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Technical Studebaker Rockers on stock cadillac 365?

Discussion in 'Traditional Hot Rods' started by ryan w dunn, Aug 12, 2015.

  1. ryan w dunn
    Joined: Aug 12, 2015
    Posts: 6

    ryan w dunn

    OK so ive fixed alot of 390s in my day but having a problem with my 58, im getting a clacking sound when the motor is under force, i checked the lifters and cam, and they look new. the heads were completely rebuilt. i have 30w oil in her psi is at about 25 when driving. the rockers on the other hand looked worn to me and seemed to be some slop on the push rods. Rather then spending 300 bucks on a new set i bought some studebaker rockers(i like to be able to adjust things). so anyhow i put a side on today and there is no way they will work. the valve will stay open with the lifter all the way down, even with the adjustment all the way up. i was told they would work all the way up to 62. any suggestions? thanks
     
  2. von Dyck
    Joined: Apr 12, 2007
    Posts: 678

    von Dyck
    Member

    Pushrods too long?
     
  3. ryan w dunn
    Joined: Aug 12, 2015
    Posts: 6

    ryan w dunn

    nope they are to spec. they are the ones that were on there and are straight and true
     
  4. chrisp
    Joined: Jan 27, 2007
    Posts: 820

    chrisp
    Member

    Yes but you replaced the rockers, they have a slight different geometry at least compared to the 390 ones and you just added length to the pushrods indirectly with the adjuster screws on the rocker arm side. That could be your issue.
     
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  5. ryan w dunn
    Joined: Aug 12, 2015
    Posts: 6

    ryan w dunn

    so i would have to replace the rods as well?
     
  6. zander208
    Joined: Sep 24, 2011
    Posts: 35

    zander208
    Member

    You need new to get some new (shorter) pushrods made to use stude rockers on that cad motor. I use Smith Bros. push rods out of Oregon (great rep, super helpful, competitive prices), but I'm sure there are dozens of places that could help you out. The easiest way to do this is to buy a pushrod measuring tool (basically an adjustable pushrod) and carefully measure/find the correct length with your rockers adjusted to neutral. That will allow for even adjustment on your rockers in either direction when the entire assembly is installed. You also need to make sure you get the right cup and ball size on your new rods. Easiest way I've found to do that is take or mail a lifter and rocker to whoever makes the rods so they can match them directly.

    You will also run into fitment issues with your valve covers if you haven't already. You might want to rethink using stock rockers if your 365 doesn't have a cam that requires adjustable rockers... They can honestly be more trouble than they are worth sometimes in those old cads.

    Cad pushrods in 331-390 are all solid, so you might be able to get them shortened (I've never tried or even looked into that option), but I would get new ones made if I were you. Hope this helps, let me know if you have any questions once you dig a little deeper.
     
    Last edited: Aug 13, 2015
    ryan w dunn likes this.
  7. 1953 chevy
    Joined: Sep 30, 2011
    Posts: 88

    1953 chevy
    Member
    from tucson

    Had this problem with a 365 we were building. There is a longer and shorter side to rocker stands. In the end had adjustable push rods made. Studebaker rockers won't work.
     
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  8. ryan w dunn
    Joined: Aug 12, 2015
    Posts: 6

    ryan w dunn

    Ok that makes sense. but another thing i noticed is that the angle of the rod would be slightly off than the original, it would be a few degrees. this wouldn't help throw a rod or bend it would it? usually you want a straight shot from the lifter to the rocker right?
     
  9. chrisp
    Joined: Jan 27, 2007
    Posts: 820

    chrisp
    Member

    Yes they do have a slight different geometry, but it shouldn't be a problem as long as nothing rubs and well adjusted, this is something that was done and still is. But if it was only for a cost purpose you might want to rethink that, especially if you can't modify or space out the valve covers and need to buy new ones from PML or Bell Auto (if he still make them)...
    Not all engines have a straight shot from the lifters to the rockers.
     
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  10. ryan w dunn
    Joined: Aug 12, 2015
    Posts: 6

    ryan w dunn

    Maybe i should just go back to stock seeing that this set up will cost me as much as new ones. but another question is the noise. the lifters had sat in the motor for about 25 years (not ran) but look new. i checked the pressure and from what i can tell are tight as a drum. the all bled oil when i compressed them. thoughts on that? thanks for all the help and knowledge so far!
     
  11. von Dyck
    Joined: Apr 12, 2007
    Posts: 678

    von Dyck
    Member

    FWIW: Mopar V-8s do not have lifter and pushrod running in alignment, Hemi's don't, 348/409's don't.
    Grabowski's Kookie Kar Cadillac engine apparently ran the Stude rockers, but magazine articles are deficient on details. My 324 Olds runs Gotha adjustables on Isky pushrods --- no problems, but harder to find than hen's teeth!
    Yeh, go ahead and work out the geometry. Carefully observe the rocker pad position on the valve stem tip. Slightly inboard of tip center-line with valve closed, slightly outboard of tip center-line at half valve lift, and back to slightly inboard of tip center-line at valve fully open. This would be ideal if you can achieve it.
     
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  12. TERPU
    Joined: Jan 2, 2004
    Posts: 2,225

    TERPU
    Member

    Bingo on the new pushrods. How you gonna cover up that mess? the rockers work, but valve covers are a real challenge with the Studes.

    Tim
     
  13. chrisp
    Joined: Jan 27, 2007
    Posts: 820

    chrisp
    Member

    To modify the stock rocker cover you can make a wood buck with the required shape, you can find pictures to see what the covers should look like (Evel car comes to mind) then hammer the shape with a ball peen hammer. You just need to be careful not to wrap the flange surface. And don't forget to do some fitting to check for interference between the rockers and covers, first you mount one and modify for one, once you're sure everything's ok for that one you can do the others.
     
  14. Oh yeah, figured all this stuff out the hard way on my roadster... with the cam I'm running I really don't need adjustable rockers so decided to just put a set of new stock rockers on.
     
  15. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,924

    Mike VV
    Member
    from SoCal

    One thing to note...there are "three" different Stude rocker designs.
    In any case of use, the latest design is the best Stude designed. These have a "round" (vs. more of an oval) pad for the rocker tip and a large "pad" (for lack of better terms !) on the bottom of the rocker arm.

    Mike
     
  16. ryan w dunn
    Joined: Aug 12, 2015
    Posts: 6

    ryan w dunn

    any idea on my post about the lifters? thanks
     
  17. dtracy
    Joined: May 8, 2012
    Posts: 223

    dtracy
    Member

    Are you sure the sound you are hearing is not detonation? Try slowing the timing down for a test, and perhaps a couple of gallons of premium fuel or a fuel additive for a test.

    Thanks, Dave.
     
  18. 57Commander
    Joined: Jul 14, 2015
    Posts: 3

    57Commander
    Member

    Stude rockers have a different angle to them
     
  19. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,155

    Rusty O'Toole
    Member

    Never mind the Stude rockers. They are for solid lifters and if you use solid lifters you will have to change cam and lifters as well as pushrods and rockers.

    I would try some lighter (thinner) oil, detergent of course, and a can of Bardahl or your favorite "frees sticky lifters" potion. Take it for a long drive but don't go too fast. You want to heat up and flush the lifters not pound the valve train.

    If no joy you may have to replace the lifters or even take them apart and clean them. I only suggest cleaning because it is so hard to get good lifters these days.

    PS by thin oil I mean 5W30 or 10W30 which is what the factory recommended. Your engine was never meant to run on straight 30 oil.
     

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