Daytona30mike

Does anyone know who manufactures the lifters in GM's 572 cu in
620 horsepower engine. It has a seat pressure of 197 pounds
and it is a hydraulic roller. Seems like alot of seat pressure and I would like to know who makes it.

Thanks!!!!!!!!!!!!!!!!!!!

cstraub

SPDC notes the cam specs but does not note if it is a soild or hyd roller. Every other crate engine they note cam type.

Your not going to run that kind of seat pressure with a hyd roller lifter for long. In race applications it is possible with restrictor pushrods and a tricked oiling system but for endurance applications I don't know of anyone who has achieved this goal running that kind of seat pressure on hyd rollers.

Chris

articfriends

iTrader: (1)

I was running 185 seat/440 open per tyler crocketts advice on 610 hyd roller,just tore motor down to freshen w/130 hours,lifters were fine other than some scuffing on the bodys from lifter bore holes being too tight. Motor buzzed to 6000 no problem,My new afr's springs are at 195 seat/460 open but i expect that to drop 5-10% after breakin,i'm running the high spring pressure so i can spin to 6000 and run 12-14psi boost if i want. Cstraub,do you think it's too much? I can get heads cut slightly to lower pressure(i already bought the springs and installed them so i don't really want to buy another set unless i'm guaranteeing catastrophic failure of lifters,Smitty

rmbuilder

Daytona30mike
That cam is a Crane Hyd Roller
316*/326*
254*/264*
.632/.632
112*
The spring run with that cam by Crane is the 99896
135 seat/415 nose
Not sure where the 197# number originated, but I would double check the source.
Smitty
We have run the Morels @ 170# + seat without any problem. Our latest set of AFRs are set up for 180# seat, but I would be careful with your choice of lifter.
Bob

cstraub

Smitty,
If the spring is made of super clean material the pressure will not drop. Blower engines are diffrent you need to jack up the seat pressure to insure you close the valve and keep it from bouncing on the seat. In your case yes I think 195# is excessive. I would shoot for around 175#.

My personal preference would be to run solid roller lifters on the hyd cam lobe with a light lash setting.

Chris

Daytona30mike

Thanks for the answers... Here is where I got the info...

http://www.sallee-chevrolet.com/Chev...ckV8s/572.html

They show it as:

2498792 Long-Block Components (Short-Block Components Plus The Following
Camshaft 88961557 - Hydraulic Roller (Valve lift: .632” I,
.632” E; Duration @ .050” 254° I, 264° E)
Lifters 17120060 - Hydraulic Roller Tappet
Cylinder Heads 12499255 - Aluminum rectangular port, 118cc combustion chamber
Head Gaskets 88961561
Intake Valves 12366987 - 2.25” Stainless steel
Exhaust Valves 88963128 - 1.88” Stainless steel
Valve Springs 88963934 - Dual valve springs, 1.564” coil dia.,
1.800” installed height, 197 Lbs.
seat pressure
Valve Spring Retainers 12366990 - Hardened chrome moly steel
Valve Retainer Key 12366992
Rocker Arms 12361323 - Aluminum roller rockers, 1.7:1 ratio
Push Rods Intake 88961559 - High performance one piece
Push Rods Exhaust 88961558 - High performance one piece
Valve Covers 12499200 - Special 572, Orange Powder Coat
Damper 88962814 - High RPM torsional damper SFI approved, 8”.
Oil Pan 88963707
Windage Tray New! Screened and louvered
Oil Pan Gasket 10106407
Oil Pump 88963707
Spark Plug 05613878 - R45XLS

So who do we believe?????????

Daytona30mike

Here is a Canadian link with the same specs...

http://www.saturnoflondon.saturncana...html#ZZ572_620

ZZ572/620 Technical Information
Horsepower 620 @ 5500 RPM
Torque 650 @ 4500 RPM
Max. Recommended RPM 6000 RPM
Compression Ratio 9.6:1
Block New! Sportsman Tall Deck Bowtie Gen VI
10.200" deck height
Bore 4.560"
Stroke 4.375"
Crankshaft Forged 4340 steel
Connecting Rods Forged 4340 steel, H-beam style, Shot peened
Pistons Forged aluminum, Full floating wrist pin
Piston Rings Plasma-moly rings
Camshaft Hydraulic roller
Valve Lift: .632" I, .632" E
Duration @ .050" 254° I, 264° E
Lifters Hydraulic roller tappet
Cylinder Heads Aluminum rectangular port
118cc combustion chamber
Intake Valves 2.25" Stainless steel
Exhaust Valves 1.88" Stainless steel
Valve Springs Dual valve springs
1.540" coil diameter
1.800" installed height
197 lb. seat pressure
Spring Retainers Hardened chromemoly steel
Rocker Arms Aluminum roller rockers 1.7:1 ratio
Push Rods High performance one piece
Intake Manifold New! Aluminum tall deck single plane 4150 series carburetor
Carburetor 850 cfm, mechanical secondary
Rear Main Seal New! One piece design
Windage Tray New! Screened and louvred
Damper High RPM torsional damper
Distrubutor H.E.I
Fuel 92 Octane
Spark Plugs R42XLS
Ignition Timing 36° total advance

I just find it hard to believe they are doing this kind of seat pressures on a hydraulic roller.

rmbuilder

Daytona30mike,
Not a question of who to believe, just correct information. The spring rate listed is in line with all other aftermarket springs at the 1.800” point. Here are spring forces rated at 1.800”
Comp 929 (Stack 1.180”)
1.800 185#
Crane 99896 (Stack 1.085”)
1.800 182#
Isky 8205 Stack (1.170”)
1.800 185#
Isky 9905 Stack (1.160”)
1.800 212#
Manley 22429 Stack (1.180”)
1.800 187#
Manley 221432 Stack (1.200”)
1.800 206#
The question, is GM actually using a 1.800” installed height with a .632” max lift cam to net a 1.168” open? As you can see that is well beyond the .060” safety factor for coil bind on all listed springs. Not many BBC heads being set up with 1.800” IH
Bob

Strip Poker 388

iTrader: (6)

My 929's comps setup at 145 at 1.900

Strip Poker 388

iTrader: (6)

Bob that doesent have very much spring in it ??and it has good bit of duration,I guess it sfor the cubes?

Rob