64 Rivi Carburetor on 401, Rebuild or Install a Fuel Injected?

[atencioee]

Hello, for those with expertise, I have a 64 Rivi w/a 401...what is best overall for operation & fuel economy...to have the original carb rebuilt or to install a fuel injected carb? What would you do?

[EmTee]

Definitely rebuild the AFB.  Those carburetors are a good design and once refreshed should give you no trouble.  If you object to having extended cranking at first start following several days idle (due to fuel evaporation) install an electric pump just ahead of the gas tank.  Get one that allows the mechanical pump to pull fuel through it when it's off.  Turn it on for 10~15 seconds right before startup to refill the fuel bowl.  It can also be turned on to alleviate vapor lock if that occurs on a particularly hot day.

 

FI will cost much more (at least $2K for the basic unit) and will likely require modification of the fuel pickup/fuel lines.  Any difference in fuel economy will barely be noticed on a classic car that is only driven occasionally...

[RivNut]

As Emtee says have the original Carter AFB rebuilt. But are you sure the carburetor is correct for the car?  In 1964 all Rivieras were built with the 425 engine.

[atencioee]

1 hour ago, RivNut said:

As Emtee says have the original Carter AFB rebuilt. But are you sure the carburetor is correct for the car?  In 1964 all Rivieras were built with the 425 engine.

Everything under the hood is OG to that car...64 Rivieras came with both the 425 and the 401...mine has the 401.

[Riviera63]

5 hours ago, atencioee said:

Everything under the hood is OG to that car...64 Rivieras came with both the 425 and the 401...mine has the 401.

As RivNut said, 1964 is 425 only.

[1965rivgs]

1 hour ago, Riviera63 said:

As RivNut said, 1964 is 425 only.

  Except for exports to certain destinations. Buick installed 401's in those. I've posted this a handful of times on this forum including the actual production numbers. As I recall around 400 '64's? I don't have access to my library. Maybe a search will produce my previous posts?

Tom Mooney

[atencioee]

2 hours ago, Riviera63 said:

As RivNut said, 1964 is 425 only.

Actually, as Tom (1965rivgs) said, there are a handful of 64s w/the 401. I have matching #s, and my Rivi is a 64-4747.

[telriv]

I've rebuilt the originals for many on this forum.

Just ask.

 

Tom T.

[1965rivgs]

11 hours ago, atencioee said:

Hello, for those with expertise, I have a 64 Rivi w/a 401...what is best overall for operation & fuel economy...to have the original carb rebuilt or to install a fuel injected carb? What would you do?

  Best overall operation and fuel economy will be fuel injection. Best value, when considering cost, will most likely be a carb, depending on who is providing that cost.

  Fuel injection has been around for ages but the OEM's refrained to use it due to cost. In the mid '80's, when complicated and EXPENSIVE feedback carbs became necessary to adequately control computer controlled fuel delivery, the cost of fuel injection became within reason.

Tom M.

[Riviera63]

1 hour ago, atencioee said:

Actually, as Tom (1965rivgs) said, there are a handful of 64s w/the 401. I have matching #s, and my Rivi is a 64-4747.

Actually, Tom said all 64's had a 425 except for exports to certain destinations, which had the 401. He believed off the top of his head to number around 400. 

[1965rivgs]

37 minutes ago, Riviera63 said:

Actually, Tom said all 64's had a 425 except for exports to certain destinations, which had the 401. He believed off the top of his head to number around 400. 

  Bill,

  Actually, Tom didn't say "all 64's had a 425" . If you review my post you will find that is correct. In my post I simply noted an exception. For all I know there may be another exception I am not aware of?

  I try to stay away from absolute descriptive terms like "all" or "every" because there are very often exceptions which I have become accustomed to encountering as time goes on. This is a perfect example of such an exception, as are the '66 Rivieras. The standard engine was a 425 but in certain circumstances it is factual that they were built with 401's. I'm not making this stuff up. It is documented in the Buick production statitics. I'm just trying to pass on good, well researched and documented information.

 

Tom

[RivNut]

Easy to tell there are two numbers stamped into the top surface of the block. The Production code Number will tell you the year and cubic inches.  K is the letter designation for 1964.  W is the designator for a 425. T is the designator for a 401.  The Engine Serial Number includes numbers that match the VIN on the cowl which will tell you if the engine is original to the body/chassis.  The numbers 64-4747 on the cowl tag tell you that it’s a 1964 model 4747 - Riviera.. the Engine serial number can be decoded as well.

 

 

This illustration is for a 1966 (M) 401 (T)

Edited July 10, 2022 by RivNut (see edit history)

[XframeFX]

7 hours ago, atencioee said:

Actually, as Tom (1965rivgs) said, there are a handful of 64s w/the 401. I have matching #s, and my Rivi is a 64-4747.

Must be an export Riviera, assembled in Belgium?

 

If it has a Carter AFB, stay with it. If considering something major, I'd search out  1966 spreadbore manifold and cruise with those itty bitty primaries of the Q-Jet carburetor. Then WAAAA when the secondaries open!

 

For an electric fuel pump, change out the oil pressure switch to one with a 2nd set of floating contacts to close when the engine is running. No adapter needed, 1/8" NPT for a 1981 Jeep CJ w/258 cu. in inline-6.

[Zimm63]

9 hours ago, XframeFX said:

Must be an export Riviera, assembled in Belgium?

 

If it has a Carter AFB, stay with it. If considering something major, I'd search out  1966 spreadbore manifold and cruise with those itty bitty primaries of the Q-Jet carburetor. Then WAAAA when the secondaries open!

 

For an electric fuel pump, change out the oil pressure switch to one with a 2nd set of floating contacts to close when the engine is running. No adapter needed, 1/8" NPT for a 1981 Jeep CJ w/258 cu. in inline-6.

Would you happen to have a part number for that oil pressure switch?  NAPA lists several for 81 Jeep CJs.  

 

[Jolly_John]

FYI: If needed, I have an already rebuilt Carter AFB for the 1964 RIV available. It's the correct '64 carb number, and is a quality rebuild job still in the box....not something some guy simply stuck a "kit" in. I wasn't prepared to offer it for sale quite yet, but then saw this posting. I can PM photos and a price. I'll eventually offer this carb as a "for sale" item here on the forum. Then, I'll include photos and pricing, of course. John

[60FlatTop]

8 minutes ago, Jolly_John said:

I wasn't prepared to offer it for sale quite yet, but then saw this posting.

I had a spare pair of '64 Riviera exhaust manifolds hanging on the wall of my garage just in case. Someone needed a set and I sold them. Every time I look at that spot on the wall and shake my head thinking "Shouldn't have done that".

 

I have no idea where the money went but I sure do remember those nice manifolds. Just a hint on how one should snap up stuff that gets offered.

[Jolly_John]

6 hours ago, 60FlatTop said:

I have no idea where the money went but I sure do remember those nice manifolds. Just a hint on how one should snap up stuff that gets offered.

Well put, Bernie. Having been in the old car hobby for quite a few years, like you, I'm a bit amazed to see how difficult it is to find any number of old BUICK parts these days, compared to just five or ten years ago. Fairly common items that we thought would be around "forever" at that time, are now take a fair amount of effort to find....and I'm not just talking about dual quad manifolds and early GS air cleaners! Always good to hear your comments here on the forum. John

[XframeFX]

8 hours ago, Zimm63 said:

Would you happen to have a part number for that oil pressure switch?  NAPA lists several for 81 Jeep CJs. 

SMP (Standard Motor Products) Blue Streak P/N: PS-133

 

All of us should install this switch. A direct replacement, 1/8" NPT.

It is double pole. Meaning one conventional set of contacts for the oil light and another set of floating contacts for electric choke, a relay to electric fuel pump or whatever you want to power with the engine running. Both contacts operate in unison, normally open.

 

 

 

 

 

 

Edited July 10, 2022 by XframeFX (see edit history)

[Rivguy]

If you are sticking with the carb, get it rebuilt at a reputable professional shop. I had that done for my '66 and it was worth it. The shop put it on a flow bench to check and adjust it. I bolted it on and it worked perfectly. Those auto parts store rebuild kits don't always come with the specific parts needed.  There was recent article in Hot Rod where a guy put a home brew throttle body fuel injection system on a '74 Corvette.  There wasn't an expectation of increased power or better fuel mileage. Cold weather starting and driveability was the goal. Though in reality, a properly set up original carb, with properly functioning choke mechanism and a properly working heat riser valve will give satisfactory results. So many heat risers have rusted in place, or were wired open or just removed over the years. Buyers of Rivieras in the Sixties expected their Buicks to start and run under any conditions. And they did. 

