This (stock) engine had a bent #8 intake PR and #8 exhaust PR was always 'loose'. Well, they found lifter parts in the oil pan - so that may explain why exhaust PR was loose. But, it bent a new PR on intake in one revolution (by hand).

Is it possible the intake lifter is spun on the cam?

Id like to see a discussion about why this happens. Here are some things I've thought of:

- coking/carbon on exhaust valve stem causes valve to stick in guide - of course the piston is coming along to 'help' it close a second later. PR gets out of seat on lifter/rocker and there isnt room for it so ya get a pretzel

-

 

Stupid phone....

Another scenario could be too much boost for valve springs and intake valves being 'blown' open when they arent s'posed to.

Or maybe ether doing the same thing ^^^.

Anyway, it seems like every time I've come across this I never fully understood what was happening. Hope y'all can help!!

 

Bueller? Lol.

This is something I've never fully wrapped my head around, but it seems semi-common with 7.3's from what I can tell.

 

I had an 1983 with a 6.9 that I had a pushrod issue with, one hole...never did figure out what caused it.

 

Spooky stuff - eh? You ask a room full of 7.3L enthusiasts... all you get is crickets and deer-in-the-headlight looks. A binding valve stem is the only thing that makes sense to me. A cam out of time could do it, but that would effect an entire side.

 

Intake side still baffling me...

Im stretching here...
But if something is amiss causing exaggerated egt's...
May hap an exhaust valve can start to go red hot... then liquify at the camfer.
Valve + port of head become patternwelded.
Pushrod breaks the weld on next revolution... but bends in the process...

Like i said...
Stretching.

 

valve guide, bent valve, or lifter issues...

 

We know this engine had lifter issues. I'm sure those lifter bits in the oil pan had an important job...

Looks like he is going to use a different longblock, but I hope he'll dissect this one enough to find a smoking gun before he takes it off the stand.

I dont mind not getting a lot of feedback sometimes. This is not an epidemic-type problem. Lots of us can contribute when there is a no start or oil leak - because that happened to us. The number of bent pushrods minus all those who never investigated and theoretically the pool of experience is very small.

 

Hope he pulls it apart to find out. Haven't had that kind of trouble since my big block chev's years ago.

 

I'm guessing heat. valve stem swells and gets sticky, push rod gets bent.

 

I've always assumed mechanical bind of some sort, be it sticky valve, worn guide, coil bind, high RPM's or hydrolock situation.

 

When I read this tread I did feel like I was a deer caught by a set of headlights! But after thinking about it for awhile I have a couple of ideas.

First of all on these 7.3's I don't you see many push rod issues with stock trucks or truck with stock tunes driven by old guys that don't run higher rpm's having this problem. I think the issue comes into play when you are running a modded engine/tunes with higher boost and higher rpm's. I would bet that this is more of an issue with younger guys who want to hot rod these engines.

Now speaking of young guys who want to hot rod or beat the crap out of everything they drive. Believe it or not I was once a young man who beat the living crap out of everything I drove and doing so I have bent, broke or blown up just about everything. And in my experience with bent push rods (Which has been quite a few !) All on gasser v8's in cars and boats. Sometimes it was due to lifter, rocker arms, bent valve, crappy weak stock push rods, too much valve spring pressure and almost always high rpms.

It has been about 3 yrs now that I have been trying to learn all I can about these 7.3/ T444E and what makes them tick. The one thing I have never liked on these engines is the stock rocker arms. I see guys addressing the issue of push rods and valve springs. But never do I see anyone going with upgraded valves with a 4 angle valve job (to deal with seat pressure) or going with roller rocker arms. I am a big fan of using roller rocker arms on anything I have build in the past and not just high preformance or anything I want to last forever.
Roller rocker arms help reduce stress/ pressure from the valvetrain and push rods.

But in this case I would say too many rpms and bent valves with worn guides is causing the issue.

 

I can relate to what hes seeing about the roller rocker arms, with our rocker arms the force that they apply on our valves and push rods is.not straight down, a lot of the force is at an angle which will eventually wear on the valves and valve guides. To address this issue. Like he.mentioned, they use roller rocker arms which keeps most of the force on top pushing straight down instead of at
an angle to the valves, id really like to see roller rocker arms for our engines...

By higher rpms do you.mean past redline or high rpms as in 2500-3200 which I believe is about all a stock or lightly modded (chip)
truck will run to, 3200 rpm

 

I think Wipe Out Enterprises makes some. Also, here is a thread about roller rockers where Clay states pricing: https://www.ford-trucks.com/forums/1...cker-arms.html

 

There is a company that makes roller rocker arms for the 7.3. I have looked into it and I can not think of the name of the company off hand. But I do remember the cost was insane I think in the area $2500. It really just isn't cost effective on these 7.3's. But if we could get the demand up maybe production cost go down .....and hopefully they would pass that down to the customer NOT!!
But at one point I had called the company and they said due to low production runs that is why cost is high. Stupid in my opinion since if they increased production run they could lower cost and in turn sell more.
Sorry for the ....