bluejeep2001

My crappy 0331 head finally started pissing too much antifreeze after a mere 230,000 miles. I just purchased a reman that surprisingly came without rockers...I think I knew that but didn't really pay attention until now. I planned on swapping out Tuesday. I plan on reusing the pushrods I have. I think I have 3 options...1) Take the rockers out of my current head, they do have 230k on them. 2) I have a 0630 head that I used in my older stroker...It has a much newer rocker set installed...only 85k on them 3) order a new set of rockers if both of the other options are no good. I know to keep the pushrods in the order that they are now but can I use the rockers from the 0630...thanks

gat

Those would be your the options. Let us know what you chose and how it worked for you.

DFlintstone

Not really knowing squat....Since the hydrolic lifters will accommodate for wear,,and you know the originals are a match, in your shoes I might go with option #1. Not going to do any damage and you can always go back without a hellish hassle. As far as I know the original can go more than 400K. Simply going to a parts catalogue, rockauto.com, or calling an auto parts store might tell you if they are the same also.

dave1123

3 things to watch for on rockers, cup wear on the valve stem contact patch, cracks around the pushrod cup, and wear where it rides on the pivot. The pivots are pretty close to 55 Rockwell hardness so wear on them will be minimal, but the rockers themselves are just case hardened pressed steel. Be sure to install the rockers on closed valves, that is on the low point of the cam, so the bridges don't twist when you tighten the hold-down bolt. If they twist, the rocker will be off center on the valve stem. The pushrods can go anywhere as long as they are straight and within 0.010" of being the same length. I bought a new set of pushrods and they measure within 0.005" of being the same length. Remember that resurfacing the head or using a thinner or thicker head gasket and refacing the valves changes the position of the plungers in the lifters. I have no idea how much travel the lifter plungers actually have, but they should be close to centered when everything is assembled. Most people never pay any attention to this because most engines have valve lash adjustment capability. The 4.0 does not. Guys that "blueprint" engines even measure the installed height of the valve springs and use shims to adjust them. Likewise you can grind the heads of the valve stems to adjust their height as well. None of this is really necessary on a 4.0, but you should be aware of how little things change how an engine performs. Nobody with a jeep really wants a race engine. Or do they?

dave1123

While we're on the subject of cylinder heads and valve hardware, maybe you guys can answer a question for me. As far back as the mid 50's Chrysler had the habit if using "free valves", in effect allowing them to spin when open to clean the seats and minimize wear. This was done by using split valve keepers that were just slightly more than 1/2 circle to allow the valve to rotate when it was off the seat. I've never had a 4.0 that far apart to see if they are that way or not. Can someone enlighten me?

I assume they are because I was told the way to see if the valve was rotating or not was to look at the stem end of the valve and if it had radial wear lines it wasn't and if it had circular wear lines, it was.

DFlintstone

Don Ness at Redwood Welding in 95531 likely knows things. .......

dave1123

Kinda hard to ask when I live in 13104.

DFlintstone

707 464 6218 Tell Don "big blonde Don" from Low Divide referred you. Don Ness takes a shot at the piston driven land speed record most years.

"stupid is forever" Gotta love that! (phone books are indeed temporary)