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Thread: All new valve train - no adjustment at rocker arms

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    Question All new valve train - no adjustment at rocker arms

    '57 TR3

    I have a completely rebuilt engine with new cam (improved performance cam from Moss), new push rods, new rocker arm assembly, and new valves with hardened seats in the head. All parts sourced from Moss.

    After bolting the rocker arm assembly in place, there is zero clearance between the rocker and valve stem with the adjusters backed all the way out. Are the pedestals the same height on all TR3s? I don't have my old ones unfortunately to compare.

    Anyone had this problem? What's a good fix?

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    Great Pumpkin TR3driver's Avatar
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    Re: All new valve train - no adjustment at rocker arms

    Pedestals should be all the same, but it sure wouldn't be the first time that new parts are simply wrong.

    Another cause is the head having been cut down, to increase compression ratio. The usual cure for that is to fit shorter pushrods (available from most of the "performance" suppliers, not sure about Moss).

    It's not likely that the valve seats were installed too deep, or are recessed already, so I think it has to be one of the two above causes.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: All new valve train - no adjustment at rocker arms

    I think Randall's probably right about new parts being wrong. The quality at Moss seems to have gone down. Items I recently purchased include the windshield sprayer opening located so, if used, all it would do is put water on the bottom of the windshield. I had one original and needed another only to plug the hole. I don't intend to use them so it didn't make any difference. Also, the rubber around the door, both top and bottom is now a lot smaller than it was several years ago when I did another car. I still have that car so the comparison was easy. Anything to reduce cost.

    Again, as Randall said, the head could have been shaved. Years ago I received a head, along with numerous other parts, that I was told had been shaved and rebuilt. Some years later I had a burned valve so decided to use the "rebuilt" head I had. It had been shaved so much that I couldn't even bolt down the rocker assembly. Shorter pushrods or thicker head gasket would have been required. Just had the burned valve head rebuilt and still have the shaved head.

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    Yoda
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    Re: All new valve train - no adjustment at rocker arms

    My guess is shaved head. Can you measure the thickness of the head at bottom? The head steps down at the bottom by the push rod tubs and when they are shaved that much you can measure it with a ruler and see the difference. If I remember correct, they are supposed to be like 3/8, but I would have to measure to be sure.

    steve

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    Re: All new valve train - no adjustment at rocker arms

    Have you considered doubling up on the head gasket or shimming the pedestals?

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    Re: All new valve train - no adjustment at rocker arms

    I would fit shorter push rods.

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    Re: All new valve train - no adjustment at rocker arms

    Quote Originally Posted by malbaby View Post
    I would fit shorter push rods.
    Agree, best solution.
    Tom
    1960 TR3A TS73117 (under endless restoration, owned since 1964)
    1959 TR3A TS58023 (in case I never finish the one above)
    1969 Triumph Herald 13/60 (a whim)
    1970 Lotus Elan Plus 2 /0023/N
    1992 BMW325IC (fun to drive)

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    Re: All new valve train - no adjustment at rocker arms

    Would it be possible (advisable) to grind the push rods down a 16th. This is more of a question than an answer. In 1974 I had to buy a thicker head gasket to reduce the compression. Might still be available but only gains you a 32nd.
    Steve

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    Luke Skywalker
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    Re: All new valve train - no adjustment at rocker arms

    Not advisable IMO but I am an amateur builder at best. You'd need to retain the radius of the end as well as the balance or weight and I'm not sure 1/16 would suffice. Also don't know haw hard the ends are or how much metal there is in them. I suppose if you've got a decent lathe you'd have a chance.
    Shorter pushrods are available at a reasonable, I think, cost, all balanced and correct, and that's certainly the way I'd go.
    I also think some of the original push rods can be shortened by taking the ends out, shortening the tube and putting the ens back in, but I've never tried it. The newer ones don't come apart.
    Tom
    1960 TR3A TS73117 (under endless restoration, owned since 1964)
    1959 TR3A TS58023 (in case I never finish the one above)
    1969 Triumph Herald 13/60 (a whim)
    1970 Lotus Elan Plus 2 /0023/N
    1992 BMW325IC (fun to drive)

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    Re: All new valve train - no adjustment at rocker arms

    The metal isn't thick enough to just grind down. With some push rods, though, the cup end is a casting which you can remove, cut some from the tubing, and reinsert the casting.

    A set of shortened pushrods is only $85 at BFE, though. Given the mess if one fails, and the work involved, I would (did) just go for a new set. The new pushrods are also stronger than stock.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Yoda martx-5's Avatar
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    Re: All new valve train - no adjustment at rocker arms

    Stock head is 3.330". I milled 0.085" from my head and had to use shorter pushrods. I got them from British Frame & Engine.
    Art
    '58 TR3A TS236xxL
    '92 Mazda Miata -- Supercharged
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    Re: All new valve train - no adjustment at rocker arms

    Ted Schumaker also makes shorter push rods to order. http://tsimportedautomotive.com/tr3_tr4a.html
    PeterK
    1958 TR3A 1966 TR4A both HVDA

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    Re: All new valve train - no adjustment at rocker arms

    I've ordered some shorter pushrods from Smith Brothers Pushrods in Redmond Oregon (www.pushrods.net). I'll see how that works out. Thanks for all the comments.

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