I’d like to test compression on the 07 5.3 V8

[Sprung Monkey]

I’d like to test compression on the 07 5.3 V8

1.is a extension required w/LS heads? Or can I just thread in tube on it’s own?

Watched the video on top of google search he had a extension appeared to be the same length as spark plug.

I’ll be removing all spark plugs and the coils.



2.will a 8” extension be to long. https://www.amazon.com/dp/B000EVYHAO/?tag=gmtnation-20

The compression tester I’m concidering (ebay) https://www.amazon.com/dp/B00SKSAB8U/?tag=gmtnation-20 doe’s have 2 extenders however I want to screw extension into head and test by myself. I think the 2 extenders are a 2 person job one holds tight on head while assistant turns engine over.

Please advice on extension requirements if any.thanks

 

[NJTB]

The compression tester should have an end that screws into the spark plug hole, then plug it in to the guage. Pull the fuel pump relay so the engine don't start. Gently open the throttle valve (butterfly), crank the engine. You'll hear about 5 'puffs', that should be enough.
The readings should be within 10% of each other. If not, you have trouble in the low cylinder.
Squrit a few drops of oil in the low one to check if it's rings or valves.

 

[Mooseman]

Shouldn't need any extension unless it's an adapter to make the tester's hose fit the spark plug hole.

 

[TJBaker57]

You may consider ordering up some spark plug wires as it is conceivable that some may break during removal. If the GMT360 is anything like the Tahoe/Yukon 5.3 you will curse the men who built this machine while trying to remove the wire and plug from cylinder #8.

 

[Sprung Monkey]

The compression tester should have an end that screws into the spark plug hole,yes then plug it in to the guage.yes Pull the fuel pump relay so the engine don't start. Gently open the throttle valve (butterfly), crank the engine. You'll hear about 5 'puffs', that should be enough.
The readings should be within 10% of each otheryes. If not, you have trouble in the low cylinder.
Squrit a few drops of oil in the low one to check if it's rings or valves.yes I see eric the car do this,dry & wet test all excellent advice thanks.

I thought the extension was required tool an clearance issue w/ LS engines like the spark plug is recessed very deep in head.
mooseman says if the tube is long enough use it, the tube appears long enough so I may proceed.
did'nt know to pull fuelpump relay & open TB I was unplugging ignitions coils
and removing all eight spark plugs.
the video I link to is useful but kindof poor tutorial implying the extension is required.notice his tool kit his tester came w/ the kit the box was molded to include the extension.I was thinking this could be a GM priority tool exclusive to LS that's why his kit doe'sn't have the other 4 adaptors the ebay kit has.

I'm completely confussed on the 2 extensions in the ebay kit.

I'm actually leaning toward plan B cylinder #1 almost TDC top dead center I think that's both rockers up position both valve up then just shove a 3/8" x 5' rope down spark plug hole the snugg valves up by pushing piston a tad higher.
this man briefly explains rope method

as of right now my main objective is to remove a valve spring
edit:if I have to buy air pressure type tools I have to know exactly whats required not just guess well a universal kit mite work anit for me.thanks for advice

 

[Sprung Monkey]

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You may consider ordering up some spark plug wires as it is conceivable that some may break during removal. If the GMT360 is anything like the Tahoe/Yukon 5.3 you will curse the men who built this machine while trying to remove the wire and plug from cylinder #8.

I've heard stories ppl at dealerships dam that sounds like drugs being dealt or something schekkie anyway they only change 6 maybe 7 plugs. always ask for old parts exspecially SP.

I've owned a 4th gen Fbody since 2001 best car I've ever owned glad she never breaks much. #6 & 8 must be removed from underneth.
yes you correct on the tightness in engine compartment. over the years I've been lucky not ruining the plug wire it's not easy.
I also use a boot grabber & a tool that kindof hooks under boot so you're pulling on boot rather than wire. thanks

 

[Mooseman]

as of right now my main objective is to remove a valve spring

Why? Unless there is a broken spring or something, there's no reason to.

 

[Sprung Monkey]

I'm hopping the noises are a valve spring couple ppl have observed a spring bouncing both think it could be broken near it's base and not rod knock as you also say not rod knock. I'll swap springs and listen. some have said that 1 or 2 pistons rings broke off, after spring I'll move on to compression.
I'm probabley pissing in the wind, I'm more mad at myself for ruining parts of the engine or the whole thing. Thanks Guys for advice.
what do you think about the rope method holding the valves up?

