roller rocker install Q's

[rrubel]

Ok. Going to take the plunge soon and try installing a set of roller rocker arms (the CAT stainless ones I asked about before). Reading through the Haynes, it doesn't seem like a huge job, but I do have some questions:

1. Is there a difference between moly-grease and lithium grease, such that I should try to dig up moly (molybdenum?)- based stuff? The Haynes says to use it.

2. The directions from CAT say to replace the pushrods at the same time I'm doing the arms. Is this just them assuming I'm doing a major buildup of the engine, or is it smart to replace the rods as well?

3. What about anything else in the valvetrain since I'm in there?

4. Anyone have a favorite method for assuring zero-lash of the pushrods?

5. If I'm installing a new rocker cover gasket, do I still need to use RTV? The Haynes wasn't clear.

5. Any gotchas I should watch for?

Thanks much...
[RICHR]

 

[tpiini]

#1; BIG difference between moly & lithium. Get the moly. You should be able to find "assembly lube" at any parts house.

#2; Pushrods and rockers wear together like lifters on cam lobes. Replace the pushrods with the rockers. The pushrod to lifter contact is essentially a no-wear point so you needn't worry about that end.

#3; Don't worry about anything else.

#4; I use the method wherein you spin the pushrod while tightening the rocker so that the zero-lash is obvious when the turning friction is felt. You'll get advice to go an additional 1/2 to full turn after zero. I personally go 3/4 turn, but am not sure if my way is best.

#5; Use a good gasket sealer instead of RTV on the rocker covers as the RTV tends to get a little "over used."

#6; Unless you've done this a LOT, it's always safer to tighten the rockers down in the normal firing order instead of relying on the batch-method. (#1. Quarter turn. #8. Quarter turn. #4, etc.) It takes longer, but you always get it right that way.

Good luck, tom

 

[Ken]

#6; Unless you've done this a LOT, it's always safer to tighten the rockers down in the normal firing order instead of relying on the batch-method. (#1. Quarter turn. #8. Quarter turn. #4, etc.) It takes longer, but you always get it right that way.

I was watching my builder adjust mine the other day and noticed that was exactly the way he did it, and he does it a lot!

_ken

 

[Eagle85C4]

Question...are you installing the stock 1.5's or going to the 1.6's?
It is my understanding that the 1.6 ratio arms will increase performance, but I am not sure if they can be used on a otherwise stock L98. Anyone done this?

 

[sscam69]

They can help. It all depends on the cam your are running.

I think if you are running a high duration camshaft it acually decreases performance so be careful.

sscam69

 

[rrubel]

Question...are you installing the stock 1.5's or going to the 1.6's?

1.5's, because that's what I happened to get a good deal on. I've been told that if I change ratios, I should only change the exhaust. Eventually, when I have more mods, I'll consider doing that - but right now just putting on rollers should make a decent difference.

So now I guess I'll be looking for pushrods. I've seen Edelbrocks for about $85/set from a couple places.

Thanks for the great replies...
[RICHR]

 

[69MyWay]

RICHR,

I don't know anything about these Stainless CAT units. Are they full roller with poly locks, or are they basically normal rockers with roller tips?

This makes a huge difference on some things.

BTW, on full roller non self aligning rockers, you have to use guide plates. Whenever you use guide plates, you have to use hardened push rods.

 

[rrubel]

My bad - they're not *stainless* steel, just aircraft-grade 4340 steel. These are 1.5, not 1.52, and are not polylock (the catalog says the 1.52's are poly) so I think that means they're normal rockers with roller tips. Just got off the phone with Mike at CAT, and he said that no special pushrods are needed, though hardened ones would be a good idea anyway.

I think I got a decent deal on them :crazy. Let's see if I still think so after I install them.

[RICHR]
<power on a budget...>

 

[sscam69]

I just bought some roller rockers and recieved them today. The engine was rebuilt and I felt that it wouldn't hurt to do a few upgrades. I also bought polylocks and a vacuum resorvoir. My car was shutting off as I pressed the brakes. I am going to install today but I am coming down with a cold or something.

Let me know how it turns out for you and if you notice a difference in performance and will let you know how it goes for me as soon as I am back on comission.

sscam69

 

[69MyWay]

Well, that is cool then. There is a big difference in price between chromolly (sp?) and just plain hardened pushrods. Hardened push rods are faily inexpensive from Summit in the Summit brand. I just got a set for my big block from them under $50. However, I put a set of the chromolly in my small block build that is in the 90 and those ran right at $100.

