Timing Marks on 1972 350 Pick up

[Momboy007]

Hello All,
Well you finally have me straightened out on my HEI conversion, now I only have one question remaining and it is concerning the timing marks, On my marks, it looks like on the counter clockwise most part of the marks there is an "A" then a bunch of hash marks, then on the furtherst clockwise, there appears to be a "B or 8" Cannot really make it out and then one in the middle of the 2 that I would assume is TDC, which mark should I try to align the timing light to to get 8 to 10 degrees BTDC?
Thanks so much everyone for you help previously and now
Rick

[Sinister]

The B is is BTDC the A is ATDC. The one in the middle is TDC. Get the mark to line up with B.

[Momboy007]

Hello All,
So the A is not for advance? That is how it was originally timed.
What I mean is just counter clockwise of the TDC mark is an A, that would be retarded, is that what you are saying, and I want to be 8 degrees, on the B, Correct?
thanks all,
Rick

[truckdude239]

yes good luck mine wont runa t 8 btdc dont know why

[Sinister]

Originally Posted by Momboy007

Hello All,
So the A is not for advance? That is how it was originally timed.
What I mean is just counter clockwise of the TDC mark is an A, that would be retarded, is that what you are saying, and I want to be 8 degrees, on the B, Correct?
thanks all,
Rick

You know I may be wrong on this. This is how I have mine timed. But now that I think about it it doesn't seem right. Here's a link to a timing tab at Summit. http://store.summitracing.com/partde...2&autoview=sku
Click on the picture. It looks like advanced is to the left. Maybe someone who knows for sure will chime in.

[Sinister]

[WorkinLonghorn]

Yeah,that's right.Advance is to the left ON THE TAB. If you are running timing TAPE on the balancer then it will look the other way relative to "0" on the tab.

[Sinister]

So the A is for advanced, anybody know what the B stands for?

[LONGHAIR]

The balancer is rotating clockwise, so if the engine was stopped with the balancer mark aligned with the "0" (TDC) anything to the left (counter clockwise) would be "before" (advanced).

So the A is for advanced, anybody know what the B stands for?

The A is not advanced.
B= before (advanced) Before Top Dead Center
A= after (retarded) After Top Dead Center

There shouldn't be much marking on the ATDC side (2 degrees usually) It was only in the begining of the emissions regulations of the late 70s-early 80s that they did that.

[Sinister]

Well, I just went out and checked my timing and it was right on the money. Must of had a brain fart. On my timing tab though, the A is to the left of TDC, and the B is to the right, which seems counterintuitive. My apologies to the original poster for the miscommunication...

[Momboy007]

Hello All,
So, correct me if I am wrong, 8 Degrees BTDC is to the left, or counterclockwise of the zero mark, or TDC on the tab?
Thanks all

P.S. Did we figure out what the a and B stand for on the tab?

Rick

[Sinister]

Originally Posted by Momboy007

Hello All,
So, correct me if I am wrong, 8 Degrees BTDC is to the left, or counterclockwise of the zero mark, or TDC on the tab?
Thanks all

P.S. Did we figure out what the a and B stand for on the tab?

Rick

Yes.
I think the jury is still out on what A and B mean.

[WorkinLonghorn]

Clean it off with a rag. That "B" is actually an "R" which stands for "Retard".(Which is what I feel like 'cause I had to actually go out and look,after all these years)

[Momboy007]

Thank You Sinister and workinlonghorn, now it all makes sense!
That helps a whole bunch
Rick

[LONGHAIR]

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[Momboy007]

Sorry Longhair,
I forgot to mention you as well and I apoligize. Your help was greatly appeciated and I feel like now I CAN DO THIS!
Thanks again,
Rick

[LONGHAIR]

It's not about that..........There are two conflicting answers here. If mine wasn't one of them, I would be as lost as when it started?

B is advanced (Before Top Dead Center)
A is retarded (After Top Dead Center)

[WorkinLonghorn]

On mine,and lots of others I've worked on it's A=Advance and R=Retard.

[Sinister]

Originally Posted by LONGHAIR

It's not about that..........There are two conflicting answers here. If mine wasn't one of them, I would be as lost as when it started?

B is advanced (Before Top Dead Center)
A is retarded (After Top Dead Center)

I just went out and cleaned my timing tab. A is to the left of TDC and what I thought was a B is actually an R to the right of TDC.
A = Advanced
R = Retarded
And I feel a little retarded myself at this point.

[LONGHAIR]

Well that would make sense if the A was on the left (counter clockwise), but I don't think I have ever seen one that way? They always have a deeper V-notch at 0* and smaller notches on the advanced side in 2* intervals.

[Momboy007]

O.K. all, so now I really confused, is BTDC counter clockwise on the timing tab, or counterclock wise, or is it Clockwise, or to the right on the tab?
Thanks again,
Rick

[LONGHAIR]

Before (advanced) is counter-clockwise ....to the left of the 0

[Momboy007]

Thanks Longhair, Now I can definately do this
Rick

[LONGHAIR]

Just to prove to myself that I hadn't lost it entirely....I went out to the garage and looked at my Chevelle. Now, I realize that this is not a '72 350, but the markings are clear. Not only is it marked as "Before - After" it is not just the letters, but the entire word. It doesn't, however have the deeper mark at TDC? It shows from 12* before to 8* after.

[Momboy007]

Thanks Longhair,
That about puts the final nail in the Which way is advance Coffin"
I timed it right after and now it is beautiful!!!!

Thanks again
Rick