My 71 Duster work in progress

[Dr.Jass]

I was just remembering some concern about galling from when I bought a set of adjustables for a 440.

But also, 273 rockers don't exactly grow on trees either.

They're not hard to find. Remember, every 273 built for four years had solid lifters (1964-'67). They're just hard to find priced reasonably when you're looking at eBay and the like. They pop up on other boards now and again for under $200 with shafts. I bought my last set at a swap meet for $25 from an idiot.

I've never seen shafts with more than one oil hole per rocker.

Every set of ductile-iron LA rockers I have have two per rocker except the W2s. Those have three: one for the rocker itself, one for the valve tip, and one for the pushrod socket. But, the W2 arms are much wider than 273 rockers because of the enormous offset between pushrod and valve. They don't use spacers--there's no room.

OE 273 solid-lifter shaft:




Trans Am (340 Six Pack) rocker shaft:



Anyone want to buy a 1983-vintage Bud Light tap handle?

I might try that on the shafts that came with the engine.

That's a good idea. There's no reason not to at least try. You could use 'em for practice if you haven't got a different old set lying around. I plan to at some point with my bent Sharp shafts. Melling's and/or Sealed Power's new shafts can be had for $40-$50 each once you're confident to attack a new set.

 

[b-body-bob]

There's a set on FABO with $200 ask, but the photos show one side is missing the spacers. I think anyway.

There's also a set on FB, unsure if the seller is interested in shipping, describes the price as "rocker arm assemblies from a 273. $150.00/ each set" so I'm unsure if he means $150 per side, or if he has more than one set (L&R) for sale. The photo shows L&R side together, and there's only 7 spacers visible.

I don't see either set as a bargain if there are missing parts. Am I wrong?

I had noticed there are no spacers with the Mancini set. Maybe they are different because they are designed to use the non-adjustable shaft and hold downs, but I need to find out if I go down that road.

 

[Dr.Jass]

It looks to me like the spacers are all there... I think there's a bit of an optical delusion happening in the photo. You could certainly ask him to be sure, but I think they're complete. I know this: I haven't been able to find the spacers easily, so if they're not all there, pass. The pushrods do you no good; they're longer than those for hydraulic cams. Those look like they've been for sale for a little while, too, so maybe offer $200 shipped.

 

[b-body-bob]

It looks to me like the spacers are all there... I think there's a bit of an optical delusion happening in the photo. You could certainly ask him to be sure, but I think they're complete. I know this: I haven't been able to find the spacers easily, so if they're not all there, pass. The pushrods do you no good; they're longer than those for hydraulic cams. Those look like they've been for sale for a little while, too, so maybe offer $200 shipped.

One thing I picked up on second look is it would be a heckuva coincidence for those spacers to be missing but the rockers to all have the same gap between them

I won't be surprised if they're already sold

 

[Dr.Jass]

One thing I picked up on second look is it would be a heckuva coincidence for those spacers to be missing but the rockers to all have the same gap between them

I won't be surprised if they're already sold

You've gotta ax the man.

 

[b-body-bob]

You've gotta ax the man.

Duh

He's gotta reply

 

[b-body-bob]

We now have a conversation going.

 

[b-body-bob]

This guy (the machinist). I call, everything's there. Always has to get out his book and remind himself what he's doing for me. Good that he's got it written down, not so good that he keeps forgetting what's going on with the work.

I'm taking the balancer up there today and picking up the parts. As per tradition "it should be no problem to get it done in the next week". Talk to me in about a month.

.

 

[b-body-bob]

Didn't make it. Will go up Monday. He's still left me hanging more than I've left him

 

[b-body-bob]

I'm the proud owner of a set of 273 rockers with all parts and grooved shafts. Seller said clean them up and go. We will see.

 

[Dr.Jass]

I think you'll find he's right, and I think you got pretty good value there for a number of reasons. You've now got a set of original groovy shafts, all the spacers, and the right shaft retainers.

Going back to "the guys that designed it", the grooves on the OE shaft alternate angles; the repros I've seen (and have) all go one way. Minor? Hell, it's probably insignificant, but why'd Chrysler go the extra mile if that's the case? Either way, you almost never see the used banana-groove shafts for sale on their own. Nobody, self included, wants to let 'em go unless they're selling the whole rocker set.
The Mancini set doesn't include the spacers, which are virtually impossible to find by themselves and have been for well over a decade. The last NOS ones I found were $15+ each. Nobody seems to make the right width.
Lastly, if you go back and look at the shaft retainers that came on your 360, they're different than those used on the ductile arms. They have a bent "guide" on either end so they contact higher on the side of the hydraulic rockers. I've never tried to use those on the ductile arms, primarily because I don't like how the contact area looks. I have seen early stamped-arm engines with the ductile-arm retainers, but Chrysler switched to the more-expensive-to-produce late style pretty quickly. Chrysler spending extra money tells me there were issues with that arrangement.

