Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 06-01-2019, 10:58 PM   #1
dgmgohl
Member
 
Join Date: Aug 2018
Posts: 53
Default Carb and Distributor Dilemma

I have a 53 Merc 255 in a 52 Mainline. I purchased this motor when the 239 gave way. I have a few questions concerning the carb and the distributor. Upon reading some threads earlier today, I read that the distributors are different between the the Merc and the Ford. Is this correct? I read further that the vacuum is different. Trying to get this motor to run right has been a challenge. My vacuum reading is a steady 19. But upon taking the car to a local shop to check vacuum and other settings, we noticed that there was no vacuum coming out of the carb. The carb is a tee pot. So is it ok to use the vacuum off the intake? I've given thought to maybe updating the carb and distributor with newer equipment. Any thoughts there? Thanks for any help and suggestions.
dgmgohl is offline   Reply With Quote
Old 06-01-2019, 11:09 PM   #2
JSeery
Member Emeritus
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 16,132
Default Re: Carb and Distributor Dilemma

The correct vacuum for the distributor is determined by the carb vacuum port. The distributor will not work off of manifold vacuum. This limits the carb you can use. A good upgrade is a SBC distributor modified to work on a flathead. Check out Bubba's site or check with Charlie NY. Both are here on the Barn.
JSeery is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 06-02-2019, 09:54 AM   #3
Flathead Fever
Senior Member
 
Flathead Fever's Avatar
 
Join Date: May 2010
Location: Yucaipa, CA
Posts: 1,091
Default Re: Carb and Distributor Dilemma

I give these long explanations. Only because I want people to understand how things work. Its so much easier to fix this stuff when you understand how it works.

Hooking the carb to manifold vacuum will cause the timing to advance at idle (If the vacuum advance diaphragm is still good). Any port located below the carb's throttle plate is "manifold Vacuum". You want a vacuum port located above the throttle (ported vacuum). That requires a carb with a built-in ported vacuum fitting. There is no way to install one. You need the correct carb or an aftermarket distributor that only uses a mechanical advance. Your Factory carb should have the correct ported vacuum fitting. You can check it by installing a vacuum gauge on the port. There should be no vacuum at idle. As the throttle is opened you should see a vacuum reading. Then you can install ah and held vacuum pump and apply vacuum to the advance and see if it is working. You can also just raise the rpm to where you have vacuum at the port and disconnect and connect the vacuum hose from the advance. You should get a rpm change as the timing changes.

There is very little vacuum inside the carb above the throttle plate when its closed. As you accelerate the throttle plates opens and the air flowing through the carb creates a vacuum at that port located above the butterflies. The vacuum advance will start operating as the air flow increases.

Here is a good illustration. Manifold vacuum below the throttle plate. Ported vacuum right about the throttle plate. Venturi vacuum located in the venturi's restriction. That one is real sensitive to air flow changes. Its used to control various smog systems like EGR valves.
Attached Images
File Type: jpg vacuum.jpg (36.3 KB, 55 views)

Last edited by Flathead Fever; 06-02-2019 at 10:11 AM.
Flathead Fever is offline   Reply With Quote
Old 06-02-2019, 11:51 AM   #4
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,260
Default Re: Carb and Distributor Dilemma

Excellent explanation on the different types of vacuum ports. I find your long explanations to be very helpful. I engage in them myself from time to time. People I know say that if they should ask me what time it is, I will tell them how a watch works. Some of us are like that.

Last edited by tubman; 06-02-2019 at 04:09 PM.
tubman is offline   Reply With Quote
Old 06-02-2019, 12:20 PM   #5
scicala
Senior Member
 
scicala's Avatar
 
Join Date: Jun 2010
Location: Detroit suburb, MI
Posts: 3,697
Default Re: Carb and Distributor Dilemma

Listen to Flathead Fever. Very good description. If your 255 still has the distributor and carburetor that came with the engine, you will be in good shape as long as the advance diaphragm doesn't leak and the vacuum line connections to it are not leaking. The springs on the breaker plate in the distributor are what is correct for the Merc teapot that came with the engine.


