2003 Yukon SLT flex fuel 5.3L whats brand would you use? cam, oil pump, lifters, timing chain

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iamdub

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I hope the heads wont get in my way as their are installed on the engine stand. I am putting the intake on last after it is all bolted up. While the motor is on the stand I have removed/replaced the front drive axle seals as before now they leaked and slung grease everywhere. Got the front axle diff filled with grease. I am now in process of replacing the ac compressor, orifice tube, drier, and all the ac like seals i can get to. I did flush the lines with ac power flush in the can. I dod not notice any metal or discolored oil coming from outside the lines. Yes orifice tube was stuck in the line. Trick i found was use a left handed/stripped bit to remove the orifice tube. Prior to dissasembling the ac system it cooled fine. The ac compressor has noise in it and the shop said it was ok but it is easiest as it will get to replace it now. Mechanic said to use long extensions bars from about the exhaust near rear to access the bolts up front.

I know on my ford mountaineer ac seals were o-rings. The gm seals look like a cloth paper flat washer. I assume no oil or lubricant is used between the two hoses??
Thanks,

Without the IM on, those bolts probably would still be decently accessible even with the heads on. I'm sure they're still much more accessible than with 3' of extensions and a wobble socket going from the bottom!

I don't know about the A/C stuff. I farm that out cuz I don't have vacuum or recharging equipment.
 

iamdub

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I got sometime to work on it yesterday. I drilled a used oil galley plug and attached a 1/4" connector to prime the motor through the oil galley.
I am trying to wrap/prep the motor bay for the motor. I'm going to prime motor on the engine stand. How long once it is primed on the motor stand should I have it installed and crank over in the truck?

Sounds like what I did, except I botched the drilling of the plug so I bought an adapter.

I wouldn't worry much about rushing it into the bay after priming. If you prime it thoroughly, it'll just be like having a motor that sat up in a parked car for however long (a few days?) before starting it. My Tahoe usually sits 5+ days a week and I don't re-prime the engine before starting it, at least not THIS kind of prime, but that's a different story.

Prime it until you have oil flowing from all rockers and turn the crank by hand both ways while doing it. After it's installed and you're ready to start it, hold the accelerator to the floor and crank it until the PCM stops the cranking (about 10 seconds). Flooring it keeps the injectors from firing (factory flood-clear feature). Do this once or twice more, letting the starter cool for a minute or so between crankings. Unplug the main harness connector on both coil packs, bleed the air from the Schrader valve on the fuel rail, then crank again but without holding the pedal. This will purge the fuel system so you don't get a rough, sputtery start from that. Plug the coil packs back in and start it as normal. You should have very minimal noise at startup. A first start vid would be appreciated!

What kind of oil primer you working with?
 
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Summajet

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I used a metal harbor freight paint tank, 2 gallon. I placed the oil in a 5 qt plastic container. I then pressurized the tank to 40 psi. Open valve on the tank and oil flowed through the hose into the oil galley. I turned the crank bolt clockwise. I did not turn it counterclock wise. I thought it would bend the valves going counterclockwise? Spark plugs are not installed. Tonight, I used the oil pressure gauge and screwed onto the oil pressure gauge hole. I turned it many times clockwise and i did not see the pressure leave zero on the gauge. I tested the pressure gauge on the air compressor and it reads. Could I have overfilled the oil filter causing it to not build pressure? I primed the new oil pump prior to installing it. I did install a new Gm o-ring between the oil pump and the oil pickup tube. I also installed a ac delco upf oil filter that has a higher micron filtration. I turned it clockwise at least 30 times. What am I missing?
Thanks,
 
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Summajet

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I do recall near the end of priming it, i had pushed air into the oil passages/system. I think i need to remove the oil galley plug and prime it again. As far as the remaining piece I need to install is the valley cover. I have the top part open and it is not gonna build pressure without it.
 

iamdub

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If you run your tank dry and push air, then you have lost at least that much prime. It's not that big a deal. The main point is to get oil flowing to all passages up top before that first start. I leave the valve covers off and go until all rockers have oil seeping out. Usually, cylinders #5 and #6 take the longest. I don't know why.

How low of PSI does your gauge read? Last one I primed was in my brother's truck. I had 60 PSI going to my priming tank and when I turned the key on, the gauge showed about 30 PSI. When I turned up the compressor regulator to 80 PSI, the pressure on the gauge went to 40 PSI. So, the oil pressure was consistently half the air pressure. I was thinking that if you have 40 PSI of air pressure, would 20 PSI of oil pressure be too low for your mechanical gauge to read?
 
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Summajet

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I know cyl 6 & 8 tow of the rocker arms seemed not to have oil pushed out the the push rod holes. Was not sure if turning the motor would help?
 

iamdub

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I like to turn the motor so the oil running through the passages gets all around the bearings, journals, lobes, etc. so it all has a good coat of oil. I figure if it's coming out of all the rockers up top, then it's well throughout the rest of the motor. Turning it backwards won't put the pistons any closer to the valves than with it turning in it's normal direction.
 
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Summajet

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After I'm done priming the motor do you put any pfte on the oil galley plug? Or do tighten it up with no thread sealer?
If i use the pfte thread sealer I will need to turn motor on stand to allow the sealant to cure and keep oil off the sealant.
I'm gonna set the compressor to 40 psi.
Am I best to drill out the oil cooler block off cover/where the oil line would connect to?
At time of pressurizing oil galley I did not have the valley cover on, I had the mechanical oil gauge where the oil pressure gauge mounts into. Was not sure if that would make a difference? If I drill and tap the oil cover I could use a copper plug with pfte thread sealant to ensure it does not leak.
I saw a YouTube video where they had primed their ls motor and while on an engine stand they rotated the crank and oil pressure read 40psi where the oil pressure gauge mounts to.
Thanks for taking the time to give me advice and guidance...
 
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Summajet

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I mounted the valley pan cover. Then I pressurized the oil galley and oil poured out of the pressure sender hole. I will test with mechanical gauge this evening. With the cover on it should force oil out of all the push rod ends.
 

iamdub

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After I'm done priming the motor do you put any pfte on the oil galley plug? Or do tighten it up with no thread sealer?
If i use the pfte thread sealer I will need to turn motor on stand to allow the sealant to cure and keep oil off the sealant.
I'm gonna set the compressor to 40 psi.
Am I best to drill out the oil cooler block off cover/where the oil line would connect to?
At time of pressurizing oil galley I did not have the valley cover on, I had the mechanical oil gauge where the oil pressure gauge mounts into. Was not sure if that would make a difference? If I drill and tap the oil cover I could use a copper plug with pfte thread sealant to ensure it does not leak.
I saw a YouTube video where they had primed their ls motor and while on an engine stand they rotated the crank and oil pressure read 40psi where the oil pressure gauge mounts to.
Thanks for taking the time to give me advice and guidance...

I put some PTFE tape on the threads of my brother's truck because I was out of the liquid stuff that I usually use. I don't see how it could be a problem. I'm not sure of the torque spec, but I know it's as tight as I could get it with the hex wrench.

I wouldn't do anything to the oil cooler block off. Why would you drill it?

Not having the valley cover in place wouldn't affect the oil pressure. Not on a non-AFM engine.

Unless you think you might have a blockage or insufficient lubrication to anything for the startup, I wouldn't fret about it. Prime it as best you can, make sure you have oil coming out of the rockers, maybe most if not all, then use the starter once you have it in the truck to crank it and pump pressure before you fire it up. My OCD won't let me fire it up unless I have oil coming from all rockers, even if I know for sure tha all passages are spotless.
 

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