Roller rocker info?

[No_Nova_Yet]

I'm doing my first rebuild on a 283. So far it's pretty much a stock rebuild except for a Performer #2102 cam. The heads are stock.. my question is should I use roller rockers? Will I benefit from these? Do I need to change anything else like push rods or springs if I use rollers? I'm new to this....thanks

[jason snyder]

I'm doing my first rebuild on a 283. So far it's pretty much a stock rebuild except for a Performer #2102 cam. The heads are stock.. my question is should I use roller rockers? Will I benefit from these? Do I need to change anything else like push rods or springs if I use rollers? I'm new to this....thanks

your valve spring pressures are minimal , and your lift is well under .500 , so you dont need roller rockers. Stay with the stockers , otherwise your just throwing away money.

[veno]

the rollers will free up some Hp... just how much on a otherwise stock 283 is very debatable........you will have decide if its worth the dollar per hp value trade off....

side note.... the roller can be transfered to a different engine if you so desire... provided you save the stock rocker to replace the roller if you sell the 283 or keep an return to stock config..

[66torchredpro]

I just happen to be reading the April 2008 CHP issue and they put 1.6 rockers on a factory 9:1 350 at 250 hp and 345 lbs torque (engine) and it gained them 7 hp and 7 lbs. I would guess this is a little more hp than your 283 is making (just a guess) and the extra cost for the full rollers would probably be a waste, but as Veno said, if you plan on future upgrades or different engine, this would be one expense you wouldn't have later.

[The Big Al]

Roller rockers are 100% great addition to any engine.

Less friction!
Less wear!
Less heat!
Adds durability!

Less wear on the valve tip
No heat build up from ball type socket in STK rocker arm.
better alignment , no side to side motion.


Stock rocker arms have had failures under stock conditions. (they are stamped steel)
They have been know to break, tilt sideways and saw into the rocker stud.

IT"S A WIN WIN!!!!!!!!
And if you ever want more cam or spring pressure, your set!

[No_Nova_Yet]

Thanks for the info. So if I did get rollers what else do I need? Do I need guide plates, different studs or anything. And what ratio whould I use 1.5 or 1.6? Thanks

[The Big Al]

You need nothing for them.

I would stay with 1.5

Your stock studs are 3/8

So 3/8 1.5 is what you need.

[tnblkc230wz]

you may want to consider 1.52 rockers if they don't take you past your spring limits.

[64PRONOVA]

You're probably not going to notice much of a performance increase (if any) with your engine combo by just adding roller rockers but they will be more reliable and accurate than stock stamped rockers.

[veno]

Not to be a nay sayer... Stock rockers live very well.... dont get hyped... they go for more than 100,000 miles in a well maintained engine using oil that has the extreme pressure additives needed for the older engines... Big Al is correct about the less wear, less friction etc... but 200.00 bucks for no real gain.... you may see 3 to 5 hp tops.... nothing you can feel... yes they are a fine addition.... if you plan on adding other components later.

Just addind roller rockers for the sake of adding them is a waste of money in the dollar per HP gained... will your engine live longer with them.... debatable, will your valve guides last longer? yes.... how much? debatable...


It comes down to a personal choice...Spend the money or not... your engine will in all probability live as long with or with out them

[bowtie0069]

They have been know to break, tilt sideways and saw into the rocker stud

Or go 200,000+ without issue.
If you have the money burning a hole in your pocket, go for it--you won't notice any difference at all. Well, except the lighter wallet!

[jason snyder]

Or go 200,000+ without issue.
If you have the money burning a hole in your pocket, go for it--you won't notice any difference at all. Well, except the lighter wallet!

exactly , well said !!!!!

[joey d]

Don't forget tall valve covers. I would save up for better heads, the extra lift from the 1.6's will be past the peak flow of the heads.

[veno]

I would save up for better heads, the extra lift from the 1.6's will be past the peak flow of the heads.

Now to start another debate...

just how does a super stocker 283 use a .700 lift roller cam then ? Since they are restricted to the stock production head. Hummmmm?

[joey d]

Now to start another debate...

just how does a super stocker 283 use a .700 lift roller cam then ?

very carefully

[shaggy]

Don't forget tall valve covers. I would save up for better heads, the extra lift from the 1.6's will be past the peak flow of the heads.

Once I bought aftermarket heads the tall valve covers are no longer needed. Something to think about when you buy valve covers if you get new heads later.

[D-Man]

Off the original topic but I'll bite..:devil:
Here's a quote by Joe Sherman:
"Poor heads require more cam to make decent power."

Here's a good quote that somewhat explains why. It also explains why it's becoming more of a common practice to kill low lift flow.

