Solid roller cam valve spring and lifter question

Friend installed a crane solid roller in his engine, Crane R-272/420-2-10 #688821
272/282@.050”, 304/314, .630/.630”, 110/105, .020”/.020” lash. He used Crower 66384 lifters which have a .750” wheel. Crane calls for their 66542 lifter which has an .815” wheel. Will this cause a loss of performance?

He also didn’t used the recommended Crane springs, he used Comp springs. They are 42 lbs light on open pressure.
99885 springs
215@1.95”
685@1.2”
618 lbs/in
.610” lift 592 lbs

943-16 springs used
212@1.95”
626@1.2”
551 lbs/in
.610” lift 548 lbs

His engine goes flat and loses power over 6000 rpm, stops pulling on the drag strip. Trick Flow 240 heads, trick flow single plane, quick fuel q950 carb. 493 RB striker, 11.9:1, 2” headers.

Would the light open pressure springs cause an issue? I told him to get the Crane springs, as 40lbs light on open pressure is a lot I thought.

could be fuel issues as in running out--not enough volume etc

An AFR gauge would tell about any fuel mixture-issues.
Valve float could be an issue.

Try a larger carb to see if the motor is running out of air on the top end. What is the RPM at the stripe? Check for coil bind. Where is the cam installed for intake max lift? What is the 'true' max lift at valve retainer?

Used 943's before, it's a proven spring in my opinion. I usually set them up at 1.88-1.90 that covers rollers in the .650-.690 range. Check for "x" pattern on the valve tips. sure sign of valve bounce /float.

Just so we get a good look at this.
1.95 installed height.
minus net lift say .610
equals 1.34
minus coil bind 1.16
equals .180 from bind
That's too much in my opinion should be .06 to .09 to make things happy.

This relates to valve spring set-up you could be having other issues. would be interesting to hear your results from a valve spring shim-up.

the smaller wheel will cause a small loss of duration.
what is the installed height?
whats the lift at the valve?
knowing this info will allow you to possible shim the valve spring and get some additional pressure.

also what do the plugs look like?

Joe

The fuel system was never an issue before, Magnafuel ProStar 500 pump, with -10 to the regulator, dual -6 feed. This is the car when a previous owner had it. Only the engine and trans is different.
https://www.dragzine.com/news/hump-day-holeshot-70-sport-satellite-pulls-impressive-wheelies/

He also ran a Q1050 carb on it, no change. RPM at the stripe is 6500, but he says it is dead after 6000. Cam is installed straight up. I am not sure about the max lift at the retainer, Harland Sharp 1.5 rockers.

Install height is at 1.95" spec. Do you think shimming them to higher pressure, to bring the open pressure to what Crane suggests, will hurt anything given that the seat pressure will also go up? If he set them at 1.87" seat they would be 256 lbs, and at 1.26" (.610" lift) 592 lbs. (at what the Crane springs would be).

The cam card also gives conflicting spring pressures. Says a 99885 spring, 215 lbs @ 1.95", and 565 @ 1.36".

I can't say what the plugs look like, he never mentioned.

usually seat is what it is. It's more about running the spring up to .06-.09 of bind. However in my opinion less than 230 seat pressure on a
race roller is asking for trouble in my opinion.

Put a Dommy on that thing and wake it's azz up already and fwiw, my Solid roller Isky .680-.660 276-281 @ .050 had 210-580 for the first few years pulling past 7000 and ran 9's and low 6's............I went to 245-620 and saw no difference...........

your not going to be able to shim it to make up the difference, you will pick up 5.1 lbs per .010.

again knowing what your total lift is at the valve will let you know how much you can shim them.


Joe

The comp springs are 551 rate, so if they can me shimmed .080”, that will add 44 lbs to the rate. Would bring it to 592 at .610”lift.

I’d adjust the installed height to 1.880-1.900 as the first step.

i run this cam in my small block and it likes a good spring at 6900 rpm i made 710 hp but it was valve balancing my exhaust should of peaked 7400 rpm i am shimming mine to 070 to coil bind with a pac 1225

My SR headed 451RB made peak power at 7200 with a moderate .435 roller lobe, 1.5 rockers, and Isky 9375/85 springs that were about 250/550.

