Patman ??

[carl97ss]

Is the only difference between the ac/decl pf-35 and pf-1218 the anti drain back valve? I knoticed the 1218 does not have an internal by-pass valve. does the pf 35 or 25 have one?

thanks!

 

[Patman]

The PF25 and 35 don't have bypass valves either, they don't need them since the GM engines these go on all have the bypass valve built right into the engine block.

So yes, the PF1218 is basically a PF35 with an antidrainback valve, so the PF1218 is the better choice.

 

[carl97ss]

My engine builder eliminated the engine oil pressure bypass valve. I'm running Mobil 1 0w40 here in Indiana. on the cold mornings, under 20F, cold idle (875 rpms) oil pressure is 58 psi and hot it's 42. going down the road, cold 72psi, hot 62psi. I have a melling high pressure oil pump. the engine is a bored and stroked LT1 to 396 c.i. making 485 h.p., 495 ft/lbs of torque.

With no pressure bypass in the motor or the oil filters, would you worry about oil starvation w/ a cold motor?

My engine builder says they have never had a cold start oil starvation problem...FYI...I've had low wear metal counts via two of Terry's oil analysis.

 

[OneQuartLow]

My bigmotor experience is dated but I'd also worry about collapsing the filter media/core, definitely with a high-volume pump. What's the builder think about dual mounts or monster filters? (ala cmfilters) They would have put some thought into their choices.

David