*TWO* Bent Push Rods on Recent Rebuild

[Tom K.]

Hey Everyone,

A few months ago, the #1 intake pushrod bended on a recent engine rebuild - total stock. After checking my valve adjustment, the head, the valve springs (all fine), I replaced that bent pushrod with a new one thinking my troubles were behind me - that the bent pushrod was some sort of fluke.

Then when timing the engine and tuning the carb yesterday, a *second* pushrod bended - this time the #2 intake.

So something strange is happening. Any ideas?

I added this latest information to my original thread ("Found an Oil Leak"). But since my issue is no longer an oil leak, I've started this thread with an appropriate title to my problem hoping to get feedback

Thanks, if you can, for brainstorming this issue with me.
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'91 Vanagon Westfalia
'70 Beetle Convertible
'71 Super Beetle Semi-Automatic: https://www.thesamba.com/vw/forum/viewtopic.php?t=714131&highlight=
'65 Ghia: https://www.thesamba.com/vw/forum/viewtopic.php?t=762478&highlight=

[VW_Jimbo]

Something sticking, lifter? Rocker? Valve? Or maybe binding?
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[Starbucket]

List what was rebuilt to give us a better picture. Did you hear anything before you found the bent push rod?

[Tom K.]

New stock cam. New valve stems and exhaust valves. New lifters. New crank if that matters. New adjusters on the rocker but used old rocker components except a few wavy washers that were worn. Hmm, maybe I'll switch the rockers this time. If it happens a 3 rd time on the other side, then I'll have a primary suspect.
_________________
'91 Vanagon Westfalia
'70 Beetle Convertible
'71 Super Beetle Semi-Automatic: https://www.thesamba.com/vw/forum/viewtopic.php?t=714131&highlight=
'65 Ghia: https://www.thesamba.com/vw/forum/viewtopic.php?t=762478&highlight=

[Pruneman99]

Are these OG pushrods? Or some aftermarket brand?

[Tom K.]

The first broken pushrod was original to the engine. The second broken pushrod happened to be the new replacement.
_________________
'91 Vanagon Westfalia
'70 Beetle Convertible
'71 Super Beetle Semi-Automatic: https://www.thesamba.com/vw/forum/viewtopic.php?t=714131&highlight=
'65 Ghia: https://www.thesamba.com/vw/forum/viewtopic.php?t=762478&highlight=

[Starbucket]

Use a flashlight and look closely at the valve stems for scoring which could have cause the valve to stick if the clearance of stem and guide are too close. Look at the valve springs for binding when fully open. Is the valve/rocker arm area look nice and oily? if not maybe the rocker arms/shaft might be plugged if not disassembled and oil passages cleaned during rebuild.

[vwoldbug]

Did you get new valve guides and who put the cylinder heads together . Are you seer any dust or shavings the same color as the valve guides . Sounds good switching the rocker assemblies around . Let us know.

[VW_Jimbo]

[Lingwendil]

Turn the engine over by hand 90 degrees at a time, and shake/wiggle the pushrod in each 90 position to make sure it isn't getting loose at any position. I had this happen on a junkyard motor and it turned out the pulley was marked wrong and we had been trying to set the valves 180 degrees out- causing the pushrods to become unseated and jamming sideways.
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73 super beetle thread http://www.thesamba.com/vw/forum/viewtopic.php?t=649622 Back on the Road!

Modify your Kadrons for SVDA http://www.thesamba.com/vw/forum/viewtopic.php?p=8115884#8115884

Cast iron VJU4BR8 SVDA reference thread- https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

Need replacement filters for original Kadron aircleaners? WIX #42087 is a perfect fit, as is Napa Gold #2087!

[VW_Jimbo]

[Tom K.]

Update: I reversed the rockers and inserted cheap expandable push rod tubes to save having to drop the engine. I fired it up and it ran perfectly for about 10 minutes.

Then the gushing oil appeared *again* on the floor. The #1 intake push rod was bent and severed its tube. This is the third time now (first was also #1 intake, second was #2 intake).

So the rocker does not appear to be the problem.

I then measured the valve lash and found that *all* of the valves were alarmingly loose - especially the #1 intake but loose everywhere else too. The looseness, I'm guessing now, is causing the push rod to fall out of its little cup and then get crushed (bent) on the next engine stroke.

So maybe I have a new problem, any thoughts on why all 8 valve lashes would increase after just 10 minutes of idling? This is a new build - new cam, new followers, new stems, new exhaust valves. I feel like I'm missing something easy. Thanks if you have any thoughts.
_________________
'91 Vanagon Westfalia
'70 Beetle Convertible
'71 Super Beetle Semi-Automatic: https://www.thesamba.com/vw/forum/viewtopic.php?t=714131&highlight=
'65 Ghia: https://www.thesamba.com/vw/forum/viewtopic.php?t=762478&highlight=

[Pruneman99]

Are you possibly setting the valve lash at the incorrect time? Idk. It sounds like after your setting the lash, and the valvetrain moves, it's opening up the lash way too much, and the pushrods are falling out of the cups and getting smashed. Like your setting the lash when the lifter is on the ramp, not the base circle.

[Tom K.]

[Pruneman99]

I've made silly mistakes in the past.

The only other thing I can think of are the valves have too little clearance to the guides, and are sticking. Unfortunately that's a teardown to fix.

[Tom K.]

What makes me think it's not the heads or valves or stems is that *both* sides exhibit excessive valve lash even though the two heads - both stock - were sourced from different places (one original to the engine is on the passenger side).

Egads. This is a weird one. I'm really hoping I have just been stupid when adjusting valves on this car. I'll be dialed in for this next attempt.

Thanks for giving it some thought.
_________________
'91 Vanagon Westfalia
'70 Beetle Convertible
'71 Super Beetle Semi-Automatic: https://www.thesamba.com/vw/forum/viewtopic.php?t=714131&highlight=
'65 Ghia: https://www.thesamba.com/vw/forum/viewtopic.php?t=762478&highlight=

[raydog]

[Tom K.]

[VW_Jimbo]

Thinking you need to double check TDC. Get a pencil. Pull the number all 4 plugs, rotate till the pencil pushes out, all the way. You may need to rotate the crank back and forth to get it 100%. Once you get it, compare it to the pulley. Is it on the case seam?

I have seen several pulleies modified with an incorrectly placed notch!

Also, the lifters stick very quickly when the oil galley between them get plugged with debri. That debri, also works into the space between the case and the lifter, causing it to bind and eventually causing the case to need new sleeves. Really think you need to pull the motor and check those lifters!

Did you clean out the oil galleys really good when you rebuilt the engine?
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[67rustavenger]