Even if you decided to replace the arms, there's well over $200 worth of parts you'd still need to run the Cranes. Whether I mentioned it previously or not, one of the reasons I prefer the 273/Crane units is because they seem to hold adjustment eternally. With a hydraulic cam of similar lift and Crane Gold aluminum arms, EFI Ed's preload needed adjustment about every oil change if not sooner. The factory's recommendation for checking (not necessarily adjusting) was yearly/12,000 miles on the 273. That was without locknuts; if you switch to locknut-style adjusters I'd expect even longer intervals.

Soak everything in solvent for a few hours and hose down with carb or brake cleaner. Lightly scuff the shafts with a red Scotch-Brite pad (manually) and rinse again. Holding the shaft vertically on a bench or such, hose the insides out through the top bolt hole with aerosol solvent, which should clean anything out of the insides of the shafts (this is an area of paranoia for which I've never found a basis in fact--they rarely get crudded up inside). The arm bores should be fine; if you'd like you could pass a brake cylinder hone through them very quickly (fine stones, well oiled, I don't think I'd count "one thousand two"). I doubt that's necessary or beneficial. I just use a finger and red Scotch-Brite manually for a quick cleanup and call it good.

 

[Dr.Jass]

Come assembly/setup time: You will need to adjust the arms initially, just like you would with solid lifters. You can use the old Direct Connection lash chart, but it's kind of a PITA and takes longer. I use the quicker Exhaust Opening, Intake Closing method. Set the intake valve preload when the exhaust valve is beginning to open. This will put the intake lifter at the base circle. Set the exhaust valve preload when the intake valve is about halfway down it's closing event. You can do this right down each bank if you prefer, but it's actually a little quicker to follow the firing order. I use a Sharpie to mark the rockers I've already adjusted. Brake cleaner takes it right off.
So, how much preload is preferred and how do I achieve it? You'll often see numbers around ~.020" tossed around, but that's a max-effort recommendation for minimum resistance. It may also be a bit noisy. I'd prefer to see ~.010" more for long-term reliability (OE stamped arms were higher yet, but no need to go there). The simple method for this is the maths: The adjusters are 24 threads per inch. 1" divided by 24 threads equals .0417" of travel for each full rotation of the adjuster. At each adjuster, tighten until the pushrod spins freely but has no up/down movement, i.e. you can spin it easily but not rattle it. Tighten the adjuster 3/4 of a turn, and boom: You've got .03125" of preload. Lovely. Next!

Interesting side note: I have so far been unable to find any factory Chrysler literature that addresses the oddball 340 Six Pack setup, which used the adjustable arms on hydraulic lifters (the only OE instance of this combination of which I'm aware). I've no idea where the factory boys set 'em, nor where the manual writers wanted 'em.

The argument rages over which pushrods to use. Melling sells 340+6 replacements under part number MPR157, with a length of 7.234". Comp Cams sells pushrods for use "with adjustable rockers and hydraulic lifters" under part number 7821-16, with a length of 7.389", which they claim as "stock length" (for what?!). That .155" difference might as well be a mile. I've heard others say even the Comps are too short. I wish I could give you a magic number but with production variances, potential prior machining to your engine, etc. I really can't say.
Best bet? Get a pushrod length tool for cup-end pushrods and a 5/16" steel ball. Mock it all up during assembly with ~1.5 threads showing below the bottom of the rocker arm (a bit different than measuring for solids--you'll be adjusting toward the lifter rather than away). Make sure the pushrod cup is not contacting the arm and the cylinder on which you're measuring is at TDC firing. Adjust the pushrod tool as if you were getting ready to set preload--spin, not rattle. Tighten the locknuts on the tool. Rotate the engine to cycle the pushrod through one complete rotation (to max lift and back) making sure the cup does not contact the arm at any point. If it does, tighten the adjuster 1/2 turn, shorten the pushrod accordingly, and try again. Once you've got clearance at max lift (you'll have more once preload is set), remove, and measure length with the 5/16" ball inserted in the cup end. Subtract .3125" and that's your length. Generally, I'll check the four corner cylinders (both valves) and average those numbers. When it comes to pushrods, longer is gooder, but again--you must be sure the pushrod cup won't contact the rocker arm at max lift.

