Dealing with a worn rocker arm stud - SOLVED
Thread Starter
|
Senior User
Joined: Dec 2009
Posts: 164
Likes: 4
Dealing with a worn rocker arm stud - SOLVED
Besides my 390 truck, I also have a 69 302 Mustang. I've rebuilt a lot of the motor, new cam, lifters, pushrods, etc., on stock heads (which I know don't flow well, so, a budget build). No matter how many times I set the rockers, later that day or the next a couple will start ticking, where they didn't before I rebuilt it. I've checked everything a million times (2nd set of lifters, etc.), and am convinced a couple rocker arm studs are worn, so some lock-nuts are backing off when they shouldn't. How would you work with this? I'm thinking the cheapest idea is get another few locking nuts and put on top. Or is it better to use thread-lok of some sort? If so, how would you apply that, since it needs to be set when the engine's hot and the studs are oily. The cam is nothing special, a Comp Cams 260H, so I don't think it's backing the studs out. Any thoughts are good, thanks.
Lead Driver
Joined: Mar 2004
Posts: 8,922
Likes: 153
Lifter preload should only be set with the engine cold. Do your heads have screw in studs with some kind of a lock nut ? Do you have guide plates ? How are you adjusting them ? How did you get the right length of push rod, did you check for the right push rod length ?
This ? probably belongs in the S.B. forum.
This ? probably belongs in the S.B. forum.
Thread Starter
|
Senior User
Joined: Dec 2009
Posts: 164
Likes: 4
I don't know if 302 studs are screw in or pressed in, I was assuming pressed in. I thought lifter preload shouldn't be set cold because they have to run first to pump up with oil? I'm assuming since I don't know what guide plates are that it doesn't have them. It's been a couple years so I'm fuzzy now how I arrived at the right length pushrod, but I knew what cam was in it before, contacted Comp Cams, and figured it out with them. I think both cams call for factory length, but again, it's been a while. I'm also sure it's the right length because the majority of valves are fine, it's just a couple rockers. The car's mostly sat because I could never solve it, and now I'm getting back to it. Question is, assuming the rest is good, how would you deal with worn rocker studs?
Thread Starter
|
Senior User
Joined: Dec 2009
Posts: 164
Likes: 4
By the way, I just looked to double-check, and I don't see any signs of the rocker studs being screwed in, I'm pretty sure they're press fit. It looks like I didn't answer your question about how I went about setting them, but it's lengthy. I have several engine books and also went by Comp Cams. I've tried setting half the valves when piston 1's at TDC and the other half with the crank 360 degrees later, but only did that once because I prefer turning it 90 degrees and going cylinder by cylinder according to the firing order. I would slowly snug them up until there's no slack, then turn it a different amount of distance farther according to different sources. Quarter turn. Half turn. 3/8s turn. I haven't done it in a while so maybe I'm getting that wrong now that I'm coming back to it. Point being, I've been meticulous and am sure it's the rocker arm studs, because that's all that's left. I'm hoping there's a better answer than yank the heads and take them to a shop, because those are some pretty awfully designed heads, but then the alternative is to get the coin for some Eddys I guess.
Thread Starter
|
Senior User
Joined: Dec 2009
Posts: 164
Likes: 4
Figured it out on the small-block forum, so just in case it happens to someone else, here's the answer: The 302's rocker arm studs are press-fit. Measure the tops with a straight-edge to see if the one(s) in question have noticeably backed out due to a higher lift cam and/or simply age. In my case, they did. The solution's either to take them to a shop and have new ones pressed in, try to convert them yourself to screw-in style, or in the case of the 302's horrible factory flow, it's best to upgrade to new heads if you can afford it.
Senior User
Joined: Oct 2010
Posts: 164
Likes: 0
Figured it out on the small-block forum, so just in case it happens to someone else, here's the answer: The 302's rocker arm studs are press-fit. Measure the tops with a straight-edge to see if the one(s) in question have noticeably backed out due to a higher lift cam and/or simply age. In my case, they did. The solution's either to take them to a shop and have new ones pressed in, try to convert them yourself to screw-in style, or in the case of the 302's horrible factory flow, it's best to upgrade to new heads if you can afford it.
Thread
Thread Starter
Forum
Replies
Last Post
zerfetzen
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
5
May 19, 2012 08:11 AM
60 F100 4X4
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
7
Oct 28, 2010 10:04 AM
freemanrebel
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
2
Oct 26, 2004 06:26 PM
TOUGHY17
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
6
Nov 6, 2001 10:27 PM