Sal
scicala is offline   Reply With Quote
Old 06-02-2019, 02:55 PM   #6
leon bee
Senior Member
 
Join Date: May 2017
Location: Arkansas
Posts: 611
Default Re: Carb and Distributor Dilemma

Sponsored Links (Register now to hide all advertisements)
Not to intrude, but this may be timely for me. That's what I get for reading all this every day. I just did a 53 mercury engine, done up as an 8BA. I used the distributor which came on the Merc engine. Haven't fired it yet, but now I gotta worry about those advance springs? More study required I suppose. And I don't see springs for sale yet.
leon bee is offline   Reply With Quote
Old 06-02-2019, 03:00 PM   #7
glennpm
Senior Member
 
glennpm's Avatar
 
Join Date: Sep 2014
Location: Wiscasset, Maine
Posts: 1,965
Default Re: Carb and Distributor Dilemma

Great explanation of vacuum source differences Flathead Fever!
glennpm is offline   Reply With Quote
Old 06-02-2019, 03:06 PM   #8
JSeery
Member Emeritus
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 16,132
Default Re: Carb and Distributor Dilemma

http://www.bubbasignition.com/49-53.html There us some information on Bubba's site.
JSeery is offline   Reply With Quote
Old 06-03-2019, 12:05 AM   #9
dgmgohl
Member
 
Join Date: Aug 2018
Posts: 53
Default Re: Carb and Distributor Dilemma

OK, but what if the distributor came off a 239?
dgmgohl is offline   Reply With Quote
Old 06-03-2019, 02:42 AM   #10
Flathead Fever
Senior Member
 
Flathead Fever's Avatar
 
Join Date: May 2010
Location: Yucaipa, CA
Posts: 1,091
Default Re: Carb and Distributor Dilemma

It says, "post quick reply". I can't seem to post a quick reply? The 1948 and earlier engines use a "vacuum brake". That is the front mounted style distributors. Those use manifold vacuum, not ported vacuum to control a spring and piston. It does not work like any distributor vacuum advance most people are familiar with. Its not complicated just different.

You need to understand what vacuum is and what effect the throttle plate opening has on it to understand how vacuum controls the timing using a vacuum brake or a vacuum advance. When the throttle plate is closed there is a high vacuum below the throttle plate. It just like sucking on a straw (now illegal here in CA) with your finger over the end, your finger being the throttle plate, there is a strong vacuum below your finger. That would be where the "manifold vacuum" port to the vacuum brake would be located below your finger. When you release your finger more air can flow through the straw but since there is no restriction (your finger) the vacuum drops below the throttle plate even though more air is flowing. The "ported vacuum" port is located right above the throttle plate. There is no vacuum there at idle when the throttle plate is closed because very little air is flowing past it. As the throttle plate opens and air begins to flow the vacuum increases at the ported vacuum port and drops at the manifold vacuum port. It depends on which side of the butterfly the port is located on as to how much vacuum you will have.
Just for fun install a vacuum gauge in your car, hooked to intake manifold vacuum. They are the simplest of all the gauges to install. You will learn a lot by just watching the readings as you drive around.

Manufacturers controlled vacuum advance and in later years many other components by turning them on or off with vacuum or the lack of vacuum. On some components vacuum opens the device and on others the lack of vacuum opened the device. Using the different types of vacuum signals gave the engineers a wide range of when and how they could turn on and off devices. If you look at late model carburetors, 1973 to around 1985 you will see several vacuum ports. Two down low on the carb, those are your manifold vacuum ports. A large one usually on the back bottom side of the carb's base plate. That goes to your PCV valve and another small manifold vacuum port to control other smog devices. About halfway up the carb there will be a ported vacuum port and possibly a third fitting which will be your venturi vacuum port. You need to understand that each port will receive vacuum to it depending on the position of the throttle plate. Its real important that the right component is plugged onto the right port. There are so meany vacuum lines on the 1980s cars there is usually a decal under the hood shoeing you where they all go.

