Question about dry sump set up.

[jkm333]

Hello all,

I have a little M Dart SBC iron block in the shop today. I am in the process of plumbing it for dry sump (5 stage) and have a question about the drilling of the block. There is a boss cast on the right rear section of the block above the bell housing lip. According to Dart (who has not been much help in the tech dept.) this can be drilled and tapped from the top to scavenge oil. It is still unclear to me wether this should intersect an oil passage beneath the boss or a hole drilled into the lifter valley?

I did not think drawing off an oil passage of any sort would be a good idea. This passage I speak of ties to both lifter passages (left and right) as well as the main oil passage coming out of the oil filter mount which has been relocated by dart from the original location that GM used which is down the center of the lifter valley and now sits to the left of the left lifter passage still traveling parallel with the block. Drilling into the lifter valley I suppose I would aim low to collect as much oil that puddles there. I did speak with Peterson who is making the oil pump and they see no problem with that line occassionally drawing air since the intake there would not always be submerged. FYI, I plan to scavenge my 3 out of 4 draw lines from the pan and my one feed can go to either of the pre drilled and tapped holes in the block located at the front and the rear. And of course the last scavenge line - which is the one in question here. Thanks in advance for any help yall may be able to provide.



Josh

 

[icrman]

You would not want to drill into a pressure supply oil passage. Because there is nothing to scavenge there. If you scavenge that then no more lube pressure.
If they recommend drilling the block it is most likely like you have said to scavenge the lifter valley. Which I'm sure is common practice. And then of course the lowest area in the engine.
If they are talking about drilling into main gallerys then it would be to supply additional oil not to scavenge it.
I would think that the manufacture of your dry sump system would have a help line, to answer questions.

 

[WilliamH]

Josh,

Here is a short synopsis of what we do on a SBC block from GM as regards dry sump modification in the valley:

Install 3" tall pipes in all eight of the drilled drain back holes between the lifer bosses. Plug the front bulkhead drain holes (near timing gear). These pipes allow air to freely circulate but prevent oil from entering the sump area.

Plug the oil drain in the right rear of the valley and any other drain backs if present. Locate and machine a hole just above this location (right rear) for your dry sump pick-up. Be sure to epoxy a coarse screen over this pick-up to prevent errant valve train parts from getting into the oil line. This location by the way is below the bell housing flange. We manufacture a special fitting to clear the flywheel if needed.

Regards,
Will

 

[jkm333]

Will,

Thanks for the info, Peterson does not have much experience with this Dart block. This particular engine has one drain back hole at the front (timing chain area) and four elongated valley drains inbetween the left and right lifter banks running parallel with the motor. I suspect you recommend blocking all these while still leaving a raise area that is open for the crankcase to breathe? As for the fitting needed to clear the flywheel, I believe that since I have the cast boss ABOVE the bell housing area that I will be able to tee into my lifter valley hole from above. I think this was Dart's original intention, they just did not have the tech support nessessary to inform me of that - not a big deal. I will also be sure to screen my pick-up at the valley.

Josh