The rocker arm to valve tip alignment is the next objective...or rather obtaining the best-fit and least lost motion.

Here are the vitals:
1) W2 Race Econo heads - so long valve (2.980" by MP's specs) but with cast-in pedestals

2) Valves
INTAKE - Manley 11702-8, 2.02" intake, 11/32" stem, 5.240" long - Pro-Flo Severe Duty Series, W2 Long Valve
EXHAUST - Manley 11703-8, 1.60" exhaust, 11/32" stem, 5.255" long - Race-Flo Severe Duty Series, W2 Long Valve

3) Rocker Arms - Harland Sharp W2 Econo 1.6 ratio rocker arms: S70026WEK, which use the on-center shaft and since they are configured for the Econo heads they use the saddle mounts (like the factory head setup)

The cam lobe lift is .365/.362, so that ends up being about 0.584/0.579 at the valve.

The problem I am encountering is as follows:

1) with the valve on the seat, the rocker arm roller is somewhat past the center of the valve
2) at full lift the rocker arm roller is nearly 2/3 through the valve tip, maybe even more?
3) if I manually push the rocker further (checking spring only, so easy to do this) the roller eventually comes back to the center of the valve, but that happens at nearly .750-.800 lift
4) I tossed on a lash cap (0.080" thick) to see if that would change things, and at least visually it appears that the roller did move back towards the center a little

I reached out to Mike @B3, hopefully I'll hear from him sometime next week.

In the meantime, I'm curious what you guys make of it?

Here are the pics: at seat and max_lift with just the valve tip and with the lash cap.

Harlan Sharp will say you need lash caps. You don’t. Wait for Mike. The shafts need to go up and back.

Nice picture and great rockers!

I thought W2 rocker shafts were offset drilled?

As the valve spring pressure increases the roller needs to be nearer the centreline (obviously).

It will start inside the centreline span 'outwards' across the centre and finish slightly inside again.

The longer valves seem to mess up this arc across the valve, so when you raise the shaft it pushes the rocker further out and making it worse.

The rocker post geometry 'angle' will always do this with 15 degree valves...

Shaft slightly 'up and back' as the previous poster has said and lash caps makes the problem worse!

madscientist and Gtxxjon,

Appreciate the feedback. Yeah, by the looks of it, as I was trying to spatially project the proper geometry (I had actually captured a quick mp4 video as well, so replayed that a few times to see how the shaft placement would re-locate the rocker tip arc) that's what seemed like the direction the shafts would have to go in.

In fact, as I tried this full sweep, the minute I removed the current cam lob max_lift limit and therefore opened the valve even further, the arc nicely came back to the center of the valve...of course that had me running something like a .800-.900 lift...LOL!


Well, you bring up a good point, because by the looks of it, if I was to use the offset shaft that would in fact move the rocker back a tad. However, the MP instruction sheet for these heads (P4529995) state the following:



Now before I had actually purchased the HS rocker arms I had a couple of calls with these guys to specifically run this requirement past them...they understood and were familiar with this setup and concurred that the on-center shaft was OK.

Because the valves I'm using are actually about 0.050 too short (as compared to the MP spec of 5.280") I figured I would toss the lash cap on there to see if maybe that's playing a bit of havoc in my setup. While that moved the roller tip a tad in (actually post valve tip center @seat), it didn't really improve the sweep and max lift situation. So I think that the shaft position has the greater impact here and cannot be corrected for with a lash cap approach.

I will give the HS guys a call as well. Tried them yesterday but it turns out they are closed on Fridays. Maybe they could send me the off-set shaft to try and possibly swap out? This stuff is all NEW and I'm just getting through the initial measurements as the install time is coming up!

I think you need shorter push rods. Get an adjustable push rod and try that.

Pushrod length doesn’t change geometry on shaft mounted rockers OTHER than a slight change in ratio from adjuster position. Once he raises and moves the shafts away from the valves he will need longer pushrods.

HS makes a offset shaft that will help with your alinement I have used them on a couple of builds

Offset shafts require milling the stands off. Just a heads up.

Regardless of what the pattern looks like, there is no linear result in flow or power from a specific geo. The greatest area under the curve is not the only factor, another is "what is the intake vacuum when the valve is here?". Rod ratio also affects this.

Prussian blue on the stem and look at the pattern it leaves is the best way to see the contact.

...ouch, good point...after all, the off-set side has to go "somewhere" and the cast-in pedestals simply have no extra room for that to happen. Good point, appreciate the reminder because that is not a route I'm wanting to pursue.

Oh, re: pattern...take a look at the videos I just added...that is a pretty wide patch, about 0.250"...I used a marker as opposed to Prussian blue, but yeah, same concept I think.

A bit of background on my testing:

1) initially I ran through several full crank turns with the rocker arms being moved by adjustable pushrods, which in turn were set to show two adjuster threads and 1/4" turn pre-load on the lifter

HOWEVER

2) that caused a problem when I was trying to check the valve to piston clearance because the lifter plunger would just collapse and so the valve itself wasn't seeing the full lift of the cam lobe

SO

3) since I do not have a solid roller lifter to test with, in order to get a valid clearance measurement I manually pushed the rocker arm against the valve tip as I was turning the crank as soon as I noticed that the plunger was collapsing on me (that gave me a clean 0.220-.250 gap), me pushing the rocker was basically meant to relieve the pressure so that the plunger would not collapse

AND

4) when I did the rocker to valve tip alignment I entirely removed the pushrods, measured my max lift position of the retainer (which is why you see that in the pics) and proceeded to manually do a sweep

Here are a couple of the video recordings:

1) [video]http://darcio.no-ip.org/mopar/w2/Measure%20-%20Rocker%20Arm%20Valve%20Tip%20Sweep-720HQ.mp4[/video]

2) [video]http://darcio.no-ip.org/mopar/w2/Me...20Tip%20Sweep%20-%20Lash%20Cap-720HQ.mp4[/video]

Buy or borrow, get, two solid roller lifters now before changing anything else to do any more testing and checking

With your light checker springs bring the engine top 10 before tdc check the clearance between valve and piston by pushing the the valves open and dial indicator. Do this every couple degrees until you get to 10 atdc.

If you have an old hydraulic you can take the snap ring off and remove the spring inside and shim it solid.

Lets see the pattern left on the valve stem.

i was looking at some rockers on some RHS Xheads and just visually i thought i was in one spot, after marking the valves and moving the rockers it ended up a bit different. I would def mark the stems and cycle the rockers to see what the pattern is...

HS rockers do that a lot of the times

Hi again Diplomacy.

The rocker and valve geometry will always be wrong with a longer valve.

The post angle and valve angle are not parallel, so the higher you go the worse it gets!

I guess an offset shaft and a 'spacer' with an offset on top of the stand will help a great deal...

Whatever the extra length the valve is, the spacer will have to be the same.

interesting post! Can't wait to see what comes up from B 3 ! Mike does great work!