RUSTY Cuda
In over my head!
My head hurts!
My 71 Duster work in progress
- Thread starter b-body-bob
- Start date
b-body-bob
Well-known member
Also, thinking about rocker arms.
Be thankful you aren't footing the bill, then your head and your butt would hurt.
b-body-bob
Well-known member
I think I'm going to go ahead and order it from Jeg's. The worst they can do is say "sorry but no".
I still haven't decided on rockers either.
they start here
Proform 66869: Small Block Chrysler Shaft Mounted Aluminum Roller Rockers in 1.5 Ratio - JEGS $289 for bushed aluminum w/shafts that use the factory hold downs for spacing. Note the Summit photo shows spacers.
Mancini Racing - A Engine Adjustable Rocker Arm Set $300 for steel that use my used shafts and hold downs
DODGE Proform Parts 440-869 Proform Extruded Aluminum Shaft Mount Roller Rocker Arms | Summit Racing $427 for a pro-form set that looks just like the $289 kit, plus spacers and a groovy cool Mopar logo.
https://www.jegs.com/i/PRW/228/3231811/10002/-1 $600 for stainless steel rockers, all new shafts and hardware, and even comes with a pushrod length checker
There's also the option to buy used rockers and hope they don't need sent off to be re-bushed.
One thing I wondered is the $600 set uses a ball-ball pushrod - is there a chance in heck that I will be able to reuse the factory pushrods? If so that brings them down to a mid-price range.
b-body-bob
Well-known member
I noticed the Howard's lifters are also listed for an AMC so they have an oil hole for pushrod oiling that the pushrod blocks off.
That nice set of $600 rockers are $50 less at Mancini's
MRE A Eng. Stainless Shaft Mount Rocker Arm Set
I went ahead and ordered the cam and lifters - went with the Howard's lifters because it kind of feels like buying insurance against flat lobes.
If it turns out I have to pay Summit's price for them, I'll likely reconsider.
That nice set of $600 rockers are $50 less at Mancini's
MRE A Eng. Stainless Shaft Mount Rocker Arm Set
I went ahead and ordered the cam and lifters - went with the Howard's lifters because it kind of feels like buying insurance against flat lobes.
If it turns out I have to pay Summit's price for them, I'll likely reconsider.
Dr.Jass
Pastor of Muppets
The only time I've ever seen lifter kill a cam was when Muscle Motors built an engine on which the #6 intake lifter bore was out of round and the lifter couldn't spin. Of course, it took four camshafts before he realized it couldn't be something we were doing wrong (the rest of us knew after cam #2). Muscle Motors went good for it after determining the issue, re-blocking the engine, supplying yet another new cam and lifters @ no charge, and paying the shipping both ways. It's a damned shame they're now a marijuana grow operation rather than engine builders. They stood behind their stuff.
b-body-bob
Well-known member
Apparently Jeg's generates a separate order for drop-shipped parts because I've got two with the same order number, one for the cam alone, and one for the cam and lifters. I was kind of weirded out until I noticed there's only one Paypal charge and it's for the expected $$.
Dr.Jass
Pastor of Muppets
If you go with any of the options listed, with the possible exception of the Cranes, I'd suggest getting in touch with Michael at B3 Racing Engines for one of his geometry-correction kits. They're not expensive but they're well worth it.
Checking against my own sources, those are pretty decent prices on rockers. I have no source for the Crane parts, but could probably match most of 'em were it not for the shipping cost. Shipped anything lately? It's obscene.
Stock 273 rockers weren't bushed. I have multiple sets of those; none show any kind of bore damage. Rocker Arms Unlimited can bush them, were one so inclined, but they can also re-shape the valve tips to optimum form relatively inexpensively.
It's doubtful, but I won't say impossible. They're probably a cost savings anyhow, though, since ball/ball pushrods are available in almost every conceivable length at a lower cost than comparable cup/ball pushrods. I don't know how stiff the springs are on those heads, but upgraded pushrods--even 5/16" ones--are cheap insurance. A bent pushrod can go amazing places and cause spectacular damage.
This has been SOP for Mopar lifters for about 40 years. Unless you find NOS Mopar lifters or very old TRW/Sealed Power units, they'll have the oil holes. Also SOP: Try and find correct lifters and pushrods for a '67-older big block. Yes, they were different. They had a shorter lifter body, longer pushrods. They've been gone long enough that virtually nobody knows of/remembers them. Pepperidge Farms remembers. So does Doc. I had 15 of 'em in Grandpa's Bucket, along with all 16 pushrods. They're all paperclips or soup cans now.
