Water Pump + Throwing parts at this truck.

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Schurkey

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How would I know by looking at it...?
The chain and new sprockets are <$50. I'm inclined to replace it put it out of my mind forever. There are dozen different options from Melling and Cloyes on rockauto.
OK, I could have been more explicit. You're pulling the timing cover off anyway; fon_dle the chain to assess how much slack it has. If there's little or no slack, there's no reason to replace the timing set.

Really? "Fon_dle" is censored?

Another option which doesn't require removal of the timing cover, is to put the crankshaft exactly at TDC, TURNING THE CRANKSHAFT CLOCKWISE AS VIEWED FROM THE FRONT OF THE ENGINE, and remove the distributor cap so you can look at the rotor. Then turn the crankshaft counter-clockwise until the distributor rotor starts to move. At the instant that the rotor begins to turn, look at the timing marks to see how far the crank has turned, in degrees. 0--5 degrees, timing chain slack is acceptable. More than 5 degrees, either the chain is worn, or the distributor gear/gear on back of camshaft is worn, or both. Inspect distributor gears, and if they're good, replace timing set.

If you do replace the timing set, I'd take the time to make sure the camshaft timing is where it's supposed to be. Errors in the machining of the crank or cam gears can affect cam timing, and you won't know unless you check using a degree wheel and dial indicator system designed for that purpose.

MOST of the SBC timing chain options won't fit your truck. The Vortec small-block can't use a double-row roller chain, or a wide link-belt chain as there won't be enough room to have the wider chain and the matching lower (crankshaft) gear and still fit the crank sensor reluctor under the timing cover; and the timing gear for the cam may have a bigger bolt-circle that won't fit the step-nose roller cam. You can immediately narrow your timing set selection by buying only a timing set that fits a '96-2000 (?) Vortec small-block engine WITH the crank sensor.

The "first-design" timing set for Vortec engines was a "silent" link-belt chain, which I find perfectly acceptable but they're not "in style". The "second-design" is a single-row roller chain, which again is perfectly acceptable.

I bought a Vortec short-block of unknown mileage, when I rebuilt it, the single-row roller timing chain was so perfect I re-used it.
 

_rgk

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I just rebuilt my Vortec. Double-row timing chain, aftermarket crank sprocket, original reluctor ring, original cam sprocket, aftermarket timing cover, original crank sensor, no issues.
 

L31MaxExpress

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OK, I could have been more explicit. You're pulling the timing cover off anyway; fon_dle the chain to assess how much slack it has. If there's little or no slack, there's no reason to replace the timing set.

Really? "Fon_dle" is censored?

Another option which doesn't require removal of the timing cover, is to put the crankshaft exactly at TDC, TURNING THE CRANKSHAFT CLOCKWISE AS VIEWED FROM THE FRONT OF THE ENGINE, and remove the distributor cap so you can look at the rotor. Then turn the crankshaft counter-clockwise until the distributor rotor starts to move. At the instant that the rotor begins to turn, look at the timing marks to see how far the crank has turned, in degrees. 0--5 degrees, timing chain slack is acceptable. More than 5 degrees, either the chain is worn, or the distributor gear/gear on back of camshaft is worn, or both. Inspect distributor gears, and if they're good, replace timing set.

If you do replace the timing set, I'd take the time to make sure the camshaft timing is where it's supposed to be. Errors in the machining of the crank or cam gears can affect cam timing, and you won't know unless you check using a degree wheel and dial indicator system designed for that purpose.

MOST of the SBC timing chain options won't fit your truck. The Vortec small-block can't use a double-row roller chain, or a wide link-belt chain as there won't be enough room to have the wider chain and the matching lower (crankshaft) gear and still fit the crank sensor reluctor under the timing cover; and the timing gear for the cam may have a bigger bolt-circle that won't fit the step-nose roller cam. You can immediately narrow your timing set selection by buying only a timing set that fits a '96-2000 (?) Vortec small-block engine WITH the crank sensor.

The "first-design" timing set for Vortec engines was a "silent" link-belt chain, which I find perfectly acceptable but they're not "in style". The "second-design" is a single-row roller chain, which again is perfectly acceptable.

I bought a Vortec short-block of unknown mileage, when I rebuilt it, the single-row roller timing chain was so perfect I re-used it.
I have seen enough of the link style chains with so much wear after less than 100K miles, I will not put one in even a stock engine.

The heavy duty/industrial/marine L30s and L31s as well as many of the GMPP crate engines like the ZZ4 all seemed to get the single roller. They last practically forever.
 

