Moparts

Fuel Vapor Seperator 3/8"

Posted By: PurpleBeeper

Fuel Vapor Seperator 3/8" - 01/23/22 01:52 AM

Who sells factory-style 440/Hemi fuel vapor seperators with 3/8" fuel line, the correct internal outlet tube length and correct vapor line orifice size? (I can make a 0.060" restrictor of some type if needed, so this isn't critical) I read something good about 521 restorations, but they're out of stock. Thanks for the Help!
Posted By: SomeCarGuy

Re: Fuel Vapor Seperator 3/8" - 01/23/22 02:12 AM

Just got one in yesterday from atlas obsolete. Google mopar mall. You need to call as they list a kit with hoses etc you may not need. They sold me one for 65.
Posted By: fastmark

Re: Fuel Vapor Seperator 3/8" - 01/24/22 10:23 AM

I bought some from Rockauto but the orofice was too big. It’s and easy mod to make it smaller. It wa not $65.
Posted By: 71birdJ68

Re: Fuel Vapor Seperator 3/8" - 01/24/22 12:49 PM

Frank Baldason has the closest one to correct with the screen inside, but I can't remember if even his has the correct size hole in it.
Posted By: SomeCarGuy

Re: Fuel Vapor Seperator 3/8" - 01/24/22 03:40 PM

Originally Posted by fastmark
I bought some from Rockauto but the orofice was too big. It’s and easy mod to make it smaller. It wa not $65.


I didn’t see any vapor seperators listed at rock auto. There are cheaper versions of what we need online at various places. I asked if the one I bought had the screen inside since people complain about some of these not working. I was told it does and they have sold around 500 without any returns.
Posted By: NITROUSN

Re: Fuel Vapor Seperator 3/8" - 01/24/22 04:14 PM

Rock auto has them. GMK213126966 for 20 bucks a guy could buy one and cut it apart to verify screen and orifice.
Posted By: SomeCarGuy

Re: Fuel Vapor Seperator 3/8" - 01/24/22 05:31 PM

Interesting they don’t list them for 69 GTX. Would be good to know if they are correct inside.
Posted By: NITROUSN

Re: Fuel Vapor Seperator 3/8" - 01/24/22 06:44 PM

Originally Posted by SomeCarGuy
Interesting they don’t list them for 69 GTX. Would be good to know if they are correct inside.


Must be a listing error as they do show them under Road Runner. One wont know until someone actually buys one to dissect it.
Posted By: gtx6970

Re: Fuel Vapor Seperator 3/8" - 01/24/22 06:46 PM

Look using 1970 charger 426


Attached picture Screenshot_20220124-114214_Chrome.jpg
Posted By: SomeCarGuy

Re: Fuel Vapor Seperator 3/8" - 01/24/22 07:14 PM

Went and pulled out a box of take off parts a shop gave to the previous owner. One was a vapor separator. Compared to the one I just got and only difference I can see is the bracket has two dimples on one and only one on the other.

Next rockauto order I’ll grab one of those. Have to see how each I have compare, can check the nipple size too. Will have one coming off the car at some point so four will be on hand.
Posted By: NITROUSN

Re: Fuel Vapor Seperator 3/8" - 01/24/22 07:25 PM

Originally Posted by SomeCarGuy
Went and pulled out a box of take off parts a shop gave to the previous owner. One was a vapor separator. Compared to the one I just got and only difference I can see is the bracket has two dimples on one and only one on the other.

Next rockauto order I’ll grab one of those. Have to see how each I have compare, can check the nipple size too. Will have one coming off the car at some point so four will be on hand.


Did you compare or measure the return orifice?
Posted By: SomeCarGuy

Re: Fuel Vapor Seperator 3/8" - 01/24/22 11:51 PM

They look the same. I didn’t mic them. In and Out stamping is same font and location.
Posted By: 375inStroke

Re: Fuel Vapor Seperator 3/8" - 01/25/22 03:39 PM

I got a couple of those from RockAuto, too, and they had an orifice in them. Didn't measure it, but it looked to be around .064"
Posted By: lewtot184

Re: Fuel Vapor Seperator 3/8" - 01/25/22 04:15 PM

if you look back at the engines that used those separators you will notice they had a matching fuel pump. the fuel pumps were 8-9psi and worked with the .060" return orifice. i did some pressure/flow testing with this and found big low rpm pressure swings with return orifice sizes of .060" and up. the old factory pump set-up should generate 1-8lb swings at low rpm but will stabilize to around 6psi at about 2000rpm. when the. 060", or larger orifice is used with a more common street pump of 5-6psi the low rpm swings are still there, but hot running pressure may reduce to 4psi. i know from experience that using the .060+ orifice with a rated 6psi pump was definitely a power loss at the track but drove ok on the street. what i do now is solder the return hole up and drill for a .035"-.040" return orifice. this seems to work well with a 6-6.5psi pump. i've tested this using a factory original hipo 440 pump, a carter 6903 and 4862.
Posted By: PurpleBeeper

