Rocker Arm help

[B3RE]

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I can't say I disagree with what you have said. Once you get into complex 3D machining, there is a lot of cool stuff you can do. Inverse feed rates, if I'm remembering the terminology correctly, makes my head want to explode. But, it's obvious that is not what is being used for machining the Speedmaster heads. With the inconsistency of the stand machining, I wouldn't be a bit surprised if they are being slammed on a fixture in a manual mill and stepped over by hand.

I've rarely programmed manually, unless the CAD/CAM software didn't want to play nice. My boss at that time was a major cheapskate and wouldn't buy the latest, or full versions of the software, so you had to muddle through the limitations.

I understand the idea of being able to comp for tool diameter. I've had to do it many times. And, I'm also familiar with doing Nurb Splines for the purpose of creating customized contours and shapes For example, needing to seamlessly transition from one radius to another in the same arc. It's been a while since I've done this stuff, so my memory of functions may be faulty, and I could be thinking of something else.

My correction kits are done on manual machines. I couldn't justify a CNC for making one off customized parts. If I was running 100 orders at the same time, I could use the machine offsets to quickly change to another order requirements. But, I build engines, do components machining, sling parts, and then make the kits as a unique service to Mopar enthusiasts. It isn't a full time manufacturing endeavor.

 

[12many]

Let’s talk cost to the customer with a set of these heads that need the stands corrected.
Ballpark setup time, actual machining of ten stands. Time, labor etc Cost: $50? $100?$200? More?

Edit: OK, let’s not. Obviously it won’t be cheap.

 

[B3RE]

Let’s talk cost to the customer with a set of these heads that need the stands corrected.
Ballpark setup time, actual machining of ten stands. Time, labor etc Cost: $50? $100?$200? More?

Edit: OK, let’s not. Obviously it won’t be cheap.

I'll let you know when I'm done with them. I might just start a new thread on what I've found and how it was addressed.

 

[Rat Bastid]

I'll let you know when I'm done with them. I might just start a new thread on what I've found and how it was addressed.

Please do! I just checked a Speedmaster head last night. A non CNC head. And the saddles were loose like socks on a rooster on them. What a bummer. I mean, Chrysler was making that radius since at least the early 1960’s and they didn’t have CNC machines to do it. And they got it right.

Just stupid a head can’t be produced without jacking up the saddles like that.

 

[TurboGLH]

Quick update on what I have/found.

I have a set of 2017 dated CNC SM heads, I'm running a fairly mild mech roller, a correction kit from @B3RE and a set of studs instead bolts.

When I installed the heads I seated the studs against the shoulder and backed them out 1/4 turn, and then torqued the nuts to 200 in/lbs. I pulled a cover today and the first one I checked at 200 in/lb was not at full torque. I stepped way down and started incrementing upwards, settling on 100 in/lbs. I ran less than 200mi last year, so they've lost 1/2 tq in that period of time.

Considering the small amount of time, I'll be checking mine frequently until they don't show indications of losing torque.

 

[4spdragtop]

200 in/lb is what SM recommends? Never used alum or studs but that seems awfully low??

 

[TurboGLH]

200 in/lb is what SM recommends? Never used alum or studs but that seems awfully low??

200 in/lb is standard for 5/16-24. Service Manual calls for 210 if I recall correctly.

 

[Bewy]

200 in/b is 16.7 ft/lb. Says 200 in my MM for SBM. You cannot go too high because you are tightening up on a tube, which will be squeezed & go out of round. The risk with low tq...is loosening up.

This is what I did on a 440, but works for SM. I used studs, Loctited into the rocker stand. Then two nuts. One tightened to torque, the other is a locking nut.

 

[PRH]

I’d be trying to determine the reason for the loss of fastener tension.

Is it the nut or stud backing off?

Or is there some settling of the shafts into the saddles/stands?

 

[TurboGLH]

I’d be trying to determine the reason for the loss of fastener tension.

Is it the nut or stud backing off?

Or is there some settling of the shafts into the saddles/stands?

I checked based on reports from a few different people that the saddles have almost a W shape, where there's a raised ridge at the bottom of the radius.

There's some pictures earlier in the thread showing the issue, and some of the aftermath of the shafts coming loose.

With that much pressure on such a small contact surface, it seems that the peak is eventually flattened out by the shaft. But with the side effect of losing torque on the nuts.

 

[PRH]

In this case the nut isn't the initial failure point. It seems, based on what


I checked based on reports from a few different people that the saddles have almost a W shape, where there's a raised ridge at the bottom of the radius.

There's some pictures earlier in the thread showing the issue, and some of the aftermath of the shafts coming loose.

With that much pressure on such a small contact surface, it seems that the peak is eventually flattened out by the shaft. But with the side effect of losing torque on the nuts.

I would have guessed it was that type of scenario going on, as opposed to the fasteners just “coming loose”.

 

[75slant6]

So from reading through this thread, when I take my bare SM heads to the machine shop to have them install the valves/springs, I should just go ahead and have them check/machine the rocker arm stands as well?

 

[cookietruck]

So from reading through this thread, when I take my bare SM heads to the machine shop to have them install the valves/springs, I should just go ahead and have them check/machine the rocker arm stands as well?

lay a rocker arm shaft on the heads and see what it looks like, maybe take a good pic for us all to see?

 

[PRH]

The shaft should fit in the saddle without it being able to be rocked.
Very light downward pressure should lock it in place.

 

[12many]

These heads are looking less and less a great value or even just mediocre value including snagging them during a Black Friday sale.

Buying bare castings, your choice of valves, springs, retainers, locks, seals, shims, shipping cost, paying for the valve job, and correcting the saddles adds up. A geometry correction kit if you’re going to do it up right. Then the time and travel to acquire and get everything in the hands of the actual shop you are paying, the gas etc.

Other than buying them fully assembled and just running them OOTB on a lower HP build

OR

you have the ability to do all this yourself

it adds up to a “False Economy”

Forget about the porting it takes to get the heads competitive with other offerings.
Will anyone be so bold and brave as to actually add up the money and time invested it took for them to get a set of these heads ready to bolt on?
Seems it Just ain’t worth it.

 

[cookietruck]

Will anyone be so bold and brave as to actually add up the money and time invested it took for them to get a set of these heads ready to bolt on?
Seems it Just ain’t worth it.

i was looking at getting bare castings and putting some Ferrea valves and beehive springs in them. Fresh valve job etc.
with the prices of the machine work here it was adding up to about $1400 for a set of heads if I got the bare castings during the black friday sale. no geometry correction kit in the price as i think i could find a rocker arm that would work well enough. The guys that push the correction kits will say any head needs one so that's really a wash as far as price comparisons go.

I wasn't sure I wanted to spend that much, and also they didn't have the bare castings available so i didn't have to make a decision...

 

[TurboGLH]

These heads are looking less and less a great value or even just mediocre value including snagging them during a Black Friday sale.

Buying bare castings, your choice of valves, springs, retainers, locks, seals, shims, shipping cost, paying for the valve job, and correcting the saddles adds up. A geometry correction kit if you’re going to do it up right. Then the time and travel to acquire and get everything in the hands of the actual shop you are paying, the gas etc.

Other than buying them fully assembled and just running them OOTB on a lower HP build

OR

you have the ability to do all this yourself

it adds up to a “False Economy”

Forget about the porting it takes to get the heads competitive with other offerings.
Will anyone be so bold and brave as to actually add up the money and time invested it took for them to get a set of these heads ready to bolt on?
Seems it Just ain’t worth it.

I already did the math, for my particular build, two years ago. If you plan to do anything more than bolt them on, the trick flow heads are the winner in my mind.

I didn't correct the saddles either, and noticed loss of torque when I checked them last week, so that's another thing I need to keep an eye on.
Plus I had the heads on/off the motor/Bridgeport 3 times machining them for pushrod clearance.

$1100 - CNC loaded heads
$100 - shipping to/from PRH
$265 - valve job/backcut/blend/flow
$200 - B3 correction kit

$1665 total

If you find my comment from a few weeks ago, by the time you sink some extra $ into these to get them into decent shape, you're within spitting distance of a set of trick flows.

I'm still ahead, by a bit, but now people have some solid info to make decisions going forward, if the head is good enough out of the box, for them, or not.

If you plan to go through them and fix the obvious stuff, I know that I'd spend the extra $ and get the TFs. If you plan to run them OOTB, then they're a moderate upgrade to a set of iron heads.

On that note, no regrets, I'm running stock J's right now, so the car should be drastically improved in the spring.

 

[75slant6]

These heads are looking less and less a great value or even just mediocre value including snagging them during a Black Friday sale.

Buying bare castings, your choice of valves, springs, retainers, locks, seals, shims, shipping cost, paying for the valve job, and correcting the saddles adds up. A geometry correction kit if you’re going to do it up right. Then the time and travel to acquire and get everything in the hands of the actual shop you are paying, the gas etc.

Other than buying them fully assembled and just running them OOTB on a lower HP build

OR

you have the ability to do all this yourself

it adds up to a “False Economy”

Forget about the porting it takes to get the heads competitive with other offerings.
Will anyone be so bold and brave as to actually add up the money and time invested it took for them to get a set of these heads ready to bolt on?
Seems it Just ain’t worth it.

I’ll keep tabs on my total expenses on mine and post them up (probably be awhile before I get around to getting it all done). I bought bare casting, Black Friday 2020. I did buy valves and head studs from SM at the same time, but I wanted to match springs to whatever cam I run so didn’t see the point of buying a complete set then swapping springs. I’ll see about putting my rocker shafts on my heads this evening and getting pictures of how they sit in the saddles.

 

[12many]

In the spirit of “backwoods mechanics” I will throw this out there for consideration. In lieu of taking the heads in to a shop and having the saddles cut the correct way, an in the field fix is to essentially “lap” the saddles to the shaft. Use adhesive backed sandpaper on the shafts, carefully lap the shaft to the saddles, back and forth, little at a time, check your work as you go only enough aluminum is removed and the shafts fit correctly, with a good radius. I know many are twitching, convulsing, shaking all over etc at the thought but.....it can be done. Just a little Patience

 

[mopowers]

In the spirit of “backwoods mechanics” I will throw this out there for consideration. In lieu of taking the heads in to a shop and having the saddles cut the correct way, an in the field fix is to essentially “lap” the saddles to the shaft. Use adhesive backed sandpaper on the shafts, carefully lap the shaft to the saddles, back and forth, little at a time, check your work as you go only enough aluminum is removed and the shafts fit correctly, with a good radius. I know many are twitching, convulsing, shaking all over etc at the thought but.....it can be done. Just a little Patience

Is there a way to account for the thickness of the sandpaper, or does it not matter?

 

[12many]

Is there a way to account for the thickness of the sandpaper, or does it not matter?

It matters, just have to remove mostly from the bottoms of the saddles using narrow strips so no material is removed from the sides at first.

 

[75slant6]

Looks like I should be alright with the saddles. It appears as though after they make the double pass, they then machine out the center a little to take care of that high spot. Is that something they’ve done for awhile or is this something new? I also checked the valve guide tightness and everything looks good there. That said, I turned off the garage lights, then used a light to check the valve/seat seal and the valves are all going to need to be lapped.

 

[Bakerlite]

I've known about those head saddle machining issues for over 4 years, and the bolt holes on the air gap knockoff intake manifolds for even longer, but people always seem to be surprised to find out about it.

 

[RustyRatRod]

I'll let you know when I'm done with them. I might just start a new thread on what I've found and how it was addressed.

Any updates on this, Mike? Thanks.

 

[B3RE]

Any updates on this, Mike? Thanks.

I've just been extremely busy with parts shortage backlogs. Finally clearing out some of the stuff from late last year, so once everything settles down a bit, I'll try to get a thread started. That's why I've been so scarce around these parts lately.