If you have a Stromberg 97 or the other early stromberg or Holley carbs you have no vacuum ports on the carb at all. That because the distributor's "vacuum brake" used intake manifold vacuum directly from a fitting on the manifold. If you wanted another intake manifold port to control a Columbia 2-speed rear end, Southwind heater or just a vacuum gauge for inside the car you needed to add a spacer plate under the carb (below the throttle plate) with an "intake manifold" vacuum port. I definitely not an expert on all things flathead. The later flathead carbs "might" only have a ported vacuum port for the distributor advance. If you wanted a vacuum gauge in the car you might need to drill a hole for a fitting in the intake manifold. There might be one there already?


Its not like today where there are millions of sensor combinations such as rpm, temperature, engine load, air conditioner on or off, throttle position and many-many-more sensor readings. The computer goes to its look up tables and finds the perfect timing for that specific combination of sensor readings and then adjust the timing by firing the plug, based off of the crankshaft position sensor. Super precise. That's how these new engines make so much horsepower. The computer is constantly tuning the engine for every possible situation. Back before about 1985 they could only control the timing advance by the centrifugal weights or the vacuum. They used a duel diaphragm advance so they could control vacuum with both kinds, manifold and ported. They could turn on and off the vacuum with solenoids. They could delay the vacuum signal with valves that restricted the flow. They could control the vacuum with coolant temperature switches that could block the vacuum flow. You want to stay far away from any of those late 1970s and on up vehicles if they carbureted. Except for maybe the Mustang GT. The rest of them all need to be crushed Just too much stuff to go wrong. Fuel injection and distributor-less engines cured all those problems. The greatest two things that ever happened to engines.

Still, I love the old stuff even if it is a pain in the butt at times. I find it more interesting to see what the engineers could do mechanically to control things. I think you had to be a lot smarter to figure out the mechanical ways of controlling stuff than to be a computer programmer. The stuff they came up with amazes me. I just bought a basket-case 1922 Mack Truck. The engine has roller lifters in it. The different ways they solved problems back then. In my next life I'm going to be a Mechanical Engineer or a machinist. Its not going to be a phone company mechanic ever again!!!!!! If your young, I beg you not to become a mechanic. Go get a mechanical , electrical or some kind of degree that lets you create stuff.

There are some good description on the "vacuum brake" on this ford barn thread.

https://www.jalopyjournal.com/forum/...-brake.766874/

Its really important for everybody to understand vacuum readings when working on cars.
If you really want to be a "gear-head" you need to know all about vacuum to work on carburetors, distributors and diagnose mechanical problems such as bad valves. You have so much good information available online, great YouTube training videos. Get yourself a combination handheld vacuum pump, vacuum gauge and an "adjustable" timing light. Make sure it is adjustable! Then play with them. The best way to learn this stuff is hands-on . You can read forever, and be book smart, pass every automotive test and not be able to fix a damn thing. You need learn all about the electrical stuff. Staring with basic electricity, Voltage, amperage and resistance A majority of the problems posted on the Ford Barn are for fuel and electrical. Those two things, over and over are what stump most home enthusiasts. For some reason they will not take the time to understand how this stuff works. There is not much to it. You just need to be interested in it and it will be easy to understand.

The guys that say," I want something I can drive" and then they rip out the early drive train or they remove the points and install an electronic ignition. They are trying to turn the antique car into modern vehicle. Its because they did not grow up with these cars. They did not ride around for decades on points and carburetors. Never once breaking down because their dad maintained his cars properly. These new guys are afraid of their cars breaking down because they do not understand how they work. They want to just get it in and go. If you understand how your old car works you will not be afraid to drive it. If it quits you'll be able to pull over, know where to beat on it with hammer and be on your way again. If your new car quits, your getting towed to the dealer because nobody else with have the technology to fix it. If you don't think new cars break just go sit at the dealer and watch them come in on the tow trucks.

