Thread: With these clearances what oil il pump do you recommend?

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Hello Everyone,

I have been putting together a SBC 350 ( 30 over, approx 350hp) and using telescopic gauges and an outside mic.

I have the following clearances Crank to Main Caps:

0.0027 across the 4 caps and the third cap having .0037.

On the rods i have have

R1 0.0019 ( using plasti gauge i got 0.0015)
R2 0.0030 ( using plasti gauge i got 0.0030)
R3 0.0022
R4 0.0029
R5 0.0023
R6 0.0023
R7 0.0023
R8 0.0030

Would these clearances warrant a HV oil pump? If so do i need a pan larger than 4qts?

Thanks

FerrariChat.com - FAQ: Motor Oil Articles by Dr. Ali E. Haas (AEHaas) Do not know if this is on this thread but very interesting reading, Pete

A high volume pump is IMO a poor substitute for properly fitted bearings!!!! Is the crank this far off, rods not resized, or cheap bearings????

I'd agree with Dave, it seems like we see more problems brought to light here from high volume oil pumps than success stories, but then maybe the guys using them without problems just don't sing their praises. Seems to me that you need to have your crank & rods cleaned up and get the right bearings like Dave suggests.

PlastiguaGE IS THE POOREST CHOICE OF ACCURRATE MEASUREMENT

telescopic gauges are probably the second worst

However-since you have different measurements on all the journals except 5 &6, I would say your rods are probably not equal---------

As far as the hv pump on a four quart pan-no-------you will pump it dry before the oil has a chance to return to it--if you want a hv pump run at least a 8 qt pan

as for the clearances you have they are within an acceptable range except your #3main(You didn't mean #5 cap did you? if so that one is ok also ) You can take the main cap and on a precision flat surface face off the mounting surface til you get a more acceptable clearance or------------take the block to a shop for align honing and recondition/ resize the rods-

And as a note for everyone about high volume pumps----many of the fastest BBC racers of years gone by used to run a small block pump as it was smaller and took less HP to turn-----------

High volume pumps and heavy weight oil are no substitute for correct clearances! As Jerry mentioned, it would cause a whole lot more harm then it could ever do good!

Originally Posted by jerry clayton

PlastiguaGE IS THE POOREST CHOICE OF ACCURRATE MEASUREMENT

telescopic gauges are probably the second worst

However-since you have different measurements on all the journals except 5 &6, I would say your rods are probably not equal---------

As far as the hv pump on a four quart pan-no-------you will pump it dry before the oil has a chance to return to it--if you want a hv pump run at least a 8 qt pan

as for the clearances you have they are within an acceptable range except your #3main(You didn't mean #5 cap did you? if so that one is ok also ) You can take the main cap and on a precision flat surface face off the mounting surface til you get a more acceptable clearance or------------take the block to a shop for align honing and recondition/ resize the rods------------

yes i was going to say that .. just no way in hell are your going to get a repeat with a snap gauges . need to get the repeat and take out the feel that can add -or+ 0005 easy on any thing you check or more . the only way is a dial bore gauge . so if your at or under .003 you could buy some .001 bearings or like jerry said sand the cap on something dead flat but you need a way to check how much your taken off so you need a bore gauge. the GM pump to use is the 3/4 pick up .or a melling m155 stock 3/4 pickup pump.used on the new 350s the only way i ever got them at to .002 was put the housing bores on the rods on the small end of spec . put the bearings the block and rods and grind the crank for oil clearance i wanted .so very few came from GM this way and after some miles and a crank polish. jerry knows well about the makers of bearings as well as i do to be all over the map for size