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Discussion Starter · #1 · (Edited)
What type of build are these required? The folks doing my head suggested them due to the geometry change with milling the heads 60tho. (I believe that is the amount) and also adjustable push rods.. opinions and reasons in laymens terms greatly appreciated.. Chuck
 

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Chuck K. said:
What type of build are these required? The folks doing my head suggested them due to the geometry change with milling the heads 60tho. (I believe that is the amount) and also adjustable push rods.. opinions and reasons in laymens terms greatly appreciated.. Chuck

It my understanding that the need for roller rockers is largely a function of camshaft lab profile (lift, etc.). I observe the rule of thumb from many on the forum- use them if the lift is over .550 and some disagree saying the the critical lift is much higher.
 

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Chuck K. said:
What type of build are these required? The folks doing my head suggested them due to the geometry change with milling the heads 60tho. (I believe that is the amount) and also adjustable push rods.. opinions and reasons in laymens terms greatly appreciated.. Chuck
I don't believe that milling heads .060" is a reason to use roller rockers. you may want to find out what the cam profile is going to be in order to make that decision...........Bill
 

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Basically, if you can afford them and want them, then get a set.............I call that "peace of mind engine building"

The motor will run with the stock rockers and big lift cams and you will be surprised just how much mileage you will get before the guides get noticeable wear on them.

Roller Rockers will almost eliminate guide wear and is supposed to improve throttle response and performance but I doubt if it would show up on a dyno.

Valve train geometry is what really needs to be done when setting up a head especially when different valves have been installed as this can and usually does change valve tip heights, which will change where the rocker sits on top of the valve tip at full closed and full open positions.

All the best, Ozzie
 

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Discussion Starter · #5 ·
I guess If I had used my head I would have provided a little more info. on the build..

Thanks all, Ozzy I follow your threads pretty regularly and have learned a lot from you, GRock, HDwrench and others, really miss Doc although I do talk with him time to time.. Being gone from Auto dealerships for 15 years now and tearing into a new motor has me questioning my sanity :sofa:

Chuck.

95" B/B
SE flat tops (cast)
Heads by Baisley hi-performance
Andrew 37G cams
.030 cometic head gasket.
Milling the heads .060
Trying to achieving 9:8 to 1 CR.
V/H Propipe.
HB125 auto. tensioner.
 

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atengnr said:
It my understanding that the need for roller rockers is largely a function of camshaft lab profile (lift, etc.). I observe the rule of thumb from many on the forum- use them if the lift is over .550 and some disagree saying the the critical lift is much higher.
.600 and higher is where they're needed. Got this from more than one mech/machinist. :corn:
 

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Chuck K. said:
I guess If I had used my head I would have provided a little more info. on the build..

Thanks all, Ozzy I follow your threads pretty regularly and have learned a lot from you, GRock, HDwrench and others, really miss Doc although I do talk with him time to time.. Being gone from Auto dealerships for 15 years now and tearing into a new motor has me questioning my sanity :sofa:

Chuck.



Thanks for those kind words Chuck, I guess that for myself and others like GRock and co. most of the threads these days were dealt with last year and the year before by us and now there are quite a number of top flight new guys coming on here that it is good to sit back and look at their responses to questions and mostly the question gets answered long before I can get on here and throw my 2c worth in.

I have regular contact with Doc, and he and his lovely wife pray for me while I'm here, and while I'm not so much into religion, I feel pretty good about it all. Hell of a lousy thing to happen to Doc, (so much for freedom of speech in America!) (Now I dont want anyone bringing this up please, and it does get to me when I think about it.)

What must be understood by all is that every one of us had to learn sometime so all the newbies to motorcycles should never be afraid to ask questions as that is a big part of what this great forum is about..............the sharing of knowledge.

All the best, Ozzie
 

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Rock on

Ozzie is on the money I will add A few thoughts.First your geometry will not change when you mill the heads.You shorten the pushrods to compensate for the shorter parts.These are roller "tip" rockers and won't free up as much hp as a full roller rocker.As Ozzie said you can install them any time on a stock engine if you like.A good idea when gettin into aggressive cam profiles. Allways check the stem protrusion during any head work this keeps the geometry within limits. I beleve that some of the noise that a lot of people get is due to excessive protrusion,(a.k.a. sunkin seats) the cam and lifter get pissed off trying to overcome the incorrect angle. If you have any doubts about the geo. put a dab of prussin blue on the valve stem install and tap the rocker lightly the inpression left on the stem should be approximatly in the center of the stem.You can also rotate the engine to full lift and back and observe the contact point you don't want it to get to close to the front or rear edge of the stem The stem moves a tremendous ammount when running. If the geo. is not correct we have seen the rocker ride off the edge of the stem,makes a mess!!A set of roller (tip) rockers in a small block chevy. is worth @ 20 hp in lost friction.It shows up on our engine dyno as @ 3 hp for the Harley
 

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If you use cam lift the "lift amount is not a set number" The only thing you really need to worry about is geometry. In the 550 area and up you are getting out of a "correct geometry" HD did not set up the valve train to run at higher lift numbers, the roller rocker can helpm in that area by reducing friction with a high lift cam. You are getting away from a HUGE wiping motion on a stock rocker. The rockers that we sell are a corrected rocker. This will work from the point where stock is getting out of the correct angle.

Al is right on the money when he says angry valve train. You might be suprised at the amount of valve train "flex" that occurs, using a corrected rock will get you the lift you are loosing back. The more radical the cam the more resons to use a rocker as such. The free hp is a bonus.

Many shops say that there is no reason or give a huge lift number based on what they have done. My first question is have they really inspected the contact area of roller / pad to the valve??? Head work will alter this. We set ours up to be correct. Cast heads valve seats are not the same they will vary a bit from head to head. So it is a head portes job to check out all the items. I am trying to keep this basic . The hd engine is not rocket science, really we are using a desing that is very forgiving provided we as engine builders do our job and make sure all is at peace with the world; LOL :D


For the small builds they are nice upgrade but not a "must have" for larger cams with more seat psi on the spring pack they become more of a must have, get into a aggressive ramp and then you cross into the MUST HAVE area. One thing that can throw a monkey wrench into the mix is "core shift" on the heads. The new 06 heads with a mustange logo on them seem to be the worst. I am seeing 60 -100 thou core shift, this can make for a bit mre work to ensure proper valve train , port alignment and so on. Not to mention if we do a welded port the cast is a SNAP CRACKLE POP deal. Poor casting seems to be the trend with the mustang logo head. There are two that we see one has a "P" logo and they seem to be mainly a decent head.

That is a bit off topic but all things need to be looked at. What I am saying is that "we cannot say well at 570 lift they are a must have item" ?? Make sense there is more that lift to be concerned with.
 

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At what basic lift do you consider the need for roller rockers and what rocker arms do you reccomend and supply? :huh:
 

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got the money

You can install roller rockers on a stock engine no problem if you have the $
As HDwrench says due to the longer travel of the higher lift cams a stock rocker wipes further across the stem.Along with the higher spring pressures that come along with hi lift cams this means more frictional HP loss.The stock rocker is supposed to be 1.625 to 1 raito ofton when we put a dial gage on the valve and we don't get the lift we should(we know the lobe lift is correct)It is because the rocker is not 1.625-1.Rollers are supposed to have the correct raito.Correct raito = correct lift=more power. At what lift value do you need to go to a roller rocker we seem to have quite wide range of opinions.I don't know. I have run up to 590 lift with stock rockers and had no problems?Most people who do extensive builds (and spend a lot of money say $1500.00 and up) will spring for the rollers.The fact is they are truely a bolt on item that will free up a little power.Probley not able to be seen on the chasses dyno.So you got the money?
I use Jims Machining and have never had a problem.There are some cheep ones on the market @$250.00 But I hear some have broken.I will let someone else guinea pig that deal.
Big Al
 
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