morfirst

The fluid level mark on the plunger is difficult to read at times. I assume if you overfill, the resistance to needle movement will be greater. Should the cylinder be filled to approximately half of it's capacity?

I tore down my 4 screw SU carbs, cleaned the components, replaced the needles, gaskets, etc. reassembled and reinstalled. When I put the 20W oil in the dampner cylinder, there seemed to be alot of resistance to needle movement. I decided to experiment with various fluids and came to the conclusion that brake fluid seems to provide the best needle movement, without backfire. Has anyone else used DOT3 brake fluid?

Could you give me some direction on float adjustment? My guess is changing the position of the float tab that contacts the float bowl fuel valve.

Prior to this procedure, I assume that you have already adjusted each of the individual carb idle screws with the unisys gauge?

In the original 72 240Z maintenance manual, it is stated that the SU carb idle adjust nut be turned until the top stop position is reached. Then the nut should be backed off three turns. Then the nut on both carbs should be adjusted 1/8th turn at a time until the 2-1/2 turn position is reached. Does this jibe with other member understandings?

I have seen where people have discussed throttle linkage wear. Does this refer to the intersection points where the throttle linkage penetrates the SU carbs and any associated vaccum leaks at those points?

Has anyone rebuilt the brake booster or is it a better idea to buy a new/rebuilt booster?

The 3 screw SU carb allows the coolant to flow through the base of the carb. The 4 screw doesn't. Does anyone know in what years the 3 screw and 4 screw SU carbs were offered? Was the 4 screw installed after the 3 screw ?

I have finished rebuilding two 4 screw SU carbs. In the manual, it indicates that the needles should be flush with the piston surface. However, I've been advised to leave a fraction of the needle shoulder, 1/16th of an inch, still visible. Anyone have an opinion?

I have a set of 4 screw and 3 screw, in reference to the Dome, SU Carbs. I prefer the 4 screw due to the ease of float access. The three screw has a nipple that makes it very difficult to remove the float safely without taking the carburetor apart. Other than that, they seem to be duplicates. I'm not sure if I should keep the 3 screw set. I can't see a time when I would them. Anyone interested?

Yes, it is a thumb tack on steroids. I'll have to look at that again. I didn't see where it affects the jet. The thumb tack bolt does have a nut on the end that limits the bolt penetration into the bottom of the carb. body cavity in which the bolt that attaches the float resides.

I am tearing down a 4 screw SU carb. There is a disc/bolt on the bottom of the carb that appears to screw into the bolt housing that attaches the carb float housing to the main body. I don't understand the purpose of this except to seal the hole on the bottom of the main housing. Anyone care to enlighten me?

I have a Monza exhaust header for a 1972 240Z. Unfortunately, I don't have the exhaust pipe adapter that converts the two 2" O.D. header outlets into one 2.5" exhaust pipe connection. Does anyone know where I could find one? Victoria British does not sell this item as a separate part and MSA states that they sell a different header.

I have a monza header for my 72 240z that has two separate exhaust pipe outlets. Each exhaust pipe outlet serves three cylinders. Has anyone installed a dual exhaust with custom bent exhaust pipes?

Do you have any words of wisdom in refernce to the balance screw that is located on the carb throttle shaft?

In the original 1972 owners manual, it indicates that there should be a certain amount of play between the main throttle linkage attached to the accelerator pedal, and the throttle linkage attached to the carburetors. I believe the reason is to allow the carburetor linkage to make a complete return back to the idle position.

My main throttle linkage and slave throttle linkage doesn't have any play between them. I couldn't locate locate any adjusting screws to reintroduce play between the two. Does anyone have any ideas?

Is there an initial setting that the Carburetor Idle Adjust Screw should be set at prior to balancing the carburetors? I'm not refering to the fast idle screw, but the individual carburetor idle screws.

Has anyone ever tried to do away with the air pump, check valve, control valve, A-B valve and servo diaphragm in relation to the exhaust system? As I see it these components allow fresh air to be dumped into the exhaust manifold to burn the exhaust gas.

Could someone tell me what the difference is between the three screw and the four screw SU carbs in reference to the carb piston housing? Is one better than the other?

Does anyone know the difference between the three and four screw SU Carbs in reference to the carb piston cover?

I have a 1972 240Z with the SU carbs. These carbs have the oil reservoir for what I call the dashpot needle piston. My problem is that when I try to fill the reservoir, the oil leaks into the air/fuel mixture which burns through the cylinder. The oil reservoir cannot maintain the seal for the piston. Obviously, I need to rebuild the carbs. My question is: Is it better to invest in a set of Weber carburetors or to rebuild the SU's?

For those of you who don't know; you can use a 240Z 1973 rear bumper on a 1972 model.

I have looked at two different parts catalogs and they make a distinction between the main central body of the rear bumpers for the 72 and 73. However, the side components of the rear bumpers are listed as the same. So at this point I'm somewhat confused. I have a 73 rearbumper on the way from a salvge yard in Arizona that is in good shape. I will let you know.

Does any know if you can use a 73' 240Z rear bumper on a 72' 240Z?