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1 last question, whats the best way to drop the distributor in and time eng

F

firedreamer

Member
Ok just dropped in Stbd eng today, First i have to say I am totally surprised and happy i am so far. 2 engines pulled out and first one back in and not a single problem ! Just ask the wife, not one swear word heard from the eng room ! ! ! ok anyway whats the best way to set in the distributor / and time the rev rotation Stbd engine. i have a timing light and pretty sure how to use it. My manuel says eng is 10deg BTDC but im looking for any "tricks" so to speak. thanks, you all are such a fantastic resource!
 
A few things to note re; the REV RH Rotation Engine.... and I'll assume that this is a SBC engine!

a... The dristibutor will still rotate in the CW direction, just as with a STD LH Rotation Engine.
b... Firing order will still begin with #1 cylinder.
c... Firing order will be opposite from that of the STD Rotation Engine.... beginning with #1, and following a CW direction.


1..... Rotate engine (CCW if viewing from front) until the crankshaft is at approximately 6* or 8* BTDC and on the C/S ONLY!
(this will place #1 piston at 6*/8* BTDC on the compression stroke)

2..... Drop ignition distributor in place with the rotor aiming towards the physical location of #1 cylinder (may require several attempts).
You may need to rotate the oil pump drive in order for the drive to align with the distributor's driven gear (inside area of the driven gear is what operates the oil pump).

3..... Place a spark plug wire into the ignition coil. Place a good spark plug in the boot of this wire, and give the spark plug body good contact with Negative (metal surface).

4..... Energize ignition system.

5...... Rotate distributor housing CCW until you see one spark event.
Repeat several times until you are comfortable in stopping immediately after seeing the spark event.

6...... when close enough, now tighten distributor hold-down-clamp bolt some.... just enough to prevent self rotation.


Minus putting the spark plug wiring back where it belongs, you are now ready to fire up with an approximate 6* to 8* Ignition Advance.... ( I.E., BASE or Initial advance of approx 6* or 8* ).

Once up and running, toss your timing light on, and set BASE advance.



NOW.... regarding BASE advance, please note that setting BASE advance is not necessarily an accurate means of knowing or determining where your more important "Progressive" or "TA" (total advance) is.

Always see your ignition advance specs via an OEM Ignition Curve Graph.

This means strobing your timing marks dynamically at 250 RPM intervals from idle speed up to the "full-in" RPM where TA occurs.
Most TA occurs at/near 3,200/3,400 RPM or so.... of which is the critical RPM to be concerned with.



Note that any change to BASE advance causes an equal change to the Progressive and TA.





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#2 is wrong ! the distributor rotor does not have to "point", at the physical location of the number one spark plug. it has to only point at the physical location wher the number one ignition wire is.
please explain the mechanical correlation of the distributor rotor and it pointing to the location of the number one hole. if the number one cylinder is on the compression stroke, and you have the line on the harmonic balancer lined up on the timing tab at @ 6-8 degrees advance, you can drop the distributor in any position you want, as long as you engage the oil pump drive, and put the number one wire in the hole that the rotor is pointing at.
 
The reason to align the rotor up with the cap on the #1 compression stroke is purely for future service of the ignition system. It dont matter as long as the firing order is correct but it makes it easier when you install new plug wires.
 
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crankbait said:
#2 is wrong ! the distributor rotor does not have to "point", at the physical location of the number one spark plug. it has to only point at the physical location wher the number one ignition wire is.

First of all Mr. Crankbait, and with all due respect, no one implied that this is a rule..... it is a preference only.


please explain the mechanical correlation of the distributor rotor and it pointing to the location of the number one hole.
For the experienced mechanic, it could be said that there becomes a rhyme and reason (I.E., preference) for aiming/pointing the rotor towards the physical location of #1 cylinder.
Many of us prefer to aim/point the rotor towards the #1 cylinder's physical location while at/near TDC C/S for #1 cylinder.

GM apparently agrees:
Sbc_fo.jpg



Oldsmobile apparently agrees:

250px-Olds_firing_order.jpg



Pontiac apparently did not agree:

260px-Pontiac_firing_order.jpg




if the number one cylinder is on the compression stroke, and you have the line on the harmonic balancer lined up on the timing tab at @ 6-8 degrees advance, you can drop the distributor in any position you want, as long as you engage the oil pump drive, and put the number one wire in the hole that the rotor is pointing at.
I have no disagreement with that at all....... as long as we begin our indexing with #1 cylinder, the distributor cap does not care about which way we index the #1 spark plug wire.
And I'll go one better by telling you that if you are experience, you do not even need to align the harmonic balancer marks @ 6-8 degrees advance.

However, for average Joe who may not be experienced and who is asking for forum help, we suggest a method that is tried and proven.

You do as you choose..... I will continue with my usual suggestion based on many years of experience.
Fair enough???? :D
Click to expand...
 
kimcrwbr1 said:
The reason to align the rotor up with the cap on the #1 compression stroke is purely for future service of the ignition system. It dont matter as long as the firing order is correct but it makes it easier when you install new plug wires.
Click to expand...

Kim, I think that Crankbait's arguement was with the idea of it being "necessary" to aim/point the rotor towards the physical location of #1 cylinder while @ #1 TDC C/S.

I do agree with you about future service work and new plug wire installation if this is followed.


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the only reason why i keep bringing this up.......is for us mechanics, we understand what is happening on a distributor installation. to a newbie that is asking for help, trying to get that rotor "aimed", at the number one cylinder is just a real curve ball to him trying to understand why that is a requirement.
 
I think this is jus what I needed guys, thanks ...... ( I hope, LOL) the engines are BBC tho, 1987 Gen 4 454ci/350hp but I will assume the procedure is the same.
 
Let's not make something out of this that simply does not exist.
It is very easy to do, even for a "newbie". :D

crankbait said:

1..... the only reason why i keep bringing this up.......is for us mechanics, we understand what is happening on a distributor installation.
2..... to a newbie that is asking for help, trying to get that rotor "aimed", at the number one cylinder is just a real curve ball to him trying to understand why that is a requirement.
Click to expand...

1.... And if a "newbie" does not understand, he will seek help from one who does.

This is not all that difficult. Even if simply dropping in a distributor (with no concern re; rotor indexing), there will always be the likely event that the oil pump drive will need to be rotated in order for the distributor's driven gear to engage correctly.


2.... Again, there is no requirement that the distributor's rotor be aimed at/towards #1 cylinder.
This is and becomes a preference only for those of us who are mechanics, and for the very reasons that we have already discussed.




 
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