Some dumb questions (roller rockers)

[Cliff Beer]

Please excuse these dumb questions here....

All of my engine building experience is with smaller displacement non-US engines. So, I've been learning about large displacement US V8s (mostly SBF,BBF) over the last 5 or so years and can really appreciate some of the inherent design advantages (simplicity and large displacement). I have a Ford Racing crate engine in my GT40 - a basic 302 with alloy heads and large holley. It makes about 350/350 according to the specs (which is plenty for me). I have no idea if I have fixed length push rods (and should therefore periodically check valve clearance) or if they are hydraulic or self adjusting or ??

My questions relate to the advantages of roller rockers, and how to install. My engine does not have roller rockers, just the basic stamped rockers. I would like to install some Ford Racing (or equiv/better) roller rockers. As I understand it, they come in a couple different ratios (1.6 or 1.7) associated with the throw of the arm past the pivot point, and also a couple different "post" sizes associated with the thread size of the post upon which they mount.

1. How would one determine what rocker arm ratio (1.6 or 1.7) to use? Something easy? Other than removing the head and using some clay on the piston......

2. What post size? Do I go measure the current post size with a thread gauge?

3. Valve clearance. Do I install the new roller rockers and then measure the pushrod length with an adjustable push rod (with the adjustment in a mid-point position) and order new push rods? What if I have self adjusting/hydraulic "lifter"??

4. Any recos on good roller rockers? Ford Racing seems like a logical choice but is there a better choice?

5. I imagine there's a very modest hp/tq gain in moving to roller rockers - on a typical 302, what would that be? Maybe 10?

6. Will roller rockers allow the engine to turn up a little higher? I believe the rpm limiter (Mallory) is set at 5,500 right now. I'd love to be able to move it up to 5,750 perhaps.

Again, please excuse the newbie questions here. Appreciate any/all thoughts.

Thanks.

 

[Jac Mac]

Please excuse these dumb questions here....

All of my engine building experience is with smaller displacement non-US engines. So, I've been learning about large displacement US V8s (mostly SBF,BBF) over the last 5 or so years and can really appreciate some of the inherent design advantages (simplicity and large displacement). I have a Ford Racing crate engine in my GT40 - a basic 302 with alloy heads and large holley. It makes about 350/350 according to the specs (which is plenty for me). I have no idea if I have fixed length push rods (and should therefore periodically check valve clearance) or if they are hydraulic or self adjusting or ?? Your pushrods will be fixed length & non hardened with existing setup, lifters will be hydraulic( self adjusting) & either roller or flat tappet

My questions relate to the advantages of roller rockers, and how to install. My engine does not have roller rockers, just the basic stamped rockers. I would like to install some Ford Racing (or equiv/better) roller rockers. As I understand it, they come in a couple different ratios (1.6 or 1.7) associated with the throw of the arm past the pivot point, and also a couple different "post" sizes associated with the thread size of the post upon which they mount.Roller rockers that simply bolt on where the existing ones fit are available in both ratios- it would pay to check valve to piston clearance if going to 1.7/1 ratio

1. How would one determine what rocker arm ratio (1.6 or 1.7) to use? Something easy? Other than removing the head and using some clay on the piston......This depends on how much mechanical talent you have removing the valve spring & replacing with a very light checking spring to verify Valve/Piston clearance is fairly simple if you know what your doing..

2. What post size? Do I go measure the current post size with a thread gauge?Should be 5/16" UNC in your current setup, thats what the bolt on roller replacements wil also use.

3. Valve clearance. Do I install the new roller rockers and then measure the pushrod length with an adjustable push rod (with the adjustment in a mid-point position) and order new push rods? What if I have self adjusting/hydraulic "lifter"??If I was doing this I would spend the few extra bucks & buy the rockers with adjustment screw @ pushrod end.

4. Any recos on good roller rockers? Ford Racing seems like a logical choice but is there a better choice?As you know im a Kiwi, I would use the Yella Terra paired shaft type in this application, there might be US vendors for this type or similarproducts from other vendors

5. I imagine there's a very modest hp/tq gain in moving to roller rockers - on a typical 302, what would that be? Maybe 10?The 1.7 setup might add that, but if the std type are in good condition then I doubt much power increase in the RPM range you mention.

6. Will roller rockers allow the engine to turn up a little higher? I believe the rpm limiter (Mallory) is set at 5,500 right now. I'd love to be able to move it up to 5,750 perhaps.Limiting factor in your case will be valve springs & hydralic lifters along with lifter preload as installed, hydraulic roller lifters will be even more limiting to higher rev limit

Again, please excuse the newbie questions here. Appreciate any/all thoughts.

Thanks.

Newbie Cliff??? you should know better than try to pull the wool over this Kiwis eyes

 

[Rick]

Crower makes a very good product.