[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?

[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

[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?

[RBAILEY]

Originally Posted by slowbird

Lifters have bushed or needle bearing roller?

needle and plugs are out

[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.

[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.

[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..

[Scott Stoneburg]

I don't have an actual number but I can say that on my 535 it took less than 85 lb/ft. I have 280lbs on the seat and right at 700lbs open pressure on the valve springs. When torquing the flex plate bolts it turned over before reaching 85 lb/ft on the torque wrench.

[RBAILEY]

Thank you all for the input.

Measuring this alone is not as precise as a process as we might like to see.

I know that there are certain points (degrees of rotation) where it is more difficult to initiate rotation from.

If you work alone as I always do it is difficult to watch the torque wrench while at same time trying to maintain an even pull while rotating the crankshaft by hand (but telltale needle on torqOmeter helps).

I'm using a 100 pound Snap-On TorqOmeter and the handle is something shorter than what I would normally turn an engine over with so pulling evenly through the rotation is more difficult.

All worries aside, I now note that when I turn the engine over with a longer ratchet the engine feels "closer" to what feels normal to me.

Engine is in the car now and no turning back. This stuff can be nerve racking!

Originally Posted by Scott Stoneburg

I don't have an actual number but I can say that on my 535 it took less than 85 lb/ft. I have 280lbs on the seat and right at 700lbs open pressure on the valve springs. When torquing the flex plate bolts it turned over before reaching 85 lb/ft on the torque wrench.

Would naturally take less pulling from the flexplate bolts though; true?

Actually, I might be running the same springs you are and I just checked and they are more in the 700 range BUT i'm not taking them down to 1.250; more like 1.350. I'm running Manley Nextec Green Stripe 1.640 PN 221425P Installed Height and Pressure: 2.100'' @ 280 lbs./in.
Open Height and Pressure: 1.250'' @ 795 lbs./in.

[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.


.

[RBAILEY]

Originally Posted by 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.


.

Thanks, now I remember where I saw something on this. I bought that book in 1985 when I convinced the little lady on our honeymoon to drive a huge motorhome accross town through Compton etc in LA to stop by the Pontiac Mecca of HO Racing. Didn't buy much but walked out of there with that McCarthy book.