Re: Fuel Vapor Seperator 3/8" - 01/27/22 02:00 AM

Originally Posted by lewtot184
if you look back at the engines that used those separators you will notice they had a matching fuel pump. the fuel pumps were 8-9psi and worked with the .060" return orifice. i did some pressure/flow testing with this and found big low rpm pressure swings with return orifice sizes of .060" and up. the old factory pump set-up should generate 1-8lb swings at low rpm but will stabilize to around 6psi at about 2000rpm. when the. 060", or larger orifice is used with a more common street pump of 5-6psi the low rpm swings are still there, but hot running pressure may reduce to 4psi. i know from experience that using the .060+ orifice with a rated 6psi pump was definitely a power loss at the track but drove ok on the street. what i do now is solder the return hole up and drill for a .035"-.040" return orifice. this seems to work well with a 6-6.5psi pump. i've tested this using a factory original hipo 440 pump, a carter 6903 and 4862.


Great info! I'm guessing that since I'm feeding my motor with a Holley blue pump regulated down to 6psi I won't experience this (or maybe bump up my regulator slightly). Would you agree?

I bought one of the Goodmark fuel vapor seperators ($35) and it has 5/16" inlet & outlet. Can anyone confirm this is correct for 440 six packs & Hemis? (I think so, but I'm not sure). I ran a bread tie wire down all the holes and all the tubes extend to maybe 1/4" from the other end of the can (like a factory one I believe). I don't know if there's a screen in there or not. I will see if I can get a pin guage in the vapor return hole and let everyone know. It's certainly necked down a lot & probably in the neighborhood of .060" (the pin guage knows for sure)
Posted By: gtx6970

Re: Fuel Vapor Seperator 3/8" - 01/27/22 03:21 AM

Originally Posted by PurpleBeeper
Originally Posted by lewtot184
if you look back at the engines that used those separators you will notice they had a matching fuel pump. the fuel pumps were 8-9psi and worked with the .060" return orifice. i did some pressure/flow testing with this and found big low rpm pressure swings with return orifice sizes of .060" and up. the old factory pump set-up should generate 1-8lb swings at low rpm but will stabilize to around 6psi at about 2000rpm. when the. 060", or larger orifice is used with a more common street pump of 5-6psi the low rpm swings are still there, but hot running pressure may reduce to 4psi. i know from experience that using the .060+ orifice with a rated 6psi pump was definitely a power loss at the track but drove ok on the street. what i do now is solder the return hole up and drill for a .035"-.040" return orifice. this seems to work well with a 6-6.5psi pump. i've tested this using a factory original hipo 440 pump, a carter 6903 and 4862.


Great info! I'm guessing that since I'm feeding my motor with a Holley blue pump regulated down to 6psi I won't experience this (or maybe bump up my regulator slightly). Would you agree?

I bought one of the Goodmark fuel vapor seperators ($35) and it has 5/16" inlet & outlet. Can anyone confirm this is correct for 440 six packs & Hemis? (I think so, but I'm not sure). I ran a bread tie wire down all the holes and all the tubes extend to maybe 1/4" from the other end of the can (like a factory one I believe). I don't know if there's a screen in there or not. I will see if I can get a pin guage in the vapor return hole and let everyone know. It's certainly necked down a lot & probably in the neighborhood of .060" (the pin guage knows for sure)


ALL the fuel vapor separators were a 5/16" inlet and outlet
Posted By: lewtot184

Re: Fuel Vapor Seperator 3/8" - 01/27/22 01:19 PM

Originally Posted by PurpleBeeper
Originally Posted by lewtot184
if you look back at the engines that used those separators you will notice they had a matching fuel pump. the fuel pumps were 8-9psi and worked with the .060" return orifice. i did some pressure/flow testing with this and found big low rpm pressure swings with return orifice sizes of .060" and up. the old factory pump set-up should generate 1-8lb swings at low rpm but will stabilize to around 6psi at about 2000rpm. when the. 060", or larger orifice is used with a more common street pump of 5-6psi the low rpm swings are still there, but hot running pressure may reduce to 4psi. i know from experience that using the .060+ orifice with a rated 6psi pump was definitely a power loss at the track but drove ok on the street. what i do now is solder the return hole up and drill for a .035"-.040" return orifice. this seems to work well with a 6-6.5psi pump. i've tested this using a factory original hipo 440 pump, a carter 6903 and 4862.


