1.6 roller rockers
08-24-2016, 11:43 PM
#5
I was different. I went with the lt4 gm 1.6 roller rockers good up to .575 lift, some have used higher lift cams and had no issues. Good quality, made by crane i believe. Pac 1218 springs and arp 3/8 screw in studs. I figure the arp studs will def be stronger than stock. Heads will be done next week. Time to bolt them on and wake the dead with the old sludge blendor.
08-25-2016, 04:35 AM
#6
The LT4 crane rockers are self aligning, anything over 6300 rpm it's good to get non self aligning rockets and guide plates to help keep the rocker from slipping off the valve and pushrod. Crane gold, comp pro mag or ultra pro mag, crower, scorpion, all are good. Stay away from Chinese pro form or other super budget rockers, and remember the power gain due to reduced friction is in the fulcrum roller, not the roller tip, hence why LS motors only have a roller fulcrum.
08-25-2016, 05:44 AM
#7
TECH Resident
The reason I said Scorpion is the quality for the price and he is budget conscious. Pius they are made in the USA! I have a set of Harlan Sharp for another motor and they look as good as those to me. Mine are 1.6 and will go on a set of iron heads from a Impala SS that I machined for screw-in studs, opened up the pushrod holes and deburred, cut down the valve guides and opened up the spring pockets on. Comp guide plates are used. Crane springs per ******, LT4 hot cam for now but we can go bigger later if we want. 6p plan, prior planning prevents **** poor performance.....
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08-25-2016, 07:52 AM
#8
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08-25-2016, 08:20 AM
#9
If you find any CAT rockers for sale, avoid those.
If you decide to go with 1.6I/1.5E as many prefer with that cam, let me know. I have a set of mixed (1.6 GMPP / 1.5 Comp) USED, good condition.
08-25-2016, 10:16 AM
#10
http://www.skipwhiteperformance.com/...roduct=V&Sub=A
Just need to either call them for correct Self Aligning # or read into the details. Pay attention to the size of the stud.
Just need to either call them for correct Self Aligning # or read into the details. Pay attention to the size of the stud.
08-28-2016, 12:05 PM
#15
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positives vs negatives in going withthis set up?
08-29-2016, 06:18 AM
#16
For a naturally aspirated setup, I don't think there is a negative.
Positives: Less stress on the exhaust side of your valvetrain, fewer incidents of exhaust valvespring breakage, higher rpm ceiling before valve float.
I've tried both 1.5 and 1.6 rockers on the exhaust side of a similar cam, GM ZZ3, and saw no performance difference over countless dragstrip passes. I DID break two Crane 10309 springs while running the 1.6's over a period of 30k miles. Not one breakage using 1.5's over another 150k miles.
It's very common to see exhausts lifts substantially higher than intake lift on "shelf" cams where an exhaust duration is selected and they just accept whatever lift that "catalog" lobe happens to have. And the GM 845 is defintely one of those "shelf" cams.
Look at custom cams where the cam designer has more freedom to pick all lobe parameters. You won't see any with exhaust lift substantially more than intake lift for NA applications. In fact, for two-valve SBC heads, as the performance/lift/duration goes up, you usually see less exhaust lift than intake lift.
Positives: Less stress on the exhaust side of your valvetrain, fewer incidents of exhaust valvespring breakage, higher rpm ceiling before valve float.
I've tried both 1.5 and 1.6 rockers on the exhaust side of a similar cam, GM ZZ3, and saw no performance difference over countless dragstrip passes. I DID break two Crane 10309 springs while running the 1.6's over a period of 30k miles. Not one breakage using 1.5's over another 150k miles.
It's very common to see exhausts lifts substantially higher than intake lift on "shelf" cams where an exhaust duration is selected and they just accept whatever lift that "catalog" lobe happens to have. And the GM 845 is defintely one of those "shelf" cams.
Look at custom cams where the cam designer has more freedom to pick all lobe parameters. You won't see any with exhaust lift substantially more than intake lift for NA applications. In fact, for two-valve SBC heads, as the performance/lift/duration goes up, you usually see less exhaust lift than intake lift.
08-29-2016, 06:25 AM
#17
I'm not sure how good the stock F-body springs are when NEW, but I wouldn't run 1.6 rockers with an old worn out set regardless.
