Jump to content

Carburetor Circuits


keithb7

Recommended Posts

@chrysler1941 Yes, I need to ditch that regulator. In order to remove the regulator I need to get the stock pump rebuilt and back on the car. Part of the problem is, there is limited time to address everything I'd like to on the car. Plus I need to acquire a rebuild kit to rebuild the original fuel pump. I am doing research now on pump kits. I see a kit on the "Then & Now" web site. I'll dig out the old original pump to disassemble, inspect and compare parts before ordering a new kit. That'll take a 2-3 weeks at best before the rebuild kit arrives. In the mean time I'll endure what I have on the car.

 

I have a list of things that I want to address on the car. Plus I want to drive and enjoy it in the meantime. I have been getting a lot of work done. Each passing week I check off more items on the list.  I am chiseling away at the car, making it better. Working full-time for a living really cuts into my garage time!

 

 

 

 

Link to comment
Share on other sites

3 hours ago, keithb7 said:

@chrysler1941 Yes, I need to ditch that regulator. In order to remove the regulator I need to get the stock pump rebuilt and back on the car. Part of the problem is, there is limited time to address everything I'd like to on the car. Plus I need to acquire a rebuild kit to rebuild the original fuel pump. I am doing research now on pump kits. I see a kit on the "Then & Now" web site. I'll dig out the old original pump to disassemble, inspect and compare parts before ordering a new kit. That'll take a 2-3 weeks at best before the rebuild kit arrives. In the mean time I'll endure what I have on the car.

 

I have a list of things that I want to address on the car. Plus I want to drive and enjoy it in the meantime. I have been getting a lot of work done. Each passing week I check off more items on the list.  I am chiseling away at the car, making it better. Working full-time for a living really cuts into my garage time!

 

 

 

 

Then and Now rebuilt my fuel pump.  Good people to deal with.  They sent me an email the day that my fuel pump arrived at their door. The very next day they sent me another email saying that it was ready and it was being sent out that afternoon to me.  Northeastern USA (MA)  to Southwestern BC Canada (Vancouver Island)   Not bad at all.

Link to comment
Share on other sites

2 hours ago, harmony said:

Then and Now rebuilt my fuel pump.  Good people to deal with.  They sent me an email the day that my fuel pump arrived at their door. The very next day they sent me another email saying that it was ready and it was being sent out that afternoon to me.  Northeastern USA (MA)  to Southwestern BC Canada (Vancouver Island)   Not bad at all.


I am ordering the rebuild kit from Then & Now tonight. I’ll rebuild the pumps when the kit arrives. I rebuilt the fuel pump on my ‘38 Ply. It seems to be reliable. This pump in my Royal looks pretty straightforward so I’ll give it a go myself. 

Link to comment
Share on other sites

I hovered over the fuel/vacuum rebuild kit purchase button at Then & Now. Freight costs stopped me. I Did not order it. I am defiant and stubborn. Sorta fed up with freight charges. I know I’m only punishing myself. Then Now probably gets 30X the business from within the USA, compared to whiny Canadians. 
 

Tonight I removed the incorrect fuel/vacuum pump and the regulator. I installed the mechanical pump from my ‘38 Ply. Its down anyway. I am still waiting for second coming, before they finish my block machining work. 
 

I found the fuel flex line hose located on the cross member near the rad, going to the fuel pump, had a straight barbed fitting. Straight up. Then the hose bent and made a 90 degree turn toward the fuel pump. It was not a pre-formed hose so it had a folded kink in it. I installed a 90 degree fitting, new flex hose and hooked it to my mechanical pump. 
 

I ran out time to test new fuel pressure. Stock style regular old mechanical pump. If I recall it was about 4 psi after I rebuilt it for my Plymouth.  I then went for a test drive. 
 

Pretty good. Runs fine. No dead spot off idle. Yet still, a stumble is there. I’m now thinking ignition or valve set. I’ll tackle those 2 next. One at a time to prove what it was. It t’werent the fuel pump or fuel pressure.  A few pics from tonight’s work. 
 

