Rocker arm to shaft clearance spec ???

[Tommy-T]

Interesting discussion.
I'm no engine builder but I do assemble my own motors and some for my pals.
My FE motors have seen many street races in the San Fernando Valley area of Los Angeles, some track time, and I generally beat them up pretty good regularly. Been doing that since the later 1970's.
I've never measured rocker arm to shaft clearance. If using Ford adjustable rocker arms, most anybody with common sense can "rock" them on the shaft when they're assembling the rocker assemblies and tell when they're ready for the trash can. I've worn out some Dove rocker arms too. The better rockers, Harland Sharp or POP for example, last a good long time.
The rocker arm side clearance can be interesting on a FE motor. I do that by feel as well but if the rocker tip is as close as I can get it over the valve tip and I can feel a drag against the solid spacer or rocker stand, I'll let it fly. I've never seen galling when a slight drag is used. I'd rather be on the tight side and have the push rod cups oiled well than looser on the side clearance.
Since we're discussing this, a stock shaft is adequate with end stands at solid flat tappet spring pressure.
A .060 restriction will flow a lot more oil than most folks realize with hot oil at 50psi.

If this drivel puts me in the hillbilly crowd, I carry that distinction with honor.

[My427stang]

   
As for restricting oil feed to the rocker shafts that is an interesting one, Dove used to tell you not to do that.

      And I agree, as in my book, most often restrictors are handy for major oil loss control in the instances of component failures, this to keep the vehicle on the track for a longer period even though the engine is in a state of self destruction.  But otherwise it's an admission that you haven't considered oiling requirements and delivery methodology adequately. 

On the FE getting the oil to drain back from the heads can be an issue.

      And I think the Ford engineers 'were' quite aware of the possible problem; as why do you suppose they went to the engineering effort and production expense for those oil catch & drain-back to the lifter valley tins, that mount under the rocker stands, this as an aid, with the intention of alleviating a certain sum of oil from having to traverse the cylinder head drain-back passages?  And for those here, how many re-utilize these (yeah, sometimes requiring reworking, or making anew, to fit aftermarket heads)?  Or did we toss 'em, and now are trying to figure out how to limit the oil to the top-end so as not to flood the under valve cover region?   


      Again, just food for thought in the "discussion".   

      Scott.

I acknowledge your point, and not being a smart guy either, but the engineering discussion just doesn't work for me.  You had lazy ramps, low spring pressure, umbrellas, or in racing horrible Teflon instead of real seals, sludge and detergent build up and machining that wasn't all that good compared to today.  It's just not the same environment. 

In fact, I would say that the stock rocker clearances and tins could easily be considered a band aid of the day.  Same era of engineers had SCJs blowing up and added oil and a pan lid, when they needed capacity and baffling.  It was not state of the art today, even if it was logical then.  Same engineers ran double reliefs on a 427 and a HP pump.  Same engineers had sledgehammer heavy rods for performance combined with crazy heavy pistons.  Old builds are old builds, that's why there are so many windowed 427s

As far as lifter valley tins, I have potential 2 uses for them, catching burnt oil from the crossover, and shielding the road draft tube.  Beyond that they did little to nothing

Now as far as numbers, I think the window of rocker to shaft clearance is wide enough to drive a truck through.    Another point, I don't restrict to help return, if the returns are plugged, fix them.  Restriction gives you slightly less up top where it isn't as critical and keeps slightly more to where it is critical, that's the punchline.   The oil still flows, as Tommy said too and FE returns are easy, not difficult, clean them up, make sure the intake manifold has room for the drain and don't block it with silicone by accident.

[MeanGene]

If this drivel puts me in the hillbilly crowd, I carry that distinction with honor.

Of course you always been there- along with most of us  Most rocket scientists are self appointed, ya know 

[pbf777]

I can feel a drag against the solid spacer or rocker stand, I'll let it fly. I've never seen galling when a slight drag is used.

