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Thread: V8 guys - let's talk about rocker arms, adjusters, shafts and pushrods

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    V8 guys - let's talk about rocker arms, adjusters, shafts and pushrods

    After fifty years, we're still learning about the Studebaker V8.

    This discussion arose because I just pulled down a '57 Packard version of the V8 which had been CASO'd with a mix of rocker arms. Some of us were trying to pin down how many variations of top end gear Studebaker V8s had over the years. Also, what can be swapped/combined and what shouldn't?

    I'm editing this as comments come in:

    1. Rocker arms - now four variations of the part numbers and casting numbers I've seen.
    A. P/N 529432 rocker with 3/4" long 7/16" hex adjuster (1951/early'52)
    B. 532177 rocker with 15/16" long (1.003"?) 7/16" hex adjuster (late'52-'54) Early casting 536136 low drilled for oil through transverse hole in type B 7/16" hex screw?
    C. 536222 rocker with high drilled 1/2" type C adjuster ('55-early'61)
    D. 1554013 rocker with type D 1/2"adjuster (late'61-'64)

    2. Adjusting screws - again, at least four variations. What years were the changeovers?
    A. 529400 Adjuster 3/4"long ('51-early'52)
    B. 532161 Adjuster 15/16" (late-'52-'56) '51 through '54 parts book show 15/16" but '55 through '58 book shows 7/8" long??? 7/16" hex with machined radius in threading w/small transverse hole. My actual measurement is 1.093" long
    C. 1541806 Adjuster 7/8 long (57-early'61) 1/2" hex with machined radius in threading, 1.008" long.
    D. 1550360 Adjuster 3/4" long (late 1961 through 1964 including Avanti)1/2" hex straight thread and larger .256" center hole. My actual measurement is .971" long.

    (BTW - very bad juju to mix the wrong adjuster with the wrong rocker. Just because it will screw in doesn't mean it will oil correctly.)

    3. Rocker shafts - now three part number variations. Generally felt the '51-59 had a large oil feed hole and the 60-64 versions had a smaller oil feed hole. Agree/disagree?

    A. 527182 Rocker Shaft ('51-early '61)
    B. 1550946 Rocker Shaft (late'61-'62)
    C. 1557612 Rocker Shaft ('63-'64) I didn't know this or what the difference is?

    Does this also correspond to the larger oil drainback hole in the head casting?

    4. Pushrods - two versions
    A. 527890 - ('51-early '61) 11-3/16 or 11.171875 - 11.21875"
    B. 1550303 - (late 61 to 64) 11-11/32 or 11.328125" - 11.375"

    (Again, using the longer pushrod with the wrong rocker arm can require the adjuster to be screwed in so far it blocks the oil feed hole on some rockers.)

    527696 Bracket or stands (same '51-'64)

    Thanks in advance for the accumulated and shared wisdom of this forum.

    jack vines
    Last edited by PackardV8; 12-14-2014 at 11:45 AM.
    PackardV8

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    So, Jack, whats so wrong with putting the engine together with whatever's laying around and just praying it doesn't grenade itself ? ? Jus kiddin, of course.
    sals54

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    OK here goes,early rocker casting no.536136 took type "a" adj screw and was low drilled for oil to screw. later rocker was low drilled casting no. unknown and used type "c" adj screw. late rocker casting no.1550613 was high drilled and used type "b" adj screw. first 2 types oiled pushrod socket through machined groove and cross drilled adj screw also valve tip and crumbling umbrella seal. high drilled type allowed oil into top of adj screw and was probably cheaper and gave more adjustment leeway. i seem to remember an adj screw with 1/2 pushrod socket and type "a" machining on threaded shank. even tho numbers dont match they all seem to get oil ok. rocker stands are all same pn IIRC, shafts changed in mid 60's dont know about pushrods, late 59-64 parts books still packed away. Hope this helps get your worms back in that 55 gal. drum you opened! Luck Doofus

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    Thanks, doofus. I'm editing your numbers back to my original post as long as no one has other arguments for or against.
    PackardV8

