Fuel Pump Mechanical or Electric

Tristan · Apr 23, 2018

I am suddenly in the market to replace my not so old mechanical unit.
I would appreciate some opinions as to the pros and cons to using an original style mechanical pump verses using an after market electric type. Cost difference? Reliability comparison? Performance difference? Cost?
If electric which are the best to get?
I understand the Chebby small block off unit works.

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DrCharles · Apr 23, 2018

A good electric costs about 3x as much (say $100 for the Facet 40285). Do not buy a cheap inline type intended for gasoline. It will not last very long.

No performance difference if they're both working. But the mechanical can have a diaphragm leak which will fill your crankcase with diesel. The Facet also has an external bowl with a filter screen to further help keep crap out of your lines.

The block-off plate is pretty generic (my Mr. Gasket one said Ford/Chevy on the package) but be sure to grind just a hair off the "tip" because it can sit on the block casting flash and cause a leak... DAMHIK

genscripter · Apr 24, 2018

I went with the e-pump years ago. I love it 1000x more than the lift pump. But there are pros and cons.

pros for the epump:

purging the air from the lines becomes a breeze. Just on the pump, and push the schrader valve, and it'll pull from the tank to the filter. No cranking needed.
Easier to access. I installed my epump on the rail with some R&D stage 1 filters. video:

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By putting it on the rail, I don't have to weasel my arm into the underside of the engine bay of my van to get to the lift pump.
the epump as a pre-filter that is easy to access and clean out. Also, the prefilter is reusable if necessary.
No cruddy metal lines to worry about. The stock system is hard to maintain and can leak or cause air intrusion. If you go with the epump, you can run a simple rubber line up to the inlet of your diesel filter. No circuitous metal lines to worry about.
Epumps make air intrusion really easy. By putting your epump on the rail, you are effectively making your fuel system a "pusher." By ensuring you always have more pressure than the IP needs, if you have a fuel hose hole after the epump, it makes it hard for air intrusion to affect the IP. Conversely, the lift pump "sucks" from the front of the engine, so if you have a hole in the lines, it's more likely to suck air than fuel (it's less effort to suck air), thus making air intrusion really tough to resolve.
When the epump fails, you are just stuck. If the lift pump diaphram fails, it fills your crankcase with diesel and likely causes longterm lubrication damage to the engine.

Cons against the epump:

fuel pressure doesn't correlate with RPM's with the epump design. This isn't really a problem if you have a stock setup, but if you run a bigger IP, your epump might lag when it comes to supplying fuel to the IP. the lift pump (so I've been told) will increase pressure with RPM's
No electrical to deal with. While wiring up an epump is pretty simple (relay on key-on circuit), it is still a potential failure point. If the fuse blows or other electrical issue arises, then you have no fuel pressure. The lift pump would survive an EMP explosion.
price. A duralift epump would be around $100, while the lift pump is around $13-$25 on rockauto.

I'm sure there are more pros and cons, but I'm just naming a few off the top of my head. I'd highly recommend the epump over the liftpump.

raydav · Apr 30, 2018

Near the top of this album are the pumps I have used, and the dual mode oil pressure switch. A little further down is the current supply/lift pump and Racor filter. There is another pic near the bottom. That "cheap" pump has been there about a decade. There is one just like it that is a transfer pump to refill the primary tank from the two auxiliary tanks.

There were a couple times the pump was turned off and the engine did not seem to notice.

Click on any pic, there will be some notes, and right and left scroll arrows.

https://goo.gl/photos/LJNV4esgmYmSzKdL8

Kagey Robin · Apr 30, 2018

https://www.oilburners.net/threads/manual-selector-valves-electric-and-mechanical-fuel-pumps.71152/

This is the setup I intend to use. I like the idea of manual valves instead of original setup plus having the bonus of an electric fuel pump is just appealing for a number of reasons.

gerlbaum · May 4, 2018

My mechanical died and I bought a new mechanical one to put in. When pulling the old one the arm fell off in the block on me. The 20 min job turned into a weekend of cussing lol. I will never put a mechanical one back on. I had a Holley and it was so darn loud. I have a Carter now and I love the Carter. They're like $70 with lifetime warranty at o reilys.

Edit, the Carter would be a push pump the facet is a suction. My obly reason for a push set up was I didn't want to try and fit it in the engine bay. Mine is mounted on an aluminum plate down by the rear tank ( I have a 38 galoon rear only).

Fuel Pump Mechanical or Electric

Tristan

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DrCharles

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genscripter

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raydav

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Kagey Robin

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gerlbaum

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