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  1. #1
    Join Date
    Nov 2004
    Location
    Portsmouth, Hampshire
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    274

    help needed for Ford BB valve clearances

    Im hoping there are some Ford engine specialaists out there or at least someone who knows far more than me!
    I have a 1970 Ford 429CI big block which was built for me a very long time ago. It had a fair number of upgrades including bigger valves, different cam, pistons etc.
    I now have it up and running and on the road but the engine sounds a little tappety so I want to check valve clearances.
    I have been searching forums to try and find some guidance on valve clearances for my engine but have ended up utterly confused, quite a lot of data suggests the rockers are not even adjustable...of course mine are different (Crane) but Im not sure if they are adjustable or what I am trying to set anything to.
    Any guidance very welcome!
    Paul

    SRV8 - 429 Ford Big Block, 4 speed toploader

  2. #2
    Join Date
    Nov 2004
    Location
    Portsmouth, Hampshire
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    274
    I will take a rocker cover off tomorrow to inspect but I have a very old picture from the build.valves and rockers.JPG
    Paul

    SRV8 - 429 Ford Big Block, 4 speed toploader

  3. #3
    Join Date
    Sep 2010
    Location
    Nova Scotia
    Posts
    825
    First of all you need to know whether they are hydraulic or solid lifters. The original 429 used hydraulic lifters. They are not adjustable, but if you have after-market rockers, then they say to reduce the lash to zero and then go 1/2 turn further, or maybe a bit more, but no more than 1 turn. I'm not even sure if that means the rocker stud nut or the rocker pushrod nut. But basically you need more than zero lash so the hydraulics can self adjust within the range of the lifter pump-up.

    If they are solid lifters (not as likely, but who knows) then you might be safe using a lash of 0.018" lash. My solid lifter cam (in a 428, which is completely different than a 429) calls for 0.016" for intake and 0.018" for exhaust (hot).

    My best advice is to keep researching this IF you can't determine what cam and lifters are in there. If you can, the cam manufacturer website or their Tech Help should provide answers.

    See post 3 on this: https://www.jalopyjournal.com/forum/...ustment.92598/
    John

    “A prudent person profits from personal experience, a wise one from the experience of others.”

  4. #4
    Join Date
    May 2011
    Location
    Flimwell
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    784
    They are non adjustable rockers by the look. So, if I’m right, you’ve probably got a knackered hydraulic lifter or two. Either that or damaged push rods. You can whip the push rods out & have a look quite easily ( make sure they go back where they came from). You have to remove the intake manifold to check the lifters.
    My bet would be a sticky hydraulic lifter which you can disassemble and clean.
    HTH.

  5. #5
    Join Date
    Jan 2002
    Location
    Reading, Berks, UK.
    Posts
    1,580
    I run a BB 460 Ford and those in your pic look like the std rockers.
    I cant see from the pics but one type had a rocker stud that had a thread only on the top part, the rocker itself had a sort of insert that went in the rocker and the lot was just tightened down on to the rocker stud with no adjustment.
    The rockers were stamped steel but the insert was alloy and used to wear a fair bit.

    There isn't any adjustment on the std rockers, think from memory there were 2-3 types depending on the year, but all were non adjustable in factory form, and yours look it.
    All in std from were hyd and all non adjustable.

    I doubt if they are solid lifter as you cant use a solid lifter with those rockers, so as someone else suggest it may be a lazy lifter not pumping up.

    If you remove a rocker cover you can loosen the rocker arm and remove the pushrod and check, but I doubt if its a bent pushrod or one popped out as it would have the symptoms of a misfire as the valve would not be opening.
    Be careful pulling a push rod out as they can stick to the lifter and you don't want to pop one of them out or its is an intake off then.

    Some, and I'm not sure which one of lifter design require a preload, on the BB Ford you twiddle the pushrod between the thumb and forefinger until there is no play up or down while you tighten the rocker nut, then just as you feel the tinniest of drag stop. Then tighten the rocker nut 1/2 to 3/4 of a full turn, its not that critical with a std cam, and that's the preload set.

    Another item to be aware of with Ford cast heads from the 289 up, lots of the rocker studs were just pressed in, these have in the rare cases slipped up a bit causing what sounds like rocker rattle. The HiPo heads always had screwed in rocker studs with a positive stop on the stud itself to stop this. In some cases I have come across studs that have pulled out a bit where up rated valve springs were fitted and a high lift cam, thus putting more load on the upward force taken by the push in stud. However this was in only a few cases of engines I have looked at, the fix was to get the studs pulled and the holes tapped and HiPo studs fitted.

    The std Ford BB pushrods were as far as memory serves 5/16" ( need to check ) these used to flex a bit under load and could sometimes bind on the head drillings or slots, its always worth fitting 3/8" pushrods and guide plates if upgrading the cam and springs on a BBF.

    Hope some of this helps

    David

  6. #6
    Join Date
    Nov 2004
    Location
    Portsmouth, Hampshire
    Posts
    274
    Thank you for such helpful responses. I decided to take my rocker covers off this morning to take a closer look and take some pictures. Part of me wishes I hadn't and part of me says I am lucky I did.
    On the nearside head the first thing I noticed was that the rod and rocker on the front cylinder were much more sloppy than the others which I could generally twist with a little binding felt. Then I spotted the more worrying problem 4 or 5 of the push rods have heavy wear on them where they go through the guide plates.
    I have taken some pictures to show the set up and the wear.
    I get the impression the front cylinder isnt building pressure and I have a bunch of push rods to replace at a minimum, the next questions is why this has happened.
    I did have an oil pressure failure after about 30 miles driving which I did spot very quickly and stopped but maybe it was enough to cause this. The other bank look perfect and all feel the same.
    I will post some pictures.
    Paul

    SRV8 - 429 Ford Big Block, 4 speed toploader

  7. #7
    Join Date
    Nov 2004
    Location
    Portsmouth, Hampshire
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    274
    pictures to show vale set up and wear marks on rods. Dont think I will be going out any time soon.
    Attached Images Attached Images
    Paul

    SRV8 - 429 Ford Big Block, 4 speed toploader

  8. #8
    Join Date
    Jan 2002
    Location
    Reading, Berks, UK.
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    1,580
    You have screw in rocker studs, which are good.
    You look like have the std rockers which are non adjustable, should be a Ford part number stamped on somewhere.
    But the push rods are way too tight in the guides.
    Have a measure as it could be they put in 3/8" push rods to do an upgrade but then cut corners by leaving the std Ford guide plates.
    Problem with those rockers is there is a bit of sideways movement, and with a tight guide that looks like the wear issue. Its false economy not to upgrade the guide plates or at least grind them out to suit.
    You might get away with a set of 3/8" pushrods, mod the guides and then give the engine one hell of an internal clean, also check the fit of the ball of the pushrod in the rocker, some have been known not to fit into the rocker arm correctly.

    Also some of the heads had drillings for the push rods to go thru and some had slots, check to make sure the push rod doesn't bind in this hold as well.

    If you want to spend a bit you could go for a set of Skorpion roller rockers, 3/8" push rods, a nice upgrade and not too expensive, check out Jegs or Summit.

    Measure the valve heads to see what you have as well.

    Good luck

    David

  9. #9
    Join Date
    Sep 2010
    Location
    Nova Scotia
    Posts
    825
    Wow! Good thing you caught that. Something is either worn or out of alignment for the guide plate to do that. When you take it apart, check the top of the valve stem to make sure it's square, the bottom of the rocker where it touches the valve and there ought to be some sort of ball shaped thing under that adjusting nut that may be worn or cocked somehow. I've never used guide plates, but I almost wonder if the plate should be flipped over so the slots change which valve they guide. Hopefully it will become evident once you take it apart. Pushrods have been known to bend, although I've never heard a satisfactory explanation as to "why".

    Another thought is that if the lifter has collapsed and is stuck down, the bottom of the pushrod could flop around causing contact with the guide. Turn the engine so the valve should be completely closed (turn so it's open, then rotate engine 1 revolution) and see if the pushrod flops around.

    Anyway, the adjustment is to get a valve fully closed, loosen the nut, then slowly tighten it while spinning and wiggling the pushrod until all the lash is gone. Then tighten another 1/2 to 3/4 of a turn. I've read both, so pick one and adjust all the valves the same. There's a quicker way to do this, but with an unknown cam, I always get the one I'm to adjust open, then rotate the engine 1 turn and adjust it. Then repeat 15 more times!

    Good Luck. I hope you don't have a valve problem and have to remove the head.


    EDIT: I take too long to type. While I was, it seems David already mentioned a number of things I did. I guess I'm not so crazy after-all!
    Last edited by Eggbert; 10-11-19 at 10:37 AM.
    John

    “A prudent person profits from personal experience, a wise one from the experience of others.”

  10. #10
    Join Date
    Nov 2004
    Location
    Portsmouth, Hampshire
    Posts
    274
    Checked the rods and they are 5/16" so standard. The guides are genuine Ford as they are stamped with logo and part code. They looks like quite a roughly stamped out item but the clearance seems similar on good and bad rods. Maybe I clean up those that have rubbed and check for consistency. They are not exactly a precision part!

    So it is possible for me to buy a set of push rods (I will buy decent hardened ones) and just slip the old ones out without removing the intake manifold ?
    I will buy a set of manifold gaskets anyway but thinking I could try this first and then rmove the intake if it isnt working.

    The odd thing is I have a whole head of good ones and only 4 out of 8 on the bad side, and it it intake and outlet valves. Im still wondering if it happened when I lost oil pressure and these were just the ones least lubricated ?
    Paul

    SRV8 - 429 Ford Big Block, 4 speed toploader

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