Initial Timing Set Up Advise - Inline 6

[Bruce F]

Hi,

I have a rebuilt inline 6 (230) installed and I am trying to get the initial timing set up. I have read several threads but still have a question or two around some issues I am having. Any input is appreciated - thanks Bruce

A. Setting # 1 cylinder to TDC - I am using paper towel method and it blows out if i turn engine over by hand (or using the remote starter) . When it blows out when turning by hand I am pretty close to the 0 on the timing mark - when I use the remote button it seems to go a bit past 0 before stopping .
question 1 - does the paper towel blow out exactly at TDC? or just near TDC and you may have to adjust a bit to get to TDC
question 2 - do I leave it at TDC 0 mark before moving to the distributor install or do I move it manually to 10 or 12 degrees advance by turning the harmonic balancer?

B. Distributor install - the threads typically say to install the distributor with the rotor facing the # 1 cylinder. When I try to do this I end up a bit off when the distributor gear and oil pump align. I tried to start and timing was way off, i had to turn distributor counterclockwise a lot to get it to fire and then the vacuum advance was in the way.

question3 - do I need to be pointing exactly at # 1 spark plug - if so do need to rotate the oil pump to do that ?

[RichardJ]

>> rotor facing the # 1 cylinder.<<

NO, NO. and NO.

The rotor points to the dist cap tower with the #1 plug wire.

[Steeveedee]

Yes, the paper towel will most likely blow out before TDC. Be sure to set the points dwell before setting final timing, as it affects timing. The relative positions of the distributor and #1 plug wire is shown in the repair manual. Like RichardJ said, the rotor should point to #1 wire when the engine is at TDC. It's best to set it up as close to factory as possible so that when someone else looks into it, it will appear "normal". Some people get confused when it doesn't look like what is in the book. You can find the repair manuals here-
https://67-72chevytrucks.com/vboard/...ghlight=hatzie

[Rust_never_sleeps]

For #2, you leave the harmonic balancer pointing to 0 when cylinder 1 reaches the top of its stroke. Initial timing will be set with the distributor

Question B: it's convenient to "clock" the distributor so that it points near cylinder #1 on the motor when that cylinder is making compression and at TDC.
IF you do this, you will also need to verify that the plug wire for cylinder #1 ACTUALLY goes where the rotor is pointing(right plug on the cap)

[Bruce F]

RichardJ /SteveeDee /Rust

thanks for the quick and helpful replies !!

I am learning as i go and this forum is invaluable

cheers Bruce

[PbFut]

Some basic info. Distributor turns half the speed of crank. The paper towel will indicate the piston is on the compression stroke. Assuming timing marks are correct relative to harmonic balancer and pointer then setting the mark on the balancer to zero will place the piston at TDC. Now place your distributor. If you need to rotate the crank for the distributor to engage the oil pump, remember, two full crank rotations to get back to the compression stroke and TDC. Rotor should have rotated 1 full revolution and be back to painting at #1 plug. Now set your wires relative to the rotor position. Though it make no difference where number one falls in the setup, as stated above, costum for the rotor to point to number one plug so if wires are removed, orientation is common for replacement.

[Rust_never_sleeps]

First thing I did with my 350 was change plugs and wires, and it wouldn't start and backfired through the carb, and seemed possessed. Previous owner had clocked it differently, so 1 was where 4 "should" have been.
I had never owned an engine before where you had more than one option for clocking the dizzy

[Dashman]

With the distributor removed, I've used a long screw driver to engage the oil pump shaft and turn it just ahead in the rotation of where the distributor gear will fully engage the camshaft gear. You need to start the distributor slight ahead of where you want the rotor to line up. It's a spiral gear, so it's going to rotate the rotor clockwise as it travels further down prior to making contact with the manifold. If you get it just right, the distributor will fall right into place.

[mr48chev]

I'm 77 years old and have been at this since I was 15 in 1962 and dropped a distributor in an engine and timed it for the first time in high school autoshop and if you get it right the first time you pat yourself on the back and do a happy dance because no matter how much experience we have that doesn't always happen and it takes more than one try.

As far as the cranking it over to bring it up on compression and "blowing a paper towel? out" that must be an amateur hack that I haven't heard of before as I was taught to hold my finger over the plug hole and taught hundreds of students to do the same when I was teaching auto mechanics. Hard to do when you are turning it by hand but I have never cranked one over by hand unless I was watching the rocker arms to know when the intake closed and it would be on compression stroke. Intake-compression-power-exhaust and if you watch the rockers you can get it pretty easy cranking it over by hand.

I've done the use the screw driver to turn the slot in the oil pump drive just right for the distributor to drop down a number of times. As Dashman said you start with the rotor turned back so that it is pointing exactly where you want it to be when you get it setting down all the way and again don't get upset if you don't get it right the first time.

You want the distributor set so the points (if it has points) are just opening for #1 when you lock it down. Then after it fires up and you have it running you hook up your timing light and set it where you want it.

[Steeveedee]

I didn't want to spend time with the screwdriver to turn the oil pump/drive; I'd just hold down the distributor body and hit the remote start button. It'll drop right in. It's timed, and the oil pump doesn't care about which side of the blade is driving it.

['68OrangeSunshine]

1 - 5 - 3 - 6 - 2 -4, is GM's Firing Order for all L6 engines.
Tattoo it to the back of your hand or scratch it on the Radiator bulkhead.
As advised by our panel of Experts, as long as your Distributor's Rotor makes contact in that sequence, it's relative position is not relevent. However, by pointing the Rotor in Cylinder #1's direction, you have a bearing. [in a Navigation sense.]

To find, absolute TDC, I use a normal yellow Pencil, and mark lines at 1'' intervals starting with the Eraser. The rubber part hits your Piston top so you don't do any damage. As you turn the Crank with a 5/8 socket on a breaker bar, you are looking for the shortest reading from the pencil.
[Keep that Pencil -- now it's a Special Tool.]

Be advised, Harmonic Balancers have elastomeric rubber to minimize vibration in-between steel parts. Over time, the rubber can deteriorate, and the Timing Marks notched into the HB's circumferance can ''Walk.'' I.E. move off the right mark.
If that's happened with an Over-50 rubber part, Replace the Balancer soonest.