L31MaxExpress

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I just rebuilt my Vortec. Double-row timing chain, aftermarket crank sprocket, original reluctor ring, original cam sprocket, aftermarket timing cover, original crank sensor, no issues.
If you did not machine down the back of the reluctor or shim it forward, I guarantee the chain is self clearencing the reluctor for you. Dumping metal into your oil pan. I tested 5 different double roller chain setups in my personal build and the chain hit the reluctor on all of them. The single roller is extremely tight as it is and a double roller is wider. One does not even have to install the parts to see them hitting each other. Hold the chain on the crank sprocket and hold the reluctor against the sprocket. The thickness of the double roller chain prevents the reluctor from seating against the sprocket. When you install the balancer, the reluctor is forced into the chain, which then wears into the back of the reluctor. You will have an awesome looking design carved into the back of that reluctor in a short period of time unless you found some kind of unicorn ultra thin double roller chain setup.

I doubt it hurts the chain because the reluctor is powdered metal. That being said I would not want the metal shavings circulating in the oil of my new engine.

With 375 pounds of open spring pressure I tried numerous double chains trying to get one behind the OEM reluctor. If I had shimmed the reluctor I would have had to have the balancer machined down or spaced out the whole accessory setup for correct belt alignment.
 
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L31MaxExpress

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The reluctor did not show any sign of wear when I removed it.
What timing set are you using? I want one on hand when I put the Mike Jones custom ground cam I am getting into my 383. I would happily buy one to test fit against an OEM reluctor.

Just FYI guys Mike Jones will regind an OEM GM cam core that is in good shape fairly inexpensively. IIRC correctly he quoted me $265 on the re-grind in an email. I am sending him the $105 '6492 steel GM roller cam I bought last year to re-grind. Even obtaining one of those cams and having it reground is still less $$$ than a Comp cast core roller. It will need longer pushrods but pushrods rarely end up at OEM length anyway with cam changes.
 
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MMcc

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Hijack away!! But let me inject an update on the original post :)

It took two weekends in the garage but this chunk of work is done.
1- Power steering flush. Replaced leaking high-pressure hose. Added a dorman cooler on the radiator support. Many thanks to the forum for hints on how to route those hoses.
1.1- PS pump is whining badly now. I used Oreilly brand PS fluid and 12oz of Royal Purple w/ conditioners. If it doesnt quiet down soon, I'll suck out the reservoir and add more Royal Purple fluid. Any thoughts here? The pump has just 40k miles on it.
2- Front main seal / timing chain cover. I didn't drop the oil pan but used enough RTV to seal the hole in the ozone layer.
2.1- I checked the timing set like Schurkey described and it was in spec. Did not replace it.
3- Water pump, thermo clutch, thermostat, upper & lower radiator hoses, water pump hoses, heater core hose and adaptor.
4- heater core hose tee and wye. Down low on the passenger side of the engine bay, there's a plastic tee and wye fitting on the supply and return lines for the front and rear heater core. The supply side was leaking at that connection so I pull off the hose but the plastic tee just crumbles in my hand. Replaced both of those. And bought a couple fittings that'd allow me to bypass the heater cores if something else catastrophically fails.
4.1- In this same location there's a small plastic gizmo plumbed into the heater lines. It has a small hose (looks like a vacuum hosing) that connects to another dudad on the firewall. Anyone know what this is?? I'll get a photo tonight. Anyways, that hose was roached and got replaced.

And half a dozen little things from the front to the back.
Learned a lot! Very glad I can move onto more fun projects like a dual battery setup, aux lights, and some other overlanding kit.

Hopefully this 215k mile burb is as reliable as can be with these parts freshened up. The fuel pump was done in October. Replaced the transmission last winter along with plugs, wires, and distributor cap.

Appreciate all ya'll.
 

Schurkey

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Hopefully this 215k mile burb is as reliable as can be with these parts freshened up. The fuel pump was done in October. Replaced the transmission last winter along with plugs, wires, and distributor cap.
How about other fluids and filters?

Fuel pump--did you replace the fuel filter?
Front and rear differential lube
Transfer case lube
Transmission fluid flush with fresh filter, when the vehicle has enough miles/hours to make it worthwhile.
PCV system work--clean/replace PCV valve, assure the hoses are in good condition.
Evaporative emissions work--assure the hoses are in good condition, verify no liquid fuel in the charcoal canister, and that the purge valve works. Some canisters have an air filter, many do not. NOBODY changes the filters on the canisters that have them, though.
 
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