I have to check my ignition timing,It is supposed to be 10 deg btdc, problem is there are 5 marks on harmonic and not numbered so i dont know which is the 10 deg mark

The manufacturers ignition timing specification for a 1992 Chevrolet S-10 Blazer 4.3L V-6 (VIN CODES W and Z) is 0 Deg. at idle with the EST bypass connector unplugged. You do not have to worry about which line to use on the balancer. There will only be one of them that is even close to the pointer on the timing cover. When the line on the balancer is aligned with the mark on the timing cover with the timing light, you are done.

If you really think you REALLY need to know which line is which, then pull #1 spark plug out and using a screwdriver or a punch in the spark plug hole, rotate the engine slowly to find where top dead center is. When you find top dead center on the intake stroke, the line on the balancer that is aligned with the mark on the timing cover will be the one you want to use (the other line will not even be close on the intake stroke OR the power stroke.)

Now, if you have your engine modified or something, (I don't know why you are asking someone at a performance shop or why he is telling you 8 to12 Deg. BTDC) then what you need is a timing light equipped with an offset adjustment. You set the offset on the light where you want it (i,e. 10 Deg.), then you align the timing marks as you would for a "normal" engine. You do not need any other marks on the timing cover. (Which is why the manufacturer did not bother to supply them for you.)

You will need a timing light....Start the engine and allow it to warm to normal operating temperature....disconnect the vacuum adavance--then slowly rotate the distrubtor while using the timing light to set it.
The timing mark for top dead center will be on the harmonic balancer, the pointer will be attached to timing chain cover, Set the timing as follows per engine size.
5.0L- BTDC 10° ± 2°
5.8L- BTDC 10° ± 2°
7.5L- BTDC 10° ± 2°

Turn off the engine and tighten the distributor bolt. Recheck the timing to verify that the timing did not move while tightening the distributor. Replace the shorting bar or vacuum line.

I hope this helps,

yes 10 deg is correct
hope this helps FixYa
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There are two kinds of timing, cam timing, and ignition timing. You don't adjust cam timing, it is set when the timing chain is installed. The timing chain cover is supposed to have a pointer welded to it with marks that line up with a mark on the harmonic balancer. (depending on the year of you engine these marks veri in appearance. Ignition timing is set while the engine is running with a strobe light that is triggered by the number one spark plug. On this engine (if it's stock) around 8-10 degrees BTDC. The ignition timing advances with cetrifical weights inside the distributor as well as a vacuum diaphragm. If either of these fail you will have a performance issue with a lack of power, and acceleration. If you are concerned about the cam gear being worn out yes they do wear out. Chevy made the gear teeth on the cam gear out of nylon to make then quieter, the replacement gears are usually cast iron. If you are thinking about changing the timing gears, the crank gear has to be pulled off with a puller, a lot of guys don't bother since it doesn't wear like the cam gear.

Your auto's spec sheet should tell you what your timing degree should be. For example, a 1969 Ford 429, 6 Degrees BTDC @ 550 rpm in drive gear - with automatic trans, with a firing order of 1-5-4-2-6-3-7-8. All this means is that you want to line up the pointer on the timing light with the 6° timing mark when the engine is idling in gear at 550 rpm. As you can see, it also says something about "BTDC" for this Ford. There is also an "ATDC." "Before Top Dead Center" and "After Top Dead Center" - top dead center is the point where the piston reaches the highest point in the cylinder and that is when the compression is the greatest. Now, your timing marks with have a line labeled "0" with marks above and below it, and depending on which way the wheel rotates, you will see the lines before the "0" (BTDC), or after the "0" (ATDC)

need timing marks of an 1989 toyota camry 4cyl

The engine timing markers down on the harmonic balancer/crankshaft pulley should be aligned with the timing indicator on the engine block to "0" degrees when the engine is in the compression stroke for the #1 cylinder, and this is TDC or "Top Dead Center". When something blows out of the spark plug hole that only means that the piston is coming up on TDC, but the crankshaft will still have to be turned until the timing markers are at "0" degrees. You should be sure that you do know how to properly align the timing marks to "0" degrees, and the timing marks must be set at "0" degrees before the distributor can successfully be installed.

Be certain that the timing marks are set at "0" degrees and on the compression stroke for the #1 cylinder, or the timing will be 180 degrees off when you install the distributor. This has to be precise and guessing will not get the distributor properly clocked in so that the ignition timing can be correctly set.

Once you are certain that the timing is set to "0" degrees "TDC", then mark the distributor housing where the #1 position on the distributor cap will be when the cap is installed on the distributor, so that the distributor housing shows a reference mark where the #1 position is, then the distributor should be installed so that the ignition rotor is pointing directly at the #1 position on the distributor housing, or just before the #1 position mark according to the rotation of the ignition rotor. The distributor should be able to turn and point the ignition rotor on either side of the #1 position mark to provide plenty of timing advance or ****** so that the ignition timing can properly be adjusted to specifications after the engine has been started.

Be sure that you follow the proper timing procedure for that vehicle and remove any timing spout connectors that are described in the set timing procedures

Also, be certain that you are actually using the #1 cylinder to set the engine to TDC and to actually time the engine with a timing light. Here is a firing order diagram that should also help to assist you. Let me know if you require any further assistance.

1987 non-turbo: 10 deg Before Top Dead Center (BTDC) @700 rpm
1987 Turbo: 10 deg BTDC @650 rpm.

To set the timing, you will need to connect a jumper wire between terminals E1 and TE1 on the diagnostic terminal. This diagnostic terminal is located just aft of the engine compartment fuse box. It is a black plastic box marked "diagnostic" on the cover, which flips open to reveal the terminals inside. There is a diagram on the inside of the cover which explains the terminal positions. On the Turbo model, you need to remove the forward section of the engine cover to gain access to the number one spark plug wire.

Your base ignition timing should be 10 deg. btdc.Make you a fused jumper wire and with the engine running jump terminals -te1 and e1.This will allow you to adjust base timing.Connect your timing light to spark plug wire number 1.Check your timing and adjust to 10 btdc if necessary.Good Luck!!!!

first you have to remove the shunt, then you set the timing at 10 degrees before top dead center 10 BTDC you have to look at the timing marks on the harmonic balancer because it has 10 BTDC and ATDC make sure you are set on BTDC