Guess who's back!?! Atl-atl's K5 Blazer + Four Wheel Camper "The Crawlin Cabin" documentation thread!

[ClovisMan]

You can usually band-aid vapor lock by putting an inline electric fuel pump on you fuel line just after the gas tank. There is other voodoo like putting wooden clothes pins on the line going into the carb and wrapping the fuel line that is under the hood with aluminum foil but I find just adding the inline pump works the best.

 

[tip]

Nice rig! I've had many squares over the years and I've always wanted to build a K5 with a FWC.

I always looked forward to your threads here and on the 'tex. Looking forward to following this one.

 

[nitro_rat]

For something like that I just use the pump they sell at Oreilleys. Here's a link to the same pump from AutoZone:

Mr Gasket 4-7 PSI Electric Gas Fuel Pump 12S

Shop for Mr Gasket 4-7 PSI Electric Gas Fuel Pump 12S with confidence at AutoZone.com. Parts are just part of what we do. Get yours online today and pick up in store.

m.autozone.com

Put it in the rubber line between the fuel tank and the metal line that runs down the frame.

Take the mechanical pump out of the loop as the electric pump can rupture the diaphragm in it. If your metal line from the mechanical pump to the carb is intact remove it. Get a 3/8" brass hose barb to go in the carb inlet. Run a piece of rubber line from the metal line on the frame in the engine compartment up to the carb.

I would recommend to use the internal filter in the Q-jet and not put a filter in the line. If you insist on using an inline filter get a metal one and not a plastic clear one!

Now is a good time to drop the tank and inspect it as well as replace the sock on the pickup. You can do all of the above with the tank up but the connections are a little more difficult.

You should be able to mount the pump to the frame rail or crossmember somewhere convenient. Run ignition hot 12v power to the pump. LMC sells a fancy relay with a timer in it that shuts off the pump in a key on/engine off situation. Sounds good but I've never used it. If you do, please report back on the results!

There are other more complicated ways to do it that may arguably be better but for your purposes the cheap inline pump back by the tank will work fine!

 

[nitro_rat]

One of the biggest problems with today's gas is that it evaporates out of the float bowls if the vehicle sits for a day or two. With the electric pump, you turn on the key, wait a few seconds for the float bowl to fill, push the gas to the floor one time. This will give a shot of gas to the engine and it also sets the choke. The engine will start with the bump of the key after that. No pumping and cranking etc!

 

[wyowandering]

With an electric fuel pump you should always use a relay to power the pump and something that turns it off if the engine dies but key is still on. The objective it to turn the fuel pump off in the event of a crash/rollover.
Also....the pump recommended earlier is pretty inexpensive so order two so you have a a spare.
I might be interested in the 5.3 and trans. I'm up in Cheyenne. PM me if you do decide to sell it.

 

[nitro_rat]

So completely bypass the stock mechanical fuel pump on the block? Keep the filter in the carb and dont run an inline filter with the new electric pump. A cheapo pump like that will be enough for the fuel this engine needs? Seems crazy.



Who you talking to about selling the 5.3? @zoomad75 ?

That pump will work fine, I've run them several times before and no problems. Maybe not a bad idea to keep a spare on hand but I never needed one...

 

[zoomad75]

With an electric fuel pump you should always use a relay to power the pump and something that turns it off if the engine dies but key is still on. The objective it to turn the fuel pump off in the event of a crash/rollover.
Also....the pump recommended earlier is pretty inexpensive so order two so you have a a spare.
I might be interested in the 5.3 and trans. I'm up in Cheyenne. PM me if you do decide to sell it.

I'll keep you in mind once the 5.3 is close to coming out.

 

[ClovisMan]

Ha, I like the wooden clothes pin idea. As for adding the electric pump, that seems like the best fix that Ive read so far. Do you know specifically what pump people use in this application?

I like the Carter rotary style pumps because they are rebuildable. Most just use a Holley Red and keep a spare in the toolbox.

Edit: I see some are recommending the small plastic inline Mr. Gasket pumps. While they will get the job done, I find that for some reason they like to crap out in high altitudes. Everyone I've ran seems to let go the ghost in the mountains. Just my experience.

 

[vargsmetal]

Since you're planning on the L29 swap anyway, how about getting a 87-91 K5 tank and sending unit, upgrade the pump to the 96+ pump. Then regulate it to run your carb for now, and then you can just hook it up to the L29 and go later. Wouldn't that work?

Sent from my SM-G965U using Tapatalk

 

[TwinDuro]

The Crawlin Cabin is looking great @Atl-atl! A ton of great information in this thread and I'm learning a ton following along. I love the proportions and size of your rig, seems just about right!

 

[nitro_rat]

Thats a direction Im considering as I research what all is required for an engine swap.

That is a very real option but you will need a $$$ return regulator to handle that pump with a carb. A regulator that won't be compatible with the L29. Money that would likely be better served funding the swap rather than stringing the carb along...

 

[zoomad75]

That is a very real option but you will need a $$$ return regulator to handle that pump with a carb. A regulator that won't be compatible with the L29. Money that would likely be better served funding the swap rather than stringing the carb along...

Agreed. Dialing a pump good for 55-65 psi down to 4-6 psi is overkill. It's going to be sending a majority of the fuel right back to the tank from the regulator.

Adding a basic fuel pump out back to limp the carb along until you are ready to swap is fine. My Dad and I did that on 454 powered RVs running carbs back in the 80's because they were vaporlocking hard in the heat and pulling large grades. Fixed them all.

 

[zoomad75]

So do you suggest running the electric in-line pump in addition to the mechanical stock pump, or bypassing the stock pump?

On the RV's because there was 30+ feet of fuel line from the tank to the engine we usually kept the mechanical pump in play to aid in pulling fuel up to the carb. But we were also using a high volume hot rod style mechanical pump too. On a much shorter K5 you could omit the mechanical because a good electric pump should be able to push the fuel the distance without requiring help of a mechanical pump. I would however leave a provision in your fuel lines near the mechanical pump to allow it to be put back into service in a pinch if something goes wrong with the electric pump.

 

[nitro_rat]

if the diaphragm breaks in the stock pump the electric pump will spray fuel around in the engine compartment...

if the electric pump fails the stock pump may not be able to suck fuel through it. you'll have to re route the fuel lines at both ends to switch back to mechanical...

 

[nitro_rat]