SBC 0il pumps

General engine tech -- Drag Racing to Circle Track

Moderator: Team

rebelyell
Expert
Expert
Posts: 752
Joined: Mon Dec 03, 2018 8:46 am
Location: SOUTH CAROLINA

Re: SBC 0il pumps

Post by rebelyell »

No matter which type pump --- do use or opt for one with the larger 3/4" OD pickup tube port.
There's good reason GM chose to do just that for all production sbc beginning early 1990's --- the larger OD tube helps to feed the pump which has less than stellar abilities to feed itself --- it pushes oil far better than it does suck oil. With that aspect in mind, an M155 is somewhat better than an M55.
RDY4WAR
Expert
Expert
Posts: 516
Joined: Tue Jun 20, 2017 12:58 am
Location:

Re: SBC 0il pumps

Post by RDY4WAR »

ClassAct wrote: Sat Nov 19, 2022 11:29 am
RDY4WAR wrote: Sat Nov 19, 2022 10:30 am
Little Mouse wrote: Sat Nov 19, 2022 10:14 am

I'm going to be using an eagle crank 3.25 stroke, I'm thinking .003 on the mains and at least .0025 on the rods, want it to make power to 8000 rpm. I have not bought heads and pistons but I'm considering using 49 cc chamber dart iron eagle with inverted dome pistons.
I would use a Melling M55HV. The clearances would be fine with a standard pump, it's the RPM that will want the HV pump.

Your clearances are fine. I would aim for .0012" per 1" journal diameter for something like that which isn't far off from what you have there.

The oil for that needs to have a high temp, high shear (HTHS) rating of ≥3.5 cP in a 5W-30 or 5W-40. I would also recommend a higher end synthetic and streetable race oil that'll have the boosted anti-aeration and anti-foaming additive content, as well as boosted friction modifier content, to help it out at high rpm. Red Line HP 5W-30/40, Amsoil Dominator 10W-30, and HPL Bad Ass 5W-30/40 would be good choices.


Just curious…why the .0012 per inch? It seems currently the trend is .0009 or even .0008 per inch. Is it the RPM or something else ??

TIA
For the RPM. I don't know exactly which block and crank he has, but I would want a little headroom to account for torsional vibrations. If the machining is precise, clearances are consistent, and it's balanced well, then .0008" per 1" is acceptable. It would allow a lower oil viscosity as well and free up a hp or two.
User avatar
Tom68
HotPass
HotPass
Posts: 2541
Joined: Mon Feb 07, 2022 3:43 am
Location: VIC OZ

Re: SBC 0il pumps

Post by Tom68 »

rebelyell wrote: Sat Nov 19, 2022 3:12 pm No matter which type pump --- do use or opt for one with the larger 3/4" OD pickup tube port.
There's good reason GM chose to do just that for all production sbc beginning early 1990's --- the larger OD tube helps to feed the pump which has less than stellar abilities to feed itself --- it pushes oil far better than it does suck oil. With that aspect in mind, an M155 is somewhat better than an M55.
The pump has no trouble feeding itself, it's submerged in oil, one of the SBC's strong points.

Windage trays are the important thing.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
novafornow
Pro
Pro
Posts: 205
Joined: Mon Feb 04, 2019 2:23 pm
Location: california

Re: SBC 0il pumps

Post by novafornow »

amc fan wrote: Sat Nov 19, 2022 12:32 pm If I remember correctly the small block standard oil pump flows more oil than a standard big block pump.
The advantage of the big block pump is it has more teeth on the gears, and it runs smoother, less spark scatter.
Thus the reason for the ST. Extremely smooth pump.
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: SBC 0il pumps

Post by 1980RS »

ClassAct wrote: Fri Nov 18, 2022 5:30 pm
1980RS wrote: Fri Nov 18, 2022 4:33 pm I just use the stock Melling pump as after I saw how much it took to drive the HV pump and figured out I don't need it.


What was the HP difference?
No hp was tested, was going by how much more effort it took to drive the HV pump over the std. pump. Was the same way on my BBC bumps also.
parkman
New Member
New Member
Posts: 10
Joined: Tue Sep 27, 2022 7:17 pm
Location:

Re: SBC 0il pumps

Post by parkman »

1980RS wrote: Sun Nov 20, 2022 1:04 am
ClassAct wrote: Fri Nov 18, 2022 5:30 pm
1980RS wrote: Fri Nov 18, 2022 4:33 pm I just use the stock Melling pump as after I saw how much it took to drive the HV pump and figured out I don't need it.


What was the HP difference?
No hp was tested, was going by how much more effort it took to drive the HV pump over the std. pump. Was the same way on my BBC bumps also.
Reeks of bad pump design and a hydraulic lock between the teeth.
amc fan
Expert
Expert
Posts: 598
Joined: Wed Jul 11, 2012 7:03 am
Location: BETHLEHEM PENNA.