 

94767749-CCED-4865-ACD6-5944F2511C60.jpeg
 

786089EF-0341-4BD1-B273-629CFBFE8260.jpeg

 

5AF7880E-0617-41A6-B46D-9B8EB1DB3319.jpeg

 

8A99077F-89D5-4F6A-96FE-4CF00210EC11.jpeg

Edited by keithb7
  • Like 1
Link to comment
Share on other sites

I know the pain in shipping cost....and I for one will not order from Canada for the same reason as yourself.  But in some cases one must pay to play.  I deal a lot with little British cars and I have had some pretty large orders shipped in this last year or so.  One or two companies over there drag their feet filling orders, some you get as quick from there as a box from California....Ohio seems to bog down anything northeast...it will not get better...nor will the cost go down...and e-commerce is getting more and more business and their attitude is beginning to show as they are steadily becoming the go-to over local shopping.  

Link to comment
Share on other sites

hmm, I bought a set of motor mounts to put a later 318 in place of a 273 in my 65 Cuda from Canada, I don't recall the shipping being crazy.  Of course, that was November of last year and I can't find the receipt.

Link to comment
Share on other sites

48 minutes ago, Plymouthy Adams said:

not so much the shipping cost...custom brokers that want to extract fees for items exempt and or less than the threshold limit.....

I used to ship some eBay sales to Canada.  What always confused me was the brokerage charges by UPS or Fedex, but never using USPS, even on items of equivalent cost.  Small enough to send USPS, no extra charge, bulky items sent UPS,  my customer got extorted.

Link to comment
Share on other sites

I’ll wait and hopefully place an order at a later time when I need multiple items. The ordering of one thing here and there leads to considerable increased costs. I have other options too once the Can/USA border opens up again. I’m stalling as we get closer each week to re-opening. 

Link to comment
Share on other sites

Is it the dry hot weather up here? How could it be that the same heat related symptoms follow me and every old Mopar car I own? Must be the mechanic causing these problems! ?

 

I attended a cruise this afternoon in my '38 Chrysler.  95 F (35 cel) ambient temp. Sunny hot afternoon. Long lines of vintage cars out cruising together through town. 200 or so cars. Lots of slow idling through town. Everything under the hood was getting pretty warm.  I tried to go up a hill in town. Low speed, heavy load. Engine was bucking and wouldn't rev up. Not enough power to climb the hill in first or second gear.  I turned the car around. I left the group of cruising cars. I coasted down some down-hill roads and drove some flat roads. I got my speed up. Everything started to cool down again. Engine power restored within minutes of faster travel speeds.  I made it up the steep long hill home without incident.

 

Some facts:

- Non-ethanol fuel 94 octane. 

- Stock 1953-era Mopar mechanical fuel pump that I rebuilt last year. Works fine. 

- Fuel pressure regulator removed

-New Spark plugs

-Carb Float set to spec

-Heat sink plate at base of carb installed

-Timing at spec. 0 deg TDC

 

Was I vaporizing fuel? I suspect so. How so, with non ethanol fuel? I am inching closer to just going full electric fuel pump. The same heat related issues seem to plague me with each old Mopar car here. Yet other folks in this group drive in 110F heat in Texas with a mechanical fuel pump and have no issues. I will carry on trouble shooting and get this dialed in one way or another.

 

Edited by keithb7
Link to comment
Share on other sites

Be careful Keith, once you go electric there's no turning back...?

  • Like 1
Link to comment
Share on other sites

5 hours ago, keithb7 said:

Was I vaporizing fuel? I suspect so. How so, with non ethanol fuel? I am inching closer to just going full electric fuel pump

In my opinion, yes! The fuel got hot enough to vaporize. I've had the same experience as you with both my older cars when they get heat soaked then sit idling in traffic. I keep my mechanical pump and installed an electric pump (in line on one car and used a "Y" and check valve on the other car) as a means to overcome vapor lock. I have a switch I turn on the electric pump only when needed. It works. I've since learned of a fuel filter with 1 inlet and 2 outlets designed to circulate fresh cool fuel continuously. This looks like a more bulletproof method but does require a  way to return fuel to the tank do it's a bit more work. So far, my electric pumps do the trick and I have 2 options for delivering fuel in case of a fuel delivery failure due to one or the other pumps..... I can get home. 

  • Like 2
Link to comment
Share on other sites

I have a similar electric pump setup. I originally set it up to aid in priming the carb after prolonged parking. But I found it’s also helpful when the engine compartment temp climbs and the engine begins to struggle to get adequate fuel. I switch on the pump and within a few seconds the engine smooths out and runs well again. Once I can get out on the open road again I’ll switch it off.

Link to comment
Share on other sites

1 minute ago, Merle Coggins said:

I have a similar electric pump setup. I originally set it up to aid in priming the carb after prolonged parking. But I found it’s also helpful when the engine compartment temp climbs and the engine begins to struggle to get adequate fuel. I switch on the pump and within a few seconds the engine smooths out and runs well again. Once I can get out on the open road again I’ll switch it off.

This is exactly why I also installed an electric. Difference from BbDakota, my Airtex pump only delivers 4.5 psi, same as mechanical pump. After hitting the switch, i can hear pump stops when carb bowl is full. No need for return. The airtex is also a flow through type.

 

Now to something more serious. 0 degrees TDC? That's way to low for modern fuel. No wonder engine was struggling. You need to advance at least 5-10. Forget degrees, get a vacuum meter and set idle and mixture for max (21) . Then adjust idle.

You'll be amazed.

 

Still trying to imagine a sink plate on carb. is that a 38 thing?

  • Like 1
Link to comment
Share on other sites

heat shields need not always be a factory item for folks who are dealing with problems in the fuel system where they think they have vapor lock or in some cases advanced percolation.  Adding them will NOT cause any additional problem but a phenolic spacer with the properties NOT to absorb and transfer heat is always a good practice also.  The 38 I am not familiar with but I do not recall a plate beneath the carb on other older flatheads.  The shied I am used to seeing is the heat shield between the exhaust manifold and the fuel pump. 

Link to comment
Share on other sites

1 minute ago, Plymouthy Adams said:

heat shields need not always be a factory item for folks who are dealing with problems in the fuel system where they think they have vapor lock or in some cases advanced percolation.  Adding them will NOT cause any additional problem but a phenolic spacer with the properties NOT to absorb and transfer heat is always a good practice also.  The 38 I am not familiar with but I do not recall a plate beneath the carb on other older flatheads.  The shied I am used to seeing is the heat shield between the exhaust manifold and the fuel pump. 

Yes Chrysler probably found out percolation already started at pump

Link to comment
Share on other sites

due to heat soak there is always a chance of percolation at the carb....this is often however kept in check by the maker in relation to the actual float level keeping this in check.  As the fuels have advance and the addition of alcohol to the fuel...folks forget that the books have not taken this into account over the decades and continue to follow the original specs thus many are inducing problems especially in the area of percolation due to the expansion rate of the fuel at operating temperature.   I would be willing to bet that many here would NEVER outrun the pump delivery to the carb even at a lesser fuel level during any WOT run as my guess is not many here will make a WOT on the flathead as normal driving.

Link to comment
Share on other sites

Base plate heat sink shown. No it wasn’t a thing in 1938. However like radial tires, I believe some small advancements are advantageous for the old car. This heat plate can’t hurt, right? If properly installed for vacuum routing. 
 

Also see pic of my fuel pump heat dam. Its going to be installed tonight. 
 


 

 

C91E9950-381C-4838-8FE1-D3C0FFABB6B1.jpeg
 

 

36838483-F431-456D-A04E-1835CF1EEA05.jpeg

Edited by keithb7
  • Like 1
Link to comment
Share on other sites

Yesterday I removed the distributor and inspected everything. Seems good. Centrifugal weights and springs, vacuum advance, points, ground wires etc, all good and functioning. I gave the breaker plate bearing a shot of lube. Everything seems good. I replaced the condenser only, and then went for a test drive.  The engine performed better yet again at higher RPM's. The car keeps improving as I complete things one step at a time, followed up with a test drive.   Still, it's not right just yet. I still think it should be idling and running smoother.

 

Today I finally completed a compression test. 1 through 6 seen here:

 

100

75

90

87

90

87

90

 

Something is going on with #2. With the wet test #2 went up to 90 psi. Planning now to go in for a full valve set.  Fingers crossed I can get that cylinder up. The engine is not consuming any oil. Indications are the engine was rebuilt 7,000 miles ago. Which is why up to this point, I was chasing almost anything but a compression test. Perhaps a post engine break-in valve set was never done? We shall see. 

 

Edited by keithb7
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use