Longer push rods ?

[Greg Reimer 7376]

Well, I pulled that 327 apart and discovered some problems, so I bought a Dart block, took it and the internal parts to Greg Luneack. I'll get back a properly bored and honed short block assy ready to assemble. We'll see if the valve lift measurements are the same, or if any difference in the block dimensions exist, and have affected the valve train geometry and the valve lift figures any. I think I'll order some more push rods and see if I can fine tune the lift dimensions that way,as well. We had such an interesting thread going that it motivated me to put more time and research into this project to see what improvement and what results might occur. I'll be back with the results.

[Billy Nees]

Originally Posted by Reed Granrt

I have seen people miss the geometry so bad that it took 20 ft.lbs more force to rotate the engine thru a revolution.

And I've had professional engine builders telling me for years that I'm nuts. I've always been less concerned about my total lift then I was about how much "torque" I could lose through crankshaft rotation with a good old bar type torque wrench.
Once you get your lift in the ballpark, try changing pushrod lengths and rotating the complete assy. minus plugs. You'll be suprised. And the more valvespring pressure you use, the bigger the difference will be.

[Reed Granrt]

Originally Posted by Billy Nees

And I've had professional engine builders telling me for years that I'm nuts. I've always been less concerned about my total lift then I was about how much "torque" I could lose through crankshaft rotation with a good old bar type torque wrench.
Once you get your lift in the ballpark, try changing pushrod lengths and rotating the complete assy. minus plugs. You'll be suprised. And the more valvespring pressure you use, the bigger the difference will be.

Billy
There is only one push rod length that will maximize the area under the curve that was ground into the camshaft. You can shift characteristics of the camshaft by changing the length of the pushrod. You can shift the area under the curve, but it will REDUCE the total area under the curve and it will change the torque to rotate it. If you shift the characteristic by changing the length and the engine likes it, then you have an opportunity to regrind and make additional gains. What you would really want is to maximize the amount of power and reduce the engine rotation friction to a minimum. If you do that, you WILL get a double whammy on power gain.
reed

[danny waters sr]

I started this topic and have made the changes and at first i saw a gain..

Since then ,i had alifter come apart and found every part of it in lifter tray (lifter come un-locked)...

I have since ordered a new set of lifters (not shubeck type).

I kept the long push rod when i changed the lifters.

Now i am knocking off the rocker arm in high gear in the 1/4 only.(not rollers )

Is it possible the old lifters were worn out and that is in fact why the longer push rod picked up the performance ?

Is it possible now with new lifters that i have this problem because of the longer push rods?

I have never had this problem til i installed the new lifters....Any suggestions or answers please ?

Thanks in advance......

[Billy Nees]

Check the plunger height in your new lifters compared to the old ones! You just may have to start all over again.

[Alan Roehrich]

Originally Posted by danny waters sr

I started this topic and have made the changes and at first i saw a gain..

Since then ,i had alifter come apart and found every part of it in lifter tray (lifter come un-locked)...

I have since ordered a new set of lifters (not shubeck type).

I kept the long push rod when i changed the lifters.

Now i am knocking off the rocker arm in high gear in the 1/4 only.(not rollers )

Is it possible the old lifters were worn out and that is in fact why the longer push rod picked up the performance ?

Is it possible now with new lifters that i have this problem because of the longer push rods?

I have never had this problem til i installed the new lifters....Any suggestions or answers please ?

Thanks in advance......

Danny, can you define "knocking the rocker off" please?

[new az stocker]

I put longer push rods in to try to get more lift and found that i too knocked off rockers. The reason was that the jam nut did not screw on the stud far enough. To get full lift i ended up ordering a cam with a bigger lobe and it seemed to fix the lift problem.

[danny waters sr]

Originally Posted by Alan Roehrich

Danny, can you define "knocking the rocker off" please?

Felt the car start missing around 6-6500 .
Got back to trailer and removed valve cover and rocker had come off.(polly -lock still on stud) not broken either. checked push rod and it was ok .i took the polly lock loose with my fingers and hex lock had not moved so i screwed it back on til it jammed (or locked) then i checked valve ajustment and was on the money. No problem til i installed new lifters.i will check the inside height later this week.i thing the longer push rods with new lifters could be the cause.

[Alan Roehrich]

So what you're saying is that the rocker jumped off of the pushrod, without the poly lock backing off?

Are you running guide plates, or self aligning rockers? With self aligning rockers, you could have enough flex to allow the rocker to pivot sideways and jump off of the pushrod, you'd be lucky not to un-key a valve.

It sounds as though you have reached the point where you have problems with flex and stability.

Are the pushrods good chrome moly pushrods, with the thick tube wall? For example, 5/16" x 0.100" wall, or 3/8" x 0.125" wall?

[danny waters sr]

Originally Posted by Alan Roehrich

So what you're saying is that the rocker jumped off of the pushrod, without the poly lock backing off?

Are you running guide plates, or self aligning rockers? With self aligning rockers, you could have enough flex to allow the rocker to pivot sideways and jump off of the pushrod, you'd be lucky not to un-key a valve.

It sounds as though you have reached the point where you have problems with flex and stability.

Are the pushrods good chrome moly pushrods, with the thick tube wall? For example, 5/16" x 0.100" wall, or 3/8" x 0.125" wall?

Yes it jumped off

Yes i am running guide plates

Yes it has3/8 comp push rods and comp replacement rockers

Never did this happen with the old lifters and the longer pushrods