 

[Redbeard]

If the valve spring is broken you should be able to see it. The amount of force it takes to compress a valve spring is a BUNCH. Hence the reason to use a Valve Spring Compression tool! Just let one of the valve spring keepers stick a little to a valve and no rope inside of the cylinder will help you. Plus it is nearly impossible to compress a spring perfectly 90 degrees to a valve to get the retainers off. I haven't looked at the video with using a rope to hold up a valve, but it sounds silly beyond measure. Don't waste your time trying to do this half A**d. Help yourself by starting with something easy, like checking the compression.

 

[aaserv]

The rope will work just fine to hold the valves in place. Should be able to get a spring compressor on loan from an auto parts store even though they sell various types really cheap. Make sure you go ahead and replace valve seals while you've got the spring off..
Trying to ck compression on my 5.3 Envoy was 1 of the hardest things Ive ever done to it. Virtually NO room on several cylinders and #8 has to be done thru the fender well and even then totally by feel as I can find no angle that will allow me to even get a look at the plug hole.
If I could find a shop around here that would #1 Do It and #2 Trust them to do all 8 correctly Id pay $125 easy and feel like I stole from them...

 

[Sprung Monkey]

The rope will work just fine to hold the valves in place. Should be able to get a spring compressor on loan from an auto parts store even though they sell various types really cheap.yes I have a dual valve spring tool years ago I gave $120 for the crane they invented it couldn't find so I ordered the knockoff for $20 the hold down bolts are zinck so thats questionable Make sure you go ahead and replace valve seals while you've got the spring off..yes I have new seals purchased all the dod delete stuff except the cam/ valley plate.
Trying to ck compression on my 5.3 Envoy was 1 of the hardest things Ive ever done to it. Virtually NO room on several cylinders and #8 has to be done thru the fender well and even then totally by feel as I can find no angle that will allow me to even get a look at the plug hole.
If I could find a shop around here that would #1 Do It and #2 Trust them to do all 8 correctly Id pay $125 easy and feel like I stole from them...yeah it's tight but it is possiable thanks for tip on the wheel well for #8 that's how the express vans are dune, I image all the AWD stuff force the wrench turner to access though well .

planning to procede w/ rope method. here's the rope I have boaters call blue steel

CWC Blue Steel Floating Co-Polymer Utility Rope, Teal W/Dk Blue Tracer (3/4" x 600' - 13900 lbs Tensile) - - Amazon.com

CWC Blue Steel Floating Co-Polymer Utility Rope, Teal W/Dk Blue Tracer (3/4" x 600' - 13900 lbs Tensile) - - Amazon.com

www.amazon.com

rope is 3/16" almost a 1/4" man in video seamed to have thicker (he was breif w/ details of rope) I intend to use has a stiffness to it this would ease shoving it in but mite not allow foldup onto itself enough. I figure if I shove 6-7' in there then snug the piston will prevent dropping the valve.

compression stuff
Amazon uselly knows if a part fits the vehicle they don’t seam to classify tools that fit/don’t fit or I missed how to check.

Would anyone know confirm the threads size of spark plug?
I use NGK TR55 spark plugs according to this site the threads are 14mm https://www.gsparkplug.com/identifying-spark-plugs

definity don't want to booger a thread.
thanks

apparently the extension I thought I needed is not required.

Amazon.com: ABN Compression Tester and Adapters – Dual Automotive Compression Gauge with 14mm and 18mm Compression Tester Adapter: Automotive

Buy ABN Compression Tester and Adapters – Dual Automotive Compression Gauge with 14mm and 18mm Compression Tester Adapter: Compression Gauges - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

redbread I'm confussed on you're method w/ leaving one retainer/ keeper are using a magnet on the top of valve stem to hold valve up? then remove 2nd keeper then slide spring over magnet? this would work however how is the spring seat swapped it won't slide over the magnet.
thanks Guys for advicing
edit: my search history for engines keeps popping up w/ engines that fit 05-07 blows my mind because the 05-06 had 24 teeth crank reluckter wheel where my 07 has 58.
example https://www.powertrainproducts.net/...MIm4z86I_W8AIVjAD5AB1-tgG-EAEYASABEgIwKPD_BwE

not sure how the rebuilders of engines are however these folks never replyed to my what they call quote starting to see shortages on everything these days dam.