rotorwrench
Well-known member
My old 49 thru 51 Lincoln/Mercury O/H Manual states 55 PSI for oil pump output pressure. This should be the same for all of the 8BA family of engines.
80# Oil Pump Upgrade
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awelker
Member
The flat on the pressure relief valve on the early engines is to oil the cam gear to block thrust face. As Bored&Stroked said this was eliminated on 8ba when they changed the thrust into the timing cover. With early timing gears it is good to have some oiling to the thrust face. I leave the relief valve out and install a squirter directed at the thrust face.
Talkwrench
Well-known member
I'd be interested in more info too as I have tapped the holes for grub screws in my new engine as I'm running the 'new' style pumps. I was just going to block them off, Cant see how the engine would leak?
Absolutely no need for 80# oil pressure! 80# does not lube any better than 30# or 40#. The actual lubrication of a main, rod or cam bearing is the hydrodynamic effect, where a rotating shaft pulls oil around with it and creates a 'wedge' of oil between the shaft and bearing. The oil pump just keeps the bearing supplied with sufficient oil so the shaft can maintain that 'wedge' of oil.
flatheadmurre
Well-known member
Rule of thumb is 10psi/1000rpm so stock shortbody setup will be enough for a pretty healthy flathead.
The statement that pressure doesn´t matter as long as you have oil getting into the bearing might work if it wasn´t for other issues like cavitation.
tubman
Well-known member
Again, the term 80# pump doesn't mean it puts out 80 psi. It has the potential to put out that much, but it will only supply what the relief spring allows. The beauty of running one of these in an early engine is that if you leave the stock relief valve in the valley and it is operating properly, you will have the oil pressure that the Ford engineers originally designed the engine to run at. Using modern, more efficient components is usually a good. idea.
And, "JSeery", I've been thinking about it, and I can't get my head on why a pump capable of 80 psi, but "blowing off" at 50 psi would take any more energy to turn than a pump capable of only 50 psi. A larger pump or one of a different design, maybe.
And, "JSeery", I've been thinking about it, and I can't get my head on why a pump capable of 80 psi, but "blowing off" at 50 psi would take any more energy to turn than a pump capable of only 50 psi. A larger pump or one of a different design, maybe.
JSeery
Member Emeritus
The oil pump is a totally mechinical device. A rod driven by gears drives other gears. The rate it is turning is determined by engine RPM. Nothing varies based on engine demand, system pressure is controlled by relief valves. Excess volumn is dumped. This excess flow which is just dumped is wasted energy. Ideally oil pump output would match engine requirements, but that would be difficult to achive. So the pump produces excess flow and then using a relief valve assures flow requirements are met. With the so-called #50 pump you can increase system pressure by increasing the relief valve spring, so there is excess flow out of the pump already. Not sure what additional flow from a higher output pump is going to do if you are just dumping more oil at the relif valve, you are just comsumming more energy at the pump for the same results downstream of the relief valve.
High flow oil pumps are beneficial in high performance applications when the bearing clearances are opened up. Additional oil flow is required to maintain the required oil film layer.
High flow oil pumps are beneficial in high performance applications when the bearing clearances are opened up. Additional oil flow is required to maintain the required oil film layer.
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tubman
Well-known member
Doesn't this violate the principle of conservation of energy? Anyway, I've been doing a little research on pump types. It's kind of hard to ferret out, but it seems that helical gear pumps are more efficient than spur gear pumps. The fact that Ford went to helical gears in the later pumps that are shorter than the straight cut gears in the early pumps, while increasing the pressure in the engine, seems to back up this conclusion. Thus, there is probably less energy consumed by a late pump blowing off through the relief valve at 50 psi than an early pump.
I'll go out on a limb here and say that going with a late pump but still using the stock relief system is probably the way to go on an early engine. For all intents and purposes, the relief valve in the pump will never come into play in this scenario. The engine will get the same amount and pressure as the stock system, but with a little less energy expended to drive the pump because of it's inherent efficiency.
JSeery
Member Emeritus
LOL, that's the whole point! More energy required in one place (oil pump) has to come from somewhere (drivetrain). I really don't know about the pump design efficiency point (straight gears vs helical gears), that may well be a factor. I was just referring to oil pumps and oil pressure in general on any engine. It would be interesting to see if there is any dyno data on the topic.
flatheadmurre
Well-known member
The deplacement of the pump is increased in 3 steps.