You'd have gone through this pushrod nonsense with anything other than OE stamped rockers, by the way. It seems like a lot of f__kin' around, but it really doesn't take long and is far less expensive than getting the wrong pushrods. If you come up with a number within, say, .040" of either the Melling or Comp options, I'd run 'em--as long as they're shorter. If they're longer you may run into pushrod-to-arm interference.

This may be "print and tape it to your forehead"-worthy (or at least put it in the car somewhere).

 

[b-body-bob]

I had noticed the retainers looked different, but then I'm always visualizing a big block so who knows. I was just pleased those came with.

It is curious that the pattern of the factory grooves alternates. I bet they had a machine that worked that way and it's just the way it ended up because it didn't matter. But you never know 70 years down the line.

Your clean up plan is about what I had planned to do but have some steel wool I might have used instead of scotch brite - just because I have it. Might not be the best idea for fear of tiny bits of it mucking up the works. I tend to err on the side of not messing things up over trying to perfect things.

I'll check with the machinist to see if I can borrow a pushrod measuring tool when the time comes. I also remember seeing one place - maybe Hughes - that "loaned" the measurement tool by charging you for it, then applying that toward the price of pushrods when you return the tool with an order.

I'm also starting to think about what I need to degree the cam. Right now it seems I need a crank turning socket and a wheel - I've already got a dial indicator and can rig up a pointer. Hopefully that's about it. The wheel isn't all that expensive but the crank socket is like $80 IIRC.

FWIW - functional art

 

[Dr.Jass]

It is curious that the pattern of the factory grooves alternates. I bet they had a machine that worked that way and it's just the way it ended up because it didn't matter. But you never know 70 years down the line.

It may be something completely arcane like LH lug nuts which, while technically serving the purpose for which they were designed, that purpose proved superfluous. Interesting to not about the lug nuts, though: Virtually everyone did that at some point (LHT on LH of car). Chrysler was just the final holdout.

Your clean up plan is about what I had planned to do but have some steel wool I might have used instead of scotch brite - just because I have it. Might not be the best idea for fear of tiny bits of it mucking up the works. I tend to err on the side of not messing things up over trying to perfect things.

Scotch-Brite seems to hold up better than steel wool in terms of tiny bits breaking off. Just an observation. Individual SB pads are usually under $2 each. It's less effective than metal-on-metal, which might be a good thing.

I'll check with the machinist to see if I can borrow a pushrod measuring tool when the time comes. I also remember seeing one place - maybe Hughes - that "loaned" the measurement tool by charging you for it, then applying that toward the price of pushrods when you return the tool with an order.

You could also buy one here, or make one out of one of the old pushrods that came with the rockers. Just measure, lop out a section, tap the inside (preferably fine thread) and use a piece of threaded rod (or cut the threaded part off a long bolt) with two jam nuts.
Then, cut up two more to make a longer one. You have a big block too, y'know...

I'm also starting to think about what I need to degree the cam. Right now it seems I need a crank turning socket and a wheel - I've already got a dial indicator and can rig up a pointer. Hopefully that's about it. The wheel isn't all that expensive but the crank socket is like $80 IIRC.

I've had the Moroso unit (27010) for years. It fits both big and small block engines. You'll use it more than you think you will, and it's only about $35. Don't forget you'll need checking springs as well, but those are easy hardware-store parts.

FWIW - functional art

I don't know that the "cool factor" is high enough to warrant the increased cost due to the licensing of the logo.

 

[b-body-bob]

I've had the Moroso unit (27010) for years. It fits both big and small block engines. You'll use it more than you think you will, and it's only about $35. Don't forget you'll need checking springs as well, but those are easy hardware-store parts.

Milodon, not Moroso. I do that too. I don't need checking springs if I degree it with the heads off, true?

Are you able to bolt the wheel to that through the 1/2" socket?

Comp cams: $75

Milodon:$35

I know the crank bolt won't pass through that.

I don't know that the "cool factor" is high enough to warrant the increased cost due to the licensing of the logo.

Pro-comp is only 16.49.

Don't forget you'll need checking springs as well, but those are easy hardware-store parts.

Why would I need those if I degree it with the heads off?

 

[Dr.Jass]

Milodon, not Moroso. I do that too. I don't need checking springs if I degree it with the heads off, true?

