Yella Terra Roller Rocker Kit Question

[Comanche91]

I have read all I can regarding roller rocker kits and am ready to pull the plug on one of the the non-adjustable Yella Terra kits mainly because it's an easy to install and there is no need for a valve cover mods. My engine is a 4.6L Hesco crate with the mild RVOB cam ( lift - .470, Duration - [email protected] lobe centers - 110). My question is should I go with the stock YT6627A 1.6 ratio kit or the optional 1.7 ratio? The main purpose of the roller rockers in my case is to quiet down the valve train noise and longevity; any performance that may be gained will be a bonus.

Also to Dino, I have seen your writeup of the Yella Terra 1.6 kit you installed a few years ago, and besides your original problem initially on cylinder #6, how is it performing today and would you do the same kit again?

Thanks all.

[Cheromaniac]

My problem on the #6 cylinder 8 years ago was two bad Crane lifters and one worn lobe on the Crane cam. I swapped my old stock cam back in with new Crown Automotive lifters and my original stock valve springs and I haven't looked back since. The engine still runs like a champ and it now has 76k miles under its belt (42k miles since that mini-rebuild). The "Yellow Terrors" are holding up great and I'd definitely recommend them, although Harland Sharp also have a set of non-adjustable 1.6 ratio roller rockers available from Summit Racing. Your RVOB cam already has 0.47" of valve lift with 1.6 ratio rockers so I suggest you don't go for 1.7's (that's if you can find them anyway).

[SilverXJ]

I would go with the 1.6:1 ratio.

[Comanche91]

Thanks guys. Unfortunately it looks like the Harland Sharp kit requires the valve cover spacer. The Yella Terra kit sure has increased in cost...................

[the grey ghost]

Where did you happen to find the 4.0 yella terra kit?

[Comanche91]

http://www.quadratec.com/products/51103_500.htm

[jeepxj3]

Harland Sharp non adjustable fit under the stock valve cover. Summit has em at the best price.

[Comanche91]

Thanks, you must mean the S40196 set here:

http://www.summitracing.com/parts/csp-s40196

I looked at those on Summit; it didn't say if they were non-adjustable or if the valve cover needed the spacer for clearance. I was going to call Harland Sharp next week to be sure.

[the grey ghost]

The first set listed are the non adjustable, the last/third set listed says it needs the valve cover spacer and shorter pushrods

[Comanche91]

The first set listed are the non adjustable, the last/third set listed says it needs the valve cover spacer and shorter pushrods

Got a link as to where these sets are listed?

[the grey ghost]

I just looked at the summit website, the second set were 3/8 stud

[Alexia]

Thanks, you must mean the S40196 set here:

http://www.summitracing.com/parts/csp-s40196

I looked at those on Summit; it didn't say if they were non-adjustable or if the valve cover needed the spacer for clearance. I was going to call Harland Sharp next week to be sure.

http://www.harlandsharp.com/amc_jeep_olds.htm

S40196 Non-Adjustable: http://www.summitracing.com/parts/csp-s40196
S40196A Adjustable: http://www.summitracing.com/parts/csp-s40196a

Dino's site also says they fit under the valve cover: http://www.jeep4.0performance.4mg.com/valvetrain.html

[Comanche91]

Thanks Alex, S40196 it is. Missed that statement on Dino's site.

[Torqsplit]

I've been running the 1.6 YT's for ~40k miles with aggressive cams and have been very pleased. Great quality stuff, fit and finish are excellent. I'm sure Harland Sharp are as-good or better but the non-adjustable's weren't available when I did my last build. I also feel like the cross-bars used to pair the HS rocker shafts seem like an after-thought, where the YT pairs are truly shaft-mounted and seem more robust/stable in comparison(no offense HS users). Of note though: the roller tips can be a bit noisy as they get some miles(or acquire healthy tolerances ), depending on your lifter preload. Tighter lash helps but isn't always ideal for cam wear. If your looking to quiet down your valve train these might not accomplish what your after. Hate to see you spend that $$ and be disappointed. I did notice crisper throttle response and slightly improved mpg on the highway, 1-2mpg. The higher rpm or bigger cam your running, the more they'll benefit. It's claimed they'll reduce valve-guide wear also, but I can't validate that yet, thankfully! If your looking for all the HP available in your setup, and don't mind the co$t, IMO they're very worth it. I just doubt they'll be quieter than your stock rockers though. Oh, and these can be very useful in dialing-in your setup if your super-OCD-anal like I tend to be. http://www.summitracing.com/parts/crn-9 ... plications Good luck!

[Torqsplit]

VC Spacer.jpg

BTW. If you go with the adjustables, I still have a Hesco aluminum VC spacer for sale.