Hey guys, I was about to check/adjust hot lash on my 340 when I ran into what might be a potential problem, although I'm really not sure as I don't have much experience with shaft mounted aftermarket rocker setups.

It's a w2 econo head with Mopar Performance shaft mounted rockers, my machinist put the engine together.

When I went to adjust the first rocker, I cinched it down and realized it no longer moved freely on its own. I realized that when I loosened it and tightened it again, I must have change the end play. I ended up having to pry carefully with a screwdriver before tightening it to keep it off the shaft hold down so that it would move freely.

When I got to the the cylinder number 5 rockers I found that both rockers would slide left to right freely a pretty good amount (didn't measure it but I would say probably 3/16 inch of play). It was actually difficult to adjust lash because the lash seemed to change depending on how far left or right I slid the rockers.

I'm a little lost here. Is there supposed to be a specific tolerance between rocker arms or is the fact that some go side to side and others need prying while tightening to move freely OK?

I've never used a setup like this so i'm a little confused by how it's supposed to work.
Pictures of the rocker setup attached.

There is no place in that set up where you should have 1/4" of side free play.You want somewhere between .015-.020 clearance/end play between pairs. If you are moving the rockers so much that it changes the lash, thats a problem.Fix it before you run it. W2 pushrod angles are bad enough, without them being self adjusting.

You also need to make sure the rocker is centered over the valve, from front to rear. If that means milling the hold downs, it's what you have to do.

Also make sure the push rods arent dragging on the
on the heads as the valves travel

Eek, the motor was already run for about 500 miles (those pics were prior to first startup hence the clean ports). I trusted my engine builder with the assembly, only noticed this when I was about to adjust hotlash after the first oil change.

I will check on the front to back centering, I really hope that's right or this could turn into a real PITA 😡

Is less than .015 of clearance ok? It looks like some don't have shims, and the cylinder#1 pair I don't think even has that much. I assume I'll need at least that for expansion so they don't rub.

FWIW this is a low rpm engine, won't see over 6500 (supercharged). The heads/valvetrain I bought on here from a member a few years back, I didn't know much about setting these up so I just gave it to my engine builder to do along with the rest of the motor. Only noticed a tiny bit of metal on the drain plug during the first oil change , no sign of anything crazy but i'll definitely check the push rod clearance was figuring my builder already did all this for how much I paid 🙁

This is the magnetic drain plug after the first oil change.

All new motors make metal during break in, which is normal as parts wear in
I run all the new the motor I build for 20 to 30 minutes to break in all the flat tappet cam motors I build and then drain the oil and cut the oil filter apart to see how much debris is in the pleats of the filter.
I do this several more times, at 500, 1000 and the 2000 miles after breaking them in to ensure that the oil filter cleans up all together after 1000 miles or third oil and filter change
On your deal if your checking the side play with the motor cold I would want .020 or more minimum per pair, .005 + side play when warmed up
Ain't hot rodding fun

Thanks cab! Tell me about it haha, between FITECH issues, supercharger belt issues and now this, I got this car fired up late summer and it hasn't been able to make get even one clean WOT one gear pull after working on it every weekend.

It definitely didn't look like any more metal than I have normally seen on new motors so I wasn't too worried. Next oil change I'll cut the filter as well.

This setup has definitely been more than I bargained for trying to get everything to work right.

this just bothers me because I cut a pretty big check to my engine builder/machinist to assemble the engine and this seems like a pretty big thing to overlook. If it's just a matter of shimming, I don't mind, but if roller tips aren't centered front to back on the valve and the perches have to be milled I am going to have to go back to him and ask what's up. I normally expect a lot of bumps in the road and still have a ton of kinks to work out on my home built procharger setup and FITECH tuning issues so it really sucks having to take time out to fix stuff that I paid to have done.

but if I wanted easy, cheap and slow I would have gotten into marathon running so I'm not complaining, just venting a little LOL!

Talk to Mike @ B3racing about the geometry

^^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^

You just know the geometry is put correct. It never is.

Another day, another waste of my time.

How thick are the shims at the bottom of the
springs.. they look real thick.. what is the
installed height
Also show your rockers at base and full lift

OK, well I may have over-reacted a little on the clearances. The gap between the cylinder 5 rockers that I thought was 1/4" was actually about 36 thousands when I checked it with the feeler gauge. it felt like a lot more...yes this is embarassing LOL

as far as the roller tips being centered forward to back, they appear to be good but I am going to try to snap some pics of them because it is hard to see with the motor in the car. I can't get my head low enough to really get a good view.

