ADHA to DFEV carb/manifold swap on '79

[wetminkey]

Intake is all sealed up with Allen plugs and one 10x1.5mm shortened bolt. It looks very nice,...factory-like.
Here's the steel EGR block-off plate (and paper template that I used to make it) that I fabricated from a piece of scrap, and the aluminum scrap that I altered to create a strut to secure the dipstick (previously attached to the side of the dual plane manifold).



Pics of their installation later,...
Full list of changes involved in this swap:
Old water choke hose goes to coolant outlet on manifold
New hose for carb to distributor vacuum
Manifold vacuum from "triple fitting" = 1.) tranny vacuum 2.) vapor canister vacuum 3.) Brakes vacuum assist
Block old carb-bowl vacuum on top of vapor canister
8mm ball stud for DFEV to attach factory Fiat linkage
Fuel supply/return will be handled with the fuel filter w/ return that geospider had referred to
And I'll need to engineer a way to get crankcase gases into the new air cleaner,...
I'm pretty sure that's the sum of it. With advanced preparation, and this information, this swap could be done in a day.
Installation pics ASAP,...
I sure hope this thread keeps everybody else from having to figure out this ADHA to DFEV swap on their own,...
BTW, the car will not pass emissions after this (but not required where I live, in farmland), but I will save all of the items removed (marked for re-installation) so that I can pass them on with the car. It would be highly probable that they might be necessary for a '79 vehicle to be licensed for the road in the future,...and they're the original parts.
Have fun with this, and, more importantly, THE RESULT!
Todd Compton.

[geospider]

looks like you are ready to go.
for the crankcase vent; assuming you have the "lunchbox" air cleaner, there is a hole with a plastic elbow that comes with it. This is a smaller diameter than the hose. You can either do a little plumbing, using a reducer and attach a smaller hose that fits. Or, I have seen folks making the hole in the cleaner larger to accept the hose size. would need a different size connector to the cleaner of course.

can't wait to hear your progress.

next month I get to do the opposite: put the old stuff back on for a day at the smog station. then of course back to the more fun application.

If AB 210 passes in Ca assembly; this would change.

George

[wetminkey]

Intake, plate, and dipstick strut installed/assembled today,...you'll like the carriage bolt that secures the dipstick to the strut,...it looks nice.
Fuel filters with return outlets came today.
The gasket sealer will be cured in 24hrs, so I'll finish tightening bolts tomorrow, hook up some hoses, and get some pics.
Coolant "T" gasket and air cleaner should be here soon, and I can start filling the cooling system in the meantime. I'll double check the new Weber's float setting and install it, also.
It sure was a lot easier installing the new intake than it was taking out the old one!!
Todd.
P.S. Man, geo, what a horrible task. I hope it goes easily for you,...

[wetminkey]

A pic, or two, as promised:

[wetminkey]

Big struggle getting the timing cover back in due to slightly bent rear cover attachments,...just took a lot of time and was quite aggravating!
That was the biggest struggle of this project, other than removing the HUGE dual port intake in the first place,...
Re-using the stock throttle linkage took a little 'figuring out' before I could find an angle that worked from idle to WOT. The DFEV has a long throw, and with the Fiat's throttle linkage, it's at an odd angle. Third try was a charm, and I just need to re-adjust my auto tranny kick-down to allow the DFEV to get to WOT, now.
All vacuum hoses fitted directly to the manifold's 'triple' fitting, and the old ADHA's water choke hose attaches to the manifold's coolant outlet without any changes.
The old ADHA solenoid 12 V+ plugs right onto the DFEV's electric choke contact.
New air cleaner for the DFEV and coolant "T" gasket will arrive tomorrow,...everything is ready for completion.
More pics, and results, ASAP.

[wetminkey]

Oh, man! OH, MAN! OH, MAN!!
And we haven't even left the garage!!