Great info! I'm guessing that since I'm feeding my motor with a Holley blue pump regulated down to 6psi I won't experience this (or maybe bump up my regulator slightly). Would you agree?

I bought one of the Goodmark fuel vapor seperators ($35) and it has 5/16" inlet & outlet. Can anyone confirm this is correct for 440 six packs & Hemis? (I think so, but I'm not sure). I ran a bread tie wire down all the holes and all the tubes extend to maybe 1/4" from the other end of the can (like a factory one I believe). I don't know if there's a screen in there or not. I will see if I can get a pin guage in the vapor return hole and let everyone know. It's certainly necked down a lot & probably in the neighborhood of .060" (the pin guage knows for sure)
i did some WOT testing using a fuel pressure gauge to come to some of my conclusions; i'd recommend the same. all factory vapor separators were 5/16" in-out and 1/4" return. a large return orifice is a power killer without adequate pressure to compensate.
Posted By: dragon slayer

Re: Fuel Vapor Seperator 3/8" - 01/27/22 11:16 PM

It is not pressure it is volume. Until the needle valves closes you do not generate any pressure other than necessary head to move fuel to the carb with a positive displacement diaphragm mechanical pump. That is why the hemi pump has a larger area (volume) per stroke moved.
Posted By: PurpleBeeper

Re: Fuel Vapor Seperator 3/8" - 01/27/22 11:51 PM

UPDATE: i measured the orifice on the 1/4" return nipple of the Goodmark fuel vapor seperator and I got .057". I can't tell if there's a screen inside or not, but it looks good otherwise from what I can tell.
Posted By: lewtot184

Re: Fuel Vapor Seperator 3/8" - 01/28/22 12:05 AM

Originally Posted by PurpleBeeper
UPDATE: i measured the orifice on the 1/4" return nipple of the Goodmark fuel vapor seperator and I got .057". I can't tell if there's a screen inside or not, but it looks good otherwise from what I can tell.
i have a repop that i'm pretty sure has cellulose on the inside. i should cut it apart to see. i haven't bought any more of them because i'm not sure who's is good and who's is bad.
Posted By: SomeCarGuy

Re: Fuel Vapor Seperator 3/8" - 01/28/22 04:43 AM

We need a master list. Unfortunately what I have isn’t marked. The new one came in no box. I didn’t install the one on my car, the used one says nothing on it.
Posted By: dragon slayer

Re: Fuel Vapor Seperator 3/8" - 01/28/22 01:55 PM

A lot of guys put a ball bearing in the vacuum hose for the distributor. Looks stock but curved for performance and they don't want vacuum adv. Frankly this is the same here. Easy to install an orifice in the return line or block it. The real issue is running the carbs with no filter.

There are metal gas line filters with a return available. Not oem. Or run a standard filter.

Someone should get one manufactured as a real filter with a blocked return.

If you're not running the brass screen at the carb inlet fitting and running this separator with no screen you are running the risk of junking up the carbs especially idle/transition. All for the OEM look. Show car not driven fine, a driving car not so good.
Posted By: gtx6970

Re: Fuel Vapor Seperator 3/8" - 01/28/22 06:40 PM

Originally Posted by SomeCarGuy
We need a master list. Unfortunately what I have isn’t marked. The new one came in no box. I didn’t install the one on my car, the used one says nothing on it.


the ones with no markings on the can are old repops .

The originals and later repops all have IN and OUT stamped in the can
Posted By: moparx

Re: Fuel Vapor Seperator 3/8" - 01/28/22 08:29 PM

and for a driver, a Wix #33041 listed for 71-73 chevy may work.
it is 4 5/8 long, and 2 1/16 od.
3/8" in and out with a 1/4" return.
i can't say if there is any restrictor or screen in the return because i don't have one to look at. i found this in my Wix master catalog.
just something else to ponder.
beer
Posted By: 70sixpkrt

Re: Fuel Vapor Seperator 3/8" - 01/28/22 08:33 PM

I bought a vapor separator from 521 Restorations last year. Supposedly his are suppose to be correct. Correct length of tubes inside. I haven't installed it yet. There is a thread on FBBO about this same subject.
https://www.forbbodiesonly.com/moparforum/threads/fuel-vapor-separator.236061/
Posted By: SomeCarGuy

Re: Fuel Vapor Seperator 3/8" - 01/29/22 03:01 AM

Originally Posted by gtx6970
Originally Posted by SomeCarGuy
We need a master list. Unfortunately what I have isn’t marked. The new one came in no box. I didn’t install the one on my car, the used one says nothing on it.


the ones with no markings on the can are old repops .

The originals and later repops all have IN and OUT stamped in the can


Mine have the in and out. Nothing as to who made it or a part number.
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