Yeah, they do your invoice and then an edited duplicate they send to Howards for the drop shipment. Stretch and I were actually within spitting distance of Howards over the weekend. They're a couple of hours south of here, on the shores of, uh, "beautiful" Lake Winnebago (why yes, it is the eponym of the ubiquitous RVs). Howards is pretty good about shipping quickly. I ordered mine through Summit and it got here prior to the ones Summit shipped, no doubt due to proximity.
71ChargerRT
Well-known member
This made me chuckle. What is the software you're using Doc, and is it still available?
I need a tuner more than anything else for my Dakota. Since I decided to swap motors around(410 stroker into the Dak and highish mile 5.9 into the 2500) I figured a bigger cam would be better to sling that little truck around. This is where I landed; Computer Controlled 210/220 Hydraulic Roller Cam for Chrysler Magnum
Should be fun!
I like where you're going with your Duster build Mr B_body!
Dr.Jass
Pastor of Muppets
Engine Analyzer Pro. There's a free trial download of it, but I've got the full version. According to Engine Builder magazine, they've found the results to be accurate "within 0.5% of actual dyno testing, all of which are well within the margin of error of any dyno. So when your real world dyno pull doesn’t show similar results to your virtual pull, you know to look for a problem." The full version will set you back $500.
The reason I say it's a pain in the ass? It's not very user-friendly. To change compression ratio, you have to enter all the parameters that affect it, rather than just punch in a CR number. If you want to try a different head-gasket thickness, you re-open the compression calculator. Surprise! Everything's blank again except the bore. Hope you wrote that shit down!
You're not wrong. I would expect the RPM range of that cam to be even lower on the stroker engine, with the restrictive heads and intake being limiting factors. It'll pull stumps and trailers with ease, but five grand is probably pushing beyond its useful powerband. It'll do the typical Magnum "fall on its face at 4,800RPM" trick, but also do mile-long burnouts effortlessly.
Something you'll want to consider, though, is your fuel injectors. With no other changes, 50 extra cubes means you've increased your displacement--and hence your required airflow--by approximately 14%. One would expect the cam change to increase that requirement further (otherwise, why do it?
). A factory injector's flow rating is about 15-20% greater than its maximum duty cycle--i.e., at 100% power output, (and hence injector pulsewidth or "open time") the injectors are only flowing 80-85% of their rated flow potential.That might lead one to think it's fine--the injectors would theoretically run right around 95-100% duty cycle. However, unlike other examples where duty cycle can be forced beyond 100% (welders, generators, etc.), EFI duty cycle cannot exceed 100%. It's physically impossible--the injector can only be open for the length of one engine cycle before it has to open again. There is no software workaround; there's no tuning that can remedy it. If anyone tells you otherwise, they're a liar (and probably trying to sell you something).
The first problem is heat. To maintain 100% duty cycle, neither the injectors nor their drivers in the PCM can have any cooling time, at 95% component life suffers dramatically. The injector is cooled somewhat by fuel passing through it, but the injector drivers don't have that luxury. A failed injector can be changed, but have you ever looked inside your PCM? Never mind the tricky surface-mount soldering--everything's buried under half an inch of potting compound. You can't even see the drivers.
The other problem is A:F ratio (and hence heat again). If it runs lean--and it probably will--it will run hot, likely to the point of destruction during exuberant driving. You can keep it out of detonation by pulling timing via tuning, but there's not a damned thing you can do about insufficient fuel delivery from the OE injectors. Late timing (if you can even tune that--twisting the distributor does nothing) exacerbates the heat issue. MAP-calculated EFI PCMs are as strict as Catholic school nuns, so any tuning error is hard-coded with no compensation.
I know I've mentioned this in the past, but I've seen the same thing tried by using a 350 EFI setup on a Chevrolet 400. Before that engine was even built, I told him it would melt or detonate itself due to running lean--but I don't know anything about Chevrolets. He was confounded by it always running hot regardless of thermostat rating or where he tried to set timing (similar setup to yours). My repeated explanation of insufficient fuel was worthless because not I'm a Chevy guy. It seized during one spirited example of showing off. The block was scrapped with the piston/rod assemblies still in it. They were melted in place, literally unremovable. That was $2,500 in tuition for the lesson learned. That engine had a knock sensor; yours doesn't. Forged pistons melt; hypereutectics explode.
Since there's no way to know your pulsewidth, either existing or what the new engine will require, I'd suggest increasing the injector flow rate by about 20-25%. 24lb/hr should be fine, and since those are still relatively low flow, high-impedance injectors shouldn't be a great expense (Ford part #M-9593-LU24A would be a wise choice, $227/set from Jeg's). Don't go any larger unless you want to replace the fuel pump too. EFI is fickle.
