Big roller cams

[Ziegelsteinfaust]

I talked to a guy who had a 496 bb a couple of days ago which sounded exactly like Satan's chariot, and I got to have one.

The cams I am looking at seem to have 550-575 lift with 1.7 rockers. A couple are bigger at close to 600.

So at which point do cams kill the valve springs that regular replacement is nessacary.

[PGSigns]

The profile of the cam is what kills lifters and springs. For the lift you are looking into a hydroulic roller with a good set of springs to match would work well and live for a good while. To me a big roller is over .760 lift for a 496.
Jimmy

[Marv D]

Originally Posted by PGSigns

The profile of the cam is what kills lifters and springs. For the lift you are looking into a hydroulic roller with a good set of springs to match would work well and live for a good while. To me a big roller is over .760 lift for a 496.
Jimmy

LOL yeah Jimmy I chuckled a bit too. I'm sorry don't mean any disrespect but my small block has .811 intake and .795 exhaust lift.
I mean even my little 327 with a hydraulic roller (and Holley MPFI) has .56 / .585 lift. with a little set of Edelbrock E-tec heads.


Zieggi,

Not a big block guy so take this with a grain of salt and just an opinion based on experiences with SBC's.
Todays cams are going towards BIG lift numbers and moderate duration. Most heads don't even come to life until after .4 lift so don't stifle the potential with not allowing the heads to breath.

What I found running a solid roller on the street was springs will loose about 10-20psi seat pressure with just a few heat cycles. Then heat and RPM seems to take their toll on seat and open pressure. I had roughly 5000 miles on that motor with a fairly aggressive solid roller (Lunati 50124) with 272/284 @ 0.050, w/ .625/.625 lift. The 'Nextek" springs had lost ~25 pounds on the seat and (as I recall) about 40psi open

The hydraulic roller cam that was in the earlier motor had .565/.578 lift and was a mild street roller (235/245 @ 0.050 as I recall) The motor had I don't know how many miles but was in there for about 5 years of weekend warrior street cruising. (maybe 20,000 I really have no idea)
Those 1.55 springs have been on the shelf for a good 5-6 years and I'm getting ready to put them back on the heads as I move the truck off the track and back onto the street with a hydraulic roller that has 247/253 @ 0.050,,, .568/.583 lift.

'Normal' these days for a retro hydraulic roller is to shim your springs up to be close to 400psi on the nose,,, and around 0.050" off coil bind. If your anywhere under 150 psi on the seat you should be good.

Your biggest problem is keeping the heavy retro hydraulic roller on the lobe at high RPM's. Lifter toss is a very ugly thing to valve train components.


Hope some of that helps

[hotrod 80]

I run a smaller 236/244 hydraulic roller for 5 years now also . I am a small block guy . I only have what i need to make power .

That said valve train control is very imortant . I just wrecked a SBC chevy with a .744/.748 lift cause as the ramp speed was to fast for the spring . It sounded wicked for 36 passes though .

[Ziegelsteinfaust]

I only have built a couple of roller cam engines, but the lifts were roughly the same as flat tappets.

Just that I remember extreme lift killing springs I do not want to kill a engine due to failure. I might build up a Ford version for my 66 F100 project with a bigger inch FE. As I am bought in on FE parts for my current engine.

[Marv D]

Yeah I guess I should have also mentioned,, with that .811 lift I have just over 800psi of spring pressure on the nose of the lobe. This 'go faster' hobby is just an endurance contest to see which part will break next. So your mileage may vary. LOL

Of all of the overhead valve motors Ford ever did I have the say the FE is the coolest!

[hotrod 80]

I was at the machine shop the other day and he had a Ford 390 FE and a LS block next to each other on the bench . They look remarkably similar .

[Super73]

My old cam is a 254/260 .625/.630
The can I just slid in is 259/274 .664/.623 this uses fairly aggressive aggressive lobes
I have another in route to try but not sure what it is yet. Brian Tooley is sending it to me.

I will see what makes better power on the chassis dyno in a few weeks.

My intake valve is 89 grams and have 165lb on the seat and 475lb open. This is a hydraulic roller.

[hotrod 80]

Mine are like 150 seat and 440 open

[GMR-PERFORMANCE]

Marv

Will be re grinding the howards I have in the engine this winter. will go up to 248/258 and keep the 555 lift 110/106 set up. the mega lift is as you know very popular. in in the right combo is great. But even with larger roller size on the lifter there is only so far and you step out over the line..
I run 145 on the seat 392 open but I do not have a **** ton of lift.. Guys that are running mega left will be much better off with a bee hive spring. You can keep the seat pressure where you want it and not have the massive PSI stack vs lift you get with a double spring.

Just set springs up from double to bee hive

175 on the seat 430 open at 660 lift old set up 182 on the seat 550/560 open GOTTA love a pac spring

[BossHogg69]

The hydraulic roller on my 468 BB is something like 245*/254* on a 107 LSA w/.646"/.603" with Crower springs that are 212# on the seat and around 515# open. It's what I would consider mild but still is a little snotty at idle (1000rpm), pulling about 9" of vacuum.

[moggey01]

I ran 660 630 lift 260 @ 50 on the street in a small block. Never had problems with valve train at all. This was not a daily driver. The bigger engine will swallow a cam.. hope this helps

[slotard]

If you want a nasty sound you should go solid roller. If they require adjustment with any real frequency something is wrong.

How do you figure out spring pressure in psi? Pounds is easy...