[RivNut]

Contact Jon at www.thecarburetorshop.com for a unique and correct gasket set.  

[carbking]

On 7/9/2022 at 6:28 AM, atencioee said:

Hello, for those with expertise, I have a 64 Rivi w/a 401...what is best overall for operation & fuel economy...to have the original carb rebuilt or to install a fuel injected carb? What would you do?

Another vote for rebuilding the AFB, if original to the car.

 

If the proper efi is purchased, properly installed with the necessary fuel system mods, it will start easier after sitting unstarted for several days (unless you install an electric pump for the carburetor), and depending on your tuning skills, might get marginally better city driving fuel economy, and might have slightly better city driveability when the ambient is above 95 degrees F.

 

Highway fuel economy should be unchanged.

 

And the efi will decrease the value of the vehicle by the amount of material/labor to re-install the correct carburetor.

 

The biggest advantage to efi is if you live in Colorado, etc. and daily commute from 3,500 feet to 12,000 feet altitude. The AFB will work almost as well under these conditions, but you would have to change step-up rods a couple of times. In this case, the efi is more user-friendly (PS- I don't live in the mountains  )

 

Other than the altitude example cited above, you should notice virtually no change from a correctly working efi, and your original carburetor (if an electric pump is installed).

 

Jon.

[telriv]

I know that many install electric pumps to facilitate cold starting/sitting problems of restart when it comes time to start. 

Myself after my car may sit for months at a time I would rather/prefer it NOT start immediately. When the engine starts immediately the bearings are running dry until oil pressure builds up. I don't pump the gas pedal to set the choke. I will crank it over it 15 second intervals, letting the starter cool somewhat in between cranks. When the oil pressure gauge moves or the oil light goes out you can now start the engine.

People tell me your wearing out the starter for no reason. It's much easier to rebuild/replace a starter than it is to drop the pan & replace engine bearings.

 

Just my thoughts.

 

Tom t.

[Riviera63]

5 hours ago, telriv said:

I know that many install electric pumps to facilitate cold starting/sitting problems of restart when it comes time to start. 

Myself after my car may sit for months at a time I would rather/prefer it NOT start immediately. When the engine starts immediately the bearings are running dry until oil pressure builds up. I don't pump the gas pedal to set the choke. I will crank it over it 15 second intervals, letting the starter cool somewhat in between cranks. When the oil pressure gauge moves or the oil light goes out you can now start the engine.

People tell me your wearing out the starter for no reason. It's much easier to rebuild/replace a starter than it is to drop the pan & replace engine bearings.

 

Just my thoughts.

 

Tom t.

 

I use Tom's method whenever my car sits for an extended period. Especially, when stored for the winter which is a 6 month hibernation. I crank until the oil light goes off (which for my car is usually 7-8 seconds), stop, pump the accelerator twice, hit the key again and it pops right off. I have been doing this for years and it has never failed me.

 

Bill

[gungeey]

18 hours ago, telriv said:

I know that many install electric pumps to facilitate cold starting/sitting problems of restart when it comes time to start. 

Myself after my car may sit for months at a time I would rather/prefer it NOT start immediately. When the engine starts immediately the bearings are running dry until oil pressure builds up. I don't pump the gas pedal to set the choke. I will crank it over it 15 second intervals, letting the starter cool somewhat in between cranks. When the oil pressure gauge moves or the oil light goes out you can now start the engine.

People tell me your wearing out the starter for no reason. It's much easier to rebuild/replace a starter than it is to drop the pan & replace engine bearings.

 

Just my thoughts.

 

Tom t.

This is the way. Spin the engine 8-10 seconds to load the bearing surfaces with oil. Set the choke by putting the accelerator pedal to the floor and releasing slowly. The carb bowl is now full. Car will start right up. Every. Single. Time.