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Ford valve-train issues.

Discussion in 'The Hokey Ass Message Board' started by Moloko, Apr 22, 2012.

  1. Moloko
    Joined: Dec 14, 2005
    Posts: 726

    Moloko
    Member

    I got a call to come over to my friend's house tonight because he couldn't get his new motor to run right. The motor in question is a 1972 351W that was rebuilt by an "engine builder".

    After doing the basic messing around with carb and timing, I knew something was up. It was back firing through the pipes with any initial timing under 20 degrees, and when it idled for prolong periods the headers started glowing. I had him pull the covers and found this;

    [​IMG]

    Every single rocker was cranked down all the way, and smashing into the valves. He had regular 3/8'' washes stacked on top of the pivot nuts because he ran out of threads and the rockers were STILL loose.

    It scuffed up the top of the retainers a bit.

    [​IMG]

    What is wrong here? I know a part is miss-matched, but I'm not a ford expert. The pushrods measure out at about 8 3/16, which appears to be the stock size for that year motor. I'm assuming the valve springs have a higher installed height than stock, and will require longer pushrods. Just checking before we got that route.

    Here are the rocker arms that were on the car.

    [​IMG]

    [​IMG]
     
  2. Moneymaker
    Joined: Sep 19, 2011
    Posts: 320

    Moneymaker
    Member

    OK,
    Those are rail type rocker arms which are correct for that vintage 351W.
    It also appears to have the correct corresponding long stem valves for said rocker arms.
    One thing that is out of place are the aluminum retainers which I believe are the culprits. For one thing the diameter is too big for those stock rockers.
    I am pretty certain that the rocker arms are hitting the retainer and are interfering with the valve action.
     
  3. Moloko
    Joined: Dec 14, 2005
    Posts: 726

    Moloko
    Member

    Yeah, but I can't see them being cranked down all the way to the point of the rockers bottoming out on the studs, no?
     
  4. Moneymaker
    Joined: Sep 19, 2011
    Posts: 320

    Moneymaker
    Member

    Does the fulcrum slide all the way down on the stud or does it stop at the shoulder?
     

  5. What was this "engine builder" supposed to have done to this thing ?

    Are the rocker studs correct ?
     
  6. Kenneth S
    Joined: Dec 15, 2007
    Posts: 1,527

    Kenneth S
    Member

    Pushrods are probably too short, stock 351W pushrods should be around 8.150" long.
     
  7. FlynBrian
    Joined: Oct 5, 2007
    Posts: 759

    FlynBrian
    Member

    "2nd" the pushrods being too short. How much were the heads milled?
     
  8. ottoman
    Joined: May 4, 2008
    Posts: 309

    ottoman
    Member
    from Wisconsin

    A real engine builder wouldn't let that out of the shop with aluminum retainers! And he would have checked the valve train geometry and installed the correct length push rods.
    Find a better engine builder.
     
  9. Moloko
    Joined: Dec 14, 2005
    Posts: 726

    Moloko
    Member

    The nut bottoms out at the shoulder before it is fully lashed.
     
  10. Moloko
    Joined: Dec 14, 2005
    Posts: 726

    Moloko
    Member

    Oh, and he didn't have a guy build this motor, he bought this motor already done from this guy who apparently is a professional engine builder. Like I said the guy actually came over to the garage and said he couldn't figure out why it wouldn't run right, he said my friend must have bought the wrong balancer and the timing was off.

    So can I solve this buy getting a pushrod length checker and buying longer pushrods that allow the rocker to sit off the retainer and get proper adjustment?
     
  11. Moloko
    Joined: Dec 14, 2005
    Posts: 726

    Moloko
    Member

    No clue. He got no specs on the motor other than "rebuilt to 1969 specs" "mild cam" ".30 over".
     
  12. I would try to match up what you have with real 351W parts, a friendly parts counter guy should be able to help out. Match up the rockers, and the pivot ball & pushrods for a start.

    The retainers are getting marked up due to the rockers being at that bizarre angle.

    Bob
     
  13. RAY With
    Joined: Mar 15, 2009
    Posts: 3,133

    RAY With
    Member

    For starters push rods to short from looking at pictures.The tupe of retainer should have no bearing on the problem.
     
  14. I'm not a fan of aluminum retainers myself, but they've come a long way in recent years. They should work fine and are not part of the basic problem here.

    Bob
     
  15. Moloko
    Joined: Dec 14, 2005
    Posts: 726

    Moloko
    Member

    Like I said the pushrods are the stock length for this motor, I think the valve installed height is higher than stock.
     
  16. The valve spring height looks about right, something you can check with a scale once you know the number. I'd be more suspect about the rocker studs, where did they come from, are they possibly for roller rockers? It definitely looks like a grand mis-match of parts.

    Bob
     
    Last edited: Apr 23, 2012
  17. They do have their place. If you want to reduce valve-train weight and expect to change them periodically, they're fine. I wouldn't use them on the street though. Again, there's a weird mix of parts there. I would expect to see roller rockers to go with those retainers especially since the stus are so long.

    Bob
     
  18. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    Ford 302 and 351 of that era need the nuts run down all the way. If the hydraulic lifter cant take up the adjustment, run good, and be quiet, different length pushrods were available from the dealer. I have used very thin flatwashers under the nuts for adjustment.
     
  19. RDAH
    Joined: Mar 23, 2007
    Posts: 465

    RDAH
    Member
    from NL, WI

    Come on you Gm & Fomoco mechanics. Those stud mounted rocker should never be tightened down till you run out of threads. Just a half turn once there is no push rod end play.
     
  20. You're absolutely correct for adjustable rockers, expect to see a few threads above the nut, not much more.

    Bob
     
  21. R Pope
    Joined: Jan 23, 2006
    Posts: 3,309

    R Pope
    Member

    Chev rockers are adjustable,Ford are positive stop on Windsors. I
     
  22. Boryca
    Joined: Jul 18, 2011
    Posts: 695

    Boryca
    ALLIANCE MEMBER
    from Detroit

    Those aren't positive stop rockers. They are definitely adjustable. The pushrods might be too short, but it seems to me that there is no fulcrum "ball" in those rockers. The OP mentioned there were regular flat washers under the nuts, which makes me believe the fulcrum has been left out!:eek:
    I'd go looking for those...[​IMG]
     
  23. FEDER
    Joined: Jan 5, 2003
    Posts: 1,269

    FEDER
    Member

    I thought rail rockers were discontinued before the 351 came out? arent they on early 260 and 289s before 66? Fed
     
  24. Moloko
    Joined: Dec 14, 2005
    Posts: 726

    Moloko
    Member

    Nah it had the balls, with washers on too. I'm going to get a pushrod length checker and set the valve train geometry like I would normally with some proper length pushrod length.
     
  25. Nothin' beats a picture to get someone in the right direction. I have never ever seen odd washers added to rocker arms. I'd be interested in how those studs measure up against some stock 351 W studs.

    Bob
     
  26. George/Maine
    Joined: Jan 6, 2011
    Posts: 949

    George/Maine
    Member

    I had a 351W 1979 and had rockers like Post #23 there is no adjustment needed,just turn down to stop. The one on right
     
  27. Yes, there are 2 types. The ball type should be adjustable, the rocker type gets torqued to a spec. With the ball type, I'd be highly inclined to set the valves the old fashioned way, once the component compatibility snafu is cleared up.

    Bob
     
  28. Kenneth S
    Joined: Dec 15, 2007
    Posts: 1,527

    Kenneth S
    Member




    That's the way to do it. What year are those heads? and are they 351W heads? The positive stop studs were used in 1968, and later windsor's, unless someone replaced the positive stop studs with the early adjustable studs.
     
  29. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,533

    Ebbsspeed
    ALLIANCE MEMBER

    The studs could be an inch or a foot long, and would not change anything. The rockers would still be in the same location to take up the slack. The motor probably had roller tip rockers on at one time and might have needed shorter pushrods. Rebuilt with stock rockers and short pushrods, and this is the result.
     
  30. Squatch
    Joined: Feb 3, 2007
    Posts: 125

    Squatch
    Member

    Is this what you believe to be the issue? If so, then longer pushrods are the fix... There is more to setting this geometry correctly. You will want the to rub centered on the valve tip throughout the lift of the cam.

    You can see how dramatically pushrod length alone will have on geometry..
     

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