Having loud valve tick on 3rd cylinder compression test showed it was weak. took valve cover off and checked everything with feeler gauge to find

First decide which cylinder is misfiring and see if the sparkplug has been damaged. Check cylinder compression. All should be about equal.

RTM , the compression test is in the included manual. in a nut shell.
a warm or hot engine, is best,
1: have a charged battery, (spins faster)
2: all spark plugs removed. (same spins fast)
3: if smart , defeat fuel or spark (pull fuel pump relay or fuse to fuel pump. (spark and flying fuel can be a serious safety issue. )
Wear PPE (google PPE if alien to you)
4: attached screw-in gauge, hose end to spark hole.
5: block open the throttle, (engine must breath or compression fails)
we call this WOT> , wide open throttle.
6: crank until the gauge peaks. most will do 170psi easy.
repeat on each cylinder, write down the results (dry test)
if any read low, add 1 teaspoon of oil to the weak cylinder
then repeat the tests. if compression rises, the rings are shot) if not the valve is shot. (write down this reading under wet tests)
if you engine, has valve lash adjusters (solids) , set this first before starting any compression test. This is standard service procedure.

Sounds like you have a flat camshaft lobe.

If the model that you have is OHC with cam working directly onto valves via lifters and you have nil compression in these two cylinders then remove the valve cover and turn over until the camshaft lobes for each cylinder in turn are pointing up,slide a feeler gauge under the heel of the cam lobe between it and the tappet,should only be .1-.3mm,especially if a hydraulic lifter(cam follower).If the gap is large the valve are bent.Similar way to test if the head has rocker arms,but essentially when the valve is closed ther should be only the slightest hint of clearance between rocker arm and valve tip.
Another test we do here is as above turn until both lobes point up on OHC.Valves for this cylinder should now be closed.I knock the centre out of an old sparkplug and fit a airline to it.scew it into the cylinder to be tested and fire the air into it.If air heard out of exhaust,the exhaust valve is problem,if out of inlet area then it is inlet valve,if heard in sump and out of dipstick tube then rings/piston at fault.Having a badly leaking inlet manifold gasket can give a similar run fault but compression will be ok.I hope this helps otherwise get back to me with your findings.

Depends on which engine you have. If you have

ADJUSTMENT Although it is sometimes possible to reuse an old cylinder head cover gasket, in most cases it makes more sense to purchase a new one before beginning the procedure. Some vehicles may require the use of silicone sealant either with or without a new cover gasket. For more details, please refer to the cylinder head cover procedures in Engine & Engine Overhaul of this repair guide and refer to the gasket manufacturer's instructions.

Z24i Engine
See Figures 1, 2 and 3
For the intake valves: 1-4-5-8 valve clearance is 0.012 in. (0.30mm). For the exhaust valves: 2-3-6-7 valve clearance is 0.012 in. (0.30mm). The pivot locknut torque specification is 12-16 ft. lbs. (16-22 Nm).

1. The valves must be adjusted with the engine warm, so start the truck and run the engine until the needle on the temperature gauge reaches the middle setting. After the engine is warm, shut it off.
2. Note the location of any wires and hoses which may interfere with cylinder head cover removal, disconnect them and move them to one side. Remove the bolts holding the cylinder head cover in place and remove the cover. Remember, the engine will be hot, so be careful!

Fig. Fig. 1: Check the valve clearance with a flat feeler gauge-Z24i engine

Fig. Fig. 2: Loosen the locknut and turn the adjusting screw to adjust the valve clearance-Z24i engine

Fig. Fig. 3: With the No. 1 piston at TDC, adjust the top set of valves FIRST; with the No. 4 piston at TDC, adjust the bottom set of valves SECOND-Z24i engine

