Orientation of oil pump drive slot

[headejm]

Question for all the BB engine experts...this is on a 383.

Should the oil pump drive slot be "exactly" parallel with the centerline of engine at TDC compression stroke? Can it be a couple of degrees off? I've installed my gear several times and cannot get to "exactly" parallel.  I'd say mine is 1 - 5 degrees off of parallel.

[anlauto]

Yes I  would say it's slightly off of  perfect parallel

DISCLOUSURE: I'm not an expert.

[Chryco Psycho]

This is a guideline , what cam are you running ? if it is not the exact factory grind on the original blank then who says the position of the gear ground onto the cam blank is exactly 100% accurate or is the oil pump drive gear exactly accurate if it is not the factory drive , for example this may affect the exact rotation of the dist by 5-6* to get the timing correct & really has no effect on anything .
Just install the drive get the dist pointed correctly for #1 firing & wire accordingly & adjust the timing so it runs best !

[71383bee]

Agreed. I think what matters most is #1 firing on its compression stroke. For initial fire up I try to set it at 10 degrees btdc.  At least it's got some  initial to help her run and then dial it up for break in.

I think they focused on the slot orientation so the vac advance on the distributor was placed in a way that timing adjustment could be made without hitting the firewall or something. Also it helps to standardize things that #1 was always at or near a certain position.


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[ply64post]

headejm

This should help you.

            Jeff

[RUNCHARGER]

"I think they focused on the slot orientation so the vac advance on the distributor was placed in a way that timing adjustment could be made without hitting the firewall or something. Also it helps to standardize things that #1 was always at or near a certain position."

Yup, this is whats I have always figured.

[anlauto]

I agree Sheldon, but on a 383, if your vacuum advance is hitting the firewall, you got way bigger concerns 

[RUNCHARGER]

Well: I have seen a few like that but the psgrs didn't usually survive. On a Hemi you only have a small area for the vacuum can to fit as well. I imagine when the engines were assembled it was pretty easy to check that the oil pump drive was correct when the engine was at TDC as well.

[headejm]

This is a guideline , what cam are you running ?

Lunati 102

all for the (typically) great responses!

[Chryco Psycho]

102  or 702 ?