Fuel pump options

[Monzaguy]

Had a lot of stuff going on and my 65 Monza sat for 3 weeks. Went to start it and it cranks strong but no start. Was hoping that the gas just drained back, but while cranking I do not see any gas down the carb throat. Disconnected a fuel line from the DS carb and cranked some more, no gas coming out. Tank has gas in it. Checked spark with a tester and it is strong.
Thought about another mechanical pump, but it seems like they are hit or miss, mostly miss. Wouldn't mind the mechanical one if someone knows where a reliable one can be purchased. Clarks looks like they are out of them.
Checked out Clarks electric pump, but I still find their catalog a bit confusing. I think what I need is the Ultimate C10295 and the bypass plate C12879. Or is there another brand I should be looking at? I would prefer to go with a complete kit that has detailed instructions, and not have to chase parts. Also, does the old fuel line need to be flared at both ends where the pump connections are made? Thanks, Mark

[terribleted]

FYI Clark's fuel pump really has no detailed instructions either. It is a custom install which will vary depending on where you decide to mount it. I just mounted one a month or so ago in a 65 Corsa. I put it behind the bulkhead wall to the right of the tunnel. I made a hole in the side of the tunnel to accept the output fuel line and purchased a 90 degree street elbow fitting in the proper sizes to go to the input end of the filter which I routed forward through holes I drilled in the bulkhead. I then purchased a piece of 3/8 metal flared fitting line, cut it to the length I needed and bent it with my tubing bender into a nice S shape so I could connect the flare fitting to the street elbow and have the other end position directly behind the fuel outlet from the tank to nicely accept a regular rubber joining hose and a couple clamps. I have yet to do the wiring from the pump to my preferred safety device, which is an inertia switch. I will mount the inertia switch under the dash to the firewall or the heavy bracket that is part of the pedal assembly and then power it from an ignition switch source that is on only in the run position of the ignition switch (not on in accessory position).

Any electric fuel pump that delivers between 2.5 and 5 max fuel pressure can be used. A safety shut off of some sort should be put in the circuit so that in event of a major crash, rollover etc., the pump will shut off. One routine is a switch that only allows the pump to run when there is oil pressure present. This may not be effective after a crash if the engine keeps running. I feel that the inertia switch is a simple and effective way to do this. It must be mounted to something solid or it may turn off from vibrations. It must be mounted in an acceptable orientation per its instructions. These switches are resettable if disengaged for any reason by pressing a button on them. I also like to include a shut off switch in the circuit so the ignition can be in run without the fuel pump running. This basic on off switch can also be used as a theft deterrent if it is somewhat (or totally) hidden and turned off when the car is parked. We put one one time in a buddies Corsa hidden in the rear cowl. you had to reach in and around behind the rear wall of the cowl from the engine bay to turn it on and off. He died and eventually some Corvair guys went to try to start the car. They fiddled around for a while trying to figure out why no fuel and eventually figured out no power to the in-tank fuel pump (lol after they figured out the the stock fuel pump in place was a dummy using Clark's bypass plate). Finally they called me and I told the the location of the switch:)

As far as your current mechanical pump not operating there are a couple things to check before pronouncing it dead. First make sure the tank is not empty. Next check that the fuel pump is properly mounted with the retaining pin bolt properly indexed in the hole in the back of the pump base. Next make sure of the condition of the joiner hose between the engine bay fuel line and the main body fuel line as a crack or air leak here will allow the pump to suck air and not fuel. Lastly check that fuel can be drawn through the fuel lines to the engine bay. You can do this by removing the input fuel line from the fuel pump and applying suction to it to see if any fuel comes through (I do this with an electric fuel pump but if you can seal a turkey baster or vacuum source of some type to the line this will suffice. You could suck on it as well but fuel tastes really bad). If there is no fuel flow then the line is blocked or the in tank filter screen is plugged etc.

[Monzaguy]

Thanks again Ted. Definitely have gas in it, and it was running great before this, and I have not messed with the pump. Will try the suction thing. So the inertia device gets wired to the pump wiring? Sorry if its a dumb question but its new to me.

[terribleted]

Thanks again Ted. Definitely have gas in it, and it was running great before this, and I have not messed with the pump. Will try the suction thing. So the inertia device gets wired to the pump wiring? Sorry if its a dumb question but its new to me.

yeah when it gets shaken hard like in a crash it breaks the circuit.