       Remember, that in the O.E.M. configuration, the springs on the shafts push the rocker arms against the stands creating a certain sum of "drag"; and though not perhaps successfully causing a complete sealing against oil loss at this juncture, it certainly inhibits "free-flow".   

A .060 restriction will flow a lot more oil than most folks realize with hot oil at 50psi.

       Yes,  the sum is quite great; and "ideally" not what might actually be required to actually "limit" oil losses for the rocker shaft array.   

In fact, I would say that the stock rocker clearances and tins could easily be considered a band aid of the day.

     Exactly!   

Have you ever used a Victor FE intake?  They don't have any provisions for rocker drip tins, . . . . . . .

        Yep sure have, since back when they were fist introduced, something like twenty years ago (+/-); and there's an abundance of aluminum (and if need be more could be added) to make drain-back provisions work just as Ford had originally intended, . . . . . . yep!  This is if you really wanted such?   

I mean, I guess I'm sorry that I don't consult with almighty Scott before I put a bolt in.

        It's too bad, but that in pretty much any discussion it always sooner or later leads to "someone's feathers getting ruffled"; and as it seems here (at least to me), for no real reason!  You seem personally affronted here, and I don't see any reason for it.  I have not called out anyone in particular for unsound practices, rather have attempted to remain attuned to the mechanical engineering aspect, solely for the purpose of "discussion".   

        And then of course, we have to have the other human behavior seemingly relevant here, that of being any time there might be perceived two opposed perspectives, bystanders must always feel the need to "pick a side", did you ever ask yourself "why"?  Damn, at our ages, I'm thinking we left the school yard behind a long time ago!   

        But hopefully, out of this melee, perhaps someone garnered something of value, and that even though it hasn't been via the smoothest of pathways, the Forum has accomplished it's purpose of attempting to be informative or sparked thought, to at least a degree.

        Scott.   

        P.S.  Oh yeah, about that bolt, remember: "lefty loosey righty tighty"!   

           

[blykins]

Scott, there's been two things that have burned my biscuits in this thread:

1.  The amount of beating around the bush without coming out and just saying what you meant.  You had probably 5-6 posts where you could have just came out and said what you meant. 

2.  This line:  "But otherwise it's an admission that you haven't considered oiling requirements and delivery methodology adequately.  "  That is a very condescending line and I don't think I'm the only one that took it as though you were talking down to the rest of us.  Didn't appreciate it, especially when you come at it like you're the only one that knows what's going on.  I don't have engines that flood the tops of the heads or have engines that have trouble returning oil to the valley or pan. 

[67xr7cat]

The valley and rocker tins are interesting, at least from a historical perspective.  The rocker tins certainly were there to help direct the oil return IMHO.  Some of the early ones that guys say are for hipo stuff have "spouts" to direct the oil to the valley.  later on Ford did not see a need for them and just used the regular ones.  The valley pan can see value in it can help keep hot oil off the underside of the intake manifold and also acts as a baffle if you have a road draft tube or early PCV at the back of the intake.  I recall in some old Ford paper saying the baffle had to do with helping to keep moisture from forming. Don't know, but we do have to keep in mind they had to make these engines survive in the desert as well as Alaska and do it with the state of the art of the time.

Anyone ever wonder why the intake is part of the head? Was an SAE paper back around 1958 where Ford said having the intake extend further into the head allowed more control over the port shape and resulted in better cold start performance.  It all was for a reason, we just don't know the why and of course if the reasoning was right or instead driven by what was believed to be right at the time. Sort of like cross drilled cranks and windowed blocks...

[cjshaker]

Anyone ever wonder why the intake is part of the head? Was an SAE paper back around 1958 where Ford said having the intake extend further into the head allowed more control over the port shape and resulted in better cold start performance.  It all was for a reason, we just don't know the why and of course if the reasoning was right or instead driven by what was believed to be right at the time. Sort of like cross drilled cranks and windowed blocks...