For the past 25 years I have based my cam design on one theory.
What happens before TDC in the intake cam is bad, and minimising the bad helps the engine breathe its maximum.
All the work done by the piston in starting airflow is done in the 1st 75* ATDC, up to the point of maximum piston velocity. From the point of maximum piston velocity on, the piston is progressively slowing down and pulling LESS hard on the intake port with every degree of rotation. Yet because of inertia, the velocity in the intake port is increasing, up to a max at BDC. If everything is done right, the cylinder is still filling when the initake valve shuts after BDC.
By minimizing Reversion before TDC, the piston starts airflow earlier, vs earlier intake valve openings which let in more and higher pressure exhaust gases. The less reversion, the earlier airflow starts after TDC. By having a cam with lots of mid-lift and high-lift area, the valve has more time(duration) to fill the cylinder with harder-flowing air/fuel(inertia ram).
The exhaust cam has its own part to play, I'll cover that later.
This has been my intake theory for 26 years.

UDHarold


A little more from Larry Meaux:

Mixture Inertia ram-effect combined with a positive pressure
acoustical wave, at around the time of .400" towards .050" Lift
or so , can be on average of 3 PSI or higher.

So if your Heads Flow Tested at .200" Lift were = 140.0 CFM @28"
...that same 140.0 CFM @.200" Lift may now be capable
of moving approx. 241.0 CFM @28"...about a 100+ CFM gain
from the above effects

so Low-Lift Flow will help you more at the Intake Valve
closing point at higher RPMs, and hurt you more at the
very Lower RPM part of Curve by increasing reverse Flow
or reversion at Intake Closing point,
and filling the cylinder too easily too quickly at the
start of the intake stroke at the lower RPM Curve.

you must need a certain amount of pressure drop
to create the great ram-effect at the intake valve closing point.
if you have too much low-lift flow too soon ,
you place a "kink" or hurt the formation of the depression
curve early in the stroke and hurt ram effect later at IVC

Where your Engine makes its Peak Torque,
is basically where your Engine is breathing its best,
after the RPM point of Peak TQ,
Cylinder filling is less and less.

Below the RPM point of Peak Torque occurrence,
there is not enough Int and Exh System velocities + Length Tuning +
due to CSA's and cylinders being fed too easily too quickly !
you are loosing your ram-effect at the IVC


Too much Low-Lift Flow can cause all kinds of problems
like reversion and overscavenging.
Increasing Low-Lift Flow is sort of like
increasing Cam's Duration at .050" and increasing
the OverLap Period....so that may force you to
use less Duration @.050" + spread Centers.

---------------------------------------------------------------

if you have a relatively lower RPM Range Engine
with good to great Low-Lift Flow,
you can or most probably need to shorten up
Cam Duration to offest the great Low-Lift Flow,
sort of like the Duration Numbers the 4 or 5 valve Head
engines have to use.

-------------------------------------------------------------

When i purchased my first FlowBench, a SF-110 in late 70's,
i immediately started trying to correlate what
Valve Lifts were important to gain great Flow Numbers at.
Going back and forth from SF-110 to DragStrip,
it started to show using .85% PerCent of the theoretical
Cam's Max Valve Lift.
Example=> .700" Lift Cam times .85% = .595"
or rounded-off to .600" Lift, so i made sure i had
great Flow in a .200" Lift range,
from .400" to .600" Lift Flow on a Bench for a .700" Lift Cam
or
from .600" to .800" Lift Flow if you had a .900" Lift Cam

later on with newer SF-600 Bench + Dyno tests + DragStrip test,
it looked more like .87 % was better to use..not a lot of difference.

By using at least a .37 Lift/Diameter Ratio Camshaft on Intake Side
and using .87% PerCent of that Lift to develope Heads on a FlowBench
has worked pretty well as a starting baseline.
The all-out max-effort 2-valve Head Engines prefer
at least a .39 to .42+ Lift/Diameter Ratios
with great Mid to High Lift Flow Numbers

Also i might add...with current technology
of "Lofting" the Valves...the .87% PerCent Factor i used
may be revised upwards to develope Heads on FlowBench
up or above the Cam's Max Lift point.

_________________
Meaux Racing Heads

There.... That's enough to get a head-ache trying to process it all..:D
It also make a good explanation for the better performance of a true asymmetrical cam. Less reversion on the intake opening yet using a longer intake closing to get the benefits of the extra "ram inertia" effect. I guess some of these old farts really do have a few noodles up stairs!!:eek: Hopefully there's a few bright understudies that will carry on their work and experience so it's not all lost with them!!!!:yes: