Author Topic: ROCKER-ARM SWAPS  (Read 544 times)

0 Members and 1 Guest are viewing this topic.

Offline Hunter02

  • Member
  • Posts: 64
ROCKER-ARM SWAPS
« on: August 24, 2014, 10:34:09 PM »
Gentlemen, I just got done reading the 'camshaft' thread started by BoringDave. Got me to thinking. (Jeez that hurts)  Back in the day, as the young asshats say, we used to swap rockerarms from one engine to another, as some have a different 'ratio' than others. I was wondering if any other makes rockerarms, with a greater lift ratio, would fit '98 TJ 2.5L? That would cut down on expense and wrenching time as opposed to a camshaft install.
Don't know if this is a stoopid question in this day and age, but the gentleman whose mind I used to mine for this info passed away on me a little over 3 years ago. My buddy knew everything. What a wealth of knowledge our little group lost.
Hunter

Offline Jeffy

  • Administrator
  • Member
  • Posts: 14921
Re: ROCKER-ARM SWAPS
« Reply #1 on: August 25, 2014, 12:16:08 AM »
Do a search, there are few guy's on there with different lifters.  Yello Terra, Mopar Performance and Harland Sharp come to mind.
Youtube Channel: https://www.youtube.com/channel/UCZNlr60GXH5OlKIFrT7P6mg
My Jeep: http://4bangerjp.com/forums/index.php?topic=2783.0
"If the motor car were invented today, there is absolutely no way that any government in the world would let normal members of the public drive one."

Offline sharpxmen

  • Chief Squirrel BlowerŪ
  • Member
  • *
  • Posts: 7093
Re: ROCKER-ARM SWAPS
« Reply #2 on: August 27, 2014, 04:26:47 AM »
I have a thread in member's projects using 1.7 big block chevy roller rockers, some info in there regarding the actual lift ratio of the stock ones (advertised at 1.6 but in reality more like a bit over 1.5 - can't remember exactly)
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline jfrabat

  • Gargantuan Mango Tree MechanicŪ
  • Member
  • *
  • Posts: 3676
  • Finally USING the Jeep!
Re: ROCKER-ARM SWAPS
« Reply #3 on: August 27, 2014, 08:28:48 AM »
If my mind does not fail me (which it has sometimes), stockers are 1.6 ratio.  Sharp did some testing, and found that, because they bend, they are more like 1.5XX (don't remember the exact ratio, but it was mid fifties I think).  I use Yella Terra 1.6, which are true 1.6 (much stronger than the stockers, plus rollers on them).  Sharp installed 1.7's (also rollers, and also stronger), but he had to modify the pushrods for it to work. 
'94 YJ 2.5L with 4" RE lift, Superwinch EPi9.0, FoMoCo e-Fan, SD30 and SD35 w/ARB-5.13, 165A alt., 33" BFG KM2 on 15" AR wheels, Sony sound system, Pavement Ends Hardtop, Hydroboost

Offline Wrench

  • Member
  • Posts: 40
Re: ROCKER-ARM SWAPS
« Reply #4 on: August 29, 2014, 06:22:04 PM »
The only direct-fit 1.7 rockers I could find are Yella Terra.

Any others on the market that are forged/roller type in the 1.6 variety will be a small improvement for the reasons stated above.

I found that even with stock springs on a stock cam, valve float was an issue even with my rev limiter set at 5200.  Any cam or lift upgrades will only make it worse unless you keep below 4500 or upgrade the springs.  If you are revving over 4k a lot, go with better springs and hardened keepers, or you risk dropping a valve.  The only other way to fight the valve float is to find lighter valves.

I have a lot of info posted here: http://4bangerjp.com/forums/index.php/topic,11234.0.html
Paul
1984 Chrkee