Intake Valve Rocker Arm Slop -- Likely Causes??

[MysticRob]

I put this in my build thread but I'm thinking I might get more eyes on and comments here...

In my Howell TBI install thread (see my sig) I've mentioned a misfire and lifter tick noise a couple times that sounded like the driver side #1 cylinder. Had time tonight to remove the valve cover and found some pretty concerning things.

Exhaust valve is on the left, intake valve on the right. I discovered the intake rocker arm was pretty loose, so I decided to tear things down a bit to figure out why. Exhaust side has no issues from what I could tell:



Both rocker bolts were tight so that wasn't the problem. I took both bolts out and discovered what has to be a lot of black gasket maker on the exhaust rocker bolt threads:


The exhaust rocker bolt hole had a ton of rubbery gunk in it too, so I cleaned it all out. Unfortunately the exhaust side is not the one making all the noise, it's the intake side!:


I also discovered the rocker bridge between the exhaust and intake rockers was bent. The other 3 bridges on that head are all perfectly straight. Not sure what caused that bridge to bend, but I took it apart and hammered it flat again. I wonder if maybe it was assembled already bent and maybe caused increased wear on the intake side to make it so loose. UPDATE: Turned out the rocker arm bolts were overtightened and that caused the bridges to get bent out of typical shape. Easy fix was to simply tap them with a hammer a bit to take the kinks out.

The exhaust side on the left here was bolted in properly so the exhaust rocker was straight and made good contact with the top of the valve, but the intake rocker had the bent side of the bridge causing the rocker to angle a bit odd on the top of the valve.
Maybe the movement of the intake lifter, pushrod, and rocker arm somehow caused that bridge to bend? I doubt it, but not ruling anything out.
I've never seen that before. I also noticed what feels like increased wear on the top of the intake valve, but it might just be my imagination.


Could be a bad cam lobe too I suppose, but I find it odd it's just that intake side on the #1 cylinder with that bent bridge. I put everything back together after cleaning, hammering the bridge straight, and inspecting everything again, but that intake rocker is still just as loose.

I also removed both push rods and they're both perfectly identical, straight and unclogged, so that wasn't affected.
Nor does it look like there's any increased wear on the intake rocker arm, either underneath where the pushrod contacts it, nor where the retainer sits in the rocker, nor where the rocker contacts the top of the valve.

Neither the intake bolt, nor the hole had any rubbery crap on it, so not sure what the hell someone did, nor why, on that exhaust side with all the rubbery gunk on it.
I'm now wondering if that rubbery crap just got into the intake lifter and clogged it, or if I have more crap circulating, or if any other rocker bolts have any crap on them.
Odd though, only the exhaust bolt had that rubbery crud and the problem-child intake-side didn't.
I'll run some engine gunk cleaner thru it, change the oil and filter again, and see if maybe it's just the lifter or not.
If not, I'll have to remove the intake and see if the lifter and / or cam lobe are toast.


Anyone care to chime in here with their thoughts?

[wiley-moeracing]

Bad cam lobe and or bad lifter. You can measure the lobe lift with a dial indicator but will need to pull the intake to get to the lifter.

[MysticRob]

Bad cam lobe and or bad lifter. You can measure the lobe lift with a dial indicator but will need to pull the intake to get to the lifter.

After I wrote all that crap I neglected to mention the ticking isn't audible past about 1000 RPM, so I'm hoping it's just crud in the lifter, though none of what I've seen thus far gives me any comfort.

I'm guessing the cam lobe is probably okay if the higher RPMs alleviate the problem, but I don't want to have to yank the intake (again) to figure it out. I'll hope the engine flush corrects the problem, but I'm really curious if there's any more gasket maker crap used elsewhere that might gum up the works.

I couldn't see anything odd in the old oil but it was so dark and gassy there could've been a dead body at the bottom and I wouldn't have seen it. I have less than 3 miles on the new oil and filter though, so maybe the flush will solve it, and maybe some thicker oil, since I think I used mostly 5W-30 and 10W-30 I had laying around.

[wiley-moeracing]

The problem with using the engine cleaner is it tends to dislodge a lot of garbage inside and will clog up the pick up and filters as well as some of the small passages.

[MysticRob]

The problem with using the engine cleaner is it tends to dislodge a lot of garbage inside and will clog up the pick up and filters as well as some of the small passages.

Oddly though, both the heads and intake area looked very clean when I had the intake and valve covers off before.


Granted that won't tell the entire story, and engine gunk cleaner might not clean or dislodge much with gasket crap, but it's worth a shot to hopefully avoid further teardown!

I shall update when I know more!

[rang-a-stang]

My bet is the lifter. Especially since it goes away after 100RPM. You probably get enough oil pressure at that point to pump it up and the ticking goes away.

I recommend ordering a valley pan gasket set now so it's waiting for you when you get home. I have a spare, brand new Comp Cams lifter in the original package sitting in my parts bin if you need one. I'd send it for cheap if you need it.

