Hey all,

I’ve been chasing my tail and losing my mind for the past well year almost messing around with this issue.

So for context, I have a 92 Dakota, 5.9 swapped, carb, rpm air gap, blah blah. Important stuff for this post: Odessa OEM replacement heads, Hughes 0814-k cam kit (mild cam, new springs/locks/etc), HS 1.6 rollers (non adjustable), Hughes 5007 lifters, and 6.936” pushrods. (I measured 6.810” zero lash, but I will get into this later).

I’ve had a tapping sound coming from the top end since I put this engine together, both times (spun a bearing, rebuild the whole thing). There’s a whole list of things I’ve tried. The first time it was built it had a comp xe 20-745-9 cam, melling OEM lifters, and a couple different sized pushrods (trying to change preload to fix the tapping) and that didn’t work. Once the engine was rebuilt, I swapped over to 5007 Hughes lifters, and with this cam and lifter combo, it calls for .120-140” preload (a lot, but it’s what they say). I’m currently at .126 and it’s still very clacky.

With this cam, I’ve tried 2 different pushrod lengths, and 3 with the old cam. Pushrods don’t seem to be the issue here. Cam and lifters have both been changed, and the problem has stayed. The only thing that has not been changed at this point is the heads (valves), and the rockers.

I’ve also checked for exhaust leaks (I just got some new hex head bolts onto some of the bolt holes on the headers (jba shorties are impossible to get tight it seems like), and it didn’t fix the problem. I felt around the flanges and felt no air moving. And for sanity, I did double gasket the valve covers with two fel pro rubber steel impregnated gaskets, and the ticking at least to my ear did not change, which seems like rocker to baffle clearance isn’t the issue.

Im kind of stumped at this point. Next on my list is to pull the covers off and use a stethoscope to see if I can pinpoint a specific cylinder it’s doing it at. I’ve found it’s louder on the driver bank, and from my minimal testing with the covers still on, screwdriver to my ear the exhaust manifold is quiet on all 4, same with the intake, but if I put the screwdriver into the oil cap and onto the baffle, I can hear it faintly ticking.

The ticking is there at idle, not as loud at cold idle but still there, and at low engine speed it is noticeable and is in line with engine speed. It kind of goes away at around 2500 or so, but it could also just be sort of blending into one solid noise and I’m just not noticing it.

Long story short, just looking to see if anyone has any feedback and or suggestions for my suffering lol

I’m planning to buy some Mopar Magnum finned aluminum covers off of eBay that seem like they have a higher tucked baffle, which would maybe help if it is a clearance thing, but TBD for now.

https://youtube.com/shorts/7rGCNQhcki0?si=wyw-inbiyflLfIka
(Older video I have, hard to hear over the belt squeal but it’s there. It is audible outside of the engine bay with the hood closed, inside the truck, and from a decent distance away)

 

I would be tempted to go with some adjustable rockers.... or, put a pushrod length checker in there, and see what ya get.

 

Im tempted to run adjustable just to make my life easier, but I’ve tried a .085” preload and a .126” and they sounded the same, maybe a little quieter with the 126. I did measure 6.81” zero lash with this combo

 

In the video it sounds like an exhaust leak but hard to tell. You may want to remove the header and have a look at the gasket. If it is a leak you will see it. Also when you installed the headers did you inspect them for issues? I got a brand new set of Mopar Performance headers and there was a pin hole where it wasn't welded fully. Glad I seen it before I put it on. I like to use studs in the heads then use flanged nuts. This combo works well with headers.

 

Studs and nuts won't always work though..... sometimes, there just isn't enough room for the nuts..... I've used allen-head bolts, and 'modified' washers in the past..... Worked pretty good. Also, use a GOOD gasket. I am a big fan of the dead-soft copper, or aluminum gaskets......

 

With the JBA headers, the clearance is so tight on some of the bolts that you can’t even fit the box end of a wrench onto the bolt to tighten it. I’m planning to buy some better hardware because the bolts that came with the headers are crap. 3/8 is semi loose, 10mm is very loose, 5/16 doesn’t fit. Problem with this is that on some bolts I have to use the open end, and it slips. Either way, still will be hard to get all the bolts to be tight due to the clearances.

i do remember checking the gaskets when I rebuilt the engine and did not see any spots that look like leaks. The gaskets had soot around where the flanges of the manifold press against it, but nothing where there is a line of buildup going to the end of the gasket or anything like that.

Im also using fel pro gaskets

 

What are you using now? It should be 5/16 18 if memory serves. Are the threads in the head good?

I haven't seen a set of headers you didn't have to modify somehow. Is the clearance issue because of a weld or the tube? If it the tube you heat it with a torch and hammer it a bit. When they make headers they put the parts on a jig and weld it up. And I don't think anybody inspects them for welds being to large not enough etc. Use grade 8 hardware it's not as soft as grade 5.

 

5/16-18x1 bolts that came with them. Definitely seem like grade 5 because they’re soft. I’m planning to run arp 12 points, that way for places I can’t fit a socket I can still get a good grip with a wrench. The pipes block a lot of the bolts, so probably have to “persuade” them a bit

 

Alright have a small update. I ordered some 5/16 12 point headed bolts to help get some even torque everywhere, and also ordered remflex gaskets. Got those on, got every bolt torqued down evenly and to spec, and the noise is still there.

Given that I’ve ruled out an exhaust leak, I’d want to say my last 2 possibilities are either a bad rocker, or the rockers are smacking the bottom of the valve cover baffles. I did try a double gasket like I mentioned, but I wonder if that’s not enough space for it to clear? I’m just really out of ideas for what it could possibly be, I know Harland rockers are great and reliable, so I find it hard to believe I would have a bad one so quickly.

 

Pull the rocker covers, and check the baffles for evidence of contact. You may just need slightly longer pushrods too.....