1. Rotate the crankshaft until the timing marks indicate that the No. 1 piston is at TDC of the compression stroke. If you're not sure of which stroke you're on, remove the No. 1 spark plug and hold your thumb over the hole. Pressure will be felt as the piston starts up on the compression stroke.
2. Refer to the accompanying illustration (upper part), then check valves (1), (2), (4) and (6) using a flat bladed feeler gauge. The feeler gauge should pass between the valve stem end and the rocker arm screw with a very slight drag. Insert the feeler gauge straight, not at an angle.
3. If the clearance is not within the specified value, loosen the rocker arm lock nut and turn the rocker arm screw to obtain the proper clearance. After correct clearance is obtained, tighten the locknut.
4. Rotate the crankshaft until the timing marks indicate that the No. 4 piston is at TDC of the compression stroke. If you're not sure of which stroke you're on, remove the No. 4 spark plug and hold your thumb over the hole. Pressure will be felt as the piston starts up on the compression stroke.
5. See the illustration (lower part), then check valves (3), (5), (7) and (8). Check and adjust valve clearance as necessary.
6. Install the cylinder head cover gasket, the cover itself and any wires or hoses which were removed. Check the engine oil level.

KA24E, VG30i and VG30E Engines
See Figures 4 and 5
These models utilize hydraulic valve lifters. Periodic adjustment is neither necessary or possible. There is however a bleed down procedure that is necessary when the valve train has been disassembled.
HYDRAULIC LIFTER BLEED DOWN

1. Remove the cylinder head cover.
2. Check the lifters for proper operation by pushing hard on each lifter with fingertip pressure.
3. If the valve lifter moves more than 0.04 in. (1mm), air may be inside it. Make sure the rocker arm is not on the cam lobe when making this check.
4. Install the cylinder head cover.
5. If there was air in the lifters, bleed the air by running the engine at 1000 rpm for 10 minutes.

Fig. Fig. 4: Cross-sectional view of an installed hydraulic valve lifter-4 cylinder engine

Fig. Fig. 5: Cross-sectional view of an installed hydraulic valve lifter-6 cylinder engine

Do you mean 1.7L? I do not see a 1.6L in the manual. Instructions from autozone.com are pasted below.

lash:

Intake, 0.007-0.009 in (0.18-0.22mm).

Exhaust, 0.009-0.011 in. (0.23-0.27mm)

Civic
1.7L Engine
NOTE Adjust valves only when the cylinder head temperature is less than 100 degrees F.

1. Before servicing the vehicle, refer to the precautions in the beginning of this section. Disconnect the negative battery cable.
2. Note the radio security code and the radio presets.
3. Remove the ignition coil cover. Remove the ignition coils. Remove the throttle cable clamps and harness holder from the cylinder head cover.
4. Remove the cylinder head cover retaining bolts. Remove the cylinder head cover from the engine.
5. Remove the grommet from the upper cover and disconnect the camshaft position (CMO) sensor connector. Remove the upper cover.
6. Set the number one piston at TDC. The UP mark on the camshaft pulley should be at the top, and the TDC marks on the pulley should line up with the top edge of the cylinder head.
7. Using the proper gauge feeler gauge, adjust the valves on cylinder number one.
8. Rotate the crankshaft 180 degrees counterclockwise. The UP mark on the camshaft pulley should be toward the exhaust side of the cylinder head.
9. Using the proper gauge feeler gauge, adjust the valves on cylinder number three.
10. Rotate the crankshaft 180 degrees counterclockwise and bring the number four piston to TDC.
11. Using the proper gauge feeler gauge, adjust the valves on cylinder number four.
12. Rotate the crankshaft 180 degrees counterclockwise. The UP mark on the camshaft pulley should be toward the intake side of the cylinder head.
13. Using the proper gauge feeler gauge, adjust the valves on cylinder number two.
14. Install the cylinder head cover.
15. As required, reprogram the ECM/PCM engine idle characteristics. Be sure all electrical items are OFF.
16. Start the engine. Hold the idle speed at 3000 RPM-s in park or neutral until the radiator fan comes on or the temperature reached 194 degrees.
17. Let the engine idle for about five minutes with the throttle fully closed.
18. If the radiator fan comes on during the five minutes, do not count this toward the five minute programming time.
19. Set the clock.

you need to remove the valve cover and if they are even adjustable there will be locknuts on a stud on one side you need feeler gauges and adjust by loosenin the nut with cylinder in compression sequence tightrn stud with screw driver or allen wrench whichever applies put feeler guage probably.018 between rocker and vale tightrn untilfeeler gauges move with some resistance lock nut tight but be sure you can still move feeler gauge get all cylnders then reinstall valve cover