I am with Tim. I am not a huge fan of oil cleaners. When I buy an older/high mileage engine (like our XJ 4.0 with 150k when I bought it), I add ~1/2 quart ATF to the oil at each oil change to slowly clean it out. First oil change with ATF is 1.5k-2k miles, second oil change is 3K miles, third and follow are 5k miles. Our AMC oil pans will hold 6 quarts without a problem so put in your 1/2 quart of ATF, then your 5quarts of oil. ATF is also thinner than most engine oils so run 10W40 or 20W50 when you add ATF. Just for clarity, I am not saying adding ATF is going to fix your ticking, I am saying after you get your ticking figured out.

[rang-a-stang]

After you cleaned that exhaust bolt, did it thread well? I wonder if that goop was put in there because someone stripped some threads and tried to use what they had to get it to hold?

[MysticRob]

After you cleaned that exhaust bolt, did it thread well? I wonder if that goop was put in there because someone stripped some threads and tried to use what they had to get it to hold?

Yeah, that bolt cleaned up fine and went in without any problems. No helicoils or other inserts in the hole, no damaged threads, bolt was fine. There was enough crud sticking out from under the bolt head that I figure some just got loose and floated around into the lifter.
I'm assuming some numpty did it, and either realized he didn't need to do that, or got yelled at by his boss, and didn't do any others, without bothering to clean that one since it was already threaded in.
While that material is still kinda gaskety/rubbery, it's definitely started to break down, and as easily pliable, so I'm hoping a flush will do the trick. Besides, I want to use some 10W-40 oil instead of what's in it now.

[MysticRob]

Well I found the ticking problem. That intake lifter is completely dished where it hits the cam lobe. What I could see of the cam lobe looks just like all the other cam lobes so I don't think it's toast.

I hit the 89 wagoneer at the salvage yard today and removed the intake and driver side valve cover to swipe all the driver side lifters, pushrods, and rocker arms. I had a soccer game to go to today so will try to get back over there to finish swiping the passenger side stuff tomorrow to have more spares just in case. I took out the exhaust lifter too just to compare it and it looks fine, just like the salvage yard lifters.

Original intake lifter closer, salvage yard lifter farther away:


Original intake lifter on the right, salvage yard lifter on the left:


Same thing here:


I put one of the salvage yard lifters in, put the pushrod in, and hand tightened the rockers and bridge bolts. That intake rocker now has absolutely NO play in it at all with the donor lifter. Before that intake rocker had movement both up and down and side to side, so I think I got lucky. I'm going to check the torque on all the rocker arms just to ensure nothing else is odd before I button it all up.

[wiley-moeracing]

so what did the cam look like?

[SJTD]

Yeah, unless that happened suddenly a day or to ago it's hard to believe the cam isn't in bad shape too.

I'd start saving up for a new cam set.

[babywag]

What I could see of the cam lobe looks just like all the other cam lobes so I don't think it's toast.

Lobe must be measured eyeballs won't do...
That much lifter wear I cannot imagine it isn't worn?

[MysticRob]

I'm not at a point where I can remove and measure the cam lobe, and have no idea how long it may have been like that since I've only had it running at higher RPMs where the noise wasn't evident (the carb was crap and the Howell kit was set way too high) till recently dialing in the throttle body.

I've driven it a total of maybe 3 miles since I've owned it, but after seeing all the goop on the exhaust rocker bolt and how tightly torqued those bolts were, I believe some clown tried a clown fix on it. Most clowny was how the exhaust bolt had the goop on it (like that was going to fix anything) when the intake side was clearly the issue. If it was an overall lubrication issue affecting everything, and not just an issue affecting that lifter, then I'd expect that exhaust lifter to look just as bad, but it looked fine, so I'll button it up and hope for the best till I'm in a position to verify everything else.

Once I get back from my 6 week deployment and make the move to Arizona I'll figure out next steps, which will likely be a full rebuild with some nice Edelbrock aluminum heads, intake, cam, etc.

For now though, the salvage yard lifter will have to do.

[rang-a-stang]

...ooohhh... used lifters on a used cam.... new lifters are not expensive, recommend just buying some cheapie new lifters. If your cam is not hashed now, it very well could be if you stick used lifters on it and run it... general flat tapped cam rule say, new lifters/used cam ok. Used lifters and used cam bad. Used lifters new cam bad.

[MysticRob]

...ooohhh... used lifters on a used cam.... new lifters are not expensive, recommend just buying some cheapie new lifters. If your cam is not hashed now, it very well could be if you stick used lifters on it and run it... general flat tapped cam rule say, new lifters/used cam ok. Used lifters and used cam bad. Used lifters new cam bad.

Yeah but general rules are for pussies.
I'm assuming nothing is good on this tired old thing but I'm short on time and need to get to a point where I can get it running well enough to get it registered in Idaho, get some plates on it, then make the 1000 mile drive to Arizona.

I also removed the passenger side valve cover and inspected the valvetrain there. If my torque wrench is to be believed, all 16 rocker arm bolts were at ~50ft lbs, which is way too much. I removed them all, hammered some of the bridges back to flat since some were bent from being over-torqued, and also found 3 other bolts had rubbery gasket maker crap on them. No idea why, as once again there was nothing wrong with the bolts, the rocker arms, or the holes. I'll blame it on someone just being an idiot.

I'll update this thread once I get it started and it turns into a grenade.