[wetminkey]

First of all, this car has NEVER idled as smoothly and consistently as it does with this new DFEV/single plane intake swap! And I'm SURE that it will FAR outperform the original ADHA/dual plane! I think it even runs cleaner,...
BUT (if using the original throttle linkage) I find it impossible to open up the DFEV fully if the throttle ball is mounted vertically on the DFEV's throttle arm. If I adjust the throttle rod so that I have an idle, I find that the rod geometry will not allow for WOT (wide open throttle). If adjusted for WOT, idle cannot be set,...
As I suspected originally, the throttle ball must be attached to the DFEV's throttle arm at a right angle (horizontally) to allow full motion without binding. My test set-up works GREAT!
I should have a 'full-duty' throttle linkage very soon and I'll post pics then.
All that's left is plumbing the crankcase ventilation hose to the new air cleaner,...
Hope your week goes well, y'all.
Todd.

[wetminkey]

This is how the DFEV's throttle arm is best attached to the 1979 Fiat's stock throttle rod so that idle and Wide Open Throttle can be achieved:



Other's may have a better method, but I found that less than full throw will be seen if the throttle ball is mounted vertically on the DFEV's throttle arm,...the geometry becomes too tight for the Fiat throttle rod ball joint just as the DFEV opens the secondary.
Attaching the throttle ball horizontally eliminates binding, and allows the DFEV to open it's secondary completely.
Still gotta plumb the crankcase vent to the new air cleaner,...I'll tackle that minor job tomorrow.
This is going to be really fun to drive! I hope I don't break anything!

[focodave]

Other's may have a better method, but I found that less than full throw will be seen if the throttle ball is mounted vertically on the DFEV's throttle arm,...the geometry becomes too tight for the Fiat throttle rod ball joint just as the DFEV opens the secondary.
Attaching the throttle ball horizontally eliminates binding, and allows the DFEV to open it's secondary completely.
Still gotta plumb the crankcase vent to the new air cleaner,...I'll tackle that minor job tomorrow.
This is going to be really fun to drive! I hope I don't break anything!

Todd,
Perhaps you'll break the sound barrier!
Good luck -- looks like a well-executed swap.
Dave

[wetminkey]

And perhaps my Spider can make that long-since planned cruise of Horsetooth Reservoir with you this year! Getting close now,...
Glad you saw my thread, Dave!

[geospider]

here is the pic you were looking for. Mine is in a vertical position. As far as I know, it fully opens, no binding.
I know tat I put a bit of a bend in the rod; easily done BTW.

what a great upgrade you have done.

geo

[manoa matt]

Why not just transfer over the ball crank arm from the ADHA to the DFEV?

[wetminkey]

Howdy, Matt!
The ball stud on the ADHA's bellcrank is oriented vertically, which results in binding of the linkage prior to either WOT (or idle, depending on initial adjustment) with the DFEV's longer throw. No matter how I oriented the Fiat throttle arm, or adjusted it, I was unable to obtain full range of throttle motion with a vertical orientation of the ball stud,...believe me, I tried different adjustments for nearly two days before I decided to go back to my initial thought of orienting the ball horizontally.
With the ball stud mounted horizontally, ALL binding is eliminated, and I was able to obtain MORE range than needed for full throttle motion. A better engineered solution,...
Thanks for asking,...I was given the impression that this swap was more 'plug and play' than it actually is. I'm glad I've done a number of carb/intake swaps on various engines in the past,...I hope this thread will help make this an easier task for other members.
Todd.

[dinghyguy]

Hi Todd,

Your work will certainly hep me (and i need it of course). I am hoping to get virtually the same stuff from various sources in the next week or so. When Fiat one get the suspension finished i can take it out of the too small garage and put Fiat two in and do the swap...…. But unlike you, i will have to rebuild the carb in addition to the intake work.

Thanks for your work.
dinghyguy

[PaulC]

Doing a similar swap with a n ADFA carb and a single plane manifold.
Currently rebuilding the carb.
Manifold rework completed.