FE Power Cylinder Heads - More Test Results

[jayb]

Ross had asked about lift at the retainer with this cam, and I was surprised to see it was only 0.786".  Without any valvetrain flex it should be 0.850", but with these big springs I'm obviously losing a lot.  I'm guessing that backing down on the spring pressure will help HP in more ways than one.

I've been trying to play detective with prior threads on this. Before you mentioned the gross lift spec. at .880". I thought you mentioned the rocker ratio being higher than expected also. So if the rocker ratio is more than 1.76 per cam card spec and you are only receiving .786" at the valve, then there's a whole lotta shakin' flexin' going on... Almost .100" loss! Did you happen to measure lobe lift and compare to the cam card?

I have some custom Smith Bros. pushrods in mine. They are 3/8" × 8.980" effective length with .145" wall, which is the thickest I could get. My cam card called for .400" lobe lift, and that is exactly what it measured. My cam card called for .700" gross. The Erson's came up short(which is what I wanted). I got around six eighty-something, almost .690" with checker springs and around .66x" with actual springs on with a little less than 700lbs.

These heads are good news for shock tower guys, congrats!

Jared, thanks for the thoughts.  You are correct that the original aluminum rocker arms ended up at a higher ratio than I had planned, but the steel rockers did not; based on the geometry they are right on 1.76:1.  So, with 0.880" gross lift at the cam, and a .030" lash, net valve lift before any deflection should have been 0.850".  That is of course assuming I can trust the cam card.  I think I will install a checker spring on one of the valves later today and see what I get.  It's possible that the cam is off, but I doubt it.  It's also possible that my rocker ratio is off - again.  I will find out later today...

So I'm down on lift at the valve by about .060".  Also, I measured the pushrod diameter this morning and found that I was wrong on their size, they are 7/16" diameter.  So I'm a little less concerned about valvetrain deflection with those pushrods, although I'm sure there's still some going on...

[jayb]

A 3/8” pushrod should theoretically open the valve, but not without deflection.  For my higher end stuff I use at least a 7/16” pushrod or a 1/2” if I can fit it in there.

Sorry, my mistake in the earlier post, the pushrods are 7/16" diameter.

[Royce]

I sure enjoyed my time assisting professor Brown in his lab the last couple months. When you think about the time, effort, and money that went into this head project it boggles the mind,  esp when executed by a lone individual. I can tell Jay has a lot of satisfaction in creating a head that is a step change in performance for the beloved FE... Can't wait to see it in competition and see the comments from the doubters when they get their butt handed to them on the track.
It's a 4 hr trip each way to make it to Jay's place for me.. it was worth it to hear that 510 bellow when the throttles on 2 dominators got yanked open and the horsepower numbers raced up the scale..

[My427stang]

A little less overlap, better cam all around, a little less open pressure stealing lift, duration and parasitic loss...I think it will be interesting.  Hopefully the peaks drive up in RPM and power, too, but I bet the curve is going to flatten out considerably and just overall be a better combo here pretty soon

Great stuff.  How am I going to fit Rasputen under a stock Boss 9 hood? 

[turbohunter]

Love the Rasputin (sp) name.

[WConley]

Nice to see everything settling down with no drama 

I remember the problems we had at Ford with new heads.  Head gasket sealing, cooling, exhaust valve seats falling out, having to move stuff around to get performance, you name it!  As Royce said, this is a supremely difficult challenge to take on as an individual.  Well done, Jay!

[GerryP]

This is fascinating bearing witness to an evolutionary step in the development of a 70-year-old design.  I liken this to building a competitive Pro Stock engine for 1970 competition.  The power levels are about the same.  Yes, I know the cammer was the Ford engine used in Pro Stock back then, but I'm thinking that this must be how it was done back then.  A lot of trial and error.  For the most part they were stuck with factory parts.  Not a lot of fancy aftermarket stuff.  So, every thing they went through back then, you're going through now.

[Chris68GT]

I'm no expert but I'm pretty sure if your pushrods are pushing on an angle you're going to lose lift to the sideways motion. You'll have to find someone better at trigonometry than I am to figure it out though.

[Dumpling]

Really stupid question, but if we were more interested in a block with a 4" bore, would the valves clear?

Stupid guilty pleasure, some of the lyrics are even appropriate
https://youtu.be/SYnVYJDxu2Q

[jayb]

I'm no expert but I'm pretty sure if your pushrods are pushing on an angle you're going to lose lift to the sideways motion. You'll have to find someone better at trigonometry than I am to figure it out though.

That's not true, an angled pushrod does not cause any loss of lift.  The lifter is straight up and down, and the rocker rotates on a shaft that is parallel to the cam bore, so the pushrod just moves up and down the normal amount, in an angled state.

[jayb]

Really stupid question, but if we were more interested in a block with a 4" bore, would the valves clear?

NOT a stupid question, since I have a 390 stroker that I want to put these heads on.  As is, the valves will not clear.  However, I'm actually planning one more version of the heads, similar to the SE design, but with a smaller intake port and port volume, and a smaller intake valve, probably a 2.15".  That should allow clearance to a .030" over 390 block, 4.08" bore.  Not sure if anything smaller will work...

[Barry_R]

Are you running any offset on the lifters?

[frnkeore]

According to motion ratio, there should be a little difference in lift, I figure .008.

That based on the push rod angle of 7.72* (std PR length of 9.59 x 1.3 offset, 1.3/9.59 = .1355 tan = 7.72*). The motion ratio of 7.72* = cosin of the angle or, .991. .991 x .5 cam lift = .4955. .4955x 1.76 = .872

A checker spring test should show this.

[Gregwill16]

Very good news imo on the SE head performance, ie more potential customers...
Do you think the SE head is overperforming expectations or is there alot more potential for the RE head?

[jayb]

Are you running any offset on the lifters?

No offset on the lifters.

To revisit the lift issue, I think I got fooled when I checked them yesterday.  I just checked two more rockers today, one intake and one exhaust, and they are both showing 0.818" lift.  With the .020" cold lash, that is .042" short of what the net lift is supposed to be.  So, I'm not off as much as I thought.

I'll be adding in some checker springs and trying again; will update those results later today.