Exhaust rocker geometry question

[63409impala]

I know you guys are probably tired of me posting questions here, but you're all I have. Noone near me knows w motors. I understand that the exhaust rocker geometry isn't ideal. Toss in a .100 longer valve and it's more so of an issue. I guess my question is about pushrod length. If I do the old half lift theory, it comes out to a 9.450 length pushrod with a lash cap. Even then, the roller tip is uncomfortably close to the edge of the valve tip. If I go shorter, the rocker sits at an uphill angle, but the roller is towards the middle of the tip and then I'm worrying about rocker/retainer clearance issues. Do I go as short as I can here without retainer/rocker contact? I don't want to mess this up. Thank you. EDIT... I also have an adjustable pushrod I'm using as well as having lightweight checker springs.

 

[Ishiftem]

Narrowest pattern that’s still on the center 3rd of the valve tip and let it eat. Throw the lash caps in the garbage. Clearance the rocker if it’s in the way of the retainer.

 

[63409impala]

What do you mean center 3rd of the valve tip?

 

[scott hall]

Think of the valve stem end in 1/3’s. Stay in middle 1/3’rd.

 

[Fathead Racing]

Its not perfect but roller rockers are forgiving as they do not have the side loading that the stock scrub type rockers. Comp Cams has enough off the shelf lengths to satisfy me.

 

[63409impala]

So its normal of the exhaust pushrod will be possibly the same length as the intake or shorter? I guess I'm always used to the exhaust being longer than the intake on a traditional big block. Again, sorry for the questions, I'm just trying to learn as best I can

 

[Barry Taylor]

Recently i was second guessing my pushrod length since i had changed from a pedistal rocker setup to a conventional rocker stud setup. Pulled stud girdle and rocker and cleaned valve tip and roller then painted with a sharpie and reassembled. Spun motor over 4-5 times and wala found it dead on. The Harland Sharp rockers do look like their hanging over a lot per what i saw with my pictures. Hope this helps!!

 

[63409impala]

Recently i was second guessing my pushrod length since i had changed from a pedistal rocker setup to a conventional rocker stud setup. Pulled stud girdle and rocker and cleaned valve tip and roller then painted with a sharpie and reassembled. Spun motor over 4-5 times and wala found it dead on. The Harland Sharp rockers do look like their hanging over a lot per what i saw with my pictures. Hope this helps!!

So, at rest do your exhaust rockers sit at an upwards angle? Just curious

 

[Barry Taylor]

Yes, in the open position. In the pics. You can see the rocker angle.

 

[63409impala]

Ok.

 

[Barry Taylor]

I really didn’t have to color the valve stem tips because i had recently freshened the motor. My machinest had surfaced the valve tips so i already had a good defined pattern. “ see pic.”

 

[Fathead Racing]

Gotta love me some Harland Sharp rockers!

 

[63409impala]

Yessir

 

[La Hot Rods]

How does the adjuster nut look in the slot during the travel of the rocker arm?

 

[63409impala]

I know with a 9.100 length pr, it was borderline hitting the rocker with the head portion of the polylock

 

[63409impala]

But then again, I can remove the .122 thick washer under the exhaust stud and possibly gain some clearance

 

[La Hot Rods]

Can you post any pictures?

 

[63409impala]

Hang tight. What would you like pictures of?

 

[La Hot Rods]

Some good side shots, valve open, valve at half lift and valve closed would be great.

 

[63409impala]

Here is the rocker at rest and at full lift with a 9.100 length pushrod. Same length as my intake pushrod. I also removed the washer from under the exhaust stud to lower the stud. Id love to find some that fit flush against the head.