Why can't I find top dead center?

1st check out if u have an INTERFERANCE engine, which would do valve damage if a timing belt brakes (I'm not sure) If its a clearance engine( no internal damage) recheck the timing marks at top/ dead/ center & make sure the engine is in time. (I think its a clearance motor, but ck).Then take it from there. General checks for a no start condition, plugs, spark, fuel pressure, COMPRESSION.

note Perform the valve clearance check and adjustment at the engine cold state. 1.Remove all of the ignition coils. 2.Remove the cylinder head cover.
caution Turn the crankshaft always clockwise. 3.Turn the crankshaft clockwise, and align the timing mark on the exhaust camshaft sprocket against the upper face of the cylinder head as shown in Figure. Therefore, No.1 cylinder goes to the compression top dead center. 4.Using a thickness gauge, measure the valve clearance with the arrow shown in Figure. If deviated from the standard value, make note for the valve clearance.
Standard value:

Intake valve 0.20 ± 0.03 mm (0.008 ± 0.0012 inch)
Exhaust valve 0.30 ± 0.03 mm (0.012 ± 0.0012 inch)

5.Turn the crankshaft clockwise 360 degrees, and put the timing mark on the exhaust camshaft sprocket in position shown in Figure. Therefore, No. 4 cylinder goes to the compression top dead center. 6.Check the valve clearance with the arrow shown in Figure. In the same procedure as 4.
7.If the valve clearance is deviated from the standard value, remove the camshaft and the valve tappet. For the camshaft removal, refer to Camshaft Removal and Installation . 8.Using a micrometer, measure the thickness of the removed valve tappet. 9.Calculate the thickness of the newly installed valve tappet through the following equation.
A: thickness of newly installed valve tappet
B: thickness of removed valve tappet
C: measured valve clearance
Equation

Intake valve: A = B + [C - 0.20 mm (0.008 inch)]
Exhaust valve: A = B + [C - 0.30 mm (0.012 inch)] note The valve tappet ranges 3,000 - 3,690 mm (0.1181 - 0.1453 inch) and has 47 types per 0.015 mm (0.0006 inch). The thickness below a decimal point is stamped on the reverse side of the valve tappet. 10.Install the valve tappet selected through the procedure 9, and put the camshaft in position. For the camshaft installation, refer to Camshaft Removal and Installation .
11.After installing the timing chain, measure the valve clearance using the procedure 3 to 6. Confirm the clearance is within the standard value.
caution Completely remove all the old FIPG, which might be remaining among the components. 12.After completely removing the liquid gasket adhering on the timing chain case, cylinder block and cylinder head, degrease them with white gasoline.
caution The cylinder head cover should be installed within 3 minutes of applying liquid gasket.

13.Apply a 4 mm bead of liquid gasket as illustrated.
Specified sealant:

THREE BOND 1217G or equivalent

14. Install the cylinder head cover and tighten the tightening bolts using the following procedures.
(1) Temporarily tighten to the following torque in order shown in the illustration.
Tightening torque: 3.0 ± 1.0 N·m (27 ± 8 in-lb)(2) Tighten to the specified torque in order shown in the illustration.
Specified torque: 5.5 ± 0.5 N·m (49 ± 4 in-lb)15.Install the ignition coils.

MEASURE AND ADJUST VALVE CLEARANCE 1. Turn the flywheel clockwise until the intake valve opens and then closes. Continue turning flywheel until the TDC (top-dead-center) mark (A) on the flywheel is upward. Both valves (B) must be closed and the piston (C) must be at the top of its compression stroke. If the valves are open, the piston is on the exhaust stroke and the flywheel must be turned one revolution
2. Measure valve clearance using a feeler gauge. VALVE CLEARANCE SPECIFICATION Item Specification Intake Valve (A) . . . . . . . . . . . . . . . . . . . . . . . 0.13 mm (0.005 in.) Exhaust Valve (B) . . . . . . . . . . . . . . . . . . . . . . 0.33 mm (0.013 in.)
3. If necessary, hold tappet and turn tappet screw to adjust valve clearance
Below you will find a complete manual with illustrations to complete rebuild, ***PRESS THE HELPFUL BUTTON****
http://www.wfmfiles.com/download/manuals/CTM2_-_16_18_20_24_HP_Onan_Engines.pdf

ADJUSTING THE VALVE CLEARANCE
Remove:
engine cooling fan
Remove:
timing plug
Check:
valve clearance Out of specification
Adjust.
Valve clearance (Cold)
Intake-0.10~0.15 mm
(0.0039~0.0059 in)
Exhaust -0.15~0.20 mm
(0.0059 ~0.0079 in)

a.Turn the crankshaft counterclockwise with awrench.b.Align the
" I"
mark on the rotor with the stationary pointer
on the A.C. magneto cover. When the

