'82 Shovel Valve lift

[indibil]

In your reply:

To use stock Evo rocker arms you must clearance the the rocker boxes and arms themselves.

Ok, I'll check it out. I have already lowered the interior of the rocker box a bit, where the arm rests on the valve. In theory with an EVO cam the pushrod goes up less.

Don't forget to clearance the boxes for oversized (spring) top collars.

Ok, I'm understanding that putting top collars high lift makes the springs higher, right? They interfere with the rocker box. Sorry for my insistence, I live in Spain and my English is bad, I help google translate.

Round off the square edges of the arms especially the top outer side of the pushrod cups

With an EVO cam, which has a somewhat lower profile, since it has a 1: 625 ratio, I thought the pushrod would go up less.

I don't cut the rocker arm lengths, I cut the rocker shaft spacers.

I have thought about it, but if instead of lowering the rockers, I cut the spacers, they do not make contact with the axle's end stop, and can block the rocker. I understand that the spacer stops at the axle when the shaft appears in the rocker box, and then leaves enough space for the rocker to move.

Or you can run aftermarket rockers (like Jim's roller rockers for shovel. They have yet a different arm ratio than shovel or Evo...)

I have a EVO OEM set, new.

Shorter stock style valve seals instead of tall Teflon or the blue vitton styles

I want to buy in W&W.

Watch for installed stem height too, as valve seats are commonly "sunk" from wear or overzealous cutting.

The engine is OEM, all original. "only" 20,000 miles. The seats are very good condition.

I like to set up valves for as much lift as I think some dude might swap cams into once the bike leaves my hands.
I shoot for .590" to .600" if I can!

good.

Get the slimmest pushrods you can if using Evo lifter blocks. As the p-rod tube angles will drag.
Don't forget to clearance blocks and camchest for roller and lobes.

The EVO N cam or EV27 have a moderate cam lobe, but i will check.

You can drill shovel "solid" lifter pedestals to oil through drilled pushrods.
Not a bad idea to update the oil pump (92 and up or HVHP) and restrict the pinion shaft.

In the past i have used EVO adjustable pushrods. In my avatar engine have this.

Thanks!

[JBinNC]

Evo rocker arms have a different geometry than shovel rocker arms, so you cannot judge where they might hit the rocker box based on a shovel rocker arm.

When cutting the rocker shaft spacers instead of the evo rocker arms, you create a step in the spacer that fits into the end of the rocker arm. The location of the shaft cannot change, as you have correctly surmised. The step just allows for the extra length of the evo rocker arm.

Fortunately, shovel heads are very forgiving of greater installed valve heights, up to .100 extra or more. It does not change the rocker arm geometry enough to be a problem. In your case, your low mileage heads should not have sunk seats.

I would not try to set up the heads for more lift than you are going to use. That is extra work, and only results in lower seat and open pressures for a given set of springs. It's a different story if you are planning to experiment with different lift cams. Your valve float limit will be less with the lower lift cams if this is the approach you take. On the contrary, if you use a heavy spring pack for the really high lifts, that is extra money you don't need to spend when using a lower lift cam. Long way of saying, set the heads up for the cam you are going to use. If you change cams later, change the head set-up at that time. Trust me on this point, it will save you headaches and $$$.

Jim

[JBinNC]

ok, thanks. I will keep all that in mind. I will look for someone who can lower me the lower collars first.
I understand that if I put high lift top collars, they can impact with the rocker boxes.

Lowering the lower collars is my preferred method of adding spring height. There are special cutters for this. You do have to watch the thickness of the head at the spring seat, as the roof of the port is just beneath.

Jim

[indibil]

Evo rocker arms have a different geometry than shovel rocker arms, so you cannot judge where they might hit the rocker box based on a shovel rocker arm.

When cutting the rocker shaft spacers instead of the evo rocker arms, you create a step in the spacer that fits into the end of the rocker arm. The location of the shaft cannot change, as you have correctly surmised. The step just allows for the extra length of the evo rocker arm.

Fortunately, shovel heads are very forgiving of greater installed valve heights, up to .100 extra or more. It does not change the rocker arm geometry enough to be a problem. In your case, your low mileage heads should not have sunk seats.

I would not try to set up the heads for more lift than you are going to use. That is extra work, and only results in lower seat and open pressures for a given set of springs. It's a different story if you are planning to experiment with different lift cams. Your valve float limit will be less with the lower lift cams if this is the approach you take. On the contrary, if you use a heavy spring pack for the really high lifts, that is extra money you don't need to spend when using a lower lift cam. Long way of saying, set the heads up for the cam you are going to use. If you change cams later, change the head set-up at that time. Trust me on this point, it will save you headaches and $$$.

Jim

Lowering the lower collars is my preferred method of adding spring height. There are special cutters for this. You do have to watch the thickness of the head at the spring seat, as the roof of the port is just beneath.

Jim

Thanks for all info.

I may misunderstand you, but instead of lowering the bottom collars, do I have to lower the seat collar on the head? But I can't lower the guide anymore, I must keep his seat.

I don't need more than .485 or .495 lift, I don't want a dragster, just use a moderate EVO tree.

I will buy the high lift springs, and the top collars, but I don't find in medium lift w & w collars, only the high lift.

Thank you.

[JBinNC]

Andrews mid lift shovel upper collars part #276150.

Jim

[JBinNC]

Thanks for all info.

I may misunderstand you, but instead of lowering the bottom collars, do I have to lower the seat collar on the head? But I can't lower the guide anymore, I must keep his seat.

I don't need more than .485 or .495 lift, I don't want a dragster, just use a moderate EVO tree.

I will buy the high lift springs, and the top collars, but I don't find in medium lift w & w collars, only the high lift.

Thank you.

When lowering the bottom collar, you are cutting the head around the guide. You are quite right, the guide position should not be changed.

Jim

[indibil]

Thanks Jim!!!

[Dragstews]

I like the KPMI springs ...

This spring kit I could had set the installed height at 1.450"- 1.470" and have 171 lbs of closed seat pressure and at 0.0550" lift 385 lbs at open ..

But I choose to set up the installed height up at 1.500"- 1.520"
Seat pressure closed is at 150 lbs and open at .600" valve lift is 385 lbs

In order to see the 1.500" had to remove 0.020" from the head spring pocket ...
All four valves are set at this height ...

[indibil]

I like the KPMI springs ...

This spring kit I could had set the installed height at 1.450"- 1.470" and have 171 lbs of closed seat pressure and at 0.0550" lift 385 lbs at open ..

But I choose to set up the installed height up at 1.500"- 1.520"
Seat pressure closed is at 150 lbs and open at .600" valve lift is 385 lbs

In order to see the 1.500" had to remove 0.020" from the head spring pocket ...
All four valves are set at this height ...

thanks!!