In the magazines that I have from '58 covering the "new" Ford engines, Ford had learned that longer port lengths had multiple benefits, like added torque, good street manners, and easier starting, as opposed to the very short runner lengths of the Y-blocks. It was a clever design for the time. As big as those cars were, the engines sat up relatively high and barely cleared the hoods even with low rise intakes, so the FE intake solved the problem of adding runner length without adding height.

Tins and valley trays certainly had their uses back in the day. All of us old farts who have taken apart old engines knows that coking under the intake can be a real problem, and that was the reason for using intake pans that covered the crossovers, as well as valley trays. Remember, people were still using non-detergent oils and running these engines daily in mixed hot and cold climates. I believe Ford also knew that oil return in the head was an issue that crept up. We're talking about mass produced engines that didn't exactly have a perfect return path for the oil in the head to begin with. "Cleaning up" the return isn't an option when it requires hand work. Not on a mass production level. For the average "home" builder, using stock parts that aren't modified, I still think they are a good idea. For hot rodders that modify their stuff to make it better, not so much.

[blykins]

Anyone ever wonder why the intake is part of the head? Was an SAE paper back around 1958 where Ford said having the intake extend further into the head allowed more control over the port shape and resulted in better cold start performance.  It all was for a reason, we just don't know the why and of course if the reasoning was right or instead driven by what was believed to be right at the time. Sort of like cross drilled cranks and windowed blocks...

In the magazines that I have from '58 covering the "new" Ford engines, Ford had learned that longer port lengths had multiple benefits, like added torque, good street manners, and easier starting, as opposed to the very short runner lengths of the Y-blocks. It was a clever design for the time. As big as those cars were, the engines sat up relatively high and barely cleared the hoods even with low rise intakes, so the FE intake solved the problem of adding runner length without adding height.

Tins and valley trays certainly had their uses back in the day. All of us old farts who have taken apart old engines knows that coking under the intake can be a real problem, and that was the reason for using intake pans that covered the crossovers, as well as valley trays. Remember, people were still using non-detergent oils and running these engines daily in mixed hot and cold climates. I believe Ford also knew that oil return in the head was an issue that crept up. We're talking about mass produced engines that didn't exactly have a perfect return path for the oil in the head to begin with. "Cleaning up" the return isn't an option when it requires hand work. Not on a mass production level. For the average "home" builder, using stock parts that aren't modified, I still think they are a good idea. For hot rodders that modify their stuff to make it better, not so much.

Well said.

[MeanGene]

In 1975, I had a friend with a '66 390 Comet, whose dad was the shop foreman for a local short-haul trucking firm that had a fleet of C800's with 391FT engines, so he was "well versed". The Comet popped a head gasket, and his dad showed us how to change the head gasket without pulling the intake, as was the factory procedure. Considering that it was shock tower car, it went pretty well, just took a lot of patience. He also told us about the problems with the oil drainbacks in the heads clogging, and had a factory Ford tool for enlarging the drainbacks in the truck engines. Only time I ever heard of such a tool, but he had one and he was pretty sharp. Flash ahead to 1977, and a gal friend who knew I had my 406 car says hey my girlfriend has a Galaxie she wants to get rid of, smokes and runs real bad. So I go look at it, pretty cherry 500 fastback with perfect interior, 390-4V etc. She starts it, running poorly on about 6 and fogging skeeters. She says can you give me $200 for it? Well, OK. I pull the plugs, fronts are fine, backs oil-fouled. Drip pan goes underneath and pull a valve cover and get black rain- the drainbacks were completely clogged and covers full of oil. Took a lot of digging with a screwdriver to get all the gunk out. A couple oil changes and it was running sweet and clean. Not a perfect return path indeed

[My427stang]

Man, great story, I have sure been there, good thing is you can drive a screwdriver straight in!  Not to mention how it stained your skin like diesel oil back then.

I blame the oil more than the FE, but sure have seen it and the gray sludge of the day that came from detergent packages.

[blykins]

I can feel a drag against the solid spacer or rocker stand, I'll let it fly. I've never seen galling when a slight drag is used.

