oil system improvement?

S

skata

Donating Member
what can be done to a motor to improve the oil system?
are there certain oil passages in the block that need modification?
are there different restrictors or bypass valves that improve flow?
what is the best oil pump to use and what volume and what pressure springs?
also, is the stock oil cooler sufficient? what's the best way to add a additional cooler?
is the oil system in the syty's the same as regular 4.3's?

i'm just full of questions. :)
 
nightdiver

nightdiver

Active member
Well, the oil cooler can flow shit. Five years ago a cutted the oil cooler to see how its made inside. Its called restriction.
I deleted the MF and bought a big one from a friend that has spare parts for military vehicles.The cooler i got has extreme flow and it comes from a french tank.
Now for the improvement you mention i deleted the bypass valve located in the block.Im sure one valve is enough
Be sure you get the oem ac oil filter and when you check your oil system remember that the pump sends the oil to the filter, then to the cooler and then it goes to the oil gallery ...pretty far imo
I think that we dont need a HV oil pump cause the same pump feeds the small block too,(but i always use a HV pump,you know ..just in case...)
 
myclone

myclone

Donating Member
Just my opinion.

oil pump:

Melling (Jegs part# 689-M55A)

Oiling system mods(basic):

Debur/smooth oil outlet on lower half of oil pump. Chamfer this outlets opening where it meets the main cap.
Do the above to the rear main cap where pump bolts on as well.
Tack weld pick up to pump(remove bypass while you do this)
Use one piece pump drive(Jegs part# 070-134-7901)
Remove bypass in block under the oil cooler adaptor and install 1/8" washer under spring or heavier spring(I do the washer thingy myself, its easier). Reinstall bypass.

Oil cooler:

IMO the stocker is fine IF you dont spend extended periods of time at WOT(Im talking miles/minutes of WOT). If you do it will prolly get over whelmed eventually but by that time the coolant temp has prolly been long over heated as well as the trans.

Oiling mods(not so basic):

Drill main bearing oiling holes in block to match holes in bearings or vice versa(whichever is larger).
Debur oil drain back holes in heads and block.
Add 2 more oil holes to upper main bearing evenly spaced and cut slot in main saddle on block from center oil feed hole to supply oil to the extra holes in bearings.
Make sure oil galley plugs in block located at either end of the cam dont protrude into oil galley partially blocking it.
Chamfer main and rod oiling holes on crank with more chamfer on the trailing edge of rotation(hard to explain that one).

Prolly more but thats off the top of my head. Oh, and no flames from you anti bypass ppl. K? :)
 
L

Lynn D. Brown

New member
Oil system mods

Oil system mods

From what I've heard, we have a pretty good oil system,
certainly compared to the 3.8 L engine (the one on the GN),
so I'm not sure I would tamper with it. The Cooling system,
on the other hand is a different story. It's hard to get too much
cooling for these hot beasts.

A few people have gotten into problems w high flow oil
pumps because the high flow rate can actually drain the
oilpan at high rpms and actually cause temporary starvation.

I may be experiencing that w my GN w its woeful oil system.
 
myclone

myclone

Donating Member
Re: Oil system mods

Re: Oil system mods

Lynn D. Brown said:
From what I've heard, we have a pretty good oil system,
certainly compared to the 3.8 L engine (the one on the GN),
so I'm not sure I would tamper with it. The Cooling system,
on the other hand is a different story. It's hard to get too much
cooling for these hot beasts.

A few people have gotten into problems w high flow oil
pumps because the high flow rate can actually drain the
oilpan at high rpms and actually cause temporary starvation.

I may be experiencing that w my GN w its woeful oil system.
Click to expand...

Draining the pan can happen. Using the "true" high volume/high pressure pump(uses a larger diameter BBC pick up) can do it. BTDT. BUT... It happened at high RPM(8k+).

In my experience I switched to the Z28 pump that used the smaller SBC/stock 4.3 pick up and never had another oil pressure prob. My theory was that the smaller pick up dia would restrict the amount of oil the pump picked up to keep the pump from draining the pan as fast(and I didnt enter any more burnout contests :wink: )

IMO it depends on what your gonna do with the motor. A HV/HP pump requires a larger capacity pan. Ditto for high RPM for extended periods with just the reg HV pump. The stock pump would prolly suffice in a NA application all the way to 6k RPM but I wouldnt do it personally. A stocker with just the Z28 bypass spring added would be better. If you want to do high RPM/extened WOT blasts then add pan capacity and the HV/HP pump with the BBC pick up.

The Z28 pump is cheap insurance and a tad larger than the standard pump is why I use it. I dont think Ive put togeather a SBC or 4.3 in recent years that I didnt use it. Even in a stock rebuild.

Stock pump is fine for stock/close to stock RPM levels but a little better with the heavier bypass spring.
Z28 pump would take care of all but the most radical builds and uses the stock pick up.
HV/HP w/BBC pick up would be for the most radical builds.

The oiling system could be better on a stock block IMO. It doesnt have priority main oiling like the SBC. I wish the 4.3 would accept the bigger SBC filter instead of the AC 52 sized. The bypass in the block opens with VERY little pressure. Ive never measured it but the spring collapses with, at most, 5lbs pressure using the trusty two fingered spring pressure tester :wink:

As for the buicks... Id gladly put up with that oiling system just to get the rolled fillet crank and the strong enough for pro mod rods theyve got.
 
jwaller

jwaller

Evil Genius/SyTy Guru
if you guys ever used a oil temp gauge you would notice that the oil temp directly follows eng temp...bc they are hooked together....

.but if you also notice you make the most hp when the oil temp is 200-225...so I removed the oil cooler and what do you know I still can't get the oil hot enough.....oh well, it's better now.. it takes a long time for my eng oil to heat up so for you guys who do nothing but sit in the lanes and cool down... only running your truck for 30sec-1min before racing. this may be a good mod for you.

just removed the lines and used a standard oil filter relocator that was on the 4x4 jimmy's..also switched radiators so that the oil cooler wasnt a restriction on the eng rad...seems the rad has a little easier time of keepin the motor cool now.
 
myclone

myclone

Donating Member
canadian said:
is it a custom radiator or a stock replacement from a different truck
Click to expand...

My guess is a S truck rad for a 4.3 2wd (with auto trans if he kept the trans cooler).
 
jwaller

jwaller

Evil Genius/SyTy Guru
I wouldnt use one at all....but if you must, use the stocker. if you dont like that then use the B&M 28k race trans/oil cooler. thats what I have in my tow vehicle.
 
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