How can I be sure I have firing position on number one? I have the timing mark at zero, and the rocker arms appear to be neutral. But, when I rotate it 360 degrees, it looks the same. The shop manual says "the #1 cylinder firing position can also be detected by a gust of air exiting the spark plug hole as the piston approaches TDC". Does this mean I can put a compression tester on it, and determine that I'm at the firing position when compression increases? I've adjusted the valves, and it just doesn't "feel" right. I'm thinking I had the number six cylinder firing position rather than number one. Thanks, as always.

 

You should be able to shake both rocker arms easily with your hands...there will be resistance in one or both if you aren't on TDC compression stroke.

 

Pull number one plug .put your finger over the opening. as you watch your valves open as some one else turns the engine over.If you are on number one both valves will be closed.as you fill compression on number one cly.As said before. if you are on number six I believe it is the exaust valve on number one will be starting to open.you can also open your dist. cap and check that is is one . :chevy :auto:

 

[/img] Report this to a moderator%20DoInsert('%20:iagree:%20');a s above . remove dist cap. rotor should be pointing at about No5 cylinder


[Modified by britvette, 2:53 AM 5/12/2003]

 

Try this. It is a foolproof method: Use steps #1 thru #3

Proper Installation of Distributor

OK ~ so, let's go the long route and make 100% sure nothing is overlooked:

1: Remove the driver side valve cover
2: Rotate engine (clockwise as you face the engine from the front) until the #1 cylinder intake valve opens, then starts to close.
3: Continue rotation until the timing mark comes into view, then bring it to TDC on the timing cover timing scale
4: Scribe the #1 plug wire orientation on the distributor then drop into the bore while trying to maintain the rotor button at the #1 location.
5: While holding the rotor at the index mark, look at bottom side of distributor shaft at the male slot and make a mental note of how the male tab is oriented.
6: Look into block where distributor will be inserted (use a strong flashlight) and look at the oil pump drive
7: If drive slot in oil pump drive is not close to the same index as distributor, use a long standard screwdriver and turn the oil pump drive to as close of a match as you can achieve.
8: Drop distributor into the block while holding rotor button at scribed mark. You may have to allow the rotor to turn slightly to firmly seat the distributor.
9: If you cannot fully seat the distributor at this orientation, allowing for movement for final timing adjustment....... Then;
10: Remove distributor and adjust the oil pump drive again with a screwdriver.
11: Thru trial and error, you will be able to drop the distributor exactly where you want it.
12: Install distributor clamp and tighten to where it firmly holds distributor in place, but allows for rotation with a little force.
13: Install valve cover
14: Verify that rotor button is pointing at the scribed mark on distributor (see step #4)
15: Install distributor cap
16: Start engine
17: Using a timing light, time the engine per proper procedure for your year and model
18: Stop engine and tighten distributor
19: Start engine and verify that the timing did not change when the distributor was fully tightened.

~ Purp :yesnod:



[Modified by PurpleC4, 7:13 PM 5/11/2003]

 

:iagree: purps got it and it's fool proof :D

 

If all you want to do is adjust your valves, the way I do it is to pull the valve covers and use the clips on the rockers that keep the oil from spraying everywhere and do it while the engine is running. Back it off till it chatters, then tighten till it stops + 1/2 turn.

 

All you need to adjust a valve is to assure that it is fully closed.

Rotate the engine till an intake valve is just opening and adjust the exhaust valve; then rotate till the exhaust valve is just closing and adjust the intake valve. This method assures that the valve being adjusted is fully closed.

 

I did this method yesterday, works great!

 

:iagree: I don't pay any attention to what cylinder I'm on. I just rotate the motor until one of the valves on that cylinder starts to open and then adjust the other one. Seems to work very well.

 

Im with Nathan just do one at a time turn the engine over until the intake valve is coming back up and just exhaust and then turn the engine over until the exhaust is opening and do the intake.

Jay

 

It's an L98 - align timing mark on pointer - look in distributor - rotor should be pointing to #1. If not, it's pointing to #6, rotate engine one full revolution - rotor now pointing to #1 - BINGO.


[Modified by NavyVet, 9:25 AM 5/13/2003]

 

:iagree: Pulling the distributor cap is the fastest/easiest way.

1-8-4-3-6-5-7-2


Cylinder number 6 should be opposite from cylinder number 1, right?


[Modified by CentralCoaster, 2:55 AM 5/13/2003]

 

Central - thanks for finding my "#6" typo! Paul

 

Paul,
The simple method you have posted is foolproof for the L98 and earlier vintage engines. Thanks for pointing out what should be obvious to most of us. The only time it will not work is if the distributor has been removed ~ then obviously, the method I have described above comes into play.
~ Stan

 

even if you have not pulled the dist yourself i would not rely on it being in the right spot i don't know how many times i have gotten cars in that some "great mechanic" has worked on that just moved the plug wires around on the cap instead of lining the dist properly... :rant: so beware of this...do it right and do it once :thumbs: