All Big Six Ordered the Scorpion 1059 Roller Rockers

Relates to all big sixes

efloth

Well-known member
It's a 1993, no upgrades at all. Just bone stock sucking down 13.5 mpg and a weak power band. It picks up a bit at 1500 but between 2 and 3k is where it pulls the most. Did you have to mod for the e85 or will it run with it regardless? I'm on a tiiiiight budget so I'm really trying to figure out what I actually need vs the ideal setup. Did you refigure your fuel mapping before you did the upgrade or just after the fact?
The only mod required for e85 is injectors and tuning. I put in the injector voltage offset data and increased the injector high slope scalar from 16 to 40 to get it running and dialed her in from there. The process is pretty simple and I created a spreadsheet to make dialing in fuel a copy/paste process. Timing adjustments started by adding six degrees across the board. Make sure your base timing is set to the stock 10btdc with the spout connector unplugged. Accel enrichment also needed to be reduced to keep her from going too rich when mashing the pedal. Ill make a video soon to document the tuning process in tunerpro. I can just send you my bin file for you to start with if you have the same injectors and rockers.
 

reracer

New member
I'm assuming people buy the Scorpion rockers to get a little more lift from their cam, and ease of installation. My question is, if you're getting a new cam, is there a benefit to running the 1.73 ratio vs the 1.6 assuming you end up with the same net lift? It appears to me that the Scorpion rockers are a little better quality than the Harland Sharps.
 

pmuller9

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I'm assuming people buy the Scorpion rockers to get a little more lift from their cam, and ease of installation.
Anytime there is near .500" valve lift or more it is recommended to go to a roller rocker arm.
The stock stamped rockers fall short of the 1.6 ratio and some have had lubrication problems and began squealing.

The Scorpion rockers are a bolt down item on the EFI head where as a stud mount requires some machining to lower the stud towers along with pushrod guide plates.

There are times when you might want to increase the valve lift when the cam has less than .500" lift. The 300 six responds well to valve lift.
Harland Sharp makes a 1.75 ratio stud mount while the Scorpion is a 1.73 ratio

It doesn't matter at this level but the Harland Sharp have a better reputation than Scorpion.
 
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reracer

New member
Anytime there is near .500" valve lift or more it is recommended to go to a roller rocker arm.
The stock stamped rockers fall short of the 1.6 ratio and some have had lubrication problems and began squealing.

The Scorpion rockers are a bolt down item on the EFI head where as a stud mount requires some machining to lower the stud towers along with pushrod guide plates.

There are times when you might want to increase the valve lift when the cam has less than .500" lift. The 300 six responds well to valve lift.
Harland Sharp makes a 1.75 ratio stud mount while the Scorpion is a 1.73 ratio

It doesn't matter at this level but the Harland Sharp have a better reputation than Scorpion.
So, you're saying there is no benefit to a higher ratio rocker/lower cam lift combination?

Example: cam lift .289 x 1.73 rocker = .500 net lift at valve
or
cam lift .312 x 1.60 rocker = .500 net lift at valve

Since a roller rocker is more efficient than a stock rocker, wouldn't it be advantageous to run a 1.73 rocker with a lower lift cam to achieve the desired lift?
 

pmuller9

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So, you're saying there is no benefit to a higher ratio rocker/lower cam lift combination?

Example: cam lift .289 x 1.73 rocker = .500 net lift at valve
or
cam lift .312 x 1.60 rocker = .500 net lift at valve

Since a roller rocker is more efficient than a stock rocker, wouldn't it be advantageous to run a 1.73 rocker with a lower lift cam to achieve the desired lift?
That is a different question to what I thought you were asking in your previous reply. Sorry about that.

If you have a choice as to how you want to accomplish a certain valve lift take the higher lobe lift with less rocker ratio providing we are comparing roller rocker to roller rocker.

Let's say the spring pressure at .500" lift is 300 lbs.
The pressure on the pushrod and lifter to cam lobe face is 300 x (rocker ratio)
For a 1.6 ratio the force on the lifter is 300 x 1.6 = 480 lbs
For a 1.73 ratio the force is 300 x 1.73 = 519.

However as I mentioned before, at .500" valve lift and above, you want to replace the stock rocker arms with roller rocker arms regardless of the rocker ratios.

Another case would be if the cam has high lobe lift and a 1.73 Scorpion rocker would push the valve springs into coil bind or push the limit on valve travel on an EFI head, the head would need to be converted to stud mount rockers with guide plates so you can use the 1.6 ratio Harland Sharp rockers.

So it depends on the situation
 
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reracer

New member
That is a different question to what I thought you were asking in your previous reply. Sorry about that.

If you have a choice as to how you want to accomplish a certain valve lift take the higher lobe lift with less rocker ratio providing we are comparing roller rocker to roller rocker.

Let's say the spring pressure at .500" lift is 300 lbs.
The pressure on the pushrod and lifter to cam lobe face is 300 x (rocker ratio)
For a 1.6 ratio the force on the lifter is 300 x 1.6 = 480 lbs
For a 1.73 ratio the force is 300 x 1.73 = 519.

However as I mentioned before, at .500" valve lift and above, you want to replace the stock rocker arms with roller rocker arms regardless of the rocker ratios.

Another case would be if the cam has high lobe lift and a 1.73 Scorpion rocker would push the valve springs into coil bind or push the limit on valve travel on an EFI head, the head would need to be converted to stud mount rockers with guide plates so you can use the 1.6 ratio Harland Sharp rockers.

So it depends on the situation
No need to be sorry. I'm always in pursuit of knowledge, and the only way to be successful is to ask someone who has more experience. I appreciate your responses immensely, as I'm sure everyone does. Thank you.
 

Pontus

Well-known member
Supporter 2021
The Scorpion roller rockers have a different Geometry that the stock stamped rocker.
The installed rocker height will be different.
Shims should go under the rail.
Bringing this over from the Promaxx thread since this is related to the rockers not the head...

Are you sure the shims go UNDER the rail? They look to be specifically cut to fit IN the rail directly under the pedestal, so why aren't they just round washer shims if they go under? If you put them under the rail, you have to keep the same shims on both intake and exhaust so you can't adjust for differences in valve seat height between the two because the bar wouldn't be level to seat the pedestals correctly. Wouldn't that be putting stress on the bar and/or the bolt? Frustratingly, none of the instructions that I can find specify where the shim goes, but the shape seems to indicate they go inside the rail and videos I'm seeing show them that way too.
 
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pmuller9

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Are you sure the shims go UNDER the rail? They look to be specifically cut to fit IN the rail directly under the pedestal, so why aren't they just round washer shims if they go under? If you put them under the rail, you have to keep the same shims on both intake and exhaust so you can't adjust for differences in valve seat height between the two because the bar wouldn't be level to seat the pedestals correctly. Wouldn't that be putting stress on the bar and/or the bolt? Frustratingly, none of the instructions that I can find specify where the shim goes, but the shape seems to indicate they go inside the rail and videos I'm seeing show them that way too.
The purpose of the rail is to keep the pedestals from turning so it is best if the pedestal sits as deep in the rail as possible.
If the valve job has the valve stem heights different enough to need a different shim height for the intake and exhaust valves then that is not a proper valve job and needs to be corrected.
 

Pontus

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The purpose of the rail is to keep the pedestals from turning so it is best if the pedestal sits as deep in the rail as possible.
If the valve job has the valve stem heights different enough to need a different shim height for the intake and exhaust valves then that is not a proper valve job and needs to be corrected.
Fair nuff, under it is then. I paid my machinist in full so I could get a firm promise to get the work finally done, so I should be seeing a freshly machined block and head by the 15th. So just to confirm my process here...
1. Check geometry first. Install rockers with adjustable pushrod, rotate motor (or should I just push on the rockers by hand for full travel?) and check that they roll on center of valve tip.
2. Add shims as necessary to correct geometry.
3. Check pushrod length at zero lash for each cyl. With dry pr and lifters?
4. Purchase pushrods that get me .020-.060" of preload.
Does that sound accurate, am I missing anything?
 

