Iron vs alum rocker arm for the street

I’ve had no problem with lots of miles on my AAR with stock iron rockers. Will the aluminums hold up as well? More companies make them I see. A customer needs a set for a street only car and I don’t want to put cheap Chinese alum ones on the car. I see they still make the Crane ductile iron ones. Will they fit under a stock valve cover?

Yes, I use Cranes under stock covers on my Stealths.

Another vote for the adj mechanical, mine have banana groove shafts. I put together a driver 69, 340 4spd swinger. Put 5,500 miles on it this summer, rockers are the furthest thing from a issue in my mind. I did the whole car that way, nothing to fail......drove it 16hrs rnd trip this summer. Didn’t want anything to fail that could fail for no reason. Mechanical all the way. Just my opinion for wiw

didn't the AAR's come with a special offset intake rocker?

Yes...AAR/TA heads use an offset intake rocker. Those are the only rockers that fit the TA head.

Harland Sharp makes Aluminum TA rocker arm. The heads require a
.550 offset on the intake.

if you have any other rockers on the head then you do not have TA heads...

I’ve had great experience with the ProComp stainless bushed rollertip rockers. They are budget friendly and a decent option if you don’t feel comfortable with cheap aluminum ones.

Will these fit under a stock cover with the oil baffle still intact?

The iron Cranes are about $450 without shafts and are just basically like stock hemi, 273 and TA rockers. I’m comfortable with a long life with those. What is the advantage of the alum ones except fort the roller tip? Do they wear out over time?

The ProComp, PRW style stainless rockers fit under the valve covers with the baffle. The real advantage to aluminum rockers is the cost to machine them. That's it.

I personally don't use needle bearings on a reciprocating shaft if I can avoid it.

If you are breaking rockers 99.999% of the time it's a geometry issue. The other .001% of the time it's a junk rocker. Mostly, it the junk bearings that fail first and kill the rocker.

I always repeat this but it's still not common enough to not say. If you are going to buy rockers, call Mike at B3 racing engines and have him sell you his geometry kit. He will tell you how to measure for it and it's a simple bolt on deal. It works and it's an absolute requirement IMO on anything other than a dead stock lift, dead stock rocker deal.

You can go to b3racingengines.com and read the tech pages he has. Worth every second of reading, and every penny of doing.

Thanks for all the advice. The problem I’m trying to resolve right now is with a customers car. She came to me with this problem statement, “ it just does not run right after this overhaul” problem. I have uncovered problems from the last three shops that she had work on it, plus the shop that patched it together to sell at the auction she bought it from. It’s a mess. I’m down to the motor now. My buds shop did the machine work and assembled the short block. Lucky for her, he came to me years ago looking for a crank and at least I sold her a four speed crank. The heads or block have been milled so much, the lifters have about .120 preload at rest. I’m sure it’s running with valves slightly open. They installed the heads and never checked preload. The shafts were still dirty and two rockers were swapped sides. It had very little power on the test drive. A stock intake fits so I’m wondering if they removed the dowel pins in the head to drop heads enough for the intake to fit. These guys were Chevy guys who disrespect mopars and don’t want to learn. The button fell out of the third member and ruined the axle bearing on one side. It had enough play in the axle for the backing plate to rub the drum. They just spaced the drum with washers! I guess people like this keep my busy!

Most likely the that .120 preload is coming from the stem height being too tall, rather than that much surfacing being done. The easiest fix for that is shorter pushrods. The correct way to do it is pull the heads and get the stem height in spec. If you go the shorter pushrod route you will still have geometry issues.

Paraphrasing Vizard: "If either valve does not close completely, that cylinder will not run."

The roller tip advantage isn't exactly as described. The curvature of a well-design pallet (such as the very special W2) and lever construction balances drag (scrubbing across the stem tip) with the need to create an oil film separating them (which requires motion, same as a crank journal). The pallet cannot "roll" across the stem, and should not.
I would suggest a B3 kit even with (nearly) stock lift, since mill, wear, valve seat condition etc. all affect installed geo.
Once you're sure the geo is as close as you need (including lateral alignment of each rocker to its stem), the reciprocating mass of the rocker tip can be safely reduced from both sides until what remains is only the stem tip width + 1/16" safety. No, it's not important, that's just my OCD.

don't use needle bearings on a reciprocating shaft if I can avoid it
X2, even with quality parts the needles are always at risk.