First of all, you'll want to perform what's called a 'LEAK-DOWN' test. The assumption you make (regarding Intake versus exhaust) is irrevelant. Interferrence is BOTH intake and exhaust valve clearances. A leak down or "cylinder leakage" test is similar to a compression test in that it tells you how well your engine's cylinders are sealing. But instead of measuring pressure, it measures pressure loss.
A leak down test requires the removal of all the spark plugs. The crankshaft is then turned so that each piston is at top dead center (both valves closed) when each cylinder is tested. Some people start with cylinder number one and follow the engine's firing order.
A threaded coupling attached to a leakage gauge is screwed into a spark plug hole. Compressed air (80 to 90 psi) is then fed into the cylinder. You don't have to use that much pressure... you can use 30 psi... percentages are the same.
An engine in great condition should generally show only 5 to 10% leakage. An engine that's still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.
The neat thing about a leakage test (as opposed to a compression test) is that it's faster and easier to figure out where the pressure is going. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve. Air coming out of the breather vent or PCV valve fitting would tell you the rings and/or cylinders are worn.
A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.
A cylinder that has poor compression, but minimal leakage, usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc.
If all the cylinders have low compression, but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt or chain may be off a notch or two.
If compression is good and leakage is minimal, but a cylinder is misfiring or shows up weak in a power balance test, it usually indicates a fuel delivery (bad injector) or ignition problem (fouled spark plug or bad plug wire). These are not ABSOLUTE conclusions -- each assumption must be VERIFIED before concluding anything. You mentioned "the lifters seem to be collapsed."... Did you VERIFY this? Since you KNOW the engine is OUT - OF - TIME because you KNOW the timing belt has SLIPPED, then you know you must PUT IT BACK IN TIME... right?...before you can continue diagnosis.... right? Otherwise, what are you MEASURING?

There can be several causes for low compression.
Chck the obvious first. the spark plugs must be checked that they are all in good condition. not burnt, the gap must be good( for your engine).Check the wires and coil so that good spark is obtained. Blue spark , not weak yellow spark. After everything is good. Check the cylinders to see if they have compression. To test the cylinders do the procedures shown below.

If the cylinder shows little leakdown or holds good compression when a little oil is squirted into the cylinder (wet compression test), it would tell you that the engine needs new valve guide seals and/or guide work. Most late model import engines have positive valve guide seals. Often, the guides are fine, but the seals are worn or cracked. The seals can be replaced on some engines without too much effort and without having to remove the head.

compression test will help you determine if the oil is getting past the valve guides or the rings. If the cylinder shows little leakdown or holds good compression when a little oil is squirted into the cylinder (wet compression test), it would tell you that the engine needs new valve guide seals and/or guide work. Most late model import engines have positive valve guide seals. Often, the guides are fine, but the seals are worn or cracked. The seals can be replaced on some engines without too much effort and without having to remove the head.

finally if the rings on one or more of the pistons can caus compression leak. It must be located and fixed.

How to Test Engine CompressionAn engine depends on an equal compression reading in each cylinder to run smoothly. If poor compression exits in one or more cylinders it can cause a rough idle condition and low power. A compression test can be performed to check wear or internal damage. To start a engine compression test gauge is needed. There are two types of gauge styles, one threads into the spark plug hole which is more accurate. The other style of gauge is constructed with a rubber plug that is meant to be pressed against the spark plug hole, this style of gauge is difficult to use. To perform a engine cylinder compression test follow the steps below.

• Remove ignition coil connector or ignition system fuse to disable power to the ignition system
  
• Test ignition system to ensure that the power to the system has been disabled
  
• Remove #1 cylinder spark plug and insert compression gauge, most gauges have a hose attachment that is installed into the spark plug hole with the gauge connecting to the gauge hose.

Engine Cylinder Compression Gauge

• After the compression gauge has been inserted, use the starter to crank the engine over for about five seconds. Use about the same five seconds to test the remaining cylinders.
  
• Record the compression reading as each cylinder is tested
  
• Remove the compression gauge and reinsert the spark plug
  
• Follow this procedure until all cylinders have been tested
  
• Compare cylinders compression reading, all readings should be within about 5% of each other

If low compression exists a cylinder malfunction exits and further inspection is required. Possible causes for a low compression condition are: burned intake or exhaust valve, broken piston or piston ring, broken valve spring or a blown head gasket.