1999 chevy s 10 doesnt have compression

Incorrect Crankshaft position and valve timing.

It has an interference engine, so the piston came up and hit the valves and jammed with piston. You now have bent valves.

Is my 1999 Tahoe 5.7 L an interference engine or not?

https://www.justanswer.com > chevy > b932h-1999-tah...
May 15, 2018 · 1 answer
Hello, it is an interference engine.

..

yes
to get compression the valves have to be closed when the piston is coming up on the compression stroke
If you have the crank out 180 degrees to the cam shaft, then at least one valve will be open on all pistons
The timing marks on the crank sprocket and the cam gear have to close to each other and in line with no 1 piston on tdc

How many miles on the engine ? Worn piston rings ! worn timing chain , jumped time ! engine worn out !

well first off you need to start by checking the compression on all 8 cylinders!!!! to rule out internal engine failure as oppose to jumped timing. its very rare that timing chains will jump especially a double roller chain. get a compression gauge take the plugs out and get a reading on all the cylinders. you should be no more then 10-20psi difference from cylinder to cylinder. but on the chevy motors if there is a problem they usually show well on a compression test! good luck post back up the results then we can go from there.

Getting the timing chain back on these engines can be tricky and requires more than just a diagram to get right. Here is how the timing chain should be reinstalled. Keep in mind that this engine can cause damage to the valves if the timing chain has any problems while the engine is running so it may not be a bad idea to setup the timing system as follows and do a compression test to make sure that everything is in order there.
Install the crankshaft sprocket with timing mark at the 5 o'clock position. Lower the timing chain through the opening in the top of the cylinder head. Carefully ensure that the chain goes around both sides of the cylinder block bosses (See 1 & 2 in picture): http://gsi.xw.gm.com/image_en_us/gif/000/000/412/412535.gif

Install the intake camshaft sprocket with the INT diamond at the 2 o'clock position. Hand tighten a NEW intake camshaft sprocket bolt. Route the timing chain around the crankshaft sprocket with the matching colored link aligning with the timing mark. Route the timing chain around the intake camshaft sprocket with the uniquely colored link (1) aligning with the INT diamond: http://gsi.xw.gm.com/image_en_us/gif/000/000/466/466558.gif

Install the timing chain tensioner guide through the opening in the top of the cylinder head. Tighten the timing chain tensioner guide bolt to 10 N·m (89 lb in): http://gsi.xw.gm.com/image_en_us/gif/000/000/412/412160.gif

Install the exhaust camshaft sprocket with the timing chain matching colored link (3) at EXH triangle aligned at the 10 o'clock position: http://gsi.xw.gm.com/image_en_us/gif/000/000/466/466570.gif

Ensure the timing marks and the colored links (1,2,3) are correctly aligned: http://gsi.xw.gm.com/image_en_us/gif/000/002/003/2003412.gif

Use a 24 mm wrench to rotate the camshaft slightly, until exhaust sprocket aligns with the camshaft. Hand tighten the NEW exhaust camshaft sprocket bolt: http://gsi.xw.gm.com/image_en_us/gif/000/000/412/412536.gif

Install the fixed timing chain guide. Tighten the fixed timing chain bolts to 10 N·m (89 lb in): http://gsi.xw.gm.com/image_en_us/gif/000/000/412/412165.gif

Apply sealant, GM P/N 12378521 (Canadian P/N 88901148) compound to thread and install the timing chain guide bolt access hole plug. Tighten the chain guide plug to 90 N·m (66 lb ft): http://gsi.xw.gm.com/image_en_us/gif/000/000/412/412164.gif

Install the timing chain upper guide. Tighten the timing chain upper guide bolts to 10 N·m (89 lb in): http://gsi.xw.gm.com/image_en_us/gif/000/000/412/412167.gif

Inspect the timing chain tensioner. If the timing chain tensioner, O-ring seal, or washer is damaged, replace the timing chain tensioner. Measure the timing chain tensioner assembly from end to end. A new tensioner should be supplied in the fully compressed non-active state. A tensioner in the compressed state will measure 72 mm (2.83 in) (a) from end to end. A tensioner in the active state will measure 85 mm (3.35 in) (a) from end to end.