[bbodie52]

Below I will include some illustrations to hopefully help you to visualize the checkpoints outlined above...

Personally, I have had very good luck with the original GM mechanical fuel pump reliability, and never had one fail in more than 10 Corvairs since 1961, when my parents purchased their first... a 1961 Monza coupe, UNTIL A COUPLE OF MONTHS AGO! I recently had the old mechanical pump die in my 1966 Monza Sedan. After having the car towed about 20 miles to my home, I discovered that my engine oil level had risen significantly, because an internal leak, or rupture was permitting gasoline to pour down past the pump pushrod and into the crankcase — not a good thing! After draining the fuel/oil mixture out of my engine, I decided to go electric. The post that the link below is tied to will explain some of the decision-making process I went through, so essentially these are my recommendations if you decide to go electric...

ELECTRIC FUEL PUMP CONVERSION IDEAS & SUGGESTIONS
viewtopic.php?f=225&t=17257

The factory mechanical pump has been tested in millions of Corvairs over decades of operation, and does a very good job of sucking the fuel from the tank to the engine and then delivering it reliably to the carburetors. A leak in either short flexible hose at the tank end or next to the starter motor will only be a VACUUM LEAK, and will not tend to leak much gasoline or create a fire hazard. Such a vacuum leak in one of these fuel hoses will appear to be a fuel starvation problem, since the fuel will not make it to the pump inlet (like a drinking straw with a split or hole in its side). Owners may think the mechanical pump has failed, when the problem is actually just a cracked or split rubber fuel hose at either end of the long steel fuel line.



Clark's Corvair Parts and other suppliers have made a strong effort to provide good replacements for Corvair mechanical pumps, if one is needed (mechanical pump rebuild kits are generally unavailable). But before you assume that the mechanical pump has failed, be sure to check out the external possibilities that can disrupt mechanical fuel pump operation. Be sure to check the two feed hoses periodically to prevent vacuum leaks on the fuel delivery side between the tank and the pump. You should also be aware that a rusty, dirty aging tank (inside the tank) can cause a blockage in the fuel inlet filter inside the tank, and that a 50+ year old tank may be ready for a replacement.

https://ssl.corvair.com/user-cgi/catalo ... ow_page=65

The filter inside the fuel tank can also deteriorate and may be clogged...



Strainer Sock, Fuel Sending Unit, 1954-88 GM, 5/16"

https://ssl.corvair.com/user-cgi/catalo ... ow_page=69

Fuel Pumps

We have only been able to locate 2 manufacturers of original style Corvair fuel pumps. Since 1973, we have consistently seen 1-2% of new fuel pumps fail. From about 1998-2001, the failure rate went to nearly 10%! We finally convinced the pump manufacturer that they were using the wrong diaphragm material! Currently, about 1%-2% of the fuel pumps continue to have problems. The problems have usually been seepage of fuel or complete failure resulting in no fuel or a rupture of the main diaphragm. The main supplier (C3403) is now using "antiwicking" diaphragms & has returned to all 3 diaphragms having fabric reinforced material. We've also added a pump from a 2nd supplier (C3403A). Our experience with both is nearly identical. A spare pump is always a good idea.

FINALLY...

The pump push rod is driven by a cam lobe on the crankshaft. The repeated "upstroke" causes the pump to form a vacuum in the feed line from the fuel source (tank or gas can). As the fuel is drawn into the pump chamber, the one-way valve in the pump inlet closes at the top of the stroke, and the spring in the pump forces the diaphragm back down to push the fuel out of the pump through the other one-way valve, toward the carburetors. The spring tension determines the fuel pump outlet pressure.


In this picture, you can see (from left to right) the woodruff key, the distributor drive gear, the fuel pump push rod cam lobe, the main journal, and connecting rod journals 1and 2.

Check to make sure you are fully inserting the pump so that the pushrod driving the pump gets a full stroke to drive the fuel pump. Proper installation of the new parts is critical,,,

To remove and reinstall the fuel pump, be sure that you have installed it properly. It is important to ensure that the fuel pump is correctly seated and installed. There is a hole in the side of the pump shaft that the tapered bolt tip must seat into. If the pump is sitting too high and the bolt is simply pressing against the side of the pump housing, rather than seating inside the tapered hole, the pump push rod will not be doing its job. Fig. 57 in the shop manual page shows the tapered hole that the tip of the bolt fits into. This ensures proper installation and seating of the pump.