Last edited by Flathead Fever; 06-03-2019 at 04:05 AM.
Flathead Fever is offline   Reply With Quote
Old 06-03-2019, 04:28 AM   #11
Flathead Fever
Senior Member
 
Flathead Fever's Avatar
 
Join Date: May 2010
Location: Yucaipa, CA
Posts: 1,091
Default Re: Carb and Distributor Dilemma

Quote:
Originally Posted by leon bee View Post
Not to intrude, but this may be timely for me. That's what I get for reading all this every day. I just did a 53 mercury engine, done up as an 8BA. I used the distributor which came on the Merc engine. Haven't fired it yet, but now I gotta worry about those advance springs? More study required I suppose. And I don't see springs for sale yet.
The springs should be fine. Just make sure the advance can move and its not stuck from years of sitting. Grab the rotor and twist it and you should see the advance plate move and then spring back. Next, with the cap off pull the advance lever back and stick your finger over the vacuum port. The lever should stay in place until you release your finger. If not the diaphragm is leaking. Where I worked you were not allowed to have personal tools and the company provided just the basics. So many times my test tools were my fingers and my mouth. I've swallowed a lot of gasoline. That's another thing, suck on the advance diaphragm and see if it moves. Your using the same tuneup tools a Ford dealer mechanic would have had in 1950.

Find an adjustable timing light. I just recently bought another really nice one new in the box at an Estate Sale. The guy was a brain surgeon that died of brain cancer. Some how that just didn't seem right. I would think a guy sucking on distributors and fuel pumps, swallowing gas. He should be the one that gets brain cancer. I think have solvent for blood?

With an adjustable timing light you can see if the springs and vacuum advance are working correctly. You don't need to send a distributor off and put on a machine to be tested. Especially a late model flathead with a factory timing mark. You just need a dwell meter or even a just feeler gauge and a timing light, adjustable timing light. If its not adjustable throw it in the trash. Say the word, say it!!!! "ADJUSTABLE". It costs a lot more but you need it to be adjustable.
Flathead Fever is offline   Reply With Quote
Old 06-03-2019, 04:47 AM   #12
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,260
Default Re: Carb and Distributor Dilemma

Just a comment. I've had two adjustable timing lights over the last couple of decades. The first was a Craftsman I got from Sears years ago, when they were really Sears. That one quit working (the adjustable advance part) after a couple of years. I later bought a medium-priced unit from Amazon on which the advance part never worked. I thought I was inept until I borrowed my neighbor's light which works fine. I returned the Amazon unit and am still mooching off my neighbor. Hopefully, others will have better luck than I did.

Last edited by tubman; 06-03-2019 at 10:18 AM.
tubman is offline   Reply With Quote
Old 06-03-2019, 05:50 AM   #13
Flathead Fever
Senior Member
 
Flathead Fever's Avatar
 
Join Date: May 2010
Location: Yucaipa, CA
Posts: 1,091
Default Re: Carb and Distributor Dilemma

Adjustable timing Light operation. In my attempt to make better gear-heads out of you I looked for a good video on checking advance. This is a really good video on timing except that they are using a more modern MSD distributor with better advance settings. This distributor also does not have a vacuum advance. These guys have lots of excellent videos. You could watch their videos all day long. They really are good at explaining how things work.

setting total and initial advanvce

https://www.youtube.com/watch?v=wifTHbb06_I


The adjustable timing light

https://www.youtube.com/watch?v=MX3vsRDfKJg

You do not want a vacuum advance on a performance engine because under acceleration the vacuum drops off which causes the vacuum advance to retard the timing. That reduces the pressure in the cylinders and you loose horsepower. More pressure is more power but too much pressure will cause detonation. You can prevent detonation with high octane (slower burning) fuel but that is not practical in your daily driver. In order to use the cheaper 87 octane fuel without pinging under acceleration you have a vacuum advance. The vacuum advance is not there to advance the timing as most people think. You could do that just with a centrifugal advance. Its there to retard the timing. Actually its there to do both, advance and retard timing. While cruising there is enough vacuum to advance the timing for more power and better gas mileage. When you mash the pedal down the carb throttle plate opens, which as we discussed before causes the vacuum signal to drop off. That causes the vacuum advance to retard or eliminate some of the advance. That decreases the pressure in the cylinder so it does not detonate on the 87 octane fuel. Some smart people figured this stuff out. Some of those vacuum advances are adjustable by sticking an Allen wrench in the vacuum port.

