help, Push rods bent and cam saga. need advice with pics

[smos001]

My pushrods bent on the # 6 cylinder of a 383 (see thread on pushrod bent previously) again.  one of the push rods worked its way down through the engine. I think in the oil pan.
Can someone look at this cam picture and tell me if the cam is in correctly. the lifters are not centered on the cam? is that normal?
also you can see some wear on the lobe of the cam without the lifter on it? is this normal wear? See the two pics.

Anybody know of a good engine builder in St. Louis MO?  : )
Thanks for the help,

[HP_Cuda]

It does look like the lifters are off centered on the cam lobes.

Who installed your cam? Makes me wonder if they even degree'd the cam right.

[RzeroB]

Cam wear looks normal to me. The lifters don't always line up perfectly on the cam lobe. The longitudinal alignment of the cam within the block isn't adjustable. The thrust face on the back side of the cam sprocket abutts against the thrust face on the front of the block thus fixing the cam's longitudinal position in the block. 

So this is twice that #6 has bent the pushrods? No other cylinder - only #6?  Has to be something specific to #6. With the cam you have valve spring coil bind isn't the culprit. With that cam valve guide to valve spring retainer clearance shouldn't be an issue either - unless the guide wasn't fully pressed into the head when rebuilt.  Bad lifter maybe? Faulty check valve allowing the oil pressure to bleed off and not maintain the proper tension on the pushrod thus allowing it to come loose and pop out of the rocker arm socket, bind and then bend?

As far as engine builders in St Louis, I'm in "The Lou" but I'm a transplant and have only been here nine years and haven't built anything during that time. Shelbydogg (Rob) on this board is a life long resident of The Lou and might be able to point you in the direction of a reputable builder or shop. Give Rob a shout and he might be able to help you find someone local who can help you out.

[Strawdawg]

flat tappet cams are supposed to be off center to the lifter.  Cam lobe is tapered and this taper combined with the convex lifter base creates the rotation on the lifter that prevents the lobe or lifter base from being scrubbed off.  That is the reason the push rod is spinning when the engine is running.

[Chryco Psycho]

flat tappet cams are supposed to be off center to the lifter.  Cam lobe is tapered and this taper combined with the convex lifter base creates the rotation on the lifter that prevents the lobe or lifter base from being scrubbed off.  That is the reason the push rod is spinning when the engine is running.

  Exactly right the lifters rotate all the time , the cam is ground tapered so the lobe only has partial contact on most of the lobe where there is lighter spring pressure  , on the ram up it will go to full contact to spread the load over a larger surface area .
 The Second picture looks wrong to me as if the surface is torn up usually from lack of ZDDP in the oil to protect the cam if so the cam is junk & the bottom of the lifter should be torn up badly as well

[smos001]

Thanks for the knowledge,
I am at a loss why the push rods are bending again. I looked at the hydraulic lifters and they are not budging when I try to push down on the top, so they are not bleeding down etc. Maybe a sticky valve guide? The timing maybe off, but it runs fine up until the push rod bend. and why # 6 only....
I stripped her down to get her ready to pull. I have a small one car garage so I am searching for a shop to do the rest, to pull the engine and put it back in after the fix or rebuild. Then I will finish her up at home. hopeful some shop with some sympathy. : )
the rear seal has a leak, I always wanted to fix...

[Strawdawg]

Did you look at the bottom of the lifter that is under the bent rod to see if it is scrubbed as Chryco suggested?


And....it would certainly bend a pushrod if the plunger cannot be depressed...but first we need to know if the cam/lifter are damaged

Steve http://tapatalk.com/m?id=10']now Free[/url]

[smos001]

here is a pic of the bottom. round wear pattern but not deep?
Also, is a hydraulic tappet able to compress by hand? I can't get mine to budge with a spare pushrod and some muscle.

[Moparal]

The lifters in the pic show some depressed.  Are you sure you don't have a tight valve guide or tight lifter bore , or other issue?

[Strawdawg]

Best I can tell, the wear pattern is the normal circular pattern one would expect.  It should not be worn into the surface and the lifter should be slightly convex on the bottom which you can tell if you set it on a piece of plate glass and it wobbles instead of standing straight up

The lifter should be full of oil and virtually impossible to depress the plunger because of the check valve inside it.  It will probably depress after a bit when installed if stopped on the nose of the lobe with spring pressure continually exerted on it. 

Did you check the preload on that lifter when you put the new pushrod in?

As Al said, a sticky valve  or lifter could cause a problem