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    Greeting's Jack, a little more info for your worm can.this was taken from 3 1/2 rocker assys. i discovered. set from 62 =1550613 casting no. rocker 1/2 waisted adj. screw, NO oil hole through waist. Top fill? 536196 rocker. 7/16 adj. screw waisted with oil passage in waist. low drilled 1550613 was high drilled. now from the Stude, Int. cat.,527890 51toearly61 pushrod.1550303late 61 to 64 pushrod. IIRC early is shorter than later pushrod. 532161 early adj. screw52-56. 532177rocker52-54.536222 rocker 55-to early 61.1541806 adj. screw 57-to early 61. 1550303 push rod 61-64 all. 1550360 adj screw late61to64 all. this will give you something to edit! if memory serves there were 2 "waisted" adj screws 1 with oil hole in waist, one without.2 thin wall adj screws straight sided, the longest had oil hole and fit low drilled rocker, the shorter had no oil hole and was for high drilled arms and filled from top. more unpacking soon, stay tuned. Doofus

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    Thanks for the info. We're getting there.

    Is it safe to say Studebaker engineers tried to modulate oil flow to the top end in two ways:

    1. The early rocker arm and adjusting screw tried to restrict oil flow at the screw. As long as the rockers closely fitting the shaft, this worked. As the rocker body and shaft wore, clearance increased and thus oil flow increased around the shaft.

    2. The later design restricted oil flow at the feed hole in the shaft and opened the flow at the adjuster. No matter what the rocker-to-shaft clearance, only a fixed flow of oil could get into the top end.

    Agree/disagree?

    jack vines
    PackardV8

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    Not safe to say yet Jack. studying Avanti shop manual shows low drilled rockers, adj. screw with 1/2 in pushrod socket in wasted screw with oil hole thru waisted portion. since Avanti had shafts with small oil hole you would think they would have short, thin wall adj. and hi drilled rockers! not so according to shop manual! the mystery deepens keep up the good work, Doofus

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    Many thanks to Ted Harbit for hours spend in his parts manuals researching this obscure topic. Any errors transferring his good work into the original post are strictly my own.

    jack vines
    PackardV8

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    Golden Hawk Member mbstude's Avatar
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    This isn't related, but just wanted to say how glad I am to see Gerald posting so much of his great info.

    Gerald, if you get a chance, post pics and details of your own rides.. I think everyone would get a kick out of seeing a '62 Lark with enough turbo boost to blow the head gaskets.

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    Thats from detonation because of low fuel pressure Matthew. you have to have at least 2 lbs. of fuel pressure above manifold pressure. at 18 lbs i was to busy to check fuel pressure and detonation was hidden by screaming turbo! bad things happen at times, all 8 holes "pushed out" gasket in same place. i'm working on cure now Doofus

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    Jack
    In post #8 you mentioned Ted Harbit's research on the rocker arm/adjusting screw
    topic.
    Is that published anywhere?
    Robert Kapteyn

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    Quote Originally Posted by rkapteyn View Post
    Jack
    In post #8 you mentioned Ted Harbit's research on the rocker arm/adjusting screw
    topic.
    Is that published anywhere?
    Robert Kapteyn
    Bob, the data in my initial post here came from Ted's research into parts books and that's why I wanted to make sure I credited him with the work.

    jack
    PackardV8

  13. #13
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    Quote Originally Posted by PackardV8 View Post
    Bob, the data in my initial post here came from Ted's research into parts books and that's why I wanted to make sure I credited him with the work.

    jack
    http://racingstudebakers.com/foo/vie...=1706&start=15

    Some of Ted's work here.

  14. #14
    Skybolt
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    Adding to what I posted in http://forum.studebakerdriversclub.c...Adjuster-Screw the screw I was working with has the 1/2" hex with 3/4" thread and total length just over 1". Spec wise it is the same as #1550360 but has the "waist" and not the full thread. This must have been made available somewhere after the 1961 transition. It could be it was the first post 61 style as engines as late as 1963, including Avantis and other R series engines, used it. Also because it still has the waist it does not have the larger bore.

    Len

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    Rather than begin a new thread, I'll just add this to the old one.

    We have a conundrum when rebuilding the Studebaker V8. That it can't be safely done without removing the end soft plugs in the rocker shafts is well documented; they're full of crud!

    The second problem and one for which I have not found a satisfactory solution is most of the rocker arm adjusting screws are also full of crud. As detailed earlier in this thread, most of the adjusting screws are a "wasp-waisted" design. Many here have worked with the V8 for years and never had a rocker apart. Here are the three designs:



    This necked-down portion is usually filled with really nasty hard carbon crud. When an engine is rebuilt, the heads and sometimes the block are milled. This shortens the assembly, requiring the rocker adjusting screws to be run in to compensate. This will loosen that long impacted crud and upon startup, bits of hard carbon will begin circulating through the new, clean bearings.

    It's impossible to clean the the screws and rockers without removing the adjusting screw. However, there's so much carbonized crud in there, it will lock up the wasp-waisted screws and the necked down portion will break off, leaving the top half of the adjuster in the rocker body.

    We've found heating the rocker to burn off the crud is the only way to remove the screw without breaking some. The downside of this is it's unknown how the heat will affect the interference fit between the threads on screw and in the rocker body.

    Your thoughts and experiences?

    jack vines
    Last edited by PackardV8; 03-02-2019 at 02:28 PM.
    PackardV8

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    Use a wire brush on/ in a bench grinder, drill press, or on a angle grinder to get the carbon that is exposed.

    A caustic cleaner will remove the crud harder to reach. It is hard to find these days. Experiment with some Detzol , muratic acid, (Spelling) or something similar. Don't use it 100% , dilute it.

    You should be able to use heat, do not 'overheat' . Do not turn it until it is cool.



    Soak time is your friend. You can use modern gas, or a combo of many things. These should be soaking the whole time you are doing everything else. Don't wait until the engine is being assembled. Soak them as soon as they come off. If you use a caustic cleaner check them every hour until you know how (strong ) it is cleaning.

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    Quote Originally Posted by (S) View Post
    Use a wire brush on/ in a bench grinder, drill press, or on a angle grinder to get the carbon that is exposed.

    A caustic cleaner will remove the crud harder to reach. It is hard to find these days. Experiment with some Detzol , muratic acid, (Spelling) or something similar. Don't use it 100% , dilute it.

    You should be able to use heat, do not 'overheat' . Do not turn it until it is cool.



    Soak time is your friend. You can use modern gas, or a combo of many things. These should be soaking the whole time you are doing everything else. Don't wait until the engine is being assembled. Soak them as soon as they come off. If you use a caustic cleaner check them every hour until you know how (strong ) it is cleaning.
    Good points all. One tip I forgot to mention is to find a spray can of brake cleaning solvent which has the red plastic wand. That wand is exactly the right size to enter the hole in the rocker body, pass through the shaft hole and into the hole which connects with the adjuster body. Fifteen out of the most recent set of sixteen would pass the cleaner around the adjuster and out the hole in the pushrod receptacle. As mentioned, soak, repeat and blow compressed air through that hole while covering the top of the adjuster

    All this helps loosen most of them so they can be removed. The conundrum I mentioned is it's impossible to determine which will come out whole and which will twist off. We went with the heat and didn't break any more.

    jack vines
    PackardV8

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    Interesting.
    Over the years, I've taken about sixty+ adjusters out of they're respective rocker arms, never had a problem..!?
    Yes they can be a bit tight, but I've never had a problem.

    Going back together after cleaning (and sometimes some lightening), they still have their locking feature intact, some more than others, but some also came apart much easier than others. That I never checked, easy out, easy back together ?

    Mike

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    Never tried it on adjusters, but on carbs and other parts I have used a torch tip cleaner. Several sizes in thousandths . They are actually round files, so be aware.

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    I have had good success soaking parts in ammonia, but it takes time--sometimes weeks. Also I do not know how it will work in confined areas, I normally use it on the outside of parts. Has any one had success with ultrasonic parts cleaners? https://www.ebay.com/itm/6L-QT-380W-...QAAOSw6IdcOc0I

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    (S), gastjohnll -

    Note that your torch tip cleaner, pipe cleaners, Q-tips, (just) soaking. etc, will...not..."remove" the ancient garbage oil that Jack is talking about.
    You MUST remove the adjuster. There is an machined groove in the adjuster itself that needs to be cleaned, and there is no access from the outside. Also, "cleaning" the lower hole in the rocker arm itself, again, because you cannot "push" the garbage out of the hole and OUT of the rocker arm, you just force it deeper into the adjuster area.

    So yes, you MUST remove the adjuster to "fully" (properly) clean the adjuster and the oil passage holes in the rocker arm itself.

    Mike

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    Quote Originally Posted by (S) View Post
    Use a wire brush on/ in a bench grinder, drill press, or on a angle grinder to get the carbon that is exposed.

    A caustic cleaner will remove the crud harder to reach. It is hard to find these days. Experiment with some Detzol , muratic acid, (Spelling) or something similar. Don't use it 100% , dilute it.

    You should be able to use heat, do not 'overheat' . Do not turn it until it is cool.



    Soak time is your friend. You can use modern gas, or a combo of many things. These should be soaking the whole time you are doing everything else. Don't wait until the engine is being assembled. Soak them as soon as they come off. If you use a caustic cleaner check them every hour until you know how (strong ) it is cleaning.
    Please don't use Muriatic or any other mineral acid. They will cause a phenomenon known as hydrogen belittlement, and those parts can snap like a pretzel.

    Use solvents or strong alkaline cleaners instead. PB Blaster is a good solvent crud softener; it may take a few days of soaking.
    Draino, soaking for several days is another safe choice. Dishwasher detergent dissolved in a bit of water and heated is effective and safe.

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    President Member bensherb's Avatar
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    Quote Originally Posted by jnormanh View Post
    Please don't use Muriatic or any other mineral acid. They will cause a phenomenon known as hydrogen belittlement, and those parts can snap like a pretzel.

    Use solvents or strong alkaline cleaners instead. PB Blaster is a good solvent crud softener; it may take a few days of soaking.
    Draino, soaking for several days is another safe choice. Dishwasher detergent dissolved in a bit of water and heated is effective and safe.
    To belittle means to put down, or make another person feel as thouigh they are not important.

    I believe you mean, embrittlement,
    a loss of ductility of a material, making it brittle. Hydrogen embrittlement is the effect of hydrogen absorption on some metals and alloys.

    Sorry, it just made me laugh.

  24. #24
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    I thought that was a pretty good pun, myself. After all, Hydrogen is the smallest atom.

    JT

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    Quote Originally Posted by bensherb View Post
    To belittle means to put down, or make another person feel as thouigh they are not important.

    I believe you mean, embrittlement,
    a loss of ductility of a material, making it brittle. Hydrogen embrittlement is the effect of hydrogen absorption on some metals and alloys.

    Sorry, it just made me laugh.
    Another proof that auto-correct sucks.

  26. #26
    President Member bensherb's Avatar
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    Quote Originally Posted by oilnsteel View Post
    I thought that was a pretty good pun, myself. After all, Hydrogen is the smallest atom.

    JT
    I hadn't thought of it that way, but it is funny that way too now you mention it. Good call!

  27. #27
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    Another sucky auto correct:

    A man received the following text from his neighbour:
    I am so sorry Bob. I've been riddled with guilt and I have to confess.
    I have been tapping your wife all the time.
    I'm not getting any at my house, but that's no excuse.
    I can no longer live with the guilt and I hope you will accept my sincerest apology, along with my promise that it won't happen again.

    The man, feeling anguished and betrayed, went into his bedroom, grabbed his gun and without a word, shot his wife and killed her.

    A few moments later, a second text message came in:
    Damn spell-check. I meant "wifi", not "wife".

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