Your flathead timing marks will be different than this engine in the video. For one, you will not have that nifty timing tape with 360 degrees marked on it. On an 8BA you will probably have one little dot on the pulley. That is the stock timing setting at 4 degrees.

The initial timing depends on the compression ratio of the engine and the octane of the gasoline. For modern octane gasoline cars almost every one I use to smog check had an initial timing at 10 degrees. So I figure 10 degrees is probably pretty good for 87 octane fuel. Just my theory. 4 degrees seems a little low to me. We can squeeze a little more power out of it by increasing the advance. More advance means more pressure (weight) pushing on the piston. Ever wonder why the engine rpm goes up when you advance the distributor?The fuel has longer to burn and expand, creating more pressure pushing down on the piston, more pressure moves the piston faster. We might as well get as much pressure as we can out of our gasoline without pinging.

Anther theory of on timing of mine is based on the 1965 Mustang. I have about thirteen 65 to '70 Mustangs. The stock timing on the 289 was 6 degrees with 8.0 to 8.5 to 1 compression. The Hipo Mustang was 10 degrees with 9.5 to 1 compression. I don't see any reason why the flathead with the same compression should not be timed about the same as the 289. You can try 10 degrees. The worst thing that can happen is it might ping under a load and you will need to dial the timing back a little or buy higher octane fuel.

The problem timing the 8BA flathead is you just have that one timing mark at 4 degrees. It was setup for an old fashioned timing light. A more modern adjustable timing light lets you program the timing light and change when the flash occurs. You can program the light to make that timing mark 10 degrees instead of 4 or you can make it the total advance at 30 degrees or whatever you degree you want. Its really a neat tool.
Flathead Fever is offline   Reply With Quote
Old 06-03-2019, 07:07 AM   #14
V8 Bob
Senior Member
 
V8 Bob's Avatar
 
Join Date: May 2010
Location: Granger (Northern) Indiana
Posts: 1,517
Default Re: Carb and Distributor Dilemma

Flathead Fever, The timing dot or mark on all late flatheads is 2 degrees BTDC, not 4. Total timing on a flathead is normally around 24 degrees BTDC, far less than 34-36 degrees on a typical OHV V-8.
V8 Bob is offline   Reply With Quote
Old 06-03-2019, 07:38 AM   #15
flatjack9
Senior Member
 
flatjack9's Avatar
 
Join Date: May 2010
Location: Oshkosh, Wi
Posts: 4,516
Default Re: Carb and Distributor Dilemma

Comparing timing of a modern OHV engine to a flathead is a not really pertinent.
flatjack9 is offline   Reply With Quote
Old 06-03-2019, 10:08 AM   #16
dgmgohl
Member
 
Join Date: Aug 2018
Posts: 53
Default Re: Carb and Distributor Dilemma

Flathead Fever, thanks for all the info. I'll post once I get everything connected the way its suppose to be.
dgmgohl is offline   Reply With Quote
Old 06-03-2019, 01:09 PM   #17
Flathead Fever
Senior Member
 
Flathead Fever's Avatar
 
Join Date: May 2010
Location: Yucaipa, CA
Posts: 1,091
Default Re: Carb and Distributor Dilemma

Quote:
Originally Posted by V8 Bob View Post
Flathead Fever, The timing dot or mark on all late flatheads is 2 degrees BTDC, not 4. Total timing on a flathead is normally around 24 degrees BTDC, far less than 34-36 degrees on a typical OHV V-8.
I said I wasn't a flathead specialist. I need to fact check everything I say so its not fake news. I make these kind of little mistakes all the time. Ticks me off! My memory is not that good anymore and I'm not even that old??? I was guessing the timing mark specification was 4 degrees from about 20 year's ago. I though for sure it was 4 degrees. I was only off a 1/10th of a degree for each year.