My bad on the brand. I always confuse the two. No, you don't need the checking springs with the heads off.

Are you able to bolt the wheel to that through the 1/2" socket?

Comp cams: $75

Milodon:$35

I know the crank bolt won't pass through that.

Nope, it won't. Now that I think about it, I believe I just used the crank bolt when I degreed mine. I was so frustrated by that infernal gear drive setup I've completely forgotten what I did, to be honest. I may have used parts of my harmonic balancer installer.
Regardless, Proform sells the same crank socket as Comp for ~$50 less. Check their number 67493. Same design with the hokey-ass set-screw to make it "fit". Both have their complaints, although I think I like the fix for the Proform better:

Not an exact fit...requires some machining Bought this to assist with my 440 rebuild. Supposed to be a direct fit for the cast crank, however it did not fit on the crank stub. Had to use a rotary tool to increase the I.D. a decent amount for it to fit. After this, the tool worked, but the key slots are too wide, allowing too much play when degreeing the cam in. Bottom line - I would look at other options that might have a better factory fit.

Could be better The roll pins that hold this together came loose several times while degreeing in my cam. This was frustrating to say the least. I had to drill the holes deeper and drive the roll pins in deeper to make it not slip while turning the engine. It would be better to have one long roll pin all the way through instead of two short ones barely in it. This made degreeing in my cam take a lot longer than it should have.

So, one doesn't fit and the other one falls apart. Both are aluminum, where my Milodon is steel. The Milodon actually fits, which makes "non-marring aluminum" the answer to a question nobody asked. You don't turn the thing with an impact. If you don't think that set screw will mar the crank, ask me about cheap oceanfront property in Idaho.
Based on those two reviews, I think I'll stick to what I've got. If I feel the need, I can just thread the outside of an ultra-short 1/2"-drive extension or cobblef__k some other inexpensive, hokey-but-effective solution.

Why would I need those if I degree it with the heads off?

You won't. It's nice to have options, though.
I did mine both ways since I ended up doing it twice (I also checked it a couple of times afterward). It was easier to do off the rocker arm, especially with an indicator stand that threaded solidly into a valve-cover bolt hole (I made one from a broken mag-base stand). If you decide to do a cam change, or need to replace a timing set (with a $50 double-roller one, expect it in ~5K miles*) you probably won't want to pull a head off to re-degree the cam.

*Stretch replaced the Cloyes double-roller set (C3028/C3028X) on a 1971 340 'Cuda at work a couple of years back. It only had about 4,000 miles on it since a complete stock +.030" rebuild. There was about 1.5" total slack in the chain. Ask around; this is not an uncommon problem. I suggested using the 9-3053X9, which the customer did.

 

[b-body-bob]

*Stretch replaced the Cloyes double-roller set (C3028/C3028X) on a 1971 340 'Cuda at work a couple of years back. It only had about 4,000 miles on it since a complete stock +.030" rebuild. There was about 1.5" total slack in the chain. Ask around; this is not an uncommon problem. I suggested using the 9-3053X9, which the customer did.

I have read, so Judge Judy would say it is hearsay, but I have read that the design leads to a slack chain because of the distance between the cogs. There is no way a double-roller set should wear out that fast so I tend to go with the hearsay explanation. So I will use a cam cover with tensioner.

Mancini Racing Timing Chain Tensioner

 

[Dr.Jass]

There is no way a double-roller set should wear out that fast so I tend to go with the hearsay explanation.

It is what it is. I've read numerous complaints about the inexpensive Cloyes sets in the past couple of years, so I avoid them like everything else where I see a pattern of failure. It's neither an LA thing nor a Mopar thing; it's just a thing.

So I will use a cam cover with tensioner.

Mancini Racing Timing Chain Tensioner

I've seen it argued this exacerbates the issue. While I don't have an opinion either way, I'm not sure what function it serves on a timing set that fits well (which is a common complaint of the Cloyes 3028--slack right out of the box). Interestingly, Chrysler never used a tensioner on roller chains, and only used them on roller cams.
The 3053 we put on the customer's 'Cuda, which is the same set I bought for Agnes' engine, is tight. It's not a banjo string, but it doesn't have any slack. Slack begets slack. Personally, I'm done doing stuff twice if I can avoid it.

 

[b-body-bob]

I picked up a pile of parts and dropped off a pile of moolah.

He expects the remaining work to be done next week. I'm nothing if not patient.

 

[b-body-bob]

FWIW this is the timing chain that was in it to begin with