You've got a lot invested already. This is no place for cut corners or crossed fingers. Long-term, it won't be "fine".
I'm a much bigger fan now that it's getting the 360/4-speed arrangement. I like big blocks just fine, but with the hackery involved with the existing setup, it was a "start from fresh" proposition anyhow. The 360 will be more fun to drive on the street, both in corners and via the longer stroke. Stock-stroke 400s tend to run like a large, overweight 340--one of the reasons I love 'em--but the A-body doesn't like the extra 200lb+ over its nose.
b-body-bob
Well-known member
I'll tell you what they really don't like, 105 PSI of compression.
Once that exhaust stud stripped, it was done. I was replacing that engine one way or another.
Just for fun I pressure tested the cooling system a couple of weeks ago and got a puddle under the car for my trouble.
Dr.Jass
Pastor of Muppets
Bullet successfully dodged.
b-body-bob
Well-known member
I've got to do a junk transfer between these two garages and get that car back over here where I can be working on it.
Lifters received today.
Lifters received today.
b-body-bob
Well-known member
Still can't make up my mind on rockers. The more I read the less I like the stainless ones. Bad bushing in one led to banana groove shafts as a necessity, led to roller rockers might not be a good idea for a hydraulic cam because there is always pressure due to no lash.
I may end up taking the easy way out and just stick the factory rockers back on it for a while.
I may end up taking the easy way out and just stick the factory rockers back on it for a while.
Dr.Jass
Pastor of Muppets
Those would certainly work, but 273 rockers look better all the time, huh? Hundreds of thousands of happy 273s probably weren't wrong. 
By the way, the Speedmaster 65cc LA heads oil through the rocker shafts. I looked at them about 15 minutes ago. The oil hole is in both the deck surface and the rocker stand. Doesn't matter now, of course, but for anyone following along and looking at both options, it's information worth knowing.
By the way, the Speedmaster 65cc LA heads oil through the rocker shafts. I looked at them about 15 minutes ago. The oil hole is in both the deck surface and the rocker stand. Doesn't matter now, of course, but for anyone following along and looking at both options, it's information worth knowing.
b-body-bob
Well-known member
I'm resisting used because of the odds of them needing rebuilt and the likelihood that will drive the price up to the cost for new.
Mancini = new iron with crane adjusters $299
I'm a believer in banana grooved shafts which are an eye-watering $180+ a pair.
*From something I read, it seems like the Chinese shaft oiling is drilled differently so there is no pointing them toward the outside. It's straight up and down and the hole goes all the way through so you can't get them wrong - unless that "innovative thinking" introduces other problems. I always put my faith in the people who designed it to begin with.
Mancini = new iron with crane adjusters $299
I'm a believer in banana grooved shafts which are an eye-watering $180+ a pair.
*From something I read, it seems like the Chinese shaft oiling is drilled differently so there is no pointing them toward the outside. It's straight up and down and the hole goes all the way through so you can't get them wrong - unless that "innovative thinking" introduces other problems. I always put my faith in the people who designed it to begin with.
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b-body-bob
Well-known member
End-user photo
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Dr.Jass
Pastor of Muppets
There's nothing to rebuild. They're not bushed and the tips aren't replaceable. You could have the tips reshaped, but there's literally nothing else to do other than replace any bad adjusters. I've had more than a dozen sets of used ones and haven't gotten a bum arm or damaged shaft yet. It's not metal-on-metal; there's a cushion of oil like a crankshaft.
The Harland Sharp shafts are the same way, but those have needle-bearing fulcrums and require oil restrictions in the heads or block. With the 273 or "Crane" rockers and such shafts, a lot of precious oil will geyser straight out the top of the rocker arms. A lot of guys peen lead shot into those top holes or tap them for set screws anyhow.
Ideally you want "down and out" oiling as factory, because that's where the majority stresses are created. Another set of smaller holes should be drilled (if not present in your shafts) to align with the pushrod oiling holes. That would not be as critical with oil-through pushrods and new lifters, of course, but cup-end pushrods very rarely have that feature.
You can literally banana-groove your own parts-store shafts at home with a file, hacksaw blade, or cutoff wheel (if you're careful--a Dremel might be better than an air grinder for such a job). They're not exactly precise machining. If you go with stock-replacement (Sealed Power, etc) shafts, make sure the end plugs are driven all the way into the shaft and are straight. See the near-catastrophic rocker arm failure in my Signet build thread.
b-body-bob
Well-known member
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.
I've never seen shafts with more than one oil hole per rocker.
I might try that on the shafts that came with the engine.