Harland Sharp rocker shaft alignment

[Illahe]

Hello gentlemen,

Has anyone ran into alignment issues with the Harland Sharp Small Block rocker shafts? The pedestal hardware bore is pushing .400+ but the heads are 5/16 hardware. I made some sleeves out of brass tubing for alignment, but still have excessive radial clearance, especially on the oil port pedestal. This concerns me with rocker arm alignment, as the pushrod tubes are at max tolerance during full lift.

 

[Newbomb Turk]

I would not use the brass sleeves. The spacers and shims are what aligns the rockers.

The bolt or stud being centered in the hole in the rocker shaft means nothing.

 

[Illahe]

I would not use the brass sleeves. The spacers and shims are what aligns the rockers.

The bolt or stud being centered in the hole in the rocker shaft means nothing.

The concern was that the hold down for the shaft doesn't seem to center itself on the hardware, effecting the shim pack when installed. Your correct that the shaft itself is a non issue. A set of PRW rocker shaft hold downs didn't have the .400" hole for 5/16 hardware and cleared up the side to side play consistently.

Thank you for the response.

 

[Newbomb Turk]

The concern was that the hold down for the shaft doesn't seem to center itself on the hardware, effecting the shim pack when installed. Your correct that the shaft itself is a non issue. A set of PRW rocker shaft hold downs didn't have the .400" hole for 5/16 hardware and cleared up the side to side play consistently.

Thank you for the response.

Yeah, some of the shafts (yours for example) are getting sized for 3/8 bolts rather than the 5/16 bolts the OE heads have.

It makes things sloppy for sure.

Edit: what heads are those? I thought all the aluminum heads had 3/8 hold down hardware.

 

[crackedback]

The half moon recess in the pedestal aligns the shaft. Where the shaft rotates inside that half moon is insignificant other than maybe oil hole alignment at each rocker.

The oil pedestal you definitely do not want restriction. JMO

IMO, this is not something you should spend any time being concerned about. Pedestal and hold down lock the shaft in place, it's not going anywhere.

 

[Illahe]

Yeah, some of the shafts (yours for example) are getting sized for 3/8 bolts rather than the 5/16 bolts the OE heads have.

It makes things sloppy for sure.

Edit: what heads are those? I thought all the aluminum heads had 3/8 hold down hardware.

Speed master.

 

[GTX JOHN]

We always tap the heads for 3/8 Hold down Hardware
when using these Rockers/Shafts.

 

[mopowers]

We always tap the heads for 3/8 Hold down Hardware
when using these Rockers/Shafts.

Do you install helicoils too?

 

[GTX JOHN]

I do....

However, I run at least 200 seat pressure on the springs.

 

[Illahe]

We always tap the heads for 3/8 Hold down Hardware
when using these Rockers/Shafts.

I do....

However, I run at least 200 seat pressure on the springs.

 

[Illahe]

Thank you for the information. I'm not running anything over 135# on the seat at this time, but If these heads end up with a roller cam they will be upgraded to 3/8 hardware.

 

[GTX JOHN]

Now thinking about it one more time,
as I recall the torque is only around 20LBs
or so on the fasteners.

The holes for the Harlan Sharp shafts are big and
I wonder if the shafts ever got slightly loose it
would have a lot of room to walk back and forth
messing up geometry on everything. I have no
experience as I always run the 3/8 bolts.

Probably would not happen but I worry about everything!

What does everyone else think?

 

[Newbomb Turk]

Now thinking about it one more time,
as I recall the torque is only around 20LBs
or so on the fasteners.

The holes for the Harlan Sharp shafts are big and
I wonder if the shafts ever got slightly loose it
would have a lot of room to walk back and forth
messing up geometry on everything. I have no
experience as I always run the 3/8 bolts.

Probably would not happen but I worry about everything!

What does everyone else think?

If the shafts are tight they shouldn’t move in the saddles.

 

[Mopar Sam]

I think @NC Engine Builder had a post on here that showed the rocker stands on the SM heads had the wrong radius for the rocker shaft diameter.

My ProComp, pre-SM heads, had 5/16 threads in the stands, but I milled the stands down for the W2 offset rocker blocks. I removed the 5/16 helicoils (That was the real pain of the job) and installed 3/8 helicoils. They were right at 1" long if I remember right. I got them from McMaster Carr.

 

[Illahe]

I think @NC Engine Builder had a post on here that showed the rocker stands on the SM heads had the wrong radius for the rocker shaft diameter.

My ProComp, pre-SM heads, had 5/16 threads in the stands, but I milled the stands down for the W2 offset rocker blocks. I removed the 5/16 helicoils (That was the real pain of the job) and installed 3/8 helicoils. They were right at 1" long if I remember right. I got them from McMaster Carr.

The pedestal casting is not very true on my cylinder heads and there is an indexing relief machined in the sides of the center pedestal to locate the thrust washer (I presume as its seems to align with the PRW 5/16 hold downs). I didn't care for the misalignment of the Harland Sharp hold downs with the 5/16 hardware and wanted a consistent thrust endplay cylinder to cylinder.

 

[1WildRT]

Keep on mind the rocker shaft is an oil passage, as such the #2 & #4 bolt holes need clearance on the bottom of the shaft... Bush those tight & you've created a problem...

 

[Illahe]

Keep on mind the rocker shaft is an oil passage, as such the #2 & #4 bolt holes need clearance on the bottom of the shaft... Bush those tight & you've created a problem...

Yes, the oil port alignment was a concern of mine. The assemblies are currently mocked up with the 3/8 sleeves on both outer mounting pedestals and the 5/16 PRW hold downs in the center 3 pedestals with a good fitment. Had I known that the set up was for 3/8 hardware the heads could have been modified for the Harland sharp system. When the 273 adjustable were previously installed the valve stem length was subject for a proper rocker arm sweep across the stem, thus the H/S system seemed to get positive review and a choice was made.

 

[GTX JOHN]

I think @NC Engine Builder had a post on here that showed the rocker stands on the SM heads had the wrong radius for the rocker shaft diameter.

My ProComp, pre-SM heads, had 5/16 threads in the stands, but I milled the stands down for the W2 offset rocker blocks. I removed the 5/16 helicoils (That was the real pain of the job) and installed 3/8 helicoils. They were right at 1" long if I remember right. I got them from McMaster Carr.

Exactly how we do our Superstock engines.
With the valvetrain we run and related RPMs we
have broken several cast in pedestals.

If you have seen a Spintron or a Video of the valve train
on one = You would understand!