" I "

mark is aligned with the stationary pointer, the piston is at the Top Dead Center (T D C).
NOTE:
•
When the piston is at the Top Dead Center(TDC) on the compression stroke, thereshould be clearance between the valve stemtips and their respective rocker arm adjustingscrews.
•
If there is no clearance, rotate the crankshaftcounterclockwise one turn.c.Measure the valve clearance using a thickness gauge

1)REPLACE SPARK PLUG. EVEN IF THE SPARK PLUG PRODUCE SPARK CAUSE IT MIGHT BE FOULED...
2) CHECK THE TIMING MARK OF THE IGNITION SYSTEM IF PROPERLU TIMED...
3) CHECK THE VALVE CLEARANCE AT THE EXHAUSTAND INTAKE VALVE. WHEN THE IT IS ON TOP DEAD CENTER POSITION.
4) CHECK THE FUEL SYSTEM...
5) CHECK THE P.S.I AT COMPRESSION STAGE.
6) REPLACE THE CAPACITOR FILTER IF IT IS CONTACT POINT TYPE....

360 with hydraulic lifters, the crankshaft wit a ratchet and socket to get each valve closed. When lifter is at bottom turn the valve adjuster out to where you have free movement then turn adjuster till the rocker arm touches the lifter, then turn the adjuster in three quarters of a turn, and that valve is adjusted. No other clearance is required on hydraulic lifters. Do this with each valve in turn as each piston comes to top dead center using the firing order as a guide. When #1 piston is up to top dead center, both valves are closed. Adjust intake and exhaust at this time. Then the next in the firing order. The firing order can be found on the intake as is each cylinder marked with it's number. If it were a Chevy small block, for example only, firing order is 1-8-4-3-6-5-7-2. I would bring # 1 cylinder up to top dead center on compression stroke by removing that spark plug and stick my finger in the hole and crank the engine till I felt my finger being pushed away with compression, then bring that piston up till the timing mark was on the "0" of the timing tab at drivers side of the harmonic balancer on the crank. Adjust both valves on #1 cylinder and then turn the crank until both valves of #8 cylinder were free moving at the rocker. Then to the next in order of fire. I would turn each adjuster out at least one full turn before starting this procedure, then adjust them in order of firing starting with #1. It isn't hard, just takes time to do it right.

I had a 4 stroke 500CC engine doing the same thing. It was sneezing fuel backwards out of the carburetor, and backfiring. I checked the valve clearances at Top Dead Center and found that I had no clearance on the intake valves. So, when compression would try to build, instead of staying inside the cylinder where it belonged, it shot backwards out of the intake (because the intake valves were ever so slightly open). So, check valve clearances and valve timing. Mine had to be set at .006 mm intake, and .010 mm exhaust. Runs perfectly now.

Remove the crankshaft hole cap on the front cover and the timing inspection hole cap from the rear cover. remove the spark plug caps and valve covers. Put 17mm socket into the front of the motor and rotate the crankshaft counter clockwise and align the "TL" mark on the rotor with the pulsar index mark(little arrow bump).The left cylinder must be at top dead center of the compression stroke(both intake and exhaust valve rockers are loose).Now adjust the valve clearances of the left cylinder. IN: 0.08 mm (0.003 in)
EX: 0.10 mm (0.004 in)
Adjust so there is a slight drag on the feeler gauge. Do not set too tight, oil pressure in the rocker bearings will zero tolerance the valves. Set the valves too tight and you damage the rocker bearings. The motor is now in the correct position to adjust the cam chain tensioner. Loosen the cam chain tensioner lock bolt located right above the rear cover timing inspection hole. When the bolt is loosened the cam chain tensioner will automatically position itself to provide the correct tension. Retighten the tensioner lock bolt. Next turn the engine and align the "TR" mark on the motor so the right cylinder is at top dead center of the compression stroke and adjust the valves.

Valve adjustment is performed with the piston at top dead center (TDC) of the compression stroke. On the flywheel, there's a "T" mark that indicates TDC. Align the "T" mark and check that all of the valves are closed (this is where they must be to check and/or adjust the valve tappet clearances). If they are not closed, rotate the crankshaft one full turn, aligning the "T" mark again. Now the vwill all be closed.

http://www.scribd.com/doc/6853/periodic-maintenance - check this out before anything. . . its a service manual.. . .

thats an old engne but . . . if your head is milled remember yourr top dead center mark may be off. . . . so check the cams to get the real top dead mark before doing the valve clearances. . . . try 6 - 8 7- 9 . .. if its loud just go lower. . . until it sounds right. . . im not from the states but i do know alot of auto supplies have service manuals for old carss. . get a hanes manual. .. . they have practically everything. . . . .

now if you wana order a manual online this would be the link. i would advise you to get a manual . . .iv done lots of cars and i always order a manual before touching anything. just to be sure.

http://www.haynes.com/products/?searchType=vehicleApplicationSearch2&searchEnd=yes&sfID1=&sfID2=&sfID3=&year=1989&make=Volkswagen&model=Golf&x=31&y=13

hope this helps