/20 09:26 AM
11/25/20 09:26 AM
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Joined: May 2019
Posts: 714 Lake Villa Il
INTMD8
super stock
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super stock
Joined: May 2019
Posts: 714
Lake Villa Il
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Agreed that hyd lifter gets it's oil pushed out when parked at an open position but the pushrod could come out if running very little preload. Some run 1/2 turn preload on an adjuster directly on the pushrod which is only .020 preload.
Could run 2 full turns for .083 with less chance of this happening.
More preload could also help, just starts getting risky if your valve/piston is close and the system loses control at high rpm. (though that's obviously a problem either way, could crash valves if it lofts and there's a ton of preload).
Doesn't change much geometry on a shaft system, well at least rocker to valve. I suppose too many threads below the rocker on the adjuster isn't the best thing but from the photos it seems like it would be ok.
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700
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Re: Pushrod Falls Out of Rocker
[Re: INTMD8]
#2851289
11/25/20 10:18 AM
11/25/20 10:18 AM
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Joined: Dec 2005
Posts: 1,495 Shelby mi.
JAKE68
pro stock
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pro stock
Joined: Dec 2005
Posts: 1,495
Shelby mi.
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I have done several hyd roller cams. The first few I had comp lifters and had the exact problem. I tried with putting more pre load in it and that worked but didn't feel comfortable with that so after that only used morels and never had a problem again.
JAKES AUTOMOTIVE
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Re: Pushrod Falls Out of Rocker
[Re: MarkZ]
#2851312
11/25/20 11:10 AM
11/25/20 11:10 AM
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Joined: Nov 2004
Posts: 3,544 Syracuse,NY
CompWedgeEngines
master
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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This a very common problem. It used to be believed ALL these types of failures was do to dirt and debris etc, but I am here to tell you, not always the case. Sometimes a little more pre load helps, but more so, the industry is having issues with hydraulic roller lifters from several manufactures. Especially Comp and Morel. ( yes, Morel also) .I am in a group of engine builders on a private forum from across the country, and almost everyday, a hydraulic lifter issue pops up. I could write for hours about this. But here is my best condensed version. Buy Gatorman, GS Products,Crane or Johnson ( NOT Hylift Johnson).
RIP Monte Smith
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
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Re: Pushrod Falls Out of Rocker
[Re: CompWedgeEngines]
#2851315
11/25/20 11:22 AM
11/25/20 11:22 AM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,514
So. Burlington, Vt.
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In every case where I’ve had a conversation with someone about the pushrods falling out........ it’s always been at start up(and was running fine when the engine was shut off)........ and was involving a hyd lifter(the motor we had here with this problem had a very mild HFT cam).
I have not heard of a single incident where the pushrod fell out during start up when a solid lifter was being used.
Some of the people I spoke to that had it happen multiple times(on random cylinders) solved it by swapping to solid roller lifters being run with very tight lash settings.
The deeper the “cup” is(whether in the rocker or the pushrod), and the more preload you run......the less likely it is you’ll encounter this issue.
Also, hyd lifters with less plunger travel will be less prone to have this issue.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Pushrod Falls Out of Rocker
[Re: AndyF]
#2851380
11/25/20 01:21 PM
11/25/20 01:21 PM
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Joined: Jan 2005
Posts: 2,540 Milwaukee WI
TRENDZ
master
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master
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
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There was a post on here not long ago. It was asking about big cam/ spring/ hydr roller lifter. I’ve never known anyone personally to make it work, I read about others that have no problem. The cure for bleed down in my shop is to put a solid lifter in the car. 100% success rate. I wish I knew more about making a hydr roller work well.
"use it 'till it breaks, replace as needed"
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Re: Pushrod Falls Out of Rocker
[Re: AndyF]
#2851423
11/25/20 03:10 PM
11/25/20 03:10 PM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,514
So. Burlington, Vt.
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I've never heard of this issue with an OEM engine so I'm wondering if the problem has something to do with aftermarket parts and/or assembly error and/or high lift lobes? The pushrod socket on an OE stamped rocker is .180” deep, and the lifters are preloaded to about 1/2 their travel. Aside from a valve getting stuck open, there isn’t any way the pushrod could come out........ even if the lifter plunger were stuck bottomed out.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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