The legendary 2.9 Free Floating Rockers

[PetroleumJunkie412]

First of all, kudos to you for going down the rabbit hole on 2.9 performance. I abused the hell out of my 2.9, and it screamed along at 5,500 RPM for a very long time before I swapped it out. They're a better motor than most think.

Second, 2024 Al would work. BUT get me REAL dimensions of what you want, I'll whip something up, don't worry about the stock. They'll be one off parts, but I'd worry about proving the their of free floating rockers before I worried about a modular kit.

Third, let me see if I can scrounge up an FE rocker from a buddy of mine.

Wait, really?? You'll turn a set out if I can pass along the dimensions??

 

[farmer]

Wait, really?? You'll turn a set out if I can pass along the dimensions??

Yup, I want to see if this will work. Never wanted to tear down my 2.9 long enough to mess with it myself, but was always curious

 

[farmer]

Wait, really?? You'll turn a set out if I can pass along the dimensions??

Went back and read through some of what you've posted.

You measured the 4 spacings as such:
2.129"
2.044"
2.016"
2.151"

Correct? Not trying to be a jerk, how much faith do you have in those measurements? You very sure about those?

According to the Kunz article, you want 0.020-0.030" clearance from the shaft to the rockers, which gives me a +/-.005" window on the length of each, which buys you a little forgiveness in your measuring, if I hit nominal.

That said, subtracting 0.025" from your above numbers gives me:
2.104"
2.019"
1.991"
2.126"
All +/-0.005"

Agree so far?

I see you listed rocker shaft diameter as 0.880", correct? The rocker arms need 0.0025-0.003" of clearance per Kunz, I can probably do that same for the spacers, although it is less crucial. Target would be 0.883" correct?

What's the outside diameter of the springs? Trying to figure out how large the OD of the spacer can be.

Numbers in green are the dimensions I'll be cutting to if you agree.

 

[farmer]

Just double checked, I have an 11" long piece of 1.5" diameter 6061 in my box. Doubt 1.5" will fit, could spin it down to 1.25"?

 

[farmer]

Talked to my FE guy, he's familiar with the 2.9 engine and says he's thinking the FE rockers are HUGE compared to the 2.9, but will get me a diameter and overall length for comparison sake.

Quick google search says factory 2.9 is 1.47 ratio, Morana ratio is 1.55, FE is 1.73. Probably a dead end.

I wonder how feasible it would be to bore out a rocker, and add an eccentric sleeve, to move the pivot location? Might have to undersize the rocker shaft to do it. Would be a very time consuming project and results may be small.

 

[PetroleumJunkie412]

Talked to my FE guy, he's familiar with the 2.9 engine and says he's thinking the FE rockers are HUGE compared to the 2.9, but will get me a diameter and overall length for comparison sake.

Quick google search says factory 2.9 is 1.47 ratio, Morana ratio is 1.55, FE is 1.73. Probably a dead end.

I wonder how feasible it would be to bore out a rocker, and add an eccentric sleeve, to move the pivot location? Might have to undersize the rocker shaft to do it. Would be a very time consuming project and results may be small.

Where have you been my whole life.

I'll update dimensions for the 89tm rockers on my truck. Guessing their dimensions will be different.

 

[Dirtman]

As much as I truly love insulting your insane, ridiculous, absurd, and baffling 2.9 obsession... You really should make a page with all your logs of this kinda crap. What works, what's failed, good, bad etc. It's all nonsensical rambling... but its interesting nonsense and I shamefully do admit I admire your conviction to this illogical endeavor.

 

[farmer]

Where have you been my whole life.

Somewhere between here...

And here..

I'll update dimensions for the 89tm rockers on my truck. Guessing their dimensions will be different.

Ok that works. It'll probably be next week that I can get to it, but you'll like the end product

 

[Snoranger]

As much as I truly love insulting your insane, ridiculous, absurd, and baffling 2.9 obsession... You really should make a page with all your logs of this kinda crap. What works, what's failed, good, bad etc. It's all nonsensical rambling... but its interesting nonsense and I shamefully do admit I admire your conviction to this illogical endeavor.

Let me sum up what you said in a meme for the younger generation...

 

[PetroleumJunkie412]

Let me sum up what you said in a meme for the younger generation...

View attachment 31560

?













??

 

[8thTon]

Somewhere between here...
View attachment 31558

And here..
View attachment 31559



Ok that works. It'll probably be next week that I can get to it, but you'll like the end product

Is that where you bury the 2.9s? How fast do they sink, and can you still hear them tapping down there when it's quiet?

 

[farmer]

Is that where you bury the 2.9s? How fast do they sink, and can you still hear them tapping down there when it's quiet?

That's where you no lift shift that 2.9, 2nd to retreat at 5500 rpm waiting to see which parts scatter first. The answer is none.

 

[PetroleumJunkie412]

Ok, so I'm sick with what I assume is the black plague, and I'm probably going to die, but I managed to get out of bed long enough today to check my current set of 89tm rockers:



Pass front 2.183"
Pass rear 2.040"
Driver front 2.036"
Driver rear 2.150"

All spring clips seem to have 0.100" between the rocker arm and roll pin

 

[PetroleumJunkie412]

@farmer and @Mightyfordranger - those are the test set. Shafts are the same, 0.880"

 

[farmer]

Ok, so I'm sick with what I assume is the black plague, and I'm probably going to die, but I managed to get out of bed long enough today to check my current set of 89tm rockers:



Pass front 2.183"
Pass rear 2.040"
Driver front 2.036"
Driver rear 2.150"

All spring clips seem to have 0.100" between the rocker arm and roll pin

Perfect, this is lining up to be a busy week, I'll see what I can come up with