Green ford f150

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Supporter 2021
The lifter lash is fixed at about half of the lifters piston travel. I don't know of any spacers currently being made for the 4.9, but I doubt that they are. The 5.0 spacers were quite common and were made of a bakelite material if I remember correctly. This also offered the secondary benefit of being an insolator against heat transfer, ABS might be able to work if fuel dosnt harm it seems to be a very tough plastic. Some of old time racers such as Dyno Don Nickelson even used plywood to make spacers and parts of intakes manifolds.
Very good insulator still have some wood carb spacers.
 

pmuller9

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1. Check geometry first. Install rockers with adjustable pushrod, rotate motor (or should I just push on the rockers by hand for full travel?) and check that they roll on center of valve tip.
2. Add shims as necessary to correct geometry.
3. Check pushrod length at zero lash for each cyl. With dry pr and lifters?
4. Purchase pushrods that get me .020-.060" of preload.
Does that sound accurate, am I missing anything?
1. Rotate the crankshaft and use the actual cam lobe lift to check center travel on valve stem tip.
4. Try for .060" to .075" preload. Check to see what the full lifter plunger travel is. It may be close to .200"
Everything looks correct.
 
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pmuller9

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On an EFI head the installed height will be closer to 1.640" on the intake and less on the exhaust.
At 1.640" the spring pressure will be 97 lbs which is fine.

We like to get rid of the stock exhaust rotating retainers which can fail and replace with intake retainers.

If you want to bring the retainers up closer to 1.700" you can use the Howards 93010 .050" up keepers.
 

HitmanX

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Supporter 2021
Ah yes, I should have mentioned it is a stock '92 EFI engine in a '92 F150. 320k, never opened to my knowledge as had an OE valve cover gasket when I replaced it.

I pestered the OP to see if he had the other six intake retainers floating around still, if not I will order a set of 12 of the Qualfast units then donate my intakes to my pal in AZ with a '95 4.9. Any advantage to having the retainers around 1.700"? I will probably go with whatever is OE spec, I have the factory manual at the house and I am sure it has installed heights for the EFI.

Just did Comp 910s on my 7.3 a few years back and that was a nuisance to shim as it was in frame!

Any recommended shims for the 903 spring set?
 

pmuller9

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Any advantage to having the retainers around 1.700"? I will probably go with whatever is OE spec, I have the factory manual at the house and I am sure it has installed heights for the EFI.

Just did Comp 910s on my 7.3 a few years back and that was a nuisance to shim as it was in frame!

Any recommended shims for the 903 spring set?
The 1.700" retainer height will give you 80 lbs closed pressure which is close to stock specs.
If you install a little tighter it will be OK but for the sake of cam lobe and lifter longevity it is better not to have a lot more spring pressure than needed.

You will not need shims because the 903 spring will not have less spring pressure than needed.
 

HitmanX

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Supporter 2021
I am using a 320k mile head, surely there is going to be seat and valve wear I would imagine. Figured the shims will get me to the correct installed height like I did on the Powerstroke. Those were all over the place!

With the Qualfast retainers, will that change OE exhaust installed height or simply eliminate that rotator?
 

pmuller9

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With the Qualfast retainers, will that change OE exhaust installed height or simply eliminate that rotator?
The OE exhaust spring is shorter than the intake spring because of the rotator retainer.
since the 903 springs are the same height the Qualfast retainers should bring the installed height for the exhaust spring close to the intake height.

As you take the head apart let us know what you find.
 
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