1. short straight gear
2. long straight gear
3. long helical gear.
Increased deplacement at same pressure takes more power...but...
The helical gears give you less pressure ripple, increased flow and less cavitation at high rpm(not much of an issue for stock).
A helical gear pump takes less energy compared to a straightcut since it runs smoother(you actually feel the difference hand priming them (yes it doesn´t work on flatheads but on other brands not to be mentioned)
1. short straight gear
2. long straight gear
3. long helical gear.
Increased deplacement at same pressure takes more power...but...
The helical gears give you less pressure ripple, increased flow and less cavitation at high rpm(not much of an issue for stock).
A helical gear pump takes less energy compared to a straightcut since it runs smoother(you actually feel the difference hand priming them (yes it doesn´t work on flatheads but on other brands not to be mentioned)
Brian
Well-known member
rotorwrench wrote; My old 49 thru 51 Lincoln/Mercury O/H Manual states 55 PSI for oil pump output pressure. This should be the same for all of the 8BA family of engines.
The Lincoln 337 pump is a monster, much bigger than the 8BA. And I use one of these in my 21 stud, have done for years, in conjunction with stock front mounted relief valve. I'm not saying its right or wrong, but to answer the original posters query, yes, you can run an 8BA pump in a 221.
The Lincoln 337 pump is a monster, much bigger than the 8BA. And I use one of these in my 21 stud, have done for years, in conjunction with stock front mounted relief valve. I'm not saying its right or wrong, but to answer the original posters query, yes, you can run an 8BA pump in a 221.
rotorwrench
Well-known member
The 337 oil pressure output was listed differently in the manual. It's normal output pressure was listed as 45-55 PSI.
To Add about gears: The straight gear pump would have the same displacement as the spiral gear pump if the dimensions of the gears and case were the same volumetrically. Output should be the same in this case. Spiral gears tend to have a thrust load due to the shape where straight gears don't but spiral gears tend to be more quiet in operation where straight gears tend to make some noise. The thrust loading may have been an important factor in the design using the spiral gears depending on where the ports are in the pump case. It may have also just been more quiet.
To Add about gears: The straight gear pump would have the same displacement as the spiral gear pump if the dimensions of the gears and case were the same volumetrically. Output should be the same in this case. Spiral gears tend to have a thrust load due to the shape where straight gears don't but spiral gears tend to be more quiet in operation where straight gears tend to make some noise. The thrust loading may have been an important factor in the design using the spiral gears depending on where the ports are in the pump case. It may have also just been more quiet.
Ronnieroadster
Well-known member
The relief valve on an early block is just dumping oil. However the relief valve on the oil pump is not dumping oil its recirculating it into the inlet /suction side of the gears. The actual dumping in the pump is just feeding the gears in effect.
Talkwrench
Well-known member
I am fascinated by this chain of discussion, I found my oil filter on 1935 Roadster was on the underside of the floorpan and the OUT connected to the pump. I have now fitted a Hildebrandt filter housing on the firewall and think it better to connect the pump hose to the filter IN port. Am I wrong? Do I need change the pump? My block is a 1942 -1948 Mercury Core & Crank Bore 3.370inch x 4-inch Stroke = 4686cc 285 cu.in.
34PKUP
Well-known member
Perhaps a clarification as to whether you are using a full flow or by-pass filter system would help others understand.
Pete
BANNED
Stock engine - stock pump.
Modified engine with more bearing clearance and bigger bearing loads - bigger pump. M15 or equivalent.
The 8ba oils the cam and distributor drive gears through an oil hole in the nose of the cam which is fed from the front cam journal.
A stock flathead oil pump can easily be made to show over 100 lb. on the gauge if all you want is a gauge reading. You won't go any faster that way.
Modified engine with more bearing clearance and bigger bearing loads - bigger pump. M15 or equivalent.
The 8ba oils the cam and distributor drive gears through an oil hole in the nose of the cam which is fed from the front cam journal.
A stock flathead oil pump can easily be made to show over 100 lb. on the gauge if all you want is a gauge reading. You won't go any faster that way.