Roller rockers messed up

[chermik1999]

I don't know what cam you have but my howards roller (.525 235@50 on 109), i get 8-10hg at idle, have run smoke through the intake to make sure i didn't have leaks just in case, it is what it is..

The 15 mins for lifter to pump up scares me though but i'm not an expert and someone else will chime in i'm sure. If you are saying it's tight and hard to start after running (due to slow turnover/tightness?) I would cut the oil filter open before i ran it again just to see if anything is in it. It's like $10 that might save you a lot more in the long run..

Im sure it's fine. As a run stand isn't enough to seat the rings, most likely still breaking in. I checked all clearances during and all was good. But ill do that for peace of mind anyway.
I did have an electrical issue at first. The solenoid was wired wrong and I burned out 2 cut off switchs. It's changed and wired proper now, but I suspect I need another solid ground to the engine anyway. Maybe the the culprit. But ill report when I open the filter.

 

[chermik1999]

On a Mopar shaft mounted rocker system, pushrod length does not change rocker to valve tip geometry.
The reason it changes geometry on an adjustable stud type rocker is the rocker pivot point changes with pushrod length.
The Rocker stands on a Mopar fix the rocker pivot point and most people just use them as is.
This means where the rocker contacts the valve tip (without changing pedestal height) only depends on the rockers arm length and the valve stem height.

The minimum scrub theory is to have the rocker pivot point 90 degrees to the valve tip at 1/2 valve lift. This does not consider rocker arm length where the rocker contacts the valve stem tip, so different rockers might contact the valve stem tip at different points.

Here is a good article: https://www.eliminatorproducts.com/...pbHZtWUhNQjdObEJtdHdqdjZLQWlMaDVzRGRrdz0=.pdf


The Miller article is very good. The one item that can be challenged, is that his belief the the 90 degree rule is gospel. Nothing is gospel in the engine building world. The 90 degree rule does function well. And you will not get into trouble using it. What does using 85 degree, or 95 degree get you? Different cam motion at different ares in the lift curve. Is this a bad thing? None of us here are running the perfect camshaft. How many different lobes are available with the exact same durationand lift, it's mind boggling. This takes way more dyno time, testing, and money than any of us have. Could it make more/less power, for sure. In my opinion the valve guide wear theroy is BS. The lifter has way MORE side load than a valve. Are lifter bores worn out quickly with agressive lobes? I will give my example. My drag car with 330#/810# spring load, .484"/.471" lobe lift (roughly 830/.800" at the valve). Rocker geometry is .060" higher than ideal. (yes it has been measured). 13 years, 1200 runs, two touch up valve jobs. Never had a guide changed for wear. Still in spec well below .002".
Doug
Doug

Ya we went over this before and i get it. Just was a brain fart. You know when you have issues, you try to think of everything.
in any event, ill recheck the valve adjustment. I agree that pump up of lifters took a long time, so maybe I have a bad lifter or something. Worst case I can always run stock stamped. It's not that high a lift cam. XE274H.
Im still swaying toward tight piston install and still needs more run time. Ran it yesterday and not as hot compared to startup. I'll do some checks today and get back to report.
Thanks Doug.

 

[451Mopar]

The Miller article is very good. The one item that can be challenged, is that his belief the the 90 degree rule is gospel. Nothing is gospel in the engine building world. The 90 degree rule does function well. And you will not get into trouble using it. What does using 85 degree, or 95 degree get you? Different cam motion at different ares in the lift curve. Is this a bad thing? None of us here are running the perfect camshaft. How many different lobes are available with the exact same durationand lift, it's mind boggling. This takes way more dyno time, testing, and money than any of us have. Could it make more/less power, for sure. In my opinion the valve guide wear theroy is BS. The lifter has way MORE side load than a valve. Are lifter bores worn out quickly with agressive lobes? I will give my example. My drag car with 330#/810# spring load, .484"/.471" lobe lift (roughly 830/.800" at the valve). Rocker geometry is .060" higher than ideal. (yes it has been measured). 13 years, 1200 runs, two touch up valve jobs. Never had a guide changed for wear. Still in spec well below .002".
Doug
Doug

I liked this statement: "Rocker geometry is NOT where the roller (or contact point) is at on the top of the valve. Forget that. Rocker geometry, especially is NOT the idea that you want to place the roller or wear pattern (shoe tip rocker) in the “middle of the valve.” "

The article dose go into the pushrod geometry of the rocker arm which is usually overlooked because there is not much we can do about it other than get a different rocker arm.
I am not sold on the 1/2 lift to pivot point formula, but I see his argument that it is the least in/out scrub movement and translates cam info more accurate.
I like rockers with the pivot a bit higher, but the adjuster a bit more inclined. This does create as he mentioned a second order effect accelerating the valve off the seat quicker and adding more dwell around max valve lift, although at slightly lower peak valve lift. I think it helps when using heavy valve springs as it should reduce valve spring induced deflection?
Wish I had a way to make my own rocker arms and test these ideas.