Pontiac 400 firing order

[Poncho-gp]

Guys I've got a 72 pontiac Grand Prix with the 400 its backfiring and very hard to start.I've been told and read that a pontiac eng fires counter clockwise ,What does this mean and what do i need to do to get it in time? Thanks...Jerry :?

 

[pontiacman469]

The distributor rotates backwards usually your number 1 plugwire is at the 1 oclock position on the cap if looking from the front of the engine,and rotating counter clockwise (towards the left) the order is 8-4-3-6-5-7-2,you might be able to correct it by turning the distributor alittle forward or backwards.

 

[mguerci]

It also sounds like your wires are 180 degree out.

 

[joe_padavano]

The distributor rotates backwards...

"Backwards"???

That's kind of a Chevy-centric view of the world, isn't it? It also doesn't really help the OP, since he may not know what "forwards" is, either.

Try this for a clearer explaination:

http://boxwrench.net/specs/pont_265-455.htm

It also sounds like your wires are 180 degree out.

He said it was hard to start, not that it didn't start. If the timing was 180 out, it wouldn't start at all.

 

[srercrcr]

Now how does a GM transmission that fits a Chevy and a Pontiac handle one going one way, the other another way?

 

[JESSE]

pontiac

i think that a dist rotation is determined by it's placement in the engine,chevy-left side of cam ...pontiac right side of cam. i'am kinda scared to take a quess at this for the fear of been flamed, does anyone know for sure?.....jesse

 

[shotgun]

Both ride on the same side of the cam as far as I can tell .

I did look down a SBC block since I am not well versed in them.

Also compared a SBC HEI vs Pontiac HEI and the gears are cut opposite.

So it's just how the gears are cut. The oil pump also goes counter clock wise.

I always have to remember to set my drill in reverse when priming a Pontiac.

The engine it's self still spins the same way.

I think chevy got it "backwards". lol

 

[joe_padavano]

Also compared a SBC HEI vs Pontiac HEI and the gears are cut opposite. So it's just how the gears are cut. The oil pump also goes counter clock wise.

I always have to remember to set my drill in reverse when priming a Pontiac. The engine it's self still spins the same way.

I think chevy got it "backwards". lol

You are exactly correct. The distributor gears are helically cut, so simply reversing the angle of the helix on the teeth reverses the rotation direction of the distributor. Since the gears are helically cut, they impart a thrust force along the centerline of the camshaft. Reversing the direction of the gear teeth also changes the direction of the thrust force. That's why some engines need cam thrust bearings between the cam and the block and others need thrust buttons between the cam and the front cover.