That’s GREG Long who just wrote a Service Bulletin article just for you and is arguably the best tech person in the Society and unquestionably the most willing to spend time helping us all out. You guys in the eastern time zone are yakking away while we on the Left Coast are still inspecting our eyelids for light leaks.
Ron, you might consider waiting for March 2021 for the next heavily-discounted Optima offer. I use a pair in parallel in my 8-cyl cars, and a pair fits easily in the factory battery box. The advantage of Optimas for underseat/underfloor locations is that they are sealed and never need distilled water, won’t outgas (unless greatly overcharged and the vent pops open), and needs far less cleaning of battery terminals. Mine can stand over the winter without a maintainer and start without issue. Yes, Optima makes only one 6V battery. I average 9 years of service before I replace mine–in pairs, as we do on diesel pickups.
IMHO, the best thing you can do now is DRIVE your car. Try to make the majority of your trips at least 45 minutes so everything gets up to temperature.
I know many old car guys swear by the optima, but as Greg says, there is only one 6v size available. and it is 1/2 the size of the original in a Pierce. While its technology manages to put out almost as much current -800 cold crank amps- it still is only rated at 50 amp hour capacity, compared to the 140 a-h of the big original. That means it will crank the engine less than half as long if it is having starting issues. Of course you will burn the starter up if you just crank continuously until it goes dead. Some have put two optimas in the tray in parallel to double capacity, but there can be issues charging two batteries hooked up in parallel. The big 6v from NAPA puts out 880 cca, is $111 and mine have actually consistently lasted 5 to 6 years – why I don’t know because I do no maintenance on them and until recently never trickle charged them.
Jim, the reserve capacity (RC) of EACH 6V Optima is 100 (i.e., 100 minutes at 25 amps) which is my primary reason for using a pair–running at night with a charging deficit. I’ve used Optimas exclusively for 20 years now. I *think* there’s a difference in how Amp-hrs (AH) is calculated these days vs the 1930s. When I began using Optimas their labels showed 100AH, meaning that a *pair* had 200AH vs factory Group 3 (8-cyl P-As) at 140AH and Group 4 (12-cyl P-As) at 165AH.
Optimas do not like to be fully discharged. My experience is that if an Optima has been discharged to less than approx 5.8V, it must be connected in parallel to another 6V battery (wet cell or an AGM like Optima) which is at least 6.1V to be brought back by charging.
Some folks (like Ed Minnie) run a pair in the battery box but only one connected, and will switch if a generator fails. (A couple of years ago, Tony W’s generator failed on a tour, so I removed one of the two Optimas from my 1934 and he used it to drive home on.)
And a pair in parallel spins the starter like 12V!
I run a single Optima (each) in my Series 80 (289 cid) and in my 48-B-5 (525 cid) but both have reduction starter motors and don’t see as much night driving as my 8s.
I’m not contesting your choice, but want to share the rationale of Optima fans.
Sorry,trying not to be too argumentative, but just to do a more apples to apples comparison, the NAPA website sells both BCI-4 and redtop batteries, and so one can compare the specs directly and should be comparable to current standards. Cold crank amps for the BCI 4 is actually listed at 975 vs 800 for Redtop, so yes, two redtops in parallel would give potentially 1600 CCA which would keep the voltage to the coil a bit higher when cranking the starter. A single redtop would gave a bit more voltage drop due to the amperage rating. The reserve capacity for the BCI-4 is listed as 250 minutes compared to 100 minutes for the redtop, so a bit more than 2 redtops in parallel.
I think the primary advantage of the Redtop is the technology allows a higher amperage capacity relative to the size of the battery and I understand they are supposed to last longer. The total energy available (amp hours x volts) I think is still pretty much a function of the volume of lead and electrolyte contained in the battery, similar to a 12 gallon fuel tank is only going to take you half as far as a 24 gallon tank regardless of the fuel pump max flow capacity. As long as the tank keeps getting filled up before it is empty (the battery recharged) you don’t have a problem.
I have had a regulator fail on my Packard and driven home about 200 miles on the single big battery. I also had to take the Packard to participate in my daughters wedding 60 miles away the day after the generator failed (3rd brush shot), and managed to do all the starts and some night driving on a single charge. I carried the Pierce’s battery in the trunk just in case, but didn’t need it. A long time ago I was on my way for the first time to a PAS meet at Monterey with my ’66 T-Bird and the generator failed. Drove to the meet and then all the way home about 300 miles on one charge on a fresh battery but didn’t use the AC.
Having two batteries of 1/2 the capacity does mean you get a good idea of when you have expended 1/2 your capacity and how much further you might be able to go on the last half.
You pays your money and takes your choice!
I have decided to switch to an electric 6 volt gas pump. Can anyone recommend a quality pump I can install in my Model 54?
Hello Ron. I would not recommend changing to exclusively an electric pump. I do recommend having an electric pump to prime or fill the carburetor after the car has not run long enough that the carburetor is dry.
The Carter 6v motor-type pump is what seems to be the best, most reliable. Do not bother with the inexpensive vibrator type pump, they just do not work for very long with ethanol-tainted gasoline. The Carter pump is an electric motor running a vane-type pump. They seem to be the best and most reliable.
The reason I would not recommend using exclusively an electric pump is that they use a fair amount of the meager electricity our generators create, so night time driving is even more of a drain on your battery. The electric pumps do wear out eventually. and when they do, the car is dead. So you need to carry a spare if you rely exclusively on an electric pump. And they are annoyingly noisy.
The factory mechanical pump works well enough to run the engine at higher speeds. If you encounter vaporizing fuel problems, then an electric pump is an asset to have to push fresh fuel through the hot mechanical pump, which clears the bubble of vapor that has the fuel pump ‘locked’.
The Carter pump with a vane type pump has to have a bypass around the pump. This is because the motor and pump can stop in a position where fuel cannot be drawn through it by the mechanical pump. So a bypass loop around the electric pump is required. And a one way check valve in the bypass loop is required, to prevent the electric pump’s fuel flow to just make a loop back to it’s own inlet. The check valve makes the pump’s flow go to the engine.
Do a search on eBay for ‘Carter 6volt fuel pump’. The pump’s part number I just can’t remember right now. The usual price is around $75.
Greg, I found your August 15 Post very informative. I am going to keep the “factory mechanical pump” as your suggested (which was recently rebuilt by Art Gould). I am considering purchasing a Carter electric fuel pump 6 volt 72pgh “P4259”. I noticed on the spec page that the pump’s fuel pressure is 6-9 psi. Is that too high? I shall install the pump with a bypass loop and check valve (one way). Any other suggestions?
Ron, the P4269 pump *is* the Carter pump but with a NAPA number. I have had them in my 1930 and 1934 for over 12 years with no issues. If you use rubber hose in and out, spend the extra money for R9 hose (SAE 30 R9), high pressure hose, which is much more robust than SAE 30 R7. I use a high quality pressure adjustable regulator, Holley #12-804, about $65, to reduce to 3-3.5 psi. (Avoid the $20 bubble pack “Purolator” regulators which will fail and leak gas sooner more often than later.)
You do indeed need a bypass and a check valve. You also need to design your electric power source given the Startix. I did not want the 7-9 amps for pump running through my ignition switch, so installed a relay–but it’s not correct yet on my 1934 with Startix. You want to have power to the pump for priming, perhaps through a momentary switch, before you turn on the ignition switch and automatically engage the Startix. And then have the option of powering the pump under vapor lock conditions. Greg or someone else here can give you better info on that and I will listen attentively 🙂
I designed my installation so that a modern inline fuel filter, EASILY ACCESSIBLE ON THE ROAD, is between the fuel tank and the first tee.
Hi Ron, I second George’s statements about a switching setup and filter location.
First the filter: Gravity never sleeps: if you have to work over your head or from underneath a fuel filter, you WILL get gasoline running down your arms!! So figure out a location to put a see-through inline fuel filter that you can inspect and change from ABOVE the filter. Locations vary with body style.
Next: a three position switch: ON-OFF-Momentary. This is what you want to power your electric fuel pump. And I like to have a light attached to the ON side, so you will KNOW that the pump is being powered. This is important because what George stated is a valid concern: adding the 7-9 amps of current through the original ignition switch is pushing your luck and the limits of capacity of the old switch. So the switch should be powered from the unstitched battery main wire to the ammeter. If you left the switch in the ON position, you would likely drain your battery in short order.. The momentary side does not need a light, it should turn off when you remove your finger from the toggle switch lever.
With a momentary switch, you can push on the lever and listen for the pump, it will spin at a high rpm when the pump is filling the carburetor’s float bowl. Once the bowl is full, the needle valve closes and the fuel pump has nowhere to push the fuel, so it slows down noticeably. This is my indication I use to stop priming the carb, and then pull full choke, 1/2 timing retard, and use my foot on the throttle, and flip on the Startix. A couple of pumps on the throttle pedal also help.
The pressure regulator on the outlet of the Carter rotary is mandatory. It will pump 8 psi and overwhelm the float valve which will overflow the carb and pour raw fuel over the exhaust manifold. A fire I have witnessed.
As I mentioned in my PASB vapor lock article a couple years back I found the thumper pumps barely might work when new, but not for me. Airtex also sells the big 6v rotary that appears to be identical to the Carter. They are way oversized for our cars, but get the job done. If the pump is set up at the back and the engine driven pump must suck through the check valve it has a definite cracking pressure drop that can increase vapor lock problems. I avoid this by mounting mine across from the engine on the other side of the frame rail in parrallel with engine pump. There are schematics and tradeoffs of the differant setups in my articles. The lowest cracking pressure fuel compatible check valve I found at McMaster carr.
Sorry to add more to this long thread, but perhaps some notes on the fire I mentioned might be apropos. On a hot summer day tour we stopped for a break and when one of the drivers tried to restart it would just crank and crank. Thinking it was vapor locked he turned the electric pump on and kept pumping and cranking. It probably flooded first from percolation from the carb bowl through the main jets and then the accelerator pump. Soon smoke started coming up and flames out the hood vents. Fuel was running down the carb and manifold. Quick action by members with fire extinguishers got it out with just damage to the hood.