On my engines I don't use the factory mark on the 8BA engines and there is no tiimng mark on the earlier engines. I have not done that many of them. On both the 59A and 8BA I find TDC with the head off. Mark the pulley at TDC, 4,8 and 12. Maybe that's where the 4 degrees stuck in my head.

Using a dial indicator I rotate the #1 piston up until it is at the top of the compression stroke and mark the pulley next to the timing pointer. You will need to make a pointer on the pre-8BA engines. Then you rotate the engine in the opposite direction until the piston comes up again at the top of its travel and make another mark. In between those two marks is true TDC. That is from the instructions that came with an ISKY degree wheel. I've never checked to see how accurate an 8BA timing mark is? If you have the head off do not put it back on with out creating a TDC timing mark on your pulley. It will make life a lot easier.

I think this is how I made the timing marks? It been a long-long time. Once I have the TDC mark I measure the diameter of the pulley and multiply it by 3.14 to find the circumference. Example, a 6" pulley multiplied by 3.14 equals 18.84 inches. Convert that to millimeters, 25.4 millimeters to the inch. 18.84" x 25.4 millimeters equals 478.54 millimeters. Divide that by 360 degrees, 478.5 divided by 360 equals 1.33 millimeters for each degree on the pulley. Make marks on the pulley at 4,8 and 12 degrees and a mark at the total advance you will want. I use a little Dremel cutoff wheel and make real tiny notches at each mark ( I don't want cracks forming from them). Then I paint them white using a bottle of "white out". Now you don't need a timing fixture to set your early distributors, you use a timng light like any other engine.
Flathead Fever is offline   Reply With Quote
Old 06-03-2019, 01:38 PM   #18
Flathead Fever
Senior Member
 
Flathead Fever's Avatar
 
Join Date: May 2010
Location: Yucaipa, CA
Posts: 1,091
Default Re: Carb and Distributor Dilemma

Quote:
Originally Posted by flatjack9 View Post
Comparing timing of a modern OHV engine to a flathead is a not really pertinent.
I didn't see you post a comment on flathead timing. But you have time to criticize someone that's only trying to help. This happens all the time. It upsets me when all I'm trying to do is help. This takes up a lot of my time but I enjoy helping people that want to learn how things work, not just the people that want a quick free fix for their cars. I like saving people money and time. That's why I usually include too much info, if that's possible?. Another elderly friend with over 50-years of Flathead experience just quit giving advice on the Ford Barn. If its not enjoyable why do it. There are a lot of guys out there with tremendous amounts of info that will not share it with you. They want you to pay for it.

I think I need a break from the Ford Barn for awhile. Why don't you take over teaching. I'll take my 40-year's working on cars professionally for a living. Fixing the problems other mechanics cannot figure out and go work on my own 14 cars or I can spend time with my two-year old napping grandson when he wakes up. I need to turn him into little gear-head. Somebody has to carry on with the flatheads. Life is too short to waste any of it.

Last edited by Flathead Fever; 06-03-2019 at 01:44 PM.
Flathead Fever is offline   Reply With Quote
Old 06-03-2019, 01:46 PM   #19
JSeery
Member Emeritus
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 16,132
Default Re: Carb and Distributor Dilemma

The issue I see is a lot of information that applies to later model OHV engines and not to flatheads. In some ways the same basic information applies to all internal combustion engines, but there is a lot that is flathead specific. Folks who have worked later model engines for most of their lives can have difficultly with the flatheads, so it is important, IMO, to not add to the confusion.

Last edited by JSeery; 06-04-2019 at 06:57 PM.
JSeery is offline   Reply With Quote
Old 06-03-2019, 01:53 PM   #20
scicala
Senior Member
 
scicala's Avatar
 
Join Date: Jun 2010
Location: Detroit suburb, MI
Posts: 3,697
Default Re: Carb and Distributor Dilemma

"Grab the rotor and twist it and you should see the advance plate move and then spring back."


Just one correction on the post #11 (above). The distributor shaft on Loadomatic distributors is solid, and you can't grab the rotor and turn it. I think Flathead Fever meant to say "rotate the breaker plate in the distributor".


Sal
scicala is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 01:59 AM.