Nutro

iTrader: (1)

Is it worth going to a full roller 1.5 for reliability or a roller tip Comp Cam rocker in 1.5 or stagger and do 1.5 on exhaust and the same thing but 1.6 on intake? Stock L98 iron heads, stock motor except SLP headers and exhaust. Stock low mile engine. I was cleaning the OEM pushrods and found one with a small knick in it and ever so slightly bent. I figure new rockers, new hardened pushrods wouldn't hurt.

AlkyIROC

For a daily driver, basically stock engine, roller tip will do just fine if you're trying to save some money.
If you want to spend a little more, a full roller is better but not all roller rockers are built the same. Inexpensive roller rockers are inexpensive for a reason but again, for a daily driver, basically stock engine, they will work just fine.

TTOP350

iTrader: (8)

Engine masters rocker arm test is all you need to know.

Buddy

What was the info on this?

.... I have Comp Cams......(fingers crossed they are good in this test... lol)

Nutro

iTrader: (1)

Yeah I just watched it a few days ago and remembered it recently. So basically, the 1.6 made the most power (18HP) up above 5500 RPM. So, in a TPI motor that rarely lives in the 5500 RPM area, roller rockers are pretty much pointless from a power perspective.
I've decided to go just go with Comp cams roller tips in 1.52 on all valves with BTR hardened pushrods and LS7 lifters.

TTOP350

iTrader: (8)

The 1.6 ratio is where its at. Being a roller didn't matter as much. However, they didn't test oil temperatures x rpm x time and i think that would help the roller shine more

Nutro

iTrader: (1)

I saw that Howard's sells a stamped steel 1.6 and was tempted but I don't want to change springs etc

erik69&85

iTrader: (1)

I put roller tip 1.6 rockers on my stock 92 305 and had no issues... and it woke the engine up... not a lot. But got it a little more zing ... didn't change anything else... would do again...

sofakingdom

iTrader: (1)

Main advantages you want to look for in rockers:

1. More consistent translation of cam lobe to valve motion. Factory rockers may "measure" 1.5, more or less, when sitting still; but under the forces put on them during operation, they average somewhere around 1.43. I've seen the ratio of valve motion to cam lobe motion - the GOLD STANDARD of rocker performance, in this regard - as low as 1.38. Few EVER exceed 1.45. If you watch them with a Strobotach https://www.ebay.com/itm/234066772294 (not that I'm endorsing this seller or anything, merely, the photo and description are particularly clear, and look like all the ones I repaired in the mid 70s) they look like a sheet of rubber or cloth flapping in the breeze. ANYTHING BUTT rigid.

2. Lower oil temp: this only applies to roller trunnion rockers. Ball type ones, the ball arrangement generated MASSIVE heat, enough to turn the ball seat in the rocker BLUE from the temperature. Oil temps can be 10 - 15 °F lower, OR MORE depending on how much stress the valve train is subjected to, than ball rockers. Ball rocker seats often turn BLUE from the heat, meaning, they're nearly RED HOT during normal operation.

3. A roller tip helps with valve guide wear. There's ALOT less force pushing the valve from side to side in the guide, with a roller tip.

Main disadvantages:

1. Aluminum rockers feel "light" in your hand, but inertially, i.e. the force required to rotate them, are VERY heavy. Steel roller rockers, while "heavier" in your hand, often have LESS weight out toward the ENDS of the rockers, particularly the valve end, and therefore are "lighter" as far as what the valve train and valve springs see.

2. Aluminum has a problem with "metal fatigue". This is an issue where after some number of mechanical cycles, the aluminum crystal structure starts to change, and eventually becomes very brittle, and it just ... breaks in half. Any of you that have experience with aircraft will know, the FAA regs require cerain parts to be REPLACED every however many stress cycles the part has been subjected to; hours of operation for jet engine parts, takeoffs & landings for landing gear parts, pressure/depressurization for some airframe parts, etc. It's why for some other parts, every however many of those, even if the parts don't have to be "replaced", they have to be stripped down to bare metal, "inspected", and only then can they be repainted. The half-life of an aluminum rocker in an engine is somewhere on the order of 20,000 miles (500 - 600k operations), meaning if you use those, you have a 50% chance of AT LEAST ONE failing by 20 - 30,000 miles depending on your gears and how you use the engine. Great for racing (short bursts), TERRIBLE for long-term duration.

3. Width: not too much of an issue with perimeter-bolt valve covers, but with center-bolt, the things that the bolts go through, don't allow enough space in between to fit most roller rockers.

4. Height: The rockers themselves aren't an issue; but the Polylocks can be too tall to fit under most stock valve covers.

