Rocker Arm Questions

[sneitzel]

I'm considering a rocker arm swap as my next mod.

I am looking at the LT4 1.6 Roller Tip Rockers from TByrne Motorsports.
http://www.tbyrnemotorsports.com/lt1/lt1valvetrain.html

How difficult a swap is this?
Can I just swap the rockers or are there other things I need to do?
What about adjusting the rocker arms?

Also, any opinions about the 1.6 LT4 parts vs. 1.6 Crane or others?

I have done many things to my car but have never tackled something like this so I would appreciate any and all suggestions. This is completely new territory for me so don't hesitate to "dumb things down" so to speak.

Thanks everyone.

[ConElite]

I would replace the pushrods with some Chromoly pushrods. That would be good. Its not that hard. The hardest thing about that job would be I would say the adjustment. Even that is pretty easy.

[ToplessFormula]

It's an easy mod. Don't sweat it.

I have had great luck with my Crane Gold Race 1.6 roller rockers but haven't used the LT4 ones. They appear to be very much the same.

[Rob B (shoebox)]

I don't recommend going from 1.5 to 1.6 ratio rocker arms without changing the valve springs.

[sneitzel]

I don't recommend going from 1.5 to 1.6 ratio rocker arms without changing the valve springs.

Rob,
I've had a couple of other people tell me the valve springs should be fine. You are the first person to recommend changing them. Could you explain your reasoning there? Is it a necessary thing or just something that's recommended?

Thanks.

[MunsonGTA]

Rob,
I've had a couple of other people tell me the valve springs should be fine. You are the first person to recommend changing them. Could you explain your reasoning there? Is it a necessary thing or just something that's recommended?

Thanks.

it depends on how much lift the stock springs can handle. you add alot more lift to the cam when you add 1.6 rockers, which can cause the springs to bind if they can't handle the lift. do you know how much lift the stock springs can handle, and how much lift your cam will have with the new rockers?

[sneitzel]

it depends on how much lift the stock springs can handle. you add alot more lift to the cam when you add 1.6 rockers, which can cause the springs to bind if they can't handle the lift. do you know how much lift the stock springs can handle, and how much lift your cam will have with the new rockers?

Everything internally is stock at this point so whatever the stock specs are that's it.

[ToplessFormula]

It doesn't add "alot" more lift. It adds slightly more lift and duration.

You should be fine. I didn't have any problems and don't know of any magazine or person that's actually had a problem either. I've heard people say it's a problem, but of them ever actually did it.

To be on the safe side, I would check for coil bind after you install them.

By doing a Google search you can actually come across some magazine articles where they did the same thing without changing the valvesprings. I researched it a few years ago when I did mine.

[Gary94Formula]

I've had 1.6 roller tip rockers on my car for the last 40K miles without issue.

[Z Ya Later]

Just do the valve springs. 1) Its cheap insurance. 2) You replace worn springs with new ones. 3) You have no nagging fear of the springs binding. 4) Did I mention cheap insurance??

Part #'s you'll need (if using the LT4 springs):

Valve Springs: $35.88/kit, need 1; total - $35.88
Valve Spring Locks: $16.39/kit, need 1; total - $16.39
Valve Spring Retainers: $26.39/kit, need 1; total - $26.39
Valve Spring Shims: $2.39/each, need 16; total - $38.24
Pushrods: $153.39/kit, need 1; total - $153.39

Total for new valve springs (not including any tools if needed, shipping and handling): 116.90
Total for everything (again, not including tools, yada yada yada): $270.29

Hope this helps.

[Rob B (shoebox)]

Rob,
I've had a couple of other people tell me the valve springs should be fine. You are the first person to recommend changing them. Could you explain your reasoning there? Is it a necessary thing or just something that's recommended?

Thanks.

Odd, on most boards I have been on over the years, the majority of people recommend new/better springs.

A stock 97 cam should be ~ 4.47/4.59 in/ex lift with 1.5 rockers.

That will be 4.77/4.90 with 1.6 rockers.

Stock spring installed height is 1.780". Coil bind (solid height) is at 1.260".

1.780 - 4.90 = 1.290 compressed height at max lift with the 1.6 rockers.

1.290 - 1.260 = .030 which is below the universally recommended .050 allowance to keep you out of coil bind trouble.

Couple that with the fact that you are asking old springs to take more abuse is a recipe for something bad, IMHO. Never would it be a chance I would take with my engine.

If you kept the revs low, I could see some people getting away with the old springs, but it is not a chance I would ever take. There is not much safety margin there.

[ToplessFormula]

Odd, on most boards I have been on over the years, the majority of people recommend new/better springs.

A stock 97 cam should be ~ 4.47/4.59 in/ex lift with 1.5 rockers.

That will be 4.77/4.90 with 1.6 rockers.

Stock spring installed height is 1.780". Coil bind (solid height) is at 1.260".

1.780 - 4.90 = 1.290 compressed height at max lift with the 1.6 rockers.

1.290 - 1.260 = .030 which is below the universally recommended .050 allowance to keep you out of coil bind trouble.

Couple that with the fact that you are asking old springs to take more abuse is a recipe for something bad, IMHO. Never would it be a chance I would take with my engine.

If you kept the revs low, I could see some people getting away with the old springs, but it is not a chance I would ever take. There is not much safety margin there.

Very good information.

I've bounced mine off the 6,200 RPM rev limiter many, many times. I frequently run to 6,000 in the 1/4 too so I can eliminate one shift. I still haven't had any problem out of my high mileage factory valve springs.

[sneitzel]

As far as revs go I keep things below the red. My car has never seen the track and probably won't as long as it is my DD.

But I do see your point Rob and it does make sense.

Valve springs can be done without removing the heads correct?
I would need a tool kit similar to this one? Valve Spring Compressor w/Air Hold Fittings
How much more difficult does this make the job?

[MunsonGTA]

As far as revs go I keep things below the red. My car has never seen the track and probably won't as long as it is my DD.

But I do see your point Rob and it does make sense.

Valve springs can be done without removing the heads correct?
I would need a tool kit similar to this one? Valve Spring Compressor w/Air Hold Fittings
How much more difficult does this make the job?

with the right tools, it's not that bad of a job. the first one will probably take you a few, then the rest will go quick once you get the hang of it.

[raroZ28]

If you have headers it will be a piece of cake to do the valve springs.

Go to harbor freight and buy a 10 dollar overhead valve spring tool, fill the cylinder with compressed air, and take them off. Not a difficult job at all. It will take longer to get the air hose into the spark plug hole than it will to do the springs.