Rail Rocker Arms vs. Non-Rail and guide plates

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Rail Rocker Arms vs. Non-Rail and guide plates

Jake Papageorge
Good Morning all, I recently built a 351 Windsor engine from a 96 F250 that was going to be transplanted into a Bullnose.  There were a ton of issues we ran into (mostly because of supply line issues) but a few of the issues really yielded some interesting results!  

My normal supplier of parts could not get me the roller tipped rocker arms I like to use on these builds for daily driver type engines.  I generally do not like to use and adjustable full roller rocker arms because when these things fail, they circulate small metal pieces from needle bearings.  I prefer only a roller tip steel rocker arm with the good old ball fulcrum for daily drivers.

I ordered a set of non-rail rocker arms to go onto this engine that had the OEM heads replaced with a set of Flotek aluminum heads and provided a fully adjustable valvetrain and upgraded the factory roller cam with a torque cam that would work better with a carburetor.  When I opened up the rocker arms, I had received a set of rail-type roller tip rockers.  I usually use guide plates and non rail stuff with hardened pushrods.  



I called up the machine shop to see if they might have any non-rail roller tip rockers available and to my shock, my machinist suggested that I just shim the rocker studs, and use the rail tip rocker arms.  

In my years of building engines, I have never intentionally used a set of rail-type roller rocker arms, but I never considered WHY I never use rail type roller rockers until this engine build!  I guess it just seemed like the thing to do, but now, I had to consider WHY it is the thing to do!  

It is not a high revving engine, so the likelihood of launching a pushrod is next to zippo!  Once I calculated the correct push rod length, there was really no reason to put guide plates on!  This engine will never see north of 4000 RPM so...............

The ports on the heads are only 180cc so it is not like the push rods are going to hit the heads.

The heads have long enough valve stems to engage the roller tips of the rockers without interference throughout the movement of the rockers.  

Why not use them?  They are still adjustable, have roller tips and align just beautifully!  

So we put them on, assembled the rest of the engine, got the new correct length pushrods from Trend, and put the engine on the dyno......

After breaking in the rings, about 30 5K pulls, this thing runs great, and not a single hint of a pushrod problem!  I took the 8 rockers off the 4 corners of the head and they all wore in beautifully!   Lash had not changed at all on any of the rockers and peak torque was achieved at 3975 so the peak torque target stayed under 4K.  None of the pushrods came even close to the heads.  

In addition to this saving me a lot of time in adjusting the adjustable guide plates, the reduction in parts will yield an overall cost savings as we can now use hardened tip pushrods and no need for push rod guide plates.  The rockers and pushrods get to align where they want to, and a good amount of time and money is saved on the build overall.  I cant see a downside.  

Anyone want to weight on this pro or con?   It feels kind of funny doing this, but I cant see a downside to this set up!  
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Re: Rail Rocker Arms vs. Non-Rail and guide plates

mat in tn
a couple decades ago I used to work on sbc engines, and they always had the ball and stud pivots. back then I may or may not have tested my equipment against others doing the same. haha. back then those rockers were the stamped steel option. I kept spares and got fairly good at roadside swaps. that is probably the reason that I never consider them today. However, you do raise a good point. the roller tipped ones you show in the picture do look to be better made and the roller tip cannot hurt. the ball and socket design are self-centering. I do like to use as much roller in the engine as is practical. but look at how many get very high mileage without being roller. I have two 5.0 s being built right now and I'm going to think this over a bit. why not is a good question. I do have a few sets of std pedestals in stock though. hard to not use them on a std engine.
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Re: Rail Rocker Arms vs. Non-Rail and guide plates

Jake Papageorge
Yea, on the stock "Goodwrench" TBI Small Block Chevy's, I have seen the stock rail type stamped ball fulcrum rockers flop many times!  Hell, I once saw a pushrod get punched right through one (I think I still have that one laying around the shop somewhere) LOL!!! But I was so intrigued by the rail type self-aligning roller tip, I had to give them a whirl!  So far, nothing but impressive! When my machinest was telling me to run em, he stated he has used that combination more times than he can count and have never had a come back.  I guess I am going to see with this set as they appear to be working very well!  

Thanks for the input!  

BTW.....I have always been a big fan of the stock Ford Pedestal rocker arm for stock applications.  You really cant find a more stable rocker arm!  It is just that with the changing of so many parts (Heads, cam, etc.) and being that many of these are street driven daily drivers, I just cant stomach using the adjustable alternative to the stock rail type rocker.  Those units that I think Scorpion makes.  
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Re: Rail Rocker Arms vs. Non-Rail and guide plates

mat in tn
i was impressed a couple years ago with a set by crane in 1.7 ratio. that set was about as drop in perfect as one can expect. it's a little pricey but not really when I compare them to the less expensive ones that I have known people to have had issues with.  and as you said earlier. who knows what other expenses will arise from random metal fragments circulating?
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Re: Rail Rocker Arms vs. Non-Rail and guide plates

85lebaront2
Administrator
In reply to this post by Jake Papageorge
My first experience with a small block Chevy, was a 1957 up the street that had thrown a pushrod through the rocker, valve cover and it had penetrated the hood and was sticking out of it.
Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

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Re: Rail Rocker Arms vs. Non-Rail and guide plates

mat in tn
now that's funny right there. I would want to open the hood and tack in place with a welder.
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Re: Rail Rocker Arms vs. Non-Rail and guide plates

Jake Papageorge
In reply to this post by 85lebaront2
Holy Cow!  Now that would be something to see!  The only part I have seen dis assemble itself from A SBC is a harmonic balancer ring!  It flew off a car when I was working the starting line at a dragstrip back in the 90's!  I really had to take a double take when that thing came sailing my way!  
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Re: Rail Rocker Arms vs. Non-Rail and guide plates

mat in tn
I bought my flareside cheeeeep because it had one hell of a bad engine shake. I said the ring came off and got wedged behind the center and the guy said "huh"? what's a ring? it had beaten a hole in the timing cover and was leaking oil. I gave it my best explanation but got blank. crickets! so I said 400 and I'll take it now.
so, anyone thinking it costs too much to buy a decent harmonic balancer when building a new engine, think again! and remember. if the rubber is coming out. it is coming apart!