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Discussion Starter #1
So when I was back home over Christmas I decided to try to adjust the valve clearance on the 4bt. Well looks like the timing pin is sheared off and while I can still reach it I'm thinking its a good idea to fix it. I've looked at the parts manual and it looks like you can get just the pin by itself. Looks like the PN is 3903924

Anyone try to replace just the pin? Is there an assembly available?

The other question is how do I set it to TDC to make sure the pin is aligned? Seems like I remember something about having to pull an injector and put some kind of stop in the injector hole.
 

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Locating TDC:
1. Locate timing pin in timing gear for TDC.
2. Remove #1 valve cover
3. Verify there is valve lash in both rocker arms by moving both rockers and noting both are tension free.

The timing pin is just an o-ringed plastic plunger. The pin just slides in the bore that it is mounted in. You should check to see if the other half is still in the gear before you install the new pin.
 

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I am debating about buying a new pin or just covering it up with a delete plate. My pin does not appear broken, but it doesn't seem to find its mark or work at all.
 

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I am debating about buying a bew pin or just covering it up with a delete plate. My pin does not appear broken, but it doesn't seem to find its mark or work at all.
Same with me.
 

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If your timing pin can't locate the hole there is a good chance it is broken off. Remove the two screws and the assembly then inspect the pin and the hole in the gear. You need the timing pin if you ever intend on adjusting the valves. The easiest way to break it is by keeping pressure on it while rotating the engine.
 

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Discussion Starter #6
The timing pin is just an o-ringed plastic plunger. The pin just slides in the bore that it is mounted in. You should check to see if the other half is still in the gear before you install the new pin.
So I should be able to just pull the little retainer ring that keeps the pin from pulling all the way out and put the new pin in? This is a bit tricky now since the engine is in the truck and there's not alot of room around there. I'll probably have to pull the PS pump to get at it.
 

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So I should be able to just pull the little retainer ring that keeps the pin from pulling all the way out and put the new pin in? This is a bit tricky now since the engine is in the truck and there's not alot of room around there. I'll probably have to pull the PS pump to get at it.
The right way is to remove the two screws and pull the assembly off the engine. Then press the pin in the direction like you were seating it in the timing gear. Clean the bore with a solvent and lube the bore and o-ring with ATF. Then reinstall in the reverse order.

Also note: A lot of these get painted into position so make sure it rotates in the bore or it's probably painted into position and not broken.
 

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The timing pin housing adjusts. Make sure you scribe the original location before you remove it. My timing pin was very difficult to move. Once I got it into the bore (for TDC), I removed the assembly and found that the o-ring was so old & dry that it hung up in the bore. Silicone spray loosened it up for a while, then it went back to hanging up. Replacing the o-ring was the cure.
 

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The other question is how do I set it to TDC to make sure the pin is aligned? Seems like I remember something about having to pull an injector and put some kind of stop in the injector hole.
With the engine before TDC, run one of the valves down into the cylinder. Put a dial indicator on the end of the rocker, or on the valve retainer, and zero. Bar the engine up until you get a thou or two of movement because of the piston pushing the valve up. Mark the damper to some point (crank position sensor works well). Bar the engine back, loosen the valve, bar the engine forward well past TDC. Run the valve back down to zero on the dial. Bar the engine backwards until you get a thou or two of movement in the dial. Mark the balancer again. Measure between these two points, and that is your TDC.
 
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