Damaged cam

[SilverXJ]

I just checked the push rods to see if they were bent or not. Not a one. In fact they were so good they made a new stock replacement rod look bad. I also used some JB weld to make two solid lifters to test 1bolt's theory of valve train bind. No offense Simon, but I am 99% sure that isn't what the problem was.

I took a look at the lifter bore to cam alignment as well. Just eye balling it it look good. Also, the bores weren't noticable off set in the casting lines. I also tool a look at the original OEM lifters and all but one showed some form of damage. I didn't clean them off before storing them and they smelled of gas and coolant, which to me indicated some other problem such as a blown head gasket or cracked head, i.e. something that caused gas and coolant to mix with the oil.

I do believe that I did some sort or damage to either the lifters or the cam when I cranked the engine in an effort to repair the thrust surface on the crank. Until then I only heard a bit of ticking through the fire wall at idle, which I thought was the roller rockers combined with a "noisy" cam. After the "fix" I noticed a louder tick from the engine audible from out side the Jeep at slow cruising speeds. There was a significant increase in valve train noise. Also, I had that hesitation/stalling issue.

[1bolt]

no offense taken as I said I'm not exactly batting a thousand on internet diagnostics, I just can't see how turning an engine over with starter bumps could possibly cause your problem. Think about it, engines dry start all the time probably 10's of thousands of times in their life span.

Anyway if everything checks out, the only thing left to do is stab another one in cross your fingers and hope it doesn't make noise when you try to break in the next cam... Hope your luck changes man.

[dwg86]

Hey Silver, check the inside of your valve cover. Maybe the ticking you heard was the springs, or rockers hitting the valve cover. All the mopar springs just barely hit the metal cover on my engine.

[SilverXJ]

Not the springs hitting the valve cover. I only had to make some room for the rear most spring. Besides, that would have been too easy.

[hatem61]

Unless you have been cranking the engine big time dry, I don't vote for it as the root cause.
I am sure you did it right, but this is just me:

CHECKING FOR COIL BIND

It's imperative to make sure that the valvesprings you're using can handle the cam you're using. If the spring binds, or becomes "stacked," you can end up with a lunched cam. So, while you're compressing springs, here is a way to check for coil bind:

1.800 Installed spring height ( as example )
-0.500 maximum valve lift
=1.300 Compressed spring height

With the spring at its compressed height, you should have a minimum of 0.060 inch clearance between the coils, measured with a feeler gauge or a wire gauge.

[1bolt]

thanks hatem thats a good nugget there. Since Chris says he installed the springs at a higher height I think coil bind or just close enough to bind to cause the extra pressure on the noce of the cam... maybe the cam is a little soft too and the two conspired (so to speak) to cause the damage... I'm stumped otherwise.

[SilverXJ]

The springs are installed at ~1.69". Lift at the valve is .462" for intake, .485" exhaust. The spring's max lift specs is .525", their stock installed height is 1.64", which would make the minimum height 1.115". Spring height under full intake lift is 1.228", and exhaust is 1.205", on exhaust that would give give me .09" before so the spring is at min height.

A pic of min heigth:

[hatem61]

I guess we are all stumped here at the moment...
But hey, this issue is not black magic, we have to keep thinking and keep looking for the root cause.
Sorry SilverXJ I believed what you said and appreciate you bearing with me ( paranoid ).
I was reading at Crane cams about premature camshaft failures, besides the wrong lubricant, wrong break-in procedure, and valve spring coil binds, here are some more mechanical interferences to look for ( I know you mentioned the contact at the valve stem was Ok, but .... ):

(1) Rocker arm slot to stud interference: As you increase valve lift, the rocker arm swings farther on its axis. Therefore the slot in the bottom of the rocker arm may run out of travel, and the end of the slot will contact the stud and stop the movement of the rocker arm. The slot in the rocker arm must be able to travel at least .060" more than the full lift of the valve.
(2) Retainer to seal/ valve guide boss interference. You need at least .060" clearance between the bottom of the retainer and the seal or the top of the valve guide when the valve is at full lift.

Otherwise, if cranking the engine was really excessive before the break-in, this might have contributed?

[Flash]

(1) Rocker arm slot to stud interference: As you increase valve lift, the rocker arm swings farther on its axis. Therefore the slot in the bottom of the rocker arm may run out of travel, and the end of the slot will contact the stud and stop the movement of the rocker arm. The slot in the rocker arm must be able to travel at least .060" more than the full lift of the valve.
(2) Retainer to seal/ valve guide boss interference. You need at least .060" clearance between the bottom of the retainer and the seal or the top of the valve guide when the valve is at full lift.

These are some vary good points.
Do you have a Checking spring ( Vary light spring to replace one of you spring with) Make checking #1 and #2, above, much easier. it also allows you to fill for any rough, or tight spots, that you may not be able to fill other wise.

[SilverXJ]

No binding here. Plenty of room between retainer and valve guide/seal too.

As for cranking the engine prior to break in, it wasn't excessive. Just about twice as long as normal start.

Yah.. so I don't know.

Bottom of the rockers, valve side


Bottom of the rockers, push rod side


Exhaust valve, full lift.


Exhaust valve rocker bolt, full lift.


Intake valve, full lift.


Intake valve rocker bolt, full lift.


Valve stem pattern

[gradon]

Looks good to me Chris

[Brian E]

I posted this as well on the Hesco site. Well I was going to post up and ask this question on wether slick 50 migh help against all the cam failure I see on flat tappet motors. Well I googled it last night and you might find it interesting to read, but basically they are getting their pants sued off for false advertizing. The goverment even got in on it. The finding where it works in some areas, but it clogs oil paths and the pick up screen. And even though some cars saw better fuel mileage they also found heavier amounts of metal in the pan afteer testing and the oil filters where by passing because they where clogged. I also did not know they where owned in part by Quakerstate, who took the brunt of the law suits. Interesting too, my freind who is a machinest says he hates working on any motor parts treated with these types of additives, they cause issue with machining.

[dwg86]

I see why your valve springs were not hitting the valve cover...you have a spacer. Was the spacer required with the Harland Sharp rockers?

[SilverXJ]

Well, even with the spacer is still hit a bit, and I didn't always have the spacer with the MP springs.

Yes, teh spacer was needed for the HS rockers. Also, you need a Tstat housing spacer. And some Jeeps with the serpentine that runs in front of the t-stat housing you need that get that modified too. Mine didn't need that though.

[SilverXJ]

Comp Cams called me today. They offered me new parts or a credit. I took the credit, which I don't know what the hell to do with. When I asked what the cause was she said "Sometimes this just happens with a flat tappet cam". BS not after only 2000 miles. I'm going to call back tomorrow and get in touch with the RMA inspection guy, Red Overt and get a real explanation.