Re: SBC 0il pumps

Post by amc fan »

Little Mouse A standard SBC oil pump outflows a big block pump. Call Melling and ask them. They probably won't give you the flow numbers but that is what my friend Jim Totenbier @ Superior Automotive Machine, Allentown Pa. who was a circle track oil pan builder/fabricator told me years ago...I had the flow numbers he gave me somewhere, but I can't find them. Size on the inlet tube of pump has great bearing on flow. Bigger is better! Oil is pushed not drawn into a pump.
Little Mouse
Expert
Expert
Posts: 859
Joined: Mon Oct 21, 2013 8:48 pm
Location:

Re: SBC 0il pumps

Post by Little Mouse »

More money but maybe I'll consider the 10 percent more flow 10555ST. Atleast it's not real high dollar like the billet pumps.
1980RS
Guru
Guru
Posts: 1636
Joined: Thu Oct 13, 2016 10:03 am
Location:

Re: SBC 0il pumps

Post by 1980RS »

I found a Moroso Pressure balanced BBC oil pump I bought in the 80's and never used it sitting in a box. Took it apart once, it's a blueprinted Melling TRW pump. Pretty cool, almost hate to use it.
steve cowan
Guru
Guru
Posts: 2253
Joined: Wed Jul 27, 2011 5:22 am
Location: brisbane AUSTRALIA

Re: SBC 0il pumps

Post by steve cowan »

Little Mouse wrote: Sun Nov 20, 2022 4:14 pm More money but maybe I'll consider the 10 percent more flow 10555ST. Atleast it's not real high dollar like the billet pumps.
I just ordered a shark's tooth with 3/4" tube,been running a stock mellings pump this year 383sbc
7500rpm 5 quart pan.
40psi oil pressure with 10" pan vacuum (45psi).
Motor out now and having a look everything looks good.
Plan on turning 7500rpm plus that's why I bought ST pump.
0.002" mains 0.0018 big ends.
5 w 30 nulon race oil.
steve c
"Pretty don't make power"
rebelyell
Expert
Expert
Posts: 752
Joined: Mon Dec 03, 2018 8:46 am
Location: SOUTH CAROLINA

Re: SBC 0il pumps

Post by rebelyell »

Tom68 wrote: Sat Nov 19, 2022 4:32 pm
rebelyell wrote: Sat Nov 19, 2022 3:12 pm No matter which type pump --- do use or opt for one with the larger 3/4" OD pickup tube port.
There's good reason GM chose to do just that for all production sbc beginning early 1990's --- the larger OD tube helps to feed the pump which has less than stellar abilities to feed itself --- it pushes oil far better than it does suck oil. With that aspect in mind, an M155 is somewhat better than an M55.
The pump has no trouble feeding itself, it's submerged in oil, one of the SBC's strong points.

Windage trays are the important thing.
At low-to-mid street revs, the smaller tube does have trouble feeding pump with a smooth, stable supply. Evidenced by the move to larger OD tubes. Perhaps ask the major pump manufacturers for further confirmation/guidance.
Agreed, windage trays are an important aspect as well as is pan-door-gate design.
User avatar
Tom68
HotPass
HotPass
Posts: 2541
Joined: Mon Feb 07, 2022 3:43 am
Location: VIC OZ

Re: SBC 0il pumps

Post by Tom68 »

rebelyell wrote: Mon Nov 21, 2022 2:56 pm
At low-to-mid street revs, the smaller tube does have trouble feeding pump with a smooth, stable supply. Evidenced by the move to larger OD tubes. Perhaps ask the major pump manufacturers for further confirmation/guidance.
Agreed, windage trays are an important aspect as well as is pan-door-gate design.
I'm gunna keep that 3/4 pickup pipe in mind next time I do a Holden V8, they have the oil pump up out of the oil on the side of the block and can give low oil pressure problems as well as needing the pump packed with Vaseline for 1st start.

Chevs I'm still not worried, at least up to large journal 3.48" stroke. Our Chev powered HK Holdens here came with a center sump pickup, so a longish 5/8 tube, the later ones actually had a swinging trap door, but even without that, 7000 rpm (SJ 3.25" stoke) Moroso windage tray as long as you want and idle around as long as you want, rock solid oil pressure, again 20W 50 days, not sure how it would handle the watery oil we use now, at least it will flow into the pickup tube easily.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
amc fan
Expert
Expert
Posts: 598
Joined: Wed Jul 11, 2012 7:03 am
Location: BETHLEHEM PENNA.

Re: SBC 0il pumps

Post by amc fan »

Industrial hydraulic pumps are all sized by cubic inches of oil displaced per revolution of the shaft. A one CID pump will put out 1 cubic inch of oil every time the shaft completes 1 turn. I would ask them what is their pumps output per revolution? This data should be available so you can make a decision.
The specific gravity of the oil will determine how much lift the pump will have.
Maybe we need someone on this forum to spin the pumps and verify the output.
I wonder if the YouTube guy "Project Farm" would be interested?
RDY4WAR
Expert
Expert
Posts: 516
Joined: Tue Jun 20, 2017 12:58 am
Location:

Re: SBC 0il pumps

Post by RDY4WAR »

A way to do it would be get a 1 gallon jug with clear markers for each quart, remove the oil filter, put an adapter in place with a hose from the block feed to the jug, and spin the pump with a drill. Hit a timer the moment the first oil hits the jug and see how long it takes to fill the 1 and 2 quart marks, then calculate the flow rate. The difficult part would be measuring the exact rpm of the drill.
amc fan
Expert
Expert
Posts: 598
Joined: Wed Jul 11, 2012 7:03 am
Location: BETHLEHEM PENNA.

Re: SBC 0il pumps

Post by amc fan »

I would use a VFD drive to control the drill.
Probably use a digital timer to start and stop the drive.
It would be interesting to see flow of the different pumps.
Post Reply