[Monzaguy]

Thank you Brad, very detailed explanation.

[bbodie52]

Part number C3403: NON-GM FUEL PUMP-62-69 FITS 60-61 IF C259 ROD USED. ** LIMIT 1/ORDER

Notice: This part C3403 is currently out of stock. You may still order, you will not be charged and you will be notified when we have this part.

Weight: 2 lbs 4 oz
Catalog Page(s): 65
Price:
1 - 1 $ 66.60
2+ $ 64.60


ADDITIONAL ITEMS - Any products listed below are possible alternate choices:
Part number C3403A (Other): 62-69 FUEL PUMP REBUILD KITS ARE NOT AVAILABLE

Notice: This part C3403A is currently out of stock. You may still order, you will not be charged and you will be notified when we have this part.

Weight: 2 lbs 4 oz
Catalog Page(s): 65
Price: $ 100.40





An electric fuel pump conversion may be in your future.

[Monzaguy]

I'm thinking the electric fuel pump will indeed be in my future. Wiring stuff is not my strong point unless its plug and play, so I had been a little reluctant. Ted explained the inertia switch, just trying to figure how that oil pressure shutoff switch gets hooked up, and how you connect the 2 switches and the pump to which part of the fuse box. Contemplating Clarks Ultimate kit C10295 and the bypass plate C12879, it looks like all I would need. Looking at the oil switch picture in Clarks, I can't figure where it goes.

[bbodie52]

A power cutoff for for the electric fuel pump that cuts power if the engine stops for any reason is also recommended. A simple oil pressure sensing electrical switch is often suggested, but such switches are somewhat bulky and in conflict with the oil pressure instrument panel warning light switch that already occupies the connection point next to the generator or alternator. A new mounting point can be created using the "Adapt-a-Bolt" offered by Clark's Corvair Parts that modifies the oil filter mount. The cost for the safety switch plus the Adapt-a-Bolt runs about $52 - $65.


An alternative fuel pump controller is an electronic system offered by REVOLUTOIN ELECTRONICS. With a price of about $65, This electronic variation uses a tachometer sensor connected to the ignition coil negative terminal to monitor engine activity. If the engine stops, the electric fuel pump power is immediately cut off. The added features not found with the oil pressure switch option include a built-in power relay, a circuit breaker that takes the place of a power fuse for the fuel pump, and an initial electric fuel pump system 3-second pump priming that initializes the fuel in the fuel lines prior to starting the engine.

Fuel Pump Controller
This universal electric fuel pump controller is designed for cars and trucks being upgraded from a mechanical fuel pump to an electric inline or in-tank fuel pump.

• Pump only runs if there is a tach signal from the ignition (Just connect to the negative side of the ignition if you don’t have a factory tach)
• Primes the pump for three seconds at initial key-on.
• Includes a 7.5 amp circuit breaker.
• Includes an internal relay.
• Includes 15 feet of 16 gauge wire to energize the fuel pump.
• One year warranty
• 30 day Money Back guarantee

Many electric fuel pump manufacturers recommend installation near the tank. These pumps do a better job of pushing the fuel long distances, and they prefer something close to a gravity feed from the tank to the electric fuel pump inlet (filtered). The correct pump must be selected, so that it provides the Rochester HV or Carter YH carburetor(s) with low pressure of 4-5 psi (the Carter YH on the turbo prefers even lower pressure). If you install this type of fuel pump at a high, distant location, such as inside the engine compartment, it may suffer from fuel starvation and might not provide enough fuel volume to the carburetors.

The electric fuel pump I selected for my Corvair was a marine type (Airtex E8251 Universal Solid State Electric Fuel Pump for Marine Applications). It is recommended for installation close to the engine, does an excellent job of pulling the fuel all the way from the tank to the engine compartment area, and provides good fuel volume (Operates at 2.5 to 4.5 P.S.I., delivers 30 G.P.H. at free flow). It is also very quiet in operation.

For an electric fuel pump, this Airtex E8251 seems to be the exception in design that works very well for the Corvair layout. It avoids having to be installed under the car, near the gas tank. It is fairly quiet in operation, and it delivers fuel pressure that is very acceptable to Corvair carburetors.


https://www.amazon.com/Airtex-E8251-Uni ... 693&sr=8-3

Make sure your electric fuel pump is installed according to the manufacturer's recommendations, in a good location, has appropriate fuel pressure for the Corvair, etc.

