250 GTE carb overhaul

40DCL probably correct depending on how early the car is. I think another weber was also used later, but not certain. DCL's are typically black. Nuts holding the carbs to the manifolds are M8 x 1.0 with 12mm wrench dimension, finished black oxide. Your photos show the air cleaner grille painted silver? Under that non-original paint is probably the original plated finish, rusted. The air cleaner grille is nickel plated, a relatively satin finish, not polished. You can prepare it by stripping the paint and slowly glass bead to bare metal using very low pressure or otherwise the grille will distort. Rinse it thoroughly in denatured alchohol to remove all residue of beads. Shape it for fit to the top after you have prepared it. Although the grille was probably plated separate before spot welding to the base originally, it is now only practical to plate the whole thing and then go back, mask off the grille and paint the platform semi gloss black.

 

I also think that the 40DCL is correct. I was told however that the inside plug engines had the carb painted black, and outside plug engines were bare metal. I don't know for sure if this is correct or not. I was also told that the inside plug engine timing chain cover was bare metal and not painted.

Be aware if you have not used Pierce before your carbs will need to be completely set up and throttle plates aligned, I was a bit surprise the first time that I couldn't just bolt them on and syncronize. Also they will not bring the base flat if they are warped etc. I was sanding for hours to bring the bases flat.

 

Correct for earlier cars. Later 36DCS.

 

From the GTE Manual.
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I understand that the color of the carbs is related to the carb tipo. DCL's (36 or 40) were generally painted black for example, whether used for inside plug or outside plug; but DCS was bare, DCZ was bare. About the timing chain covers, the timing chain covers on the inside plug 128C, 128D motors were painted silver (not bare metal) like the other engine castings (except the black wrinkle finish cam covers, etc.). This practice continued with the early outside plug engines which appear also with silver painted timing chain covers. At some point the practice changed to black wrinkle finish also for the timing chain covers.

 

The Weber data sheets that I have lump these 3 carbs together. They use the same jets, chokes, tubes etc. The main difference is castings; DCF= sand cast "anticorodal aluminum", DCZ= pressure die cast Zamac(Zinc?), relatively soft and quite heavy, the bases warp severely when (over)tightened, DCL= pressure die cast aluminum. I think that only the DCLs were painted.
Later cars used DCS which are Zamac with diaphragm type accelerator pumps.
Anton

 

I'm surprised to hear you say that they don't align (do you mean take up the backlash in the sector gears?) the throttle plates. Everyone else I've heard on here and Tom Yang says that syncing is all thats needed after a Mike Pierce overhaul. $7-900 per carb is a lot. What does he do besides fit new throttle shafts? Does anybody have pics of a recently overhauled Pierce Weber?

 

We have 36 DCLs on our Pf coupe, not painted, no paint on nuts or anything. Black wrinkle finish on the cam covers. Pierce sent me replacement needle valves and seats about 4 years ago and they were perfect. It is a bit tricky getting all three carbs nestled in your two hands and settled down onto the intake manifold, took me several tries to get everything lined up. I only removed the top plates of each carb, so had to line up the floats, to settle the tops down on the bodies of the carbs. Wished I had three hands! Got them in eventually and everything hooked up and the engine sparked right to life and runs great. Best of luck.

 

DCL's:
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In regard to Glassman's comments:
"Be aware if you have not used Pierce before your carbs will need to be completely set up and throttle plates aligned, I was a bit surprise the first time that I couldn't just bolt them on and syncronize. Also they will not bring the base flat if they are warped etc. I was sanding for hours to bring the bases flat."

I have had several sets of Webers rebuilt by Pierce manifold and have been through their shop and discussed the process for rebuilding old worn out Webers.
The do not mill, sand or otherwise remove metal off the bottom of the carbs as that is the worst possible way to deal with the warped base. The problem is that the whole carb body is warped by years of over tightening as the phenolic spacers between the carb and intake manifold degrade and compress.
As a result this causes additional wear to the bores of the throttle shafts.

So their process for truing the carbs is by putting them in a very ridged clamp fixture and heating the carb body while it is under the pressure necessary to straighten it, and then letting it cool and then repeating the process until the carb body is true again. Once the carb body is straightened they then bore them for oversize throttle shafts and reassemble the carbs. In the process they check float heights and replace all jets and gaskets. The finished carb is then set up on a flow bench and balanced.
So if you have a motor that is in new condition with good compression and proper ignition, they should bolt on and be synchronized.
However this is rarely the case. Most 40yr old Ferrari's are in a little less than optimum condition in one or more areas and the carbs need to be adjusted to balance out a problem existing in that situation.

Heres a picture of Mike Pierce checking one of my 36 DCS carbs on the flow bench. Along side you can see a set of repro 38 DCN carbs they were rebuilding as well.

Aloha,
Mark
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