Flathead tuning and other issues. - Ford Truck Enthusiasts Forums
 

Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1948 - 1956 F1, F100 & Larger F-Series Trucks
Log In 


1948 - 1956 F1, F100 & Larger F-Series Trucks Discuss the Fat Fendered and Classic Ford Trucks

Flathead tuning and other issues.

Reply
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 07-18-2015, 12:51 PM
JPMallory's Avatar
JPMallory JPMallory is online now
Senior User
 
Join Date: Feb 2014
Location: IN
Posts: 399
JPMallory has a good reputation on FTE.JPMallory has a good reputation on FTE.JPMallory has a good reputation on FTE.
Flathead tuning and other issues.

I'm having some issues with my flathead, and I'm turning to the smartest group I know for advice--you guys.

Here's what's happening currently:
The truck starts and idles fine. (At around 600 rpm). After I get it up out of my driveway and drive about half a mile, I have to stop on an incline before I can turn. Once I hit that incline, it starts to sputter, and will die if I don't immediately hit the gas. It does the same thing when I back down the driveway after returning home.


Here's what was going on before I started messing with stuff:

  • Carb was leaking fuel, and has been for some time now.
  • Motor started missing/running rough. Not often, but the last couple of times I had taken it out (before I started working on things, that is) it ran rough until it had warmed up, and then seemed be fine.

Here's what I've done
:
  • I rebuilt the carb the other day, to fix the fuel leak issue. This is the first time I've rebuilt one.
  • I emptied the sediment bowl on the fuel pump, as it had a fair amount of crap in it.
  • After rebuilding and reinstalling the carb, I made some adjustments to the idle rpm, dwell, and to the spark plug gaps based on the specs I've read here: Flathead Tuneup Specifications for 1949-53 V8 (239 & 255).
Here are some questions I have:
  • Where do you think I should be looking?
  • From the MacVP link, it stated that the idle rpm should be 475. Is that where I need to be? It's at 600 now, and was around 750 (or higher) for the past year. If I take it any lower than it is now, it barely runs.
  • What should the spark plug gap be set to? I've found some conflicts between my Motors manual and the MacsVP page. I've set them to .030
  • Same question for the dwell. I adjusted the point gap (it was around .010) to .016, and the dwell fell to 30, so I readjusted until it reached 28. I don't know what the gap is set to now, but it's certainly above .016.
  • Who's idea was it to let me work on a truck anyway?
Reply With Quote
  #2  
Old 07-18-2015, 12:58 PM
ALBUQ F-1's Avatar
ALBUQ F-1 ALBUQ F-1 is online now
postin' fool
 
Join Date: Jul 2004
Location: NM
Posts: 20,731
ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.
Stock fuel pump?
Stock coil/ignition?
Is the incline up or down (front lower or higher than rear)?

38Coupe recommends setting the float level on Holleys quite a bit lower than spec to help with ethanol related issues. If the problem is on inclines, that sounds like spillover from too high a level.

With stock ignition, .025 on plugs. No real benefit IMO to go higher, but a stronger hotter spark may mask an overrich condition. How do the plugs look?

You're OK on dwell. Did you re-time after setting dwell? You need to. Are you getting vacuum advance?

475 RPM may be spec, but most usually idle better around 600. Have you adjusted the idle mix screws? Put them lean (screw in) until it starts to sag, then out only enough to reduce missing.
__________________
Ross
1952 F-1 Flat V8 3-on-the-tree, MSD, Rochester 2G, Red's Headers

"Never attribute to malice that which is adequately explained by stupidity" -- Hanlon's Razor
Reply With Quote
  #3  
Old 07-18-2015, 01:11 PM
JPMallory's Avatar
JPMallory JPMallory is online now
Senior User
 
Join Date: Feb 2014
Location: IN
Posts: 399
JPMallory has a good reputation on FTE.JPMallory has a good reputation on FTE.JPMallory has a good reputation on FTE.
Quote:
Originally Posted by ALBUQ F-1 View Post
Stock fuel pump?
Stock coil/ignition?
Is the incline up or down (front lower or higher than rear)?

38Coupe recommends setting the float level on Holleys quite a bit lower than spec to help with ethanol related issues. If the problem is on inclines, that sounds like spillover from too high a level.

With stock ignition, .025 on plugs. No real benefit IMO to go higher, but a stronger hotter spark may mask an overrich condition. How do the plugs look?

You're OK on dwell. Did you re-time after setting dwell? You need to. Are you getting vacuum advance?

475 RPM may be spec, but most usually idle better around 600. Have you adjusted the idle mix screws? Put them lean (screw in) until it starts to sag, then out only enough to reduce missing.
Stock fuel pump.

Coil/ignition, I don't know for sure. PO converted the truck to 12v. Do those get changed for 12v conversion?

Up. Front end is on the higher elevation.

I'll take a look at the float and readjust it. Thanks.

All the plugs were coated with carbon. Pretty consistent across all of them. I should have mentioned that earlier.

I did not re-time, as I don't have a timing light. (yet). I'll pick one up today and I'll learn how to set timing.

I did adjust the idle mix screws, and that's how I settled on around 600 rpm.

Thanks!
Reply With Quote
  #4  
Old 07-18-2015, 01:27 PM
ALBUQ F-1's Avatar
ALBUQ F-1 ALBUQ F-1 is online now
postin' fool
 
Join Date: Jul 2004
Location: NM
Posts: 20,731
ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.ALBUQ F-1 has a spectacular reputation.
The coil probably got changed as part of the 12v conversion (plus added ballast?), but what I was after is that you don't have a high energy system (pertronix or MSD).

Definitely sounds like sloshing. There is a vent tube from the fuel bowl to the throat of the carb going front to back. You really have to have a high level to get it coming out of there, tho.


Click the image to open in full size.
__________________
Ross
1952 F-1 Flat V8 3-on-the-tree, MSD, Rochester 2G, Red's Headers

"Never attribute to malice that which is adequately explained by stupidity" -- Hanlon's Razor
Reply With Quote
  #5  
Old 07-18-2015, 02:17 PM
fordf348's Avatar
fordf348 fordf348 is online now
Senior User
 
Join Date: Jan 2011
Location: near Philadelphia Pa
Posts: 338
fordf348 is starting off with a positive reputation.
How is your gas tank?.........crud in the fuel pump bowl does not sound good......I played with mine for years before I put in a new tank and problems went away
Reply With Quote
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
70 F250 390 ignition problems zackinno70 1967 - 1972 F-100 & Larger F-Series Trucks 1 03-11-2016 12:36 AM
Distributor Lobes - Question Rusty_S Y-Block V8 (239, 272, 292, 312, 317, 341, 368) 31 07-04-2015 05:15 PM
Tune-up Specs Questions rpaxton939 1948 - 1956 F1, F100 & Larger F-Series Trucks 11 03-07-2014 08:51 AM
cant set dwell on points hallgren87idi 1973 - 1979 F-100 & Larger F-Series Trucks 5 11-24-2013 11:22 AM
Need help tuning a Holley 4160 chumley360 FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 7 06-14-2009 07:17 PM


Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1948 - 1956 F1, F100 & Larger F-Series Trucks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump



All times are GMT -5. The time now is 05:16 PM.

 

Advertising - Terms of Use - Privacy Statement - Terms of Service - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup