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Rocker shaft stud kit

Started by Sunny Jim, December 16, 2018, 04:03:32 AM

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Sunny Jim

Time to do the top end. So 117 CP set at 10.8;1. Sticking with the CR460 -  Nothing too fancy, But I would like to replace the rocker shaft bolts with a stud kit or whatever.
Can anyone give me a recommendation please?

BigT

What's wrong with reusing the stock 12 point bolts?

Sunny Jim

I only want to pull it apart once and given some discussion on rocker bolt issues, I figured I would ensure all is well on assembly. That's it really.

Durwood

Fueling sells an ARP kit.

I have been using the stock bolts without issue, clean them and the holes up in the heads, re apply loc-tite, torque to spec.

BigT

Quote from: Sunny Jim on December 16, 2018, 05:21:13 AM
I only want to pull it apart once and given some discussion on rocker bolt issues, I figured I would ensure all is well on assembly. That's it really.

I've read about a few issues with the head bolts snapping on re-use but not the rocker bolts.

RoadGlideRob

Quote from: Sunny Jim on December 16, 2018, 04:03:32 AM
Time to do the top end. So 117 CP set at 10.8;1. Sticking with the CR460 -  Nothing too fancy, But I would like to replace the rocker shaft bolts with a stud kit or whatever.
Can anyone give me a recommendation please?

I used the Feuling kit, part #3037 for the rocker arms and also bought their Cam bolt kit.

RoadGlideRob

Quote from: BigT on December 16, 2018, 05:56:54 AM
Quote from: Sunny Jim on December 16, 2018, 05:21:13 AM
I only want to pull it apart once and given some discussion on rocker bolt issues, I figured I would ensure all is well on assembly. That's it really.

I've read about a few issues with the head bolts snapping on re-use but not the rocker bolts.

bolts aren't the issue,  its the rocker arm shafts that are cracking.  the stud kit spreads the torque better on that shaft with its very thin walls.  I think GMR has posted some pics on his facebook page of shafts that have cracked with the stock bolts.

BVHOG

In the fueling info they show the problem being the rocker support stands cracking, the fueling kit works well but is no bargain. I called ARP and bought studs and nuts separate and make it a part of every top end build. The fueling Cam bolt kits are a must IMHO
If you don't have a sense of humor you probably have no sense at all.

BigT

Quote from: BVHOG on December 21, 2018, 05:22:48 PM
In the fueling info they show the problem being the rocker support stands cracking, the fueling kit works well but is no bargain. I called ARP and bought studs and nuts separate and make it a part of every top end build. The fueling Cam bolt kits are a must IMHO

Are there a ARP part numbers for the studs and nuts?

les

Can someone please post the specification for the studs (size, TPI each end, length)?

PoorUB

Quote from: les on December 26, 2018, 01:49:45 PM
Can someone please post the specification for the studs (size, TPI each end, length)?

They would be grade 8, 5/16" UNC on both ends, not sure of the length, but if you have a bolt handy, add 1/2". anyone know the specs for a HD P/N 1039?
I am an adult?? When did that happen, and how do I make it stop?!

14Frisco

Quote from: PoorUB on December 26, 2018, 04:34:02 PM
anyone know the specs for a HD P/N 1039?

SCREW, 5/16-18 x 2-1/2 hex flange hd. (Grade 8)

les

Usually, double threaded studs have a course thread on one end and a fine thread on the other.  Hopefully, I'll get lucky and someone who's got a set of the Feuling on the bench will take a quick measurement and post.

The True Value Hardware store a couple of miles from my house sells fasteners, including automotive studs.  This is where I get my studs for the cam plate.  Let's see...  Each of those cam plate studs cost less than 4 bits a stud.  I'm guessing the bigger ones will be less than a buck a stud.  Hmmm...I'll let you guys put 2-n-2 together.

Once I get the measurement, I'll run down there and see if they have this size.  Until then, you can continue buying the $140 set.

BigT

December 27, 2018, 03:35:55 AM #13 Last Edit: December 27, 2018, 03:42:58 AM by BigT
      The screw isn't listed in my HD 2017 parts book hardware list but measures 1-1/4" long not 2-1/2".  Total length including the 12 point head looks to be 1-9/16"

PoorUB

Quote from: BigT on December 27, 2018, 03:35:55 AM
      The screw isn't listed in my HD 2017 parts book hardware list but measures 1-1/4" long not 2-1/2".  Total length including the 12 point head looks to be 1-9/16"

I believe the 2-1/2" is correct, from my memory these screws are fairly long. The rocker support is probably over an inch thick, plus the screw goes through the lower rocker box and into the head.

I am an adult?? When did that happen, and how do I make it stop?!

BigT

Quote from: PoorUB on December 27, 2018, 05:29:47 AM
Quote from: BigT on December 27, 2018, 03:35:55 AM
      The screw isn't listed in my HD 2017 parts book hardware list but measures 1-1/4" long not 2-1/2".  Total length including the 12 point head looks to be 1-9/16"

I believe the 2-1/2" is correct, from my memory these screws are fairly long. The rocker support is probably over an inch thick, plus the screw goes through the lower rocker box and into the head.

My ruler might be a tad better than you memory. LOL My motor is apart and I listed actual measurements

Ohio HD

I'm sure BigT is correct as part number 1039 isn't the correct number anyway.

Below is what I think is needed.


10200503 - SCREW 5/16-18 X 1-1/4 12 PT. HEAD GRADE 8

PoorUB

I forgot where I was at. I was thinking Twin Cam. :oops:
I am an adult?? When did that happen, and how do I make it stop?!

Billy

Quote from: PoorUB on December 27, 2018, 06:50:12 AM
I forgot where I was at. I was thinking Twin Cam. :oops:

Haha. I was just getting ready to post this.

I believe you're thinking about a Twin Cam.

The M8 has raised bosses on the cyl heads which cradle the rocker shafts and secures them with bolts in the ends. The lower rocker boxes can be removed with the rocker arms in place providing there is enough backbone clearance.
Lazyness is the Mother of Invention

les

Quote from: Ohio HD on December 27, 2018, 06:26:39 AM
I'm sure BigT is correct as part number 1039 isn't the correct number anyway.

Below is what I think is needed.


10200503 - SCREW 5/16-18 X 1-1/4 12 PT. HEAD GRADE 8


Yes, that is the part number.  So, if the bolts are 1 1/4" long, I'll look to see if True Value has studs in the 2" length range.

les

December 29, 2018, 12:08:22 PM #20 Last Edit: December 30, 2018, 05:11:08 PM by FSG
So, I just ran down to the hardware store and bought this automotive stud.  It is $2.34 including tax.

5/16"x18x24x2"

The course end has about .525" of usable thread depth.  The fine end has a good 1" of usable thread depth.

Now, we need to get someone on here to perform some measurements on a real M8 rocker assembly to verify that the .525" depth of the stud's course thread (18 TPI) is enough completely ground out at the bottom of the bolt hole, the 2" stud is an appropriate length to cap off with the 5/16"x24 ARP nut, etc.


[attach=1,msg1274084]

les

A 10-piece set of ARP nuts from Summit Racing is about $15.  A set of eight 2" studs is about $20.

If these studs work, the entire kit comes in under $35.

BigT

The stock 1-1/4" bolt protrudes 3/4" thru the rocker shaft. I was able to thread in just over that (.8) into the head rocker boss. The 1st 1/2" of the head rocker boss is machined out to clear the rocker and has thinner walls around the threads. Having a full 3/4" of thread engagement would optimal.   The rocker shaft takes up  a 1/2".   A 2" stud seems like it's going to be too long.

les

Quote from: BigT on December 29, 2018, 02:05:58 PM
The stock 1-1/4" bolt protrudes 3/4" thru the rocker shaft. I was able to thread in just over that (.8) into the head rocker boss. The 1st 1/2" of the head rocker boss is machined out to clear the rocker and has thinner walls around the threads. Having a full 3/4" of thread engagement would optimal.   The rocker shaft takes up  a 1/2".   A 2" stud seems like it's going to be too long.

The 2" length being too long is not a problem.  Pre-threading a thread chaser and a cutoff wheel solves that problem.  When you say a full 3/4" of thread engagement would be optimal, are you saying that the .525" available thread on the stud is about a quarter inch not enough?

BigT

Just saying that the last 1/4" is in the thickest part of the casting.