More details re the above CAD diagrams for Hughes 1.6 BB rockers measurements taken w/ soft checking spring:

B - Std shaft location "low pivot geo"
- Sweep: 085” & centered
- T&D cup adjuster w/ 9.575" OAL pushrod
- 1st half cam lift (.2136) / valve lift .348 = 1.629
- 2nd half cam lift (.2136) / valve lift .332 = 1.554
- OA ratio = .680 / .4272 = 1.592; ratio change = -.075

D- B3RE shaft relocation for mid-lift geo at net .650"
- Sweep: 045” & slightly inboard of centered
- T&D cup adjuster w/ 9.795" OAL pushrod
- 1st half cam lift (.2136) / valve lift .339 = 1.587
- 2nd half cam lift (.2136) / valve lift .328 = 1.536
- OA ratio = .667 / .4272 = 1.561; ratio change = -.051

Estimated loaded ratio loss at peak lift based on prior measurements w/ 600# open load springs: ~ .05

'A' OA estimated loaded ratio ~ 1.54
'B' OA estimated loaded ratio ~ 1.51

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In case anyone reads this the wrong way, I'm NOT "blaming" Hughes for this. Hughes' rockers were made for years by Probe Industries, and this is the same basic design that Probe had before Hughes started selling their rockers. When Probe quit -- or sold off -- its rocker business, I believe Hughes picked up Probe's tooling, etc., and has continued to make them using the same design.

Could Hughes redesign their rockers? Sure, if Dave & Co. thinks it's a problem. I'm guessing he doesn't, so they'll likely stay the same. I've run 'em successfully on a couple of builds, but I didn't understand the nature of their ratio / geometry "quirks" until I did all of my before & after checks w/ the B3RE kit.

I give up.

Pic of T&D 1.45" 1.60 ratio on left; Hughes 1.52" 1.60 ratio on right; difference in pushrod adjuster screw locations & angles very apparent, and all this factors into how the different designs "work" when installed in different configurations w/ respect to the valve & shaft relationships.

In case Dave Hughes or one of his minions checks out this thread... "Look! I'm running Hughes rocker arms (old style intakes & new style exhausts) on my Victor heads!"

Seriously, I sold the T&Ds because they didn't get me the ratio increase I was looking for. The net lift between the two brands of "1.6" rockers as set up to run on my heads was virtually identical.

How much cam lift were you losing on the 1.55 rockers instead of the advertised 1.6 rockers. And how much ET do you think it was costing you in your street strip car?

I'll let you reverse-engineer the answer from the following: .650" net lift w/ .018" lash and .433" lobe

Since you may be mathematically challenged, it's right about .020" net lift.


Fixed... and I have no idea since my P O S hasn't made it back to the track w/ the new engine build, nor will the engine go back on the dyno before the car is running again.

The other thing was I was expecting to use them in my spare engine build (fresh short block) that might also end up with a different cam. The new cam choice would be influenced by the net ratio vs the lift my valve springs can support, and the lower ratio than expected didn't fit w/ what I'd been considering.

How much do you think it would cost you in your... what did Ray call it... oh, yeah... tin can?

Hey don’t blame me because you own a fat car. Lmao 😂.

So after all of this measuring , losing, gaining lift I ask. What was the difference at the track? Or was it never track tested?
Doug

I've seen .001 to .003 gain or loss at the 1/4 mile tracks when tightening up the lash or loosening them up by .006 to .010
I tighten them up until it stops getting quicker and faster

I seen the same thing with valve lash loops at the track. Minimal if any on the small block with a solid roller at .700" using a T&D rocker which Pittsburghracer now owns. With a victor head and 1.6 Harland Sharps just bolted on with lash and as the engine would run gave me these patterns. Not perfect, but doesn't look bad and just had the guides checked and giving an outstanding A+ no wear from Sanchez. So their not hurting anything anyway. I haven't done any measuring except for piston to valve clearance.

This exactly!

All I'm saying is with the shaft spaced up and over like that there is NO way it stays still. ONLY way I would ever correct geometry would be to mill the stands off and make new ones that TOTALLY surround the shaft. W2's were a good example. I would bet some of your lift loss is from flex in the studs.

Man now I feel like I was ripped off. You advertised them as 1.6 rockers and now when I put them on this winter and take my Indy rockers off my “tin can” is going to be a DOG. I need a Lawyer. 1-800-slo-ride.

I stated above that the T&Ds were never tested on the dyno or the track. The engine was dynoed with the Hughes rockers and I purchased the T&Ds afterwards.

I measured the T&Ds and the Hughes as described above. I have a high level of confidence that my measurements are accurate given the context in which they were taken, from the repeatability of the #s, and the fact that the CAD simulations Mike Beachel ran only varied from my data by .002-.003" max lift.

The response I got from Sheldon at T&D was that they over-ratio their rockers; even my soft spring measurements showed this was not the case for my rockers. There's no geometry issue and no flex issue, it's what they measured.

Cab Burge didn't go into details, but mentioned seeing something similar with a single-shaft system he checked. Andy said T&D made a mistake where his 1.70 rockers measured 1.65 loaded; seems like they have made this mistake more than once. Regardless, there is a lack of consistency somewhere.

I asked my question because I wanted to know if what I found was typical of others' experiences. The answer appears to be "it depends."

You don't like my findings or disagree with my methods? No problem. However, coming up with your own -- rather than simply pi$$ing on mine -- would add more value.

Dave, your sweep patterns look far more reasonable than the HS Victor pic I posted above. I wonder if there was a fulcrum distance reduction between the first rockers and yours. The ones I measured were even longer than the Hughes' 1.52". If yours are still off the heads, could you check the distance between the shaft pivot centerline and the roller tip centerline?

What's the tin can weigh, anyway? I was wondering if we switched engines whose car would pick up and whose would slow down.

The Mental Masturbation Nationals!

I’ll just say I’m a racer that races almost every week (7 months a year) at the track for the last 46 years or so. I have never raced a car that weights more than 3200 pounds as I want to go as fast as I can, on a budget, with zero tricks on fancy gadgets. It would be stupid for me to race a FAT car and I never will. If you want to line up, let’s go.

It’s been a few years since I measured any rockers for ratio correctness.
The last ones were Jesel 1.7’s on Indy 572-13’s....... I don’t remember what the exact numbers were, but the gist of what I saw was there wasn’t any “extra” ratio built in.......and that with 800lbs open load they did lose a little....... but not much.

The farthest off on the high side I’ve measured were some HS 1.6’s on a set of Indy SR’s.
1.67 with checking springs and still about 1.63 with 700lbs spring load.

I’ve tested several BBM rockers that lost over .05 ratio going from checking springs to full spring load.

Are you afraid to admit how light your car is???