I think the block had been milled too much. The reason I pulled the intake is because of the terrible leak where the corner of the head met the block. They did not put enough sealant in the corner under the intake pan gasket. When removed, the intake surface was way down from the top rail where the gasket is bolted too. I’m still going to do some more tearing down after I talk to the customer.

How far would you have to mill it to be .120 " long on the push rods ?
Seems unlikely , but I have been wrong before.
It would have to be a real butcher to do this kind of work and allow it out the shop door.

It could have milled on a previous rebuild. This car was raced and hacked together to sell. They even restamped the block and sold it as matching number. It was milled again this time or the heads milled to get more compression the first time. Then you throw in a couple of valve jobs and the seats sink some. Then you have a cam with a slightly larger base circle. It all adds up to too much preload. I think lifters have around .060 preload anyway from the factory. I have not even checked to see if the pushrods are stock length yet. They could be off as well. I would not put it past these guys to pull the dowel pins out of the heads to slightly drop the head down enough to make the intake fit.

And yes they were butchers. They let the car leave the shop with both rear axles that had .250 end play. The distributor had 80 degrees total advance. It would barely get to 2500 rpm.

Problem is they see themselves as problem solvers. Intake don't fit? Pull the dowels. Now it fits.

Kevin

Don't know how far you can move the head down with the dowel pins out. You still have to get the bolts in the head and that will limit how far down the head can go, and it ain't much.

I agree it does not get much but with these guys, who knows. I’ll pull them soon. I just have to talk to customer. I’m so tired of calling her with bad news

If I had seen that kind of stuff I woulda just pulled the motor, and pulled it completely apart as step one.

I imagine that’s what going to happen. I’m confident the short block was done properly but the more bad things I found they did on the rest of the repairs they did, I’m sure they could not even properly put on the heads or even keep it clean during assembly.

they see themselves as problem solvers

I have one you'll find amusing. In (what was) the Iron Curtain countries Harley-Davidson WW2 leftovers are very valuable but extremely expensive to rebuild. "We need those small needle bearings for the transmission shafts, but $$$ and hard to find".
What to do?
They used short sections of wire coat hangars, cut to length, packed in heavy grease.

Quite a few years ago, when I had plenty of time and no $$$, I cobbled quite a few piles of old junk together.
They always ran surprisingly well and nothing ever failed.

Even on old junk, cleanliness and attention to details matter........ and it helps if you kinda know what you’re doing(which is about how it was back then....... I “kinda” knew what I was doing).

Somewhat related to the topic question: Anyone else seen their "traditional" iron adjustable rockers (e.g. Crane) leave noticeable wear patterns even on chromed aftermarket rocker shafts? The last set I ran (mid-to-late '90s) left grooves on the loaded areas of the shafts that matched the machining pattern inside of the rockers. I always thought having bushed iron/steel rockers would have been a better idea after seeing that.

I had the same problems with galling trying to use the Speed Pro Hi Po rocker shafts with ductile iron rockers Ended up only using either Iskys or RAS shafts, that cures those problems
I had to learn the same lesson on CAT aluminum roller rocker arm also, don't use the Speed Pro Hi Po shafts on them either

My Cranes are bushed by RAS and run on undersized shafts. Plus I run full time oiling, to the top, via the lifter galley.

No problems.

When the rocker grabs the shaft it's usually a volume/pressure issue. I don't like idle oil pressure less that about 45 pounds hot. It's also why I always use a HV pump. You get more oil there, sooner.

I've used both Isky and Crane on their recommended shafts without any unusual wear with both solid and hydraulic FT cams with moderate VS pressure.

I've used Isky and Crower (they use to have ductile iron rockers too) on "other" shafts. Not good.

I've measured the OD of the shafts from various manufacturers and found they vary .003" from smallest to largest. This may explain galling when switching them up.

These are Manicinis House brand iron adjustables. I know nothing about them. Probably made overseas to be able to have the low price.

https://www.manciniracing.com/maraenadroar.html