All electric fuel pumps should have their inlet filtered (by a fuel filter in a metal housing, for safety) to protect the pump. The power should be on only when the engine is being cranked or the engine is running. A safety power switch that senses engine oil pressure or uses a tachometer sensor at the ignition system will insure fuel cutoff if the engine is not running.

I recommend the electronic fuel pump controller. Its cost is a little higher than the oil pressure switch, but because the location for mounting the switch on the engine is already occupied by the instrument panel oil pressure warning light switch, and this area is crowded next to the generator/alternator, the Adapt-a-Bolt may be needed to place the additional fuel pump safety switch at the oil filter location. The cost of these two items is close to the electronic controller cost, and the electronic controller also offers additional features not included with the simple oil pressure switch.

The installation instructions are displayed below, and are simple. It basically involves providing ignition switched power and ground to the controller, connecting the tachometer sensor wire to the coil negative terminal, and connecting the power leads to the electric fuel pump. It is no more complicated than the oil pressure switch alternative, and offers many advanced features over the oil pressure switch. It also avoids the plumbing problems associated with connecting the oil pressure switch to an engine oil pressure sampling point, like the oil filter mount using the adapt-a-bolt.


Revolution Electronics Electric Fuel Pump Controller
https://www.revolutionelectronics.com/P ... _Pump.html https://www.amazon.com/Revolution-Elect ... 023&sr=8-3

Revolution Electronics Electronic Fuel Pump Controller Installation (Page 1 of 2)

Revolution Electronics Electronic Fuel Pump Controller Installation (Page 2 of 2)

OTHER OPTIONS...

Holley 12-810 Fuel Pump Safety Pressure Switch
https://www.amazon.com/Holley-12-810-El ... 335&sr=8-3




Mr. Gasket 7872 Fuel Pump Safety Switch
https://www.amazon.com/Mr-Gasket-7872-S ... 335&sr=8-9




https://ssl.corvair.com/user-cgi/catalo ... ow_page=28

Part number C7521: ADAPT-A-BOLT-STOCK FILTER* IF USING W/ OIL TEMP SENDER-NEED TO DRILL ADAPTOR DEEPER

Weight: 0 lbs 6 oz
Catalog Page(s): 28,27D(RM19)
Price: $ 26.40

[terribleted]

I'm thinking the electric fuel pump will indeed be in my future. Wiring stuff is not my strong point unless its plug and play, so I had been a little reluctant. Ted explained the inertia switch, just trying to figure how that oil pressure shutoff switch gets hooked up, and how you connect the 2 switches and the pump to which part of the fuse box. Contemplating Clarks Ultimate kit C10295 and the bypass plate C12879, it looks like all I would need. Looking at the oil switch picture in Clarks, I can't figure where it goes.

I personally feel the inertia switch is all that is really needed and wiring it in line between the power and the pump under the dash is a lot easier than running wire or wires all the way to the rear of the car for an oil pressure shut off switch, not to mention the issues with hooking the pressure shut off to oil pressure. If there is a crash and the engine keeps running the pressure shut off will continue to deliver fuel. If there is a crash and the engine stalls or is shut off the pump will turn off. When you go to start the car that has been sitting with a oil pressure shut off switch it is necessary to carnk the engine for a period of time until it builds oil pressure before the pump will start and fill the carbs allowing the engine to start (unless you wire in a switch to bypass the oil pressure safety switch). I am pretty sure that well mounted the Inertia switch will kill the fuel pump period and no lag to get oil pressure when trying to start the engine either. Any safety device is almost overkill as a situation where it would save you butt has a very low percent chance of occurring in the first place. In a bad crash (most likely situation where you could not turn off the ignition killing the pump) there is no doubt in my mind that the inertia switch would open killing it for you.

[corvair500]

Here is one for sale on ebay . If one wishes to take a chance

https://www.ebay.com/itm/313674202695?e ... SwfSthQOo7

[Monzaguy]

Thanks Corvair500.

[Monzaguy]

Thank you Ted & Brad for all the information, it has made the process much easier for me to understand. Definitely going to go with the electric pump.