Why do people due this to themselves
Buy and use parts that are not recommended for their application
Why did he make the cam seem smaller to the motor using those small wheel rollers
You reap what you sew
Does the motor nose over at 6000 RPM in all gears or just at the finish line?
All the BB solid roller cam motors I've built and used all revved well past 6000 RPM, even my old six pack 4.300 stroke 400 pump gas motor in the car at the track
From 220 lbs. on the seats to 325 lbs. on the seats and from 620 Lbs. over the nose to 870 Lbs. over the nose
Good luck, let us know what you find
BTW, I do set all the springs up from .060 to .075 from coil bind on all the springs, no matter what the pressures

He did some trading for the cam, and had the crower lifters already. No one stocks Crane parts in Western Canada, and a couple shops told him to run the comp springs.

It revs past 6000 no problem, but goes flat past 6000 in all the gears.

I guess we might need a better definition of “goes flat”.

I assumed you were saying the motor didn’t want to rev past 6k.

If the motor will pull 7k in like 2nd year, it’s unlikely the springs are your issue(or the lifters or lifter wheels).

That being said, it’s a cheap and easy test to decrease the spring installed height and see if the point where the motor goes flat changes at all.

I don’t know if the pushrods have been mentioned, but I’d want 3/8” .080 wall heat treated at a minimum.

you don't have anywhere close to enough valve spring. and roller diameter will totally change the way you motor sees the cam not just duration I run well over 300 on the seat and will pull past 9000

.433 lobe with Hughes 1.6 rockers, Victor heads, PAC 1243 spring(same as comp 943), 1.900 installed height, peak power at 6800-7k.

Chip is running the same spring at 1.950 in his 572 hemi with .420 lobes, and when he’s spraying it, it turns about 7500 through the traps.

It revs higher than 6000 no problem, but noticeably less acceleration rate above 6000.

Does it have mufflers on it?

If so, have you tried uncorking it?

I agree think it is running out of air or fuel--pumps need 12 volts to do the job--I have seen many run without relays and correct voltage --they just will not do the job

would also be interested in what timing is doing--have seen Mopar ECU's that really retard and move timing and limit RPM

whopping spring pressure just leads to dead lifter wheels and bearings all over the place
I have a small block with 230/550 pulls 7800 RPM with ease and parts look great so.....

More pressure helps our heavy Mopar valve trains COPE with stuff better but it is easy to put together a combo that simply looses control of the entire valve train I see it happen on the dyno all the time--get to a certain RPM and thing just dies right in front of you Does it have Titanium retainers?
IMO any race engine should have them they work miracles and we consider them a 100% Must for any race engine--they are best $ spent on any engine in Cost vs. results

+ 3/8" x .120"-wall pushrods, FWIW...

I think he's running out of fuel. My solid flat tappet cam It'll go to 7400 with no problem.

It has 2"x4" headers, dual 4" exhaust with crossover, flowmaster 40 series, 4" all the way to the bumper. I told him to pull the exhaust and put 18" extensions on and try it.

It has relays for all systems, relay for the fuel pump is in the trunk with the fuel tank, pump, and dual Optima D35 yellow top 620CCA batteries wired in paralell properly with 1/0 cable all around. MSD 140 amp alternator with 3:1 pulley ratio, 4 gauge charge wire. MSD Digital 7 plus ignition box and HVC 2 coil.

Titanium retainers and Smith Bros 5/16" x.116" wall pushrods.

He did say that on the weekend he noticed that when the dual cooling fans were on, the fuel pressure would jump around, and drop. The regulator is mounted on the front of the engine, and the fan on that side blows hot air right on it. When he cooled the car down between rounds more, so the fans didn't come on during a run, or in the staging lanes, the pressure stayed solid. So he is moving the regulator to the fender, and wrapping all the fuel lines under the hood with foam pipe insulation. But, the performance didn't change even when the pressure was moving around.

I’m going with this:



Had a customer with a low deck 511 with a .640 roller and 943 springs at 1.900.
Ended up dropping an exhaust valve.
Sent me the heads to repair.

There were witness marks 1/4” away from where the exhaust pushrods passed through the heads!!!
All the areas near where the pushrods passed through the heads showed that there was a ton of pushrod flexing going on. Enough so that there was not only a witness “mark”, but it had actually pounded a raised lip at the deck of the head.
Again..... that was 1/4” away from the pushrod.
The intake pushrod tunnels were closer to the pushrods, which limited the amount they could deflect, but the area around the exhaust pushrods was much more spacious, allowing for much more flex. The severe flexing is just another way to lose valvetrain control...... and the result was a dropped valve.

They were heavy wall heat treated 5/16” in that motor.