Topic: Yella Terra Rockers

[mrcabinet]

Here's the response that I received from Harland Sharp:

If you only need 8 rockers then I suggest purchasing them in pairs.  The part # would be 40196-1 and you would need 4.  In order to get a 1.7:1 ratio you would have to custom order them.  With a 1.7:1 on the 4.0 you have pushrod clearance in the head and they don’t work.  So make sure you have room to move the cup in before you order them.  The cost would be around $275 + shipping.  Let me know if you would like to order them. Thanks


Randy Becker Jr.
Harland Sharp / Custom Speed Parts
19769 Progress Dr.
Strongsville, OH 44149
Phone: (440) 238-3260
Fax: (440) 238-2204
Web: www.harlandsharp.com

The price is certainly more attractive than the Yella Terra. But, If what he says is correct, does the 2.5 have more rod clearance in the head than the 4.0? If not, then the 1.7 sound like they'd require more modification to work than I am comfortable doing.

[sharpxmen]

I have some trouble understanding what he meant there, only thing i can relate to is during my testing with the chevy roller rockers came to light that I need to deburr the casting off the pushrod openings in the head, it's very close but it works, i think the newer 4.0L heads have smaller openings (can't remember exactly who but one of our members had replaced his hyd lifters and posted a photo to show us that you can't just pull the lifters out anymore but you need to take the head off) - maybe that's what this guy was referring to.

as far as the "room to move the cup in" comment i cannot think of anything.

EDIT: maybe he meant to say "you _don't_ have _enough_ pushrod clearance in the head" or "you have pushrod clearance _issues_ in the head and they don't work" which would have made sense

[robertsiii]

mrcabinet what year is your wrangler?   im not sure what he is talking about either. on my 1990 yj  i had no problems with clearance .i did replace my rods with new stock rods while i was in there . my yj is TBI . ,Dont know if a multi port injected head has different  clearance then mine. hope this helps.

[mrcabinet]

I know its been a while, but I just finally ordered a set of the Harland Sharp 1.6 rockers today. I was a little gun shy of the 1.7 after what he said about the clearance issues. Since I haven't been able to find any other info, will I be safe using the Yella Terra installation instructions? (http://www.quadratec.com/Assets/Installation/30759.pdf) I'm going to change the push rods while I'm in there and use an actual valve cover gasket.

[sharpxmen]

yeah, those H/S 1.7 require a valve cover spacer, upside is they are adjustable (I dont think Yella Terra are).

[sharpxmen]

Since I haven't been able to find any other info, will I be safe using the Yella Terra installation instructions? (http://www.quadratec.com/Assets/Installation/30759.pdf) I'm going to change the push rods while I'm in there and use an actual valve cover gasket.

definitely change the pushrods, if i were you I would replace the lifters also.

as far as instructions they're straight forward, but i would check the lifter preload when installing them - for the stock bolts which are 5/16-18 should be between 1/2 turn and 3/4 turn somewhere in the middle (it's 27 thou for 1/2 turn). The way i do it i get the left hand index finger and thumb covered in cam assembly lube and twist the pushrod left/right while finger tightening the bolt (just barely touching the pushrod enoungh to make it twist), when the pushrod stops turning you're at 0 preload, from there you should be able to go up to 1 full turn or very slightly over that (.060 should be your max preload, the bolt advances .055 per turn). I put a dot with a marker on the pushrod so i can tell when it stops turning.

keep us posted how it goes, you should have gone with the 1.7 but the valve cover makes it challenging, i'm still working on finishing mine, have another 5'' or so to weld and then paint it - it's been a pain cleaning and degreasing the  2 halves and taking the powdercoat off (unless it's a really strong paint but i doubt it as it's really hard to take off) and still had contamination here and there.

EDIT: i believe you can get shims for the pedestals under the rockers to adjust to proper preload for the yella terra, harland and hesco ones.

[mrcabinet]

I  had always heard that you shouldn't change the lifters unless you're changing the cam shaft too, supposedly because they're "worn in" and wouldn't ride correctly on the cam. Is that not the case?

[sharpxmen]

what do you do if there's a bad lifter that is making noise? you can replace the lifters, reason i'm saying you should is because it is a known issue with the AMC 2.5 (noisy lifters) so while you're in there might as well take care of it, they can be had cheap enough but i would suggest a name brand (like clevite).

[sharpxmen]

i just read some of the instructions and they are saying pretty much the same thing about preload, there are also shims provided in the kit so you should be covered. They do however say 1-1/2 turns but i think that's too far (you'd end up with little over .080 preload, i wouldnt go more than .060).

4/ Taking note of the zero free play point, evenly tighten the two mounting bolts to 25
ft lbs. Ideally this should be ½ to ¾ turns from the zero free play point.
5/ More than 1 ½ turns will require installation of the silver spacer washers supplied
in the kit under the mounting pedestals on the head side.
6/ In very unusual circumstances when less than ¼ turn is required to achieve correct
torque setting, the rocker pedestal spacers will need to be shortened (clearance
between base of rocker and stud pad must be maintained.)

[mrcabinet]

I went ahead and picked up a set of lifters. Can't hurt, right? I know Yella Terra includes shims with their kits, but am not sure if HS does. I'll email them and see if they can throw a few in.

[sharpxmen]

you need a strong (good) magnetic tool to pull them out. Also buy some cam assembly lube and pour on the cams and on the lifters before installing them.

EDIT:

I went ahead and picked up a set of lifters. Can't hurt, right? I know Yella Terra includes shims with their kits, but am not sure if HS does. I'll email them and see if they can throw a few in.

harland sharp are adjustable so you wouldn't need shims (so they won't be including any).

[mrcabinet]

Actually, the 40196 that I ordered are non-adjustable. The 40196A are the adjustable ones. I haven't heard back yet regarding my request to send some shims with the rockers.

A few years back I had a non-engine related assembly project that I needed a tool to grab the inside lip of some stainless inserts, so I have a lifter removal tool that I can actually use what it was intended for now!

[mrcabinet]

Got the rockers, push rods and new lifters installed today. I should have gone with the 1.7 after all - there's plenty of room in there. The rockers were a piece of cake (only needed 2 shims), but the lifters were a royal PITA! they came out easily but were a real booger getting them back in. At one point I even considered getting a new gasket and pulling the head. It probably would have been faster!

First impressions are positive - smoother, quieter, a little more low end torque and it definitely revs up faster and easier. On my "test hill" by my house, I typically hit it at 55 and then have to down shift to 4th, then 3rd to make it over the top at 45. Today I only downshifted to 4th and crested it at 50. So, all in all, a nice little upgrade to compliment the other mod.s that have been done.

[sharpxmen]

Got the rockers, push rods and new lifters installed today. I should have gone with the 1.7 after all - there's plenty of room in there. The rockers were a piece of cake (only needed 2 shims), but the lifters were a royal PITA! they came out easily but were a real booger getting them back in. At one point I even considered getting a new gasket and pulling the head. It probably would have been faster!

First impressions are positive - smoother, quieter, a little more low end torque and it definitely revs up faster and easier. On my "test hill" by my house, I typically hit it at 55 and then have to down shift to 4th, then 3rd to make it over the top at 45. Today I only downshifted to 4th and crested it at 50. So, all in all, a nice little upgrade to compliment the other mod.s that have been done.

yeah, there's plenty of room but in my case it was hitting up front (on the end closest to the radiator), if you look at the valve cover it comes at an angle and not straight like in the back. Even without that part being slanted i think would have probably hit the breather baffles. If you get the adjustable ones they're taller.