Re-jetting (or not) the DFEV

[wetminkey]

I doubt a leak at the intake, since I sealed the new gasket around all intake and water openings,...but a possibility. Bolts have been re-torqued, too.
The DFEV's speed screw has always been set to 1.5 turns out,...no more. It states how important that is in the literature that comes with it,...
I may have the chance to remove the cam covers tomorrow, and start checking valve gaps. If they're good, then it's time to talk to racer-Mike again about the Weber,...!
Process of elimination is painfully slow, but works really well! I'm really glad that the 100 degree weather has moved on! The garage was becoming unbearable later in the day,...
Bodywork is about done,...down to tiny stuff.

[wetminkey]

Opened it up and found all valve gaps at 0.018. #4 exhaust is probably 0.019, but ALL of the others are 0.018. I checked all of them twice. No abnormalities inside the boxes,...all looks good.
Intakes are supposed to be 0.015 - 0.019 and exhaust, 0.018 - 0.021,...so I'm OK. Wish the intakes were more like 0.015 gap, but they're within the normal range. Thoughts?
TDC sure seems to be where I have marked it, and #4 valves are fully closed at that time. Timing belt timing must be proper - it's easier to tell for sure with the cam box covers off.
Now I have a full assessment of the engine, at THIS time,...valve lash and compression check.
So, I'll guess that the Weber needs some adaptation to 5000 ft above sea level. Time to talk extensively with racer-Mike!
More soon. Todd.

[18Fiatsandcounting]

To answer your question about your valve clearances, your measurements sound fine to me.

Any chance you could put the original ADHA carb back on and see if you still have the same issues? At this point, it's hard to tell whether the issue is with the new DFEV or something else.

-Bryan

[wetminkey]

Here's that TDC, with the pencil:

I double checked it and everything is RIGHT ON, including my newly painted TDC marks.
Valves/cams and distributor at TDC:

I've got a couple of new cover gaskets, and a couple of new shims coming. While I'm here, I'll tighten the gaps on the intake side, so that I open the valves a bit more,...exhaust side is just right.
As I said, I now have a full assessment of the engine, with measurements, and the DFEV is the only item left. Engine internals are as they should be,...
Racer-Mike has the jetting book and the experience,...I wonder if he has a jetting kit?! That would be really cool!
Only problem is that he's nearly deaf. Can you guess how he got that way,...?!

[18Fiatsandcounting]

Sounds like a plan. Be careful on lowering the valve clearances too much, as the clearances are there to keep the valves from being held open on the backside of the cam lobes, when the engine is running really hot. The clearances decrease as the engine heats up, which is why they're measured cold. If you have a valve or two that's held open, even slightly, during the combustion period, bad, very bad...

-Bryan

[SteinOnkel]

Wish the intakes were more like 0.015 gap, but they're within the normal range. Thoughts?

My thoughts are that it is a range. If they wanted them to be 0.015, the spec would be 0.015

Had the same discussion with my doctor the other day. Blood test came back "Low normal, within range" and she wanted to prescribe expensive pills. I think not.

[wetminkey]

Very true. However, the gaps will only get larger, over time. Since I have the easy access now, I might as well change them to the larger shims,...cheap and easy to do for this low-mile engine. I even had a proper-sized shim for #2 intake in my stash of new ones,...so I only needed three.
Gives me time to study up on rejetting Webers,...
I'm a retired nurse. I don't talk to doctors,...

[manoa matt]

Couple of things to check.

Does your accelerator linkage allow full travel? Have someone push the gas pedal to the floor and watch the linkage and how the primary and secondary throttle plates react. Then with the helper keeping the pedal floored, pull the linkage more to see if there is still travel that is not being transmitted to the carb throttle shafts. Adjust the cable or push rod to allow full travel. The secondary should hit its full rotational travel stop point before the pedal hits the floor.

Under the distributor cap on top of the advance plate will have a number stamped either 11 or 16. with a tiny degree circle The 11 is a 22 deg. advance distributor, the 16 is a 32 deg. advance distributor. With a timing light confirm you are getting the proper advance. The 79-80 carbed cars used one type and the FI cars used the other, however I can't recall which used which.

Also confirm the vacume advance works when you suck on the hose. Also the hose should be connected to a ported vacume nipple on the carb. The vacume advance also has an adjustment but you need to remove the distributor to get the vac advance dismounted from the distributor, unless you are patient, have a tiny ratcheting screwdriver, and a mirror. The white plastic end that intercepts the advance weight ball can be adjusted by dismounting it from the ball and screwing in or out. The vac advance module like the carb linkage can not be reaching full advance if it was rebuilt and assembled in a middle position.

[wetminkey]

Let me guess, Matt,...you haven't read through the thread,...

[manoa matt]

I did, I saw what others have said about the vac advance being not needed or noticeable. I do not agree with those statements. I have the 22 deg the 34 deg vac advance electronic distributors, and currently run the MarelliPlex type that does not have the vac advance. There are huge rev differences and performance curves between the three. If you run the 22 deg unit without the vac advance, your rev's will top out early.

In my experience rebuilt or new items such as carburetors and distributors are simply put back together. They are not adjusted so they are plug and play, rather the source of many frustrations, or sub-optimal performance.

I'm just trying to help and offer further insight. I can't offer any advice on the 28/32DFEV. My personal preference is for the 32ADFA and 34ADF as they were specifically designed for Fiats, and there is a wealth of information on them which takes out much of the guesswork.

If you have not seen this publication, it is a must, and a bible for 124 spider owners. Check the ignition section of the second download "Engine Maintenance and Modification" https://sites.google.com/artigue.com/fiat/home

[wetminkey]

Like I said, Matt,...
Brand new, complete distributor already installed,...advance already checked with timing light.
The DFEV is the ONLY variable left.

[manoa matt]

https://www.amazon.com/Weber-Carburetor ... =8-1-spell

https://www.amazon.com/Weber-Carburetto ... 243&sr=8-4

[wetminkey]

Thanks, man, but I've got a seasoned race car driver that lives just up the road! He's tuned and raced numerous Webers, and he owns the Weber carb book, too! How lucky is that?!
I'll post here as I learn and work through it,...
Thicker intake shims will be here Monday. I'll install my new shims, then measure and record my valve gaps and shim sizes. Then it's on to the Weber,...I'd best borrow that book from racer-Mikey, and start studying up, soon!
Went through my Spider's doors today,...quite thoroughly. Windows crank so easily, and quietly, now!

[wetminkey]

Racer-Mikey has a book for side-draft Webers, not down-drafts, so I went internet searching and found this in short order:
http://www.lcengineering.com/LCTechPage ... titude.pdf
Quite interesting,...
I think I'll also get one of the Weber tuning books that Matt had recommended. Again, I'll post what I discover.
New shims in tonight, I'll measure intake valve gaps tomorrow.

[blazingspider]

However, the gaps will only get larger, over time.

Not true. Valve lash gets tighter on a TC motor as the valves wear into the valve seats.