I do know the stock springs that came on B-body LT1's are useless for any upgrade even when brand new.
08-29-2016, 06:35 AM
#18
As bowtienut was saying, 1.6 rockers and new springs do a lot for a stock motor. The stock springs on a 20 year old car are worn, and were only designed for the factory 5500rpm redline. A lot of people have tested that 6300rpm is the fastest way down the track on the stock cam, and stock springs hate life up there. Just adding good new springs and 1.6 rockers and going from 5500rpm shifts to 6300rpm shifts can drop your 1/4 time by 0.5 seconds (long tubes assumed, 5500 with long tubes vs 6300 with long tubes). It's more about the added RPM keeping the motor in its happy place after a shift, when shifting at 5500 you fall too far down the rpm range. You want to shift where the torque to the driveshaft of the next gear equals the torque to the driveshaft of the current gear, and since the next gear has a lower ratio, your torque multiplication falls even though you are only making 250lb ft at 6300 vs 350 at 4000.
08-29-2016, 01:26 PM
#19
TECH Resident
1.6's all around are best for the stock cam. Self-aligning for 3/8" studs. You'll have to decide if the benefit vs cost is worth it. I'm sure it is if you find a good used set. Replace your valvesprings with something better, as I'm sure your stockers are pretty much used up. With 1.6's and better valvesprings, you'll not only pick up 10-15 extra hp, but your rpm band will be extended, giving more performance than just an extra 10-15 hp at peak hp would.
I'm not sure how good the stock F-body springs are when NEW, but I wouldn't run 1.6 rockers with an old worn out set regardless.
I do know the stock springs that came on B-body LT1's are useless for any upgrade even when brand new.
I'm not sure how good the stock F-body springs are when NEW, but I wouldn't run 1.6 rockers with an old worn out set regardless.
I do know the stock springs that came on B-body LT1's are useless for any upgrade even when brand new.
08-29-2016, 03:27 PM
#20
If that's the roller tip only rocker, don't bother, either get full roller or save your money, all the friction reduction comes from the fulcrum, not the tip.
As bowtienut was saying, 1.6 rockers and new springs do a lot for a stock motor. The stock springs on a 20 year old car are worn, and were only designed for the factory 5500rpm redline. A lot of people have tested that 6300rpm is the fastest way down the track on the stock cam, and stock springs hate life up there. Just adding good new springs and 1.6 rockers and going from 5500rpm shifts to 6300rpm shifts can drop your 1/4 time by 0.5 seconds (long tubes assumed, 5500 with long tubes vs 6300 with long tubes). It's more about the added RPM keeping the motor in its happy place after a shift, when shifting at 5500 you fall too far down the rpm range. You want to shift where the torque to the driveshaft of the next gear equals the torque to the driveshaft of the current gear, and since the next gear has a lower ratio, your torque multiplication falls even though you are only making 250lb ft at 6300 vs 350 at 4000.
As bowtienut was saying, 1.6 rockers and new springs do a lot for a stock motor. The stock springs on a 20 year old car are worn, and were only designed for the factory 5500rpm redline. A lot of people have tested that 6300rpm is the fastest way down the track on the stock cam, and stock springs hate life up there. Just adding good new springs and 1.6 rockers and going from 5500rpm shifts to 6300rpm shifts can drop your 1/4 time by 0.5 seconds (long tubes assumed, 5500 with long tubes vs 6300 with long tubes). It's more about the added RPM keeping the motor in its happy place after a shift, when shifting at 5500 you fall too far down the rpm range. You want to shift where the torque to the driveshaft of the next gear equals the torque to the driveshaft of the current gear, and since the next gear has a lower ratio, your torque multiplication falls even though you are only making 250lb ft at 6300 vs 350 at 4000.
Ty McBride
Team Leader/Owner
McBride Motorsports
1997 Comp TA
Mods
-Pace Setter Long Tube Ceramic Coated Race Headers and Off Road Y-Pipe
-SLP 2OTL Resonator dumped before axle
-EGR and AIR Pump Delete
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-Moser 12 bolt rear end with larger 33 spline axles
-Eaton Detroit Truetrac
-MOSER Upgraded performance cover with main cap studs
-4.10 gears, and a 1350 yoke
-58mm TB -P&P Intake Mani
-CC503 Cam
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Suspension Mods
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