       Remember, that in the O.E.M. configuration, the springs on the shafts push the rocker arms against the stands creating a certain sum of "drag"; and though not perhaps successfully causing a complete sealing against oil loss at this juncture, it certainly inhibits "free-flow".   

A .060 restriction will flow a lot more oil than most folks realize with hot oil at 50psi.

       Yes,  the sum is quite great; and "ideally" not what might actually be required to actually "limit" oil losses for the rocker shaft array.   

In fact, I would say that the stock rocker clearances and tins could easily be considered a band aid of the day.

     Exactly!   

Have you ever used a Victor FE intake?  They don't have any provisions for rocker drip tins, . . . . . . .

        Yep sure have, since back when they were fist introduced, something like twenty years ago (+/-); and there's an abundance of aluminum (and if need be more could be added) to make drain-back provisions work just as Ford had originally intended, . . . . . . yep!  This is if you really wanted such?   

I mean, I guess I'm sorry that I don't consult with almighty Scott before I put a bolt in.

        It's too bad, but that in pretty much any discussion it always sooner or later leads to "someone's feathers getting ruffled"; and as it seems here (at least to me), for no real reason!  You seem personally affronted here, and I don't see any reason for it.  I have not called out anyone in particular for unsound practices, rather have attempted to remain attuned to the mechanical engineering aspect, solely for the purpose of "discussion".   

        And then of course, we have to have the other human behavior seemingly relevant here, that of being any time there might be perceived two opposed perspectives, bystanders must always feel the need to "pick a side", did you ever ask yourself "why"?  Damn, at our ages, I'm thinking we left the school yard behind a long time ago!   

        But hopefully, out of this melee, perhaps someone garnered something of value, and that even though it hasn't been via the smoothest of pathways, the Forum has accomplished it's purpose of attempting to be informative or sparked thought, to at least a degree.

        Scott.   

        P.S.  Oh yeah, about that bolt, remember: "lefty loosey righty tighty"!   

           

Dude, there ain't nobody that got anything from your vague posting with zero information.  Do you honestly think that anyone could garner any information whatsoever from the 20 questions you asked with no answers?  The only thing that anyone gleaned is that you know how to use an eyeroll emoji like a 14 year old girl and your posts read like a King James version Bible.

[Joe-JDC]

I thought sesquipedalianism was dead.  This post proves me wrong.  Joe-JDC

[pbf777]

. . . . . .  there ain't nobody . . . . . . .  Do you honestly think that anyone  . . . . . . . . .

       Maybe you should allow others to speak for themselves rather than constantly choosing to sweep the bystanders under your wing to bolster your own tenuous position; which again is just another behavioral practice of insecurity and immaturity.   If your apparently emotionally immature self, and perhaps your feelings of domination over this domain might feel threatened, please rest assured that such was never my intention and that you will have been successful at running-off any such possible threat.

       But then, in revue, what informative substance relevant to the O.P.'s inquiry have you brought forth in this thread?   

       I leave you to it. 

       Good day,
       Scott.

     

[blykins]

Rocker arm clearance .002-.0025.

Restrict at heads .080", or oil through pushrods with head feeds completely restricted.  Works perfectly fine with standard volume, B pump, HV pump, doesn't flood anything.  Good oil pressure, will work with 750 lbs of spring load over the nose without wearing rocker bushings out.

Your turn, Captain Wordcount.

[Thumperbird]

Easy guys.

I believe Scott was/is just merely looking for some tantelizing technical discussion behind the theory of oiling lubrication in it's varied applications within the FE engine.
I get this, there is a very complex system at play at it's core, fluid dynamics within a series/parallel circuit, loads, cycle times, cooling, you name it.   
Yes, the question was what clearance, but why "exactly"?  That is where the fun lies, just like understanding or hypothesizing about "exactly" why one should not cut the short side of an intake runner beyond don't do it... 

I would like to think there is room here for that type of discussion. I certainly enjoy it.