Many roller-tip rockers such as the Comp 14xx series will fit under ANY valve covers. The nuts they supply however, unless they've changed them, are TOTAL CRAP. Replace them with either double-nut grade 8 hardware (bottom nut grade 8, upper "jam" nut can be regular grade 5), or stock GM ones if you're cheeeeeeep and willing to take a risk (double-nut from the hardware store is better).

On a TPI motor you will gain ESSENTIALLY NOTHING from 1.6 ratio compared to 1.5 ratio of otherwise equal rockers. That is, the gains these people are talking about aren't from the RATIO; it's from replacing stock floppy sheet rubber with genuine HARD material (this concept will resonate particularly with females) that accurately transfers cam lobe action into valve motion in a manner CONSISTENT from one valve to the next.

You can get an AMAZING improvement in almost any engine, but CERTAINLY ANY "stock" one, by upgrading the valve springs. Note that many of the people who claim they got "improvements" from replacing rockers, also replaced springs at the same time. While I absolutely WILL NOT call them "liars" or anything of the sort, the improvements from putting in springs that actually CONTROL valve motion, can be pretty dramatic, even if the "nominal" valve motion is unchanged. I.e., same rockers, just better springs = better running engine. Since the results of the 2 upgrades are then intertwined and confounded, it's impossible to be sure that what they're claiming as the benefits of the rockers, are in fact not due to the better springs. Stock springs are TOTAL CRAP compared to ALMOST ANY aftermarket ones.

sofakingdom

iTrader: (1)

I got tired of typing, butt should have mentioned:

1.6 rockers, roller or otherwise, achieve their increase in ratio (RATIO = distance from valve to stud, ÷ distance from stud to push rod) by REDUCING the push rod side of things, since a rocker can't possibly alter the stud <–> valve distance. I.e., they get their higher "ratio" by moving the push rod seat closer to the stud. Many if not MOST heads will NOT accommodate this without enlarging the holes in the castings where the push rods pass through, toward the stud. Meaning, grinding or machine work is USUALLY required. Not always practical with the heads installed although very eeeeeeezzzzy otherwise.

AlkyIROC

Many many years ago, I had some Crane Energizer roller rockers before switching to Crane gold. I broke one of the gold rocker trunions. Thought I's press out a trunion from an Energizer rocker and put it into the Gold rocker. Even though both rockers are made by Crane, the quality of the different trunions was very obvious. The swap would have worked but it would have been weaker. Decided to take the gold rocker back to the speed shop and they replaced it under warranty. So like I said before, inexpensive rockers are inexpensive for a reason.

As already mentioned, a roller tip rocker only helps reduce drag across the tip of the valve and reduces some side forces.

Since switching from a 1.5 rocker to a 1.6 sounds good and in most cases will be a simple swap however the pushrod hole might need to be modified to allow the pushrod closer to the rocker stud. Lets say you have a 0.500" valve lift with a 1.5 rocker. That means the lobe lift is only 0.333". Put a 1.6 rocker on that lobe and you now get 0.533" of lift. Are the valve springs capable of that increased light? Will the bottom of the spring retainer hit the top of the valve seal? On a low lift cam such as 0.420 lift there normally isn't an issue but when using higher ratio rocker on higher lift cams, more tolerances need to be checked. Also a higher ration rocker only increases lift. It doesn't change LSA and only changes duration so slight that it isn't worth measuring. You would be better off just doing a cam swap to achieve desired performance levels.

On my race engine, I've had many different type of rockers over the years. I've finally installed shaft rockers. A shaft rocker is much more precise and moves the rocker tip directly over the tip of the valve. This means I had to modify a bunch of pushrod holes going through the heads to help with pushrod alignment. When you're spinning an engine to 7800 RPM, valve train stability is a must. Even my pushrods are huge with thick walls to reduce deflection. For a street engine this is overkill other than bragging rights and showing how much less money is in you pocket.

Anything is better than factory stamped steel, low tolerance rockers but you don't need to go overboard on high end rockers in a street car.

A 1.6 rocker will be an improvement however it probably won't be felt in the butt dyno. A set of roller tip 1.5 rockers compared to lower ratio stock rockers is an improvement but that's the same as changing your spark plugs to "brand X" plugs because the advertisers said they are better and saying you feel a difference but simply changing your spark plugs to normal new plugs will feel exactly the same.

erik69&85

iTrader: (1)

Yes... my car looks totally stock....

Didn't change any springs or have machine work done... but the engine did have 90k miles on it ..

And I did feel it in the butt dyno...the engine had more snap down low... as for top end .. no idea... I don't drive there... even with a manual...

midias

I noticed a large difference with 1.6RR vs 1.5RR and the tuning changes I had to make aligned with more airflow. Although my setup is not stock, aftermarket heads and sniper EFI. Running a XE274 cam with 490 lift now ~523