Oil pump and timing chain questions

[furyus2]

Guys, when installing an oil pump in a 340 small block, should there be a gasket between the pump and rear main where it bolts to? Eberg says no gasket or it will blow out. What are your thoughts.
On the timing chain, I've read a lot and am confused. Do I align the gears with the cam at 6 O'clock and the crank at 12, or do they both need to be at 12 and if so, why? Thanks

 

[krazykuda]

Yes, use a gasket on the oil pump. It won't blow out. Mancini racing sells gaskets for them single for $6. You can also make one yourself with gasket paper.

Timing chain. Align the marks with the cam at 6 O'clock and the crank at 12 o'clock, the crank keyway should be slightly on the right of the marks at about a 30° angle. I find the easiest way to to that is to install the chain and gears together and line up the marks using a thin screwdriver or sideways ruler going through the center of the gears and then line up the marks to it. Then turn the crank and cam to where you can get the chain and gears on without disturbing your setting. You may have to turn the cam and or crank to do this. Then after the chain and gears are installed, verify the marks again. Remember to use a straight edge and pass it through the center of the cam and crank bolts, and then look for the marks to align up at 12 o'clock on the crank gear and 6 o'clock on the cam gear. The crank keyway should be about 30° to the left of the crank gear mark at 12 o'clock.

 

[TrailBeast]

Just so you know, they can be put in at 12 on the crank and 12 on the cam but you would then have to turn the distributor or wires 180 out.

I do that sometimes just to screw with people that think they know what they are doing.
I won a hundred bucks doing that one day as the owner of the car bet me it wouldn't run. (He lost)

 

[63dartman]

it is easier to line the marks up with the marks at 12 and six. Once the chain is on your at TDC for #6. Just rotate the crank one revolution until the crank and cam are both at 12 o'clock and you will be TDC for #1.

 

[furyus2]

Thanks, I did it at 6 o'clock. I feel better now. Thanks for the replies.

 

[crackedback]

I never use a gasket on the oil pump to main cap junction. I've had them blow out before and it's tear down time.

It's best to degree the cam, lining up the dots leaves a lot to be desired with the rotten tolerances of products these days. Timing sets that are 8* retarded with the dots lined up, etc.