Running rich high rpm missfire

[SilverXJ]

So... I lied. I busted out the dial indicator last night. My cam is wiped- lift is only about 0.300¨ on a few of the lobes according to a dial indicator placed on top of the valve retainer..

Remove the rocker arm and measure on top of the pushrod. You won't get an accurate measurement with hydraulic lifters measuring off the spring. How did you measure preload?

[6TIME]

So... I lied. I busted out the dial indicator last night. My cam is wiped- lift is only about 0.300¨ on a few of the lobes according to a dial indicator placed on top of the valve retainer..

Ditto on measuring lift....Pull the rocker and measure at the pushrod then multiply by rocker ratio. Another thing to remember is that valvespring pressure will make the lifters will bleed down after oil pressure stops. I've watched them relax while running the motor with the valve cover off immediately following shut down...Some will hold pressure longer than others.

[doublins]

Ok I will measure lobe lift the way you recommend when I get home.

Three things I noticed worth mentioning:

1) When I removed the rockers on #1, only the exhaust lifter caused the pushrod to rebound. The Intake lifter simply sat there, bottomed out. I could not push it down any further, nor would it spring up. It´s like there´s no spring there.
2) When the rockers are torqued down. I cannot physically tilt either rocker back towards the pushrod... it´s like the lifter cores are bottomed out in the lifter. Once torqued down, the rockers seem locked rigid. How hard should it be to move them in a typical correct setup?
3) There are 12 shiny marks on the valve cover where some part of each rocker has been making contact with the oil baffle.

[Busey]

does your cam card show a camlift ?
my cam card had valve lift, which in my case was .448 and camlift which was .280
I would think you could pull a rocker and set a dial indicator up in the end of the pushrod.
sorry about your bad luck doublins

[doublins]

does your cam card show a camlift ?
my cam card had valve lift, which in my case was .448 and camlift which was .280
I would think you could pull a rocker and set a dial indicator up in the end of the pushrod.
sorry about your bad luck doublins

It has lift, which is advertised at 0.484¨ I´m assuming that to be valve lift, not cam lift. Anyone know the rocker ratio of the Harland Sharp roller rockers?

[superstingray77]

S4096 s40196a and non a all show 1.6 ratio.

[Busey]

my cam card stated 1.6 rocker ratio- if yours is the same your camlift would be .303 which is close to your measurement
hopefully you cam is still good

[Retlaw01XJ]

Since you have a dial indicator, you can check lifter preload with it.
- Piston should be at TDC with both valves closed (compression stroke).
- Loosen rocker until you can just feel play in the pushrod, and slowly tighten rocker while spinning the pushrod with your fingertips. When you get to zero lash/preload, you'll notice pushrod becomes more difficult to spin.
- Put dial indicator on the rocker, directly over the pushrod. On the edge of the oil hole works okay.
- Zero the dial, and tighten the rocker. Dial movement will indicate lifter preload. Spec is 0.020- 0.060".
- To get the preload in spec, use different length pushrods or shim the rockers.

[SilverXJ]

1) When I removed the rockers on #1, only the exhaust lifter caused the pushrod to rebound. The Intake lifter simply sat there, bottomed out. I could not push it down any further, nor would it spring up. It´s like there´s no spring there.

Depending where the cam lobes were the exhaust could have been loaded. With correct preload you may not even notice any rebound, or it take a few minutes. Or it rebounded while you were removing the rockers. It usually is hard to compress a filled lifter by hand.

2) When the rockers are torqued down. I cannot physically tilt either rocker back towards the pushrod... it´s like the lifter cores are bottomed out in the lifter. Once torqued down, the rockers seem locked rigid. How hard should it be to move them in a typical correct setup?

It may be hard to compress a filled and pumped up lifter by hand.

3) There are 12 shiny marks on the valve cover where some part of each rocker has been making contact with the oil baffle.

What rocker arms do you have?

While doing all of these measurements the piston needs to be done a TDC on the compression stroke so you are on the heel of the lobe. This is extremely important to get any good measurements.

[BDD]

After a little time away from my jeep,I finally figured it out.It's what I feared from the start.I also have a cam lobe or two on the way out.I cant explain why it ran so well below 4000 rpm,but it has one cuped lifter,and one lifter just starting to stop spinning.
I talked to zack at 505 and told him his cam was going flat at 30,000 miles.He asked me how many dist gears I chewed up,I told him two.He then told me to get rid of my hv oil pump,as it puts to much load on the dist/cam gear.When it wears it spits metal on #3 and #4 cam lobes,the ones I have a problem with.Makes sence to me.I also run 15w40 rotella and have 80lbs of oil pressure,cold. I can see how that would be hard on the dist/gear.

Ordered a stage two hydraulic from him and it is being nitrided.I ordered mopar 5249464 springs,p4452032 retainers,and p4452030 3 groove retainers for my 1998 0630 head. The keepers dont fit? They appear to have 3 grooves with 4 ribs.My valves have two grooves with three ribs,if that makes sence. Any one know what part # I need for theese valves?
Can I order the one groove valves and run p4529218 keepers with 4452032 retainer?

After all the time I spent researching I though 4452030 was the right part,but they dont fit.

[doublins]

1) When I removed the rockers on #1, only the exhaust lifter caused the pushrod to rebound. The Intake lifter simply sat there, bottomed out. I could not push it down any further, nor would it spring up. It´s like there´s no spring there.

Depending where the cam lobes were the exhaust could have been loaded. With correct preload you may not even notice any rebound, or it take a few minutes. Or it rebounded while you were removing the rockers. It usually is hard to compress a filled lifter by hand.

2) When the rockers are torqued down. I cannot physically tilt either rocker back towards the pushrod... it´s like the lifter cores are bottomed out in the lifter. Once torqued down, the rockers seem locked rigid. How hard should it be to move them in a typical correct setup?

It may be hard to compress a filled and pumped up lifter by hand.

3) There are 12 shiny marks on the valve cover where some part of each rocker has been making contact with the oil baffle.

What rocker arms do you have?

While doing all of these measurements the piston needs to be done a TDC on the compression stroke so you are on the heel of the lobe. This is extremely important to get any good measurements.

First off, let me get this out of the way I cried wolf and am very embarrased at jumping to conclusions. I was not thinking rationally because my worst fear was having a THIRD wiped cam, and this clouded my judgement.

So, my cam is ok. For some reason, it took like three days for the lifters to bleed down, they finally did though. The lifter cores were not bottomed out.

1) I removed the rockers and measured lobe lift at the pushrod, all 12 lobes were in spec- my lobe lift was actually within a couple of thousandths of the cam card number for all I and E lobes.
2) Preload on each rocker was between .030 and .045 as measured with the dial indicator- I initially tried using the ¨scribe two lines on the pushrod and measure with calipers¨ method, but I got terribly inaccurate results that way- the dial indicator method was faster, easier, and gave accurate, repeatable measurements.
3) I noticed that my Harland Sharp rockers had contacted the oil baffle inside the valve cover and actually broken it free from the spot welds. I installed the Hesco valve cover spacer when I re-assembled everything- now the ¨valve train noise¨ I was having is gone.
4) I discovered the source of my top end power loss... despite having tried to rule out a clogged cat via a vacuum gauge test (It passed the test when I checked manifold vacuum at idle vs holding steady at 2500rpm), I finally pulled the exhaust and peeked inside of the cat after ruling out distributor gear wear, fuel, ignition, and a wiped cam. The inside of my cat looked like a box of rocks! The cat material was completely broken up and parts of it were melted solid.

So, again, I apologize for overreacting and crying wolf. My motor is fine. The cat was the problem, and after I replace it I´ll give feedback tomorrow afternoon. I am so happy to have found the problem, and that it was an easy fix, as opposed to having to pull the motor yet again.

[BDD]

Please delete this thread as it has been hijacked,and is not helping the op. Thanks