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-   Ford Inline Six, 200, 250, 4.9L / 300 (https://www.ford-trucks.com/forums/forum52/)
-   -   question about the dp (https://www.ford-trucks.com/forums/1167720-question-about-the-dp.html)

fordboy300 06-09-2012 12:24 PM

question about the dp
 
Well on my truck I have the carb sitting the right way but right now the throttle cable sometimes it get stuck at times because it to close to the heater box and my friend its best if I turn the carb the other way. But I told him the primaries have there own spot as well as the secondaries. But then he told me that as long as the intake feed all six I should be okay. Do you think this really matter I remember when I first got the intake it said why the intake sit how it does but I lost it.

F-250 restorer 06-09-2012 10:49 PM

With the DP the throttle linkage should be facing the firewall. Both the primaries and the secondaries have separate channels that the air/fuel mix travels. The primaries travel a smaller channel, and the s. travel a larger one beneath the p. channel. When they reach the head they mix. That affect is supposed to create economy and performance. If you change the orientation of the carb on the manifold, you defeat the purpose of the dp.

BigBlue88 06-10-2012 08:52 AM

In addition to the performance design, the dp primary runners are much smaller than the secondary runners. If you rotate the carb, you will get uneven draw on each half of the carb.

Also, primaries are on the bottom of the dp manifold for manifold heat & driveability. Linkage towards firewall.

fordboy300 06-10-2012 05:25 PM

Thanks guys well ill just keep the carb how it is then.

fordboy300 06-13-2012 10:39 PM

So many of you may frown on this but my friend and i turned my carburetor around, just to see if the throttle linkage would bind up like it did when it was turned the "correct" way, and it didn't at all. With the carb this way i noticed right away that it idled way smoother and it even picks up way better then it did before. Maybe i had it sitting the wrong way the whole time. ha ha. :-X18

BigBlue88 06-14-2012 08:53 AM

Which way are the primaries facing now?

Brad_81Ford 06-20-2012 09:18 PM

I, too, am curious about this. As of right now, my throttle linkage is facing the front of the truck. I have some bogging under WOT; could this be the source of my problem? I have an Edelbrock 500 mated to the Offenhauser DP intake, via a generic spacer from Auto Zone.

f100jim 06-21-2012 01:42 AM

IIRC On the 6019-DP the smaller runners are on the bottom. These are fed by the two carburetor holes closest to the engine. Your carb should be mounted sideways with the primary bores closest to the engine.

Harte3 06-21-2012 10:17 AM

Brad_81Ford: Do you have heat plumbed to the intake? If not, therein lies a good part of your problem. If you do have heat then the air flap on the secondaries needs to be adjusted so the do not open too soon.

Rogue_Wulff 06-21-2012 12:17 PM


Originally Posted by Brad_81Ford (Post 11975902)
I, too, am curious about this. As of right now, my throttle linkage is facing the front of the truck. I have some bogging under WOT; could this be the source of my problem? I have an Edelbrock 500 mated to the Offenhauser DP intake, via a generic spacer from Auto Zone.

Sounds like you have the wrong way round. The smaller primaries should be closest to the engine. This would put the throttle linkage towards the rear/firewall.


Originally Posted by f100jim (Post 11976680)
IIRC On the 6019-DP the smaller runners are on the bottom. These are fed by the two carburetor holes closest to the engine. Your carb should be mounted sideways with the primary bores closest to the engine.

Like this.

AbandonedBronco 06-21-2012 12:51 PM

Proper Offenhauser DP carburetor orientation:

https://www.supermotors.net/getfile/...new-intake.jpg

https://www.supermotors.net/getfile/...holley-390.jpg

Brad_81Ford 06-21-2012 02:17 PM


Originally Posted by Harte3 (Post 11977604)
Brad_81Ford: Do you have heat plumbed to the intake? If not, therein lies a good part of your problem. If you do have heat then the air flap on the secondaries needs to be adjusted so the do not open too soon.

No there is not. I had intended to install the heating plate, but the one I bought was all goofed up. The holes weren't aligned correctly and the tubes were way too long to fit comfortably under the intake. The temperatures have been in the 90s all week. Would those temperatures still require a heating plate?

If that's the case, I'll just remove the intake and exhaust manifolds to get at the bottom of the intake. From my experience, trying to bolt it up while the intake was installed turned out to be a big PITA. I'll also turn the carburetor around. That should solve a lot of my issues, it seems.

quaddriver 06-21-2012 02:19 PM

just promise me that when you are done, 1 primary feeds each of the planes, and 1 secondary feeds each of the planes, or both primaries fee 1 plane, and the secondaries feed the other plane.

AbandonedBronco 06-21-2012 02:29 PM


Originally Posted by Brad_81Ford (Post 11978425)
The temperatures have been in the 90s all week. Would those temperatures still require a heating plate?

Yes. Your coolant heats it up to 195° or so (over 100° more than your ambient air). The exhaust heat was even MORE than that, so it's asking for quite a bit of heat.
Not only that, but the air/fuel mix moving through the intake will actually cool it down.

On a 100° day, I drove for 3 hours on the interstate and when I reached my destination, I hopped out and put my hand on the underside of the intake (when there was no coolant plate), and it was cool to the touch. It wasn't even remotely hot. I would wager it was 10 - 20° less than the 100° it was outside.


If that's the case, I'll just remove the intake and exhaust manifolds to get at the bottom of the intake. From my experience, trying to bolt it up while the intake was installed turned out to be a big PITA. I'll also turn the carburetor around. That should solve a lot of my issues, it seems.
Heh, yes, it's MUCH easier to put it on outside of the vehicle. I remember when I first installed one, I tried putting it on while it was in the truck and it was very frustrating.

BigBlue88 06-21-2012 02:29 PM

Manifold heat is required, even in the summer. Look at an aviation carburetor icing chart. A venturi or throttle will get cold enough to form ice even at 100F air temperature without external heat.


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