Topic: Yella Terra Rockers

[mrcabinet]

If I remember correctly, there's a couple of guys on here running the Yella Terra rocker arms in conjunction with cams. I would like to hear from anyone that is running them without a modified cam.  I have some funds in the Jeep's piggy bank that need to be spent before the end of the year, and I am thinking that they would go well with all the other "standard" mod.s that I have done. Any and all feedback is appreciated!

[aparke4]

i would like to know as well... i am looking at the roller rockers now and will be doing a mild cam soon...

[sharpxmen]

i don't run them but this is what i can tell you from my measurements:
the stock rockers are supposed to be 1.6 ratio, however due to flex they are more 1.52
with any roller rockers you'll be getting the advertised ration (1.6 or 1.7 or whatever they are), so even with a 1.6 same as stock you will see an improvement.
you can run roller rockers with the stock cam, no issues there
if you use a more aggressive cam you might need springs, depends on lift and overlap/separation, higher lift and 1.7 most likely requires a rework of the head/vakves to get more travel so the spring dish and stem retainers won't hit the seal and guide.

[jfrabat]

I run them on a modified cam (MOPAR one).  They are not cheap, and the difference they make is not HUGE (I would rate it as not that noticeable), but my mind feels more at ease with them on.  I even ran them for a looooong while with the stock springs without issues, but later changed to stiffer springs just in case (actually, I bought them, but I dont remember if I ever installed them; they may be in the warehouse in Panama!!!)   

[mrcabinet]

Thanks for the input! According to their rep., YT does make 1.7 rockers for the 2.5, but he couldn't say if I'd need a cover spacer or different springs. I like the thought of the 1.7's but don't want to run into any issues if I order them.

[sharpxmen]

you don't need different springs, i measured the clearance with 1.7 roller rockers and works just fine with a stock cam. Forgot about the valve cover, you probably need a riser or a makeshift cover (i have 2 i plan to cut and weld together to make a taller one) but i don't know if that applies to the stock cam or not.

[jfrabat]

Wouldnt the 1.7 and stock cam be about the same as the 1.6 with the more aggressive cam?  That's what I run, and they dont hit the cover...  by the way, the cam is a .450 lift 256 duration Mopar High Performance camshaft.

[sharpxmen]

Wouldnt the 1.7 and stock cam be about the same as the 1.6 with the more aggressive cam?  That's what I run, and they dont hit the cover...  by the way, the cam is a .450 lift 256 duration Mopar High Performance camshaft.

depends on the cam and resulting lift at the valve, with more lift you might need different retainers and dishes or even longer valves, in that case the rockers might sit higher as you would need to line-up the tip of the rocker with the valve stem and to make sure the angle and position is proper thru the whole valve travel, you would probably need longer pushrods in that case.

[mrcabinet]

Hmmm. I think I'll try calling them tomorrow and see if I can get more details on the 1.7. Their e-mail responses are painfully slow.

[sharpxmen]

Hmmm. I think I'll try calling them tomorrow and see if I can get more details on the 1.7. Their e-mail responses are painfully slow.

they're in Australia (unless they have an office here).

[Jeffy]

Hmmm. I think I'll try calling them tomorrow and see if I can get more details on the 1.7. Their e-mail responses are painfully slow.

I've emailed them before and got a response in a reasonable amount of time.

[mrcabinet]

You're right about being in Australia, but they do have an office in Mississippi. I'll try contacting them next week.

The sales rep that previously e-mailed me said that both the 1.6 and 1.7 are true bolt ons and shouldn't require any modifications to the springs or valve cover. The 1.7 are a standard item for the 4.0 but a special for the 2.5l. I have the part number for the 1.6, but I'd really like to get a part number for the 1.7 so I can shop around for them. He also strongly suggested checking the push rod length if installing the 1.7, but I'd be out of my comfort zone if I got into that aspect of it.

[robertsiii]

Put  a Set of  Harland  Sharp 1.7 s in back in march and have been very happy with the performance .Just order 8 of the I6 rockers .

[mrcabinet]

Would you happen to have a part number for those? All I saw on harland's web site was the 1.6's. How was the install? Any modifications to the pushrods, springs or valve cover? Most importantly, how was performance and gas mileage affected?

[robertsiii]

if you call harland sharp and  tell them you want to order 8 of the inline 6 rollers  1.7 ratio they will take care of you. Simply remove the factory rockers and rocker stands and replace with your new Harland Sharp roller rockers. no mods required to rods and valve cover. performance stroke was increased through out the power range . i  get 15 mpg. the higher octane gas you run, the better your performance. hope this helps . happy holidays