****If the timing chain tensioner is not in the compressed state, perform the following steps. Remove the piston assembly from the body of the timing chain tensioner by pulling it out. Set the J 45027-2 (2) into a vise. Install the notch end of the piston assembly into the J 45027-2 (2). Using the J 45027-1 (1), turn the ratchet cylinder into the piston: http://gsi.xw.gm.com/image_en_us/gif/000/000/797/797246.gif

Inspect the bore of the tensioner body for dirt, debris, and damage. If any damage appears, replace the tensioner. Clean dirt or debris out with a lint free cloth. Install the compressed piston assembly back into the timing chain tensioner body until it stops at the bottom of the bore. Do not compress the piston assembly against the bottom of the bore. If the piston assembly is compressed against the bottom of the bore, it will activate the tensioner, which will then need to be reset again. At this point the tensioner should measure approximately 72 mm (2.83 in) (a) from end to end. If the tensioner does not read 72 mm (2.83 in) (a) from end to end repeat the steps required to return it to it's compressed state above.

Install the timing chain tensioner. Tighten the timing chain tensioner to 75 N·m (55 lb ft). Use a suitable tool with a rubber tip on the end. Feed the tool down through the camshaft drive chant to rest on the timing chain. Then give a sharp jolt diagonally downwards to release the tensioner: http://gsi.xw.gm.com/image_en_us/gif/000/000/412/412158.gif

Use a 24 mm wrench to hold the camshaft. Tighten the NEW camshaft bolts to 85 N·m (63 lb ft) plus 30 degrees: http://gsi.xw.gm.com/image_en_us/gif/000/000/630/630311.gif

loud knocking is usually a piston problem[wrist pin-piston-piston rings -rod bent damaged-crank -bearing ]piston hitting valve pull plugs and check for fouling it will narrow down area do compression test but knock usually doesnt last long before engine usually goes south other which u can hope for and can sound like a knock would be the exhaust gasket good luck

Do a Compression check on each cylinder. They should be really close, not 10-15-20 pound different. Make sure when you do the compression check, you first do it will all plugs out, let engine spin a couple times, put in one plug at a time and write down the pressure reading you get. Then pull plug again, squirt in about 3-4 squirts of motor oil into the firing chamber, turn engine a couple times, put back in plug and write down the new reading you get. Do the same to each cylinder.... That is called a DRY/WET compression check.... Dry or Wet the variation should be 5 pounds or less either way. If your WET pressures go up significantly, then you have weak rings... The Dry test is test both piston rings and values. The WET test ONLY checks the rings. If all is well there, then with the new items you have on your engine, take it to a Dynometer Tuner and have it tuned for about $150.00... It will be the best money you ever spent. Doing the WET/DRY test yourself will save you a bunch of money and be very very important information to the tuner guy. Be sure you write down the readings completely and clearly. Good luck...

For the rear you need to turn the piston as you crank with the C clamp. It's a lot easier with the right tool. Any good parts store has the tool. The tool to use is a universal brake caliper tool, I picked mine up from Pep boys for $10 bucks. The tool fits on a socket wrench and you turn it clockwise to depress the piston into position.
If everything is apart and you don't have an extra car, just used a pair of sturdy needle nose pliers to get int the groves and twist, no pressure needed.
Tork it down just enough to get the caliper back on. Once it is all bolted back up you will pull many many times on your e-brake handle to tighten the piston back up against the new pad.
Good luck, but try to use the tool.

What did you check as far as timing chain etc goes? Did you confirm all sprockets are aligned properly & crank, cams etc turning as they should?

Yes those are the next step, especially the coil.