My builder said the geometry was funky but he didn't think it would be an issue on a low rpm engine. The last engine the ran on looked about the same and he was taking it up to 7500 IIRC. Not saying it's good, but maybe good enough? I really don't know. I'm just going by what I'm being told.


Poly, makes sense that the lash was changing as i slid the rocker side to side, as you said, it would be changing the pushrod angle as you moved it. I take it the large 36 thousanths clearance is causing that as the others barely move


What I am also worried about is can they be too tight side to side? Most of these rockers seem extremely tight side to side. I mean you can move them freely up and down when they are off the valve but some of them I can't feel any side to side movement. I need to find the rest of my feeler gauges to check but I'm pretty sure most of them are less than .015 of clearance. I could be wrong though, as I just called 39 thousandths a 1/4 inch LOL

Mr P body, i will snap some pics of that.

And when I say this thing won't see over 6500rpm's I mean that. I plan to shift at around 6000 and set the rev limited pretty soon after it. It's a 295cfm flowing head, indy single plane, D1SC procharger with intercooler on E85 on a not so crazy bottom end (factory forged crank, H beam rods, stud girdle...that's it) so I figure it may be able to take boost, but not RPM's. It'll make more power than I need at 6000 with 8PSI so I don't plan on really revving it much higher.

RPM has ZERO to do with rocker arm geometry. Before you do anything further, get ahold of Mike at B3 racing engines (b3racingengines.com) and let him help you fix the geometry BEFORE you bother to do anything else.

Bad geometry is bad geometry. RPM means nothing.

I have typed this out so many times in so many places it feels beyond redundant. I can tell you that a great number of engine builders have no idea about rocker arm geometry, let alone rocker arm geometry with a shaft system. I am certainly not an expert, but I learned a long time ago the hard way that you must fix it. It's crazy to say my RPM's are low so I can let it slide.

In 38 years of doing this I have seen more destruction and broken parts from rocker geometry and general valve train issues than almost anything else.

I can tell you that when you fix your geometry, you will have to buy longer pushrods.

Don't put it off. Fix it now.

Is your builder responsible for that mixed and matched bastardized pushrod set?

And remember, its a w2, so the intake rocker pushes to one side as it gets on the lobe. When setting lash, you have to sorta hold/push it over while you set lash.

Also, Make sure your rocker shims are on the side of the intake rocker that gets the load from the pushrod angle. Or said another way- on both sides of the exhaust rocker its paired with. IMO a shim isnt necessary on the one side of the intake rocker that is opposite the offset adjuster.

Yes, get a hold of Mike. I had the same deal with my W2 econos. Mine were so off that the rocker arm was hitting the retainer and the roller was just about off the valve tip. I had the correct rocker shafts and the 1.5 ratio blue MP rocker arms. The shim kit helped dramatically. My W2's are late 70's vintage and I'm pretty sure the MP and Crane stuff, even though everything says that they'll fit, is actually meant for the race heads, especially the long valve versions.

B3 Mike is the man for the job.

Hey guys, just getting around to reading some more of these replies in depth now, it was a busy week and I only had time to skim posts on here before.

I ended up getting some spacers and spent a few hours getting all the rockers perfectly centered side to side on over the valve and now they all have about 8-10 thousandths of clearance side to side. Setting the lash went very smoothly after all the movement was gone.

I spoke to my builder about the geometry and he keeps telling me he thinks it would be fine. This whole top end was run already by David Dean here on the forums on a 340 block decked .030 making just short of 600hp. that's who I bought it from, pushrods and all. I gave the whole top end I purchased to my machinist/builder and told him that if anything else was needed to get it to work, I'd be willing to pay for it. He checked the valve springs, measured pushrods and told me everything seemed good to reuse as is.

I just emailed Mike at B3 with pictures of the setup just to get his opinion on it.

Mr. P Body, here are a few pics I took, let me know if you need a different angle. that's full lift on the intake rocker
IMG_4498 by Kris A, on Flickr
IMG_4491 by Kris A, on FlickrIMG_4490 by Kris A, on Flickr