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rustyj14

Briggs broken valve push rod?

rustyj14
12 years ago

All of you learned heads can give me the answer on what breaks the aluminum push-rods in the bigger B&S over-head valve engines. I replaced one 2 years ago, and now it has bit the dust, so to say. I think it is a Briggs, but its too dark and rainy to go look. The old one has sort of a fluted look on one end. The owner took it out, so i don't know which end was in toward the cam. I would think the broken end was out toward the cap/cover. The new one doesn't have the "fluted" look.

I just got it off the truck and covered up when the storm hit, is why i didn't get a chance to inspect it. Tree branches fell, babies screamed, firemen went running, sirens howled, and women hid under their beds--it was that bad here! ;0)

Comments (9)

  • andyma_gw
    12 years ago

    please post follow up. Ive gotta cobble together some sorta horizontal for my back up Ariens. snow blower, so an inspiring fix would give me courage.

  • walt2002
    12 years ago

    Hmm, does sound like it was bad, glad everyone OK (?)

    B&S push rods are rounded on both ends and can be placed either end in.

    One big cause of broken aluminum push rods of early B&S models 28 & 31 series and up until fairly recently was the "rub block" which held the push rods in place. It wears a thin spot in the aluminum push rod which eventually gives away. Should not have happened in two years though unless very high usage. This is why I always recommend reversing the aluminum push rod when doing a valve adjustment.

    Later models have revised rocker arm positioners which eliminate the need for the rub block and this wear problem has vanished.

    Another cause or a contributing cause is a sticking valve. I would also check that in this latest case that the valve guide has not worked up causing the valve spring retainer to hit it bending the push rod. Valve guide should not be more that about 1/8" above the head casting. May be hard to tell because of the valve seal on the intake valve.

    IF the valve guide has come up, out, that is another thing, contact me at address below, put in proper format and remind me.

    Walt Conner
    wconner5 at frontier dot com

  • rustyj14
    Original Author
    12 years ago

    Thanks, Walt: The owner of his tractor has a very large yard to mow, with hilly and flat areas, and usually mows twice a week during the grass growing time, not so much later on in summer.
    The machine hasn't been very well taken care of. I told him i thought its' time for replacement might be near, considering how much it is used thru the summer, also "rode hard and put away wet"!
    Well, i have two push mowers to get running. One had a half full to the top of dip-stick tube condition, and a plugged air filter. The other one had a plugged air filter, and low oil. Both are filthy! Good owner care!
    Rusty J.

  • rustyj14
    Original Author
    12 years ago

    Walt, and others: I took the bull by the horns, and removed the cyl. head. I had found, this a.m., that the rod didn't move up or down when i turned the flywheel. I held the rod into the lifter and it is stuck!
    This lawn tractor is approximately 13 years old, awful dirty around the whole thing, the owner mows a large yard with it, and it is the dark green series, made around 1998, according to the emissions sticker.
    The owner called a bit ago, and said he'd think about what to do with it. I told him i thought it was too old for a non-mechanic type to mess with, especially needing a new short block. Thanks for your help. Rusty J.

  • walt2002
    12 years ago

    You didn't say what the model number of the engine is. IF it is a 31 series, I expect the lobe is worn off the camshaft. The cam lobes were not properly hardened on some earlier 31 series engines and they would wear comletely off. Doubt the lifter is stuck.

    Walt Conner

  • rustyj14
    Original Author
    12 years ago

    Yep, Walt, thats about what the problem is! The push rod doesn't move up or down when i turn the crank-shaft.
    So, the owner is going to think it over until Monday, then give me an answer of what to do with it.
    I have several engines here that i could sell him, but i haven't heard anything yet. And, seeing how hard the machine has been used over 12-13 years, i'd say its time to retire it. If he did install an engine, the tranny would probably be the next thing to break.
    I have a nice red LT3000 Craftsman lawn tractor here, that needs a hydro tranny. Could i adapt a standard tranny to it? Would it be worth doing the swap? Also, i have an old Murray with a 12 h.p. good engine in it, which i could use in the Craftsman with the worn cam. It'd be a lot of work switching it over, though. I don't want to get into too much changing of stuff.
    It is late. I'm going to bed! Later: Rusty J.

  • rustyj14
    Original Author
    12 years ago

    Well, the owner of the tractor called this morning and told me he bought a new J.Deere lawn tractor, and for me to keep the old one! It'll probably get another engine, and be used here on the home place for a while. Way he talked, he didn't want it back.
    And, a feller stopped today-said he has 2 Bolens tractors that he doesn't know if he's going to sell or keep. told me to come see them, and talk about the problem! Might go there tomorrow. I already have one bolens, 1400 Eliminator, that cranks, but no spark. Has the Tec horizontal crank-shaft engine in it. Drive shaft and all that. 3 blade deck.Would sell for best offer.

  • therd3
    11 years ago

    "You didn't say what the model number of the engine is. IF it is a 31 series, I expect the lobe is worn off the camshaft. The cam lobes were not properly hardened on some earlier 31 series engines and they would wear comletely off. Doubt the lifter is stuck.

    Walt Conner"

    Walt, How do you know about this I have a 31 series that is just 2 weeks out of warranty that the cam lob wore off and wont start. Is Briggs covering this beyond warranty time of 2 years?

  • romore_gw
    11 years ago

    Briggs might do a policy adjustment where they supply parts and you pay labor. You need to take it to an authorized service center to have it looked at. However, if you have taken it apart they will not consider covering any costs.

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