Voxego

Ok, if you JUST swap the 1.5s for 1.6 Roller Rockers, what are the advantages/disadvantages? Extra HP? Fewer MPG? I am planning next years to do list...

Thanks!

J

l98tpi

Basically, you get an increase in valve opening and get more air into the cylinder for combustion. That is if you can flow enough air at a specific rpm to allow more air to flow into that cylinder. One thing to watch out for when switching to a higher ratio rocker arm is valve side load. Most on here say there is a increase in power by adding 1.6 rockers. One other thing to consider is going with roller rockers as well as the 1.6 rockers. I'm not an engine expert, but I'm sure there will be some chime in.

weaselbeak

If you're using stock valve covers there might the possiblity you would have to clearance the undersides of them? I'm not sure mine look like they are going to hit but I'm not going to be running a stock cam.

Kool88vette

I installed Comp Pro Magnum 1.6 RRs and their pushrods. You can get a kit from Summit Racing for about $300.00. They should add about 15 HP.

1963SS

If you change to a 1.6 from a 1.5 you will increase lift. Say, for example, that your lift is .430 with a 1.5 rocker. When you change to 1.6 the lift will be (.430/1.5) x 1.6 or .458. That's almost an extra 1/32" of lift. The effective duration will be raised about 2 degrees or so and the area under the curve will be helped as well.

Although I've never seen a dyno with just this change, I'd think there may be about 10 horsepower to be gained. There would probably be another 10 horsepower or so by switching to 1.6 roller rockers.

So from a stamped steel 1.5 to a full roller 1.6 may be around 20 horsepower. That's noticeable.

leesvet

Its REAL hp too....not "implied" or "bolt-on" hp thats more placebo than real.

1.6 RR are a genuine performance upgrade. Less drag, less friction, more lift & duration...poor mans cam upgrade.

Not marketing crapola with wild claims on "their" test engine in a lab under controlled conditions that nobody else will ever be able to duplicate in a car on the streets...

go for it.

dogfish246

Just remember to change the valve springs as well... Otherwise you will have valve float or worse, a spring might break on ya!

ToniH

Years ago I ported the plenum, got my injectors cleaned and installed Crane Gold 1.6 RR's with new stock valve springs. My trap speed went from very consistent 97mph to 102mph on same track with identical weather.

Don't know what did what but I was pleased.

EDIT: yes, I had to trim the valve covers insides to make them fit.

racerxz51

1.6 roller tip rockers will fit under the stock valve covers, aluminum full roller generally need a tall rocker cover which may interefere with the wiper motor. The 1.6's on my otherwise stock at the time 84 were worth a half second and4 mph repeatable in the quarter-appx 20hp

1963SS

1.6 Comp Pro-Mags fit under stock valve covers with a little trimming of the reinforcement webs inside. No problem with leaks either. Just sayin'.

Strick

On the OEM magnesium valve covers you have to cut off the oil tangs inside the covers. Then you'll have plenty of room for the roller rockers. When I did mine several years ago, my motor really liked the roller rockers from Crane. On my 92 LT1, you have to make sure you don't have coil spring binding. The fix, buy some LT4 springs.

Oh, I forgot, you'll have to buy push rods for your application. At least that is what Crane told me and I bought new ones they recommended.

Hot Rods

I'm leaning towards the scorpion self aligning 1.6 full roller rockers for my 92 LT1 . I will also get the LT4 springs and valve seals. I thought I did not need new push rods for this modification. If I do I did not see any news of that in the forum search areas. This engine has original cam and it is a 6 speed convertible with free flowing exhaust . It is a blast to drive and these rockers sound like they will make a difference in the 92 LT1 !

ToniH

I didn't need new pushrods and have not heard that anybody did.

yakmastermax

This thread got me into doing a little research.

from what i've learned so far, increased rocker arm ratio equates to increased valve lift assuming camshaft and pushrods are the same.

increased lift is better for power and torque right? not to mention aftermarket rockers are most often roller, an efficiency upgrade over stock.

however, at what point will the lift be too much for the application? is there an RPM range for certain ratios? can ratios meant for one RPM range be used in another range with a change of springs? change of camshaft?

thanks for the education!

Voxego

Coolness! Can you change the springs with the heads on? I'd think you would have to pull them off.

STL94LT1

Yes.

btr85vette

I put on a set of 1.6 rollers a couple of months ago and love them. The motor runs smoother, and revs better. It feels like I gave up a little of the bottom end but gained some on the top end. Its one of the cheaper real upgrades you can do. I highly recommend it.

Now, can't wait to see how they work with the headers going in next weekend...

65Z01

Indeed yes. Some use compressed air to hold up the valves, I used the "rope trick". Here I turned the crank till a piston hit a stop, removed the stop and threaded in some 3/8" dia nylon rope, when "full" turned the crank till tight. When the keepers were removed any valve spring dropped very little.

It's also a great time to install new valve seals; local GM dealer had them for ~$50.