I would suggest getting new push rods as I have seen one engine eat the stock style push rods with roller rockers installed. However, since yours are maybe only roller tip, you might get away with it just fine and you are not running guideplates.

The length of the push rod matters as well for tip top performance, least amount of friction, and long life. Install an intake and exhaust rocker and adjust it.

Now, rotate the engine around. What you really want to do is stop the rotation when the valve is 1/2 through the travel point either or or down. Note the position of the roller tip on the valve stem. You want to see it dead center. You can change where it rides on the valve stem by buying longer or shorter push rods.

This is how you dial it in to absolute rolling perfection. Most people fail to even inspect this movement and end up eating a valve or not getting the expected hsp gain out of a motor after the roller rocker swap.

 

[tvalley641]

IMHO, I doubt you will feel any difference off the line, and pulling through mid-range unless you go whole-hog 1.5's (no more, no less), stainless forged (not stamped)... the works. You may be able to max out your revs a bit. Don't be too disappointed, however, as you should increase the life of the upper end through decreased friction, aka less heat. Who knows how much that might be though.

I'd be real interested in your before and after clock times. Can you do that first, under the same weather conditions? That would be real neat to check out.

Ted

 

[rrubel]

I'd be real interested in your before and after clock times. Can you do that first, under the same weather conditions? That would be real neat to check out.

I'll see what I can do. I have a G-Tech, and I've been meaning to get some before-times, but haven't found a suitable location to test it yet (none of my other cars come even close to triple-digits in the 1/4 mi, so the usual test road is out ). I don't think our local dragstrip has opened for the season yet.

IIRC, my bro-in-law went from 301 CHP to 330-something CHP in his LT-1 with the addition of a K&N panel filter, cold thermostat, and roller rockers. I've done 13.48 in the 1/4 in that car. If I can get a similar 10% boost from roller rockers, K&N, maf screen/TB airfoil, and a thermostat, I'll be most happy for a start.

[RICHR]

 

[tvalley641]

That combo would be fine with me to.

Ted

 

[LT1Vettepilot]

Looking forward to some numbers

Definetly let us know what kind of performance gains you get with the new rockers. I just got my baby back from the service center. Had some warranty work done to her. Anyways, I happen to be rather lucky in that my service guy is a Corvette specialist and has built several high performance Corvettes. 650 horsepower to 850HP. If you've heard about the Viper Challange, the Blue Corvette that spanked the Vipers was built my mechanic :cool . I talked with him the other day about the roller rocker install versus an entire LT-4 Hot Cam kit. The numbers he is figuring is as follows:
Just roller rockers won't give a noticiable gain
LT-4 Hot Cam kit, full Borla exhaust with headers, a little head work, would yield about 350HP at the wheels. This was a combination he has already used and dynoed. Rather pricey for me at the moment, but would be a solid setup and still give great reliable daily driver characteristics, 20+mpg etc.
So I'm curious as to what you will get out of just the rockers.

 

[sscam69]

I installed them yesterday. And just in time to! I live in a desert and the wind kicked up as soon as I had finished. You could look directly at the sun because the sky was filled with dust.

As for performance gaiins other than piece of mind of a better valvetrain that can handle higher rpms I could not feel anything different. Something wierd happened and I don't know what to attribute it to. When I finished up I took the car out and I noticed she was running at 220 deg. She didn't go over but I couldn't for the life of me figure out why she would run that hot. I took her out at night and she ran just fine at 180.

I forsee a problem in the future. The days are starting to get hotter around here averaging about 75 deg. The only difference other than the rockers was the temp of the ambient air at night and during the day. The roller rockers are the same ratio as the originals, 1.5 Uh Oh! Could this be a problem in the summer?

Could it be the rockers breaking in? Its a long shot but thats my best guess other than the temperature difference of the air.

sscam69

 

[rrubel]

It'll be probably a month or so before I can get mine installed - need to budget for the pushrods (I want the chromoly ones as long as I'm in there) and can't take the car offline at the beginning April because I promised it to a friend for his wife's birthday ... I foresee this as a several-weekend job.
[RICHR]