Questions for Roller rockers in 289/302

J

jesserose17

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Feb 20, 2004

#1

• Feb 20, 2004

• #1

I currently have rail rockers with screwed in studs on my 289. I am wondering if it's worth the work to replace the rail rockers with roller rockers? Any HP increase? Would I have any problem if I go for 1.7 instead of 1.6? I believe I would need the guideplates and hardened rods if I go for roller rockers, right? Would I be able to just bolt in the guideplates under the studs?

 

LMan

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Feb 20, 2004

#2

• Feb 20, 2004

• #2

By itself, this isnt worth it, IMO. The breakdown:

1. going to 1.6 RRs - next to nothing, a small friction reduction, and yes, you will need your heads cut for screwin studs (if you have pressed- in now), guideplates, and hardened pushrods.

2. going to 1.7 RRs - the equivalent of going to a slightly hotter cam. Same work involved.


nothing wrong with RRs, I have them myself, but combine it with head porting, bigger valves, etc. Then your RR will be part of a good overall package, and you do all the work at once. I am surprised you would have screwin studs with rail rockers, that makes no sense, since Ford used rail rockers to AVOID having to use guideplates/hard pushrods/slotted pushrod holes. Are you sure they arent pressed in?

If your studs are really screw-in, then you have to check your geometry once you put in guideplates (raises the stud up), new pushrods, prob...all this is why Id do it as part of an overall head upgrade.

 

J

jesserose17

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#3

• Feb 20, 2004

• #3

LMan said:

I am surprised you would have screwin studs with rail rockers, that makes no sense, since Ford used rail rockers to AVOID having to use guideplates/hard pushrods/slotted pushrod holes. Are you sure they arent pressed in?

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Since the engine was rebuilt by PO, I am not 100% positive if I have screw-in studs, but I see the hex nut as part of the stud itself (seated on the head, below the rockers) - so I assume I have it, correct? Probably I would be better off waiting until I get a good set of heads, like the AFR 165's or do you recommend any other heads? Thanks for the input LMan.

 

LMan

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#4

• Feb 20, 2004

• #4

well, that does sounds like it, but Id have to see a pic to be absolutely sure. Odd to go to all the trouble to tap for studs and then not use RRs or guideplates

AFRs are good heads, theres no doubt there. There are a lot of options in this area, tho, so consider others too: GT40s, E-boks, Darts (Roush 200, I think now), even 351 heads (C or D00E castings) are good if cleaned up. Just depends on your budget, doesnt it always?

I would combine a cam and head change together, if you can afford it. If you do it seperately, make sure you pick compatible items so you dont have to backtrack. The classifieds here are filled with folks who backtracked

 

J

jesserose17

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#5

• Feb 20, 2004

• #5

LMan said:

I would combine a cam and head change together, if you can afford it. If you do it seperately, make sure you pick compatible items so you dont have to backtrack. The classifieds here are filled with folks who backtracked

Click to expand...

Yes, I agree... the cam is unknown at this point, however, I do know it's not stock cuz of the lumpy engine sounds when idling. I suspect it's probably Edelbrock cam which could be a part of the Edelbrock performance package since I also have Edelbrock 600 CFM carb and Edelbrock Performer intake manifold which was installed by PO.

 

D

D.Hearne

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Feb 20, 2004

#6

• Feb 20, 2004

• #6

Roller rockers by themselves full rolllers, not just roller tipped) are good for at least a 10-15 hp increase, just due to the reduced friction. And combine that with 1.7 ratio, even more power. And yes they work good with even stock heads. I've used them on two sets of heads, both the dog E6SE's and a set of ported E7TE's. Your current pushrods may or may not work with them., Best to check the geometry when installing them.

 

J

jesserose17

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Feb 21, 2004

#7

• Feb 21, 2004

• #7

D.Hearne said:

Your current pushrods may or may not work with them., Best to check the geometry when installing them.

Click to expand...

By checking geometry, I assume you mean the length of pushrods?

 

D

D.Hearne

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#8

• Feb 21, 2004

• #8

Yes, the proper length will be determined by checkin to see how the rocker tip contacts the valve stem tip. This is what's mean't by checking the geometry. You want as small a contact patch on the tip of the valve as possible, and also centered on the valve tip. Anything else tends to shorten the life of the valve guides.The roller tips help some in this regard too.

 

J

jesserose17

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#9

• Feb 21, 2004

• #9

D. Hearne I got it... thanks for the tip!

 

Route666

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Feb 22, 2004

#10

• Feb 22, 2004

• #10

D.Hearne, On a stroke of a rocker, from highest position to lowest position, does the point at which the rocker touches the valve stem go from the rocker side of the center of the valve stem to the other at the bottom of the stroke, OR does it go from the rocker side of the center of the valve stem to the other side of the center of the valve stem and back to the rocker side of the center of the valve stem when the rocker is at the lowest position?

 

D

D.Hearne

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Feb 22, 2004

#11

• Feb 22, 2004

• #11

It should travel from the intake side of the valve tip to the exhaust side at full lift, then back to the intake side when closed. But you also want to get as small a contact patch as possible at the same time.

 

Route666

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Feb 22, 2004

#12

• Feb 22, 2004

• #12

ok, tah!