[RBAILEY]

So this is my first engine with a roller cam and springs that have over 600 open pressure and a fairly aggressive ramped comp cams 760 lift solid roller.

Wiht just the shortblock it takes 25 to 30 FP to initiate rotation and a steady 20 to maintain.

With both heads on and just one cylinder valve gear in place and adjusted the foot pounds shoot up to 55 when it hits the exhaust ramp (a little less on the intake ramp?).

With engine fully assembled, all valves adjusted etc the FP is now 85-90 to initiate and 75-80 to maintain.

What's normal for this?

[slowbird]

Lifters have bushed or needle bearing roller?

[RBAILEY]

Originally Posted by slowbird

Lifters have bushed or needle bearing roller?

needle and plugs are out

[25stevem]

Now you know why unreleaved cams are used in pro stock and other classes.
These steel core cams twist up like a candy cane from front to rear due to that type of spring pressure!

[slowbird]

Originally Posted by 25stevem

Now you know why unreleaved cams are used in pro stock and other classes.
These steel core cams twist up like a candy cane from front to rear due to that type of spring pressure!

600lbs open is nothing

[Scott Roberts]

Originally Posted by slowbird

600lbs open is nothing

This..I ran 1150 at the nose...race only but no issues... all weekend and never touched the valves..

[mgarblik]

That's really up there! 1/2" push rod I assume?

[Scott Roberts]

Originally Posted by mgarblik

That's really up there! 1/2" push rod I assume?

If you're asking me, yes..we ran big everything...it was blown alcohol..

[krisr]

Originally Posted by 25stevem

Now you know why unreleaved cams are used in pro stock and other classes.
These steel core cams twist up like a candy cane from front to rear due to that type of spring pressure!

I'm running 580lbs open pressure in my 400 and I'd drive it 95% on the street. It's a but of pressure, but it's not HUGE. Maintenance wise, my valves haven't moved in years.

OP - when you say "FP is now 85-90 to initiate and 75-80 to maintain", that's spark plugs out yeah?

[cgeise]

Valve train geometry is critical hear -- if wrong can cause a huge diff in rotational forces --

[RBAILEY]

Originally Posted by cgeise

Valve train geometry is critical hear -- if wrong can cause a huge diff in rotational forces --

Do you have a FP number from any of your builds?? What is a normal FP range?

TD shaft system setup has been laboriously poured over.

Rocker arm is 90 to the stem at half lift. Centering is also good. Stand height adjusted/shimmed for 750 lift wit TD gauge. Had to modify the stand to get the arm tips where they needed to be. had to move stand away from springs to get tips towards center of valve and also alleviated rocker arm/1.640 dia spring interference. To me it seems the TD rockers they use on KRE HP heads are a bit on the long side considering that once I got the rocker roller moved towards valve tip center by moving stands away from the springs, I then ran into pushrod hole interference on the side opposite the rocker stud bosses (intake manifold side of the pushrod hole) I'm saying this because even after moving the stand only that distance required to get the roller on the center of the valve tip, it resulted in the pushrods hitting the head on the intake manifold side of the pushrod holes.

[mgarblik]

Very hard to say if that rotational torque is an issue. Valvetrain adds allot of drag when turning slow without oil pressure to float the cam. The Boss Bird engine with only 6:1 compression took 125-140 to begin turning it. About 100-110 to keep it rolling. This was a complete engine assembly with blower, magneto, and everything in place. Short block about 20 Lbs. to keep rotating with the high tension oil rings.

[Dave Polichena]

Originally Posted by RBAILEY

Do you have a FP number from any of your builds?? What is a normal FP range?

TD shaft system setup has been laboriously poured over.

Rocker arm is 90 to the stem at half lift. Centering is also good. Stand height adjusted/shimmed for 750 lift wit TD gauge. Had to modify the stand to get the arm tips where they needed to be. had to move stand away from springs to get tips towards center of valve and also alleviated rocker arm/1.640 dia spring interference. To me it seems the TD rockers they use on KRE HP heads are a bit on the long side considering that once I got the rocker roller moved towards valve tip center by moving stands away from the springs, I then ran into pushrod hole interference on the side opposite the rocker stud bosses (intake manifold side of the pushrod hole) I'm saying this because even after moving the stand only that distance required to get the roller on the center of the valve tip, it resulted in the pushrods hitting the head on the intake manifold side of the pushrod holes.

Curious as what you did to move the stands, they are bi-directional. One side for Edelbrock, the other for traditional head. Standard heads have a shorter rocker arm at the pivot. I think 1.42 vs 1.52? You have to do a lot of grinding for the slots and recess for the bolts to clear.
Been there with the pushrod hole, get it where you need it and put a brass sleeve in there

[RBAILEY]

Originally Posted by Dave Polichena

Curious as what you did to move the stands, they are bi-directional. One side for Edelbrock, the other for traditional head. Standard heads have a shorter rocker arm at the pivot. I think 1.42 vs 1.52? You have to do a lot of grinding for the slots and recess for the bolts to clear.
Been there with the pushrod hole, get it where you need it and put a brass sleeve in there

I'll try to find a pic of the stands they came out real nice; did it on a mill and made eccentric washers for top side to positively locate, also made a 1 piece .100 shim for under the stand instead of the ground washers TD supplies.

I also ordered longer stand bolts from TD and then lathed them down to length for maximum thread engagement in the heads.

My KRE HP heads are odd in that they require spacers for the intake manifold and this led me to wonder if there are not other oddities in the rocker stud pad locations etc.

[Steve C.]

Interesting tid bit....

Within Pete McCarthy's Super Stock Pontiac book he states the following:

"Trial fit the crank (use old rope seal if in decent shape for drag reduction). If it can't be spun easily by hand, do everything over until it can. (A complete short block should not take more than 30 lbs. to spin)."

Also NO solid roller cams were discussed within the book. Only hydraulic flat tappet and solid flat tappet cams. He did state at that time NHRA specs allow slightly more lift than factory figures.
And I'll suggest he discusses bearing clearances, ring gaps, etc. which may factor in.


.

[Skip Fix]

Don;t have a specific number for you but swapped from SFT to solid roller springs while the motor was in the car and turning it over by hand every spring I added it got tougher to turn and those were only 240 seat.