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Anyone try "tuning" a Gov-lock?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blue85, Mar 25, 2002.

  1. Blue85

    Blue85 Troll Premium Member

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    Anyone try \"tuning\" a Gov-lock?

    I was thinking about how the gov-lock works and if it would be worthwhile to try changing it's characteristics a little bit by putting in different springs.

    The governor uses centrifigual force against a spring to open and initiate locking. Changing that spring to a weaker one could make it lock up with less wheel spin, but at the risk of locking up in a tight corner.

    There is a lever that swings out based on centrifigal force on the whole carrierto prevent locking over a certain carrier rpm. This is to prevent having a locked rear over a certain speed, like 30mph. So by changing that spring, you could keep it locked to a higher speed. This could be valuable in mud, where you spin the rear tires really fast, even though the vehicle speed is not that high and you want to keep both wheels spinning.

    But once you lock, will the rearend stay locked until torque is removed or does it unlock on it's own due only to speed?

    Oh, and please don't say "just get a detroit locker", as that's not the topic...
     
  2. HarryH3

    HarryH3 1 ton status Author

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    Re: Anyone try \"tuning\" a Gov-lock?

    I tuned up the Gov-Loc in my S-Jimmy. It's laying on the garage floor. There's a Zexel Torsen diff where the Gov-Loc used to reside. /forums/images/icons/cool.gif

    Seriously, while you could probably play with a Gov-Loc to make it more aggressive, it wouldn't make it any stronger. They have a tendency to fail explosively when used with big tires and/or a heavy right foot. /forums/images/icons/frown.gif
     
  3. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Re: Anyone try \"tuning\" a Gov-lock?

    While I'm one of those people who would normally say just get rid of it, this does sound pretty interesting. I think a lot of Gov-lock failures are due to the diff trying to lock when the difference in tire speed is large, thus creating a big shock to the system.

    The idea behind the Gov-lock is really good, it's just implemented poorly.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Anyone try \"tuning\" a Gov-lock?

    While I can't answer all of them, "speed" alone is what governs unlock. Ask anyone on here thats tried tospin a gov-lock in low traction situations, you'll notice that both tires start spinning, but as the "speed" the diff sees increases, the thing will unlock.

    I'm with HarryH3....the carrier, and the tiny gears are what the problems are, moreso than the lock/unlock speed. I'll admit that lessening the time spent to lock at different axle speeds might reduce "shock" on the carrier, but without looking at the service manual scan on my page, I think the difference is "only" 100RPM anyways.

    I'm not good enough with math/physics to figure out what kind of turn you'd need to be making to achieve that kind of axle RPM difference, but it must be more than the stock wheelbase can manage, since I have never noticed it lock while turning under any conditions.

    I'm thinking the gear is lock, and I would imagine a tooth count change would be the only way to "tune" the lock point to lower RPM's
     
  5. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: Anyone try \"tuning\" a Gov-lock?

    I am one of those people that would say get rid of it and don't waste your time. I blew mine apart on the street with a stock 350. I wouldn't waste your time with trying to tune it, just run it till it breaks, or you switch to a heavier duty rear axle.
     
  6. Blue85

    Blue85 Troll Premium Member

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    Re: Anyone try \"tuning\" a Gov-lock?

    Thanks Dorian for actually staying on topic. As for the rest of you, a thousand lashes...(j/k)

    I think we all know the weaknesses of the Gov-lock, especially the 1/2-ton versions. The 3/4 and 1-ton ones are tougher and may be adequate for many of us. You've got to think about age and wear though, when casting judgement. do you "know" that your EZ-locker or true-trac or whatever will not blow up after 120,000 miles?

    But back to the topic. The unlock at higher speed and lock at a certain differential wheelspin features are both controlled by springs and weights. Why can't we just change the springs? A heavier one would go on the latching bracket to keep it locked at higher speeds. A pair of weaker ones would go in the governor assembly to lock it up sooner. If you could lock while the difference in wheels speeds is lower, there would be less stress on the locking mechanism. I wouldn't adjust this one too much, though.

    I think that the biggest improvement in the gov-lock would be if you could walk the cam in slower to spread the clutch engagement over a second or two. The problem is that by the time the governor opens, the two sides are moving so fast relative to each other that the tiny governor assembly tries to slam the cam mechanism over very fast. They seem to have already designed for this as the driving gear is quite large with many teeth and the driven gear on the governor is probably about 6 teeth.
     
  7. Blue85

    Blue85 Troll Premium Member

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    Re: Anyone try \"tuning\" a Gov-lock?

    I just realized something. You HAVE to make the gov lock unlock at high speed. The differential works based on the absolute difference between the left and right sides, but the difference in wheelspeeds in a turn is relative to the vehicle speed for a given turning radius. That means that the faster you take a corner, the more likely it is for the governor to lock (if the latching plate is not swinging out of the way). So by decreasing the wheelspin needed to lock and increasing the speed at which it always unlocks, the differential becomes more and more likely to lock up in turns.

    How close it is in it's stock form to doing that, I have no idea. But if you just diable the movement of the latching plate and let it lock at any speed, as you take turns tighter and faster, at some point the diff will lock up solely because of the turn, assuming that the truck doesn't roll before that point.

    Just something else to think about...
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Anyone try \"tuning\" a Gov-lock?

    Yeah, I'm not comfortable spinning the 10 bolt gov-lock with the 33's, trying to do a skid pad lockup test lol. Maybe if I had a 14 bolt I'd try it, but I don't.

    The gov-lock I had in the truck before this one was slightly messed up when I got it...it wouldn't unlock, or was locking way too early...going around corners on the street, the axle would hop. Since it was my first truck, at first I thought I was hitting curbs, but after a couple of times, I knew that wasn't it.

    My friend got in the diff (before I knew anything about gov-locks) and somehow broke the cam on the carrier. I sold the truck before I knew how I should be testing it, and before I put non-bald tires on it, so I'm not sure exactly what was happening. I *think* it would still lock up, I tried it on grass trying to move a car body one time, and they were both spinning according to a witness.

    I'd assume mine is working ok, but its strange to have the rear up on jackstands, and put it in gear. On mine at least, one tire spins for a couple of seconds, then "clunk!" the other locks in, and releases. I'm assuming its just so noticeable because there is no weight on it, but it surprised me the first time I did it. (trying to find source of drivetrain noise)
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Anyone try \"tuning\" a Gov-lock?

    I have a 14 bolt SF with a Gov-loc. It's great until you hit the mud, then it starts acting up and doesn't want to lock.

    I'm going to fix it with Lincoln and a whole bunch of 6011 before I drive my truck again.
     

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