240260280

Try not to cringe at the Premium Napa Metal from China. Yes it is a rotor...not the rusted hull of the titanic. Neat thing is that the rust makes the rotor thicker over time so it will always exceed the minimum wear thickness.

Luv this thread!

For a 1-5-3-6-2-4 sequence in our I6 engines, from an exhaust-cross-pulse & reversion perspective, are the front 3 and the back 3 collected together out of historical convenience of location? i.e. 123 go to one tube and 456 to the other? Another pattern of less convenience could be 135 going to one tube and 246 to another tube? Would something like a 2 to 3 to 1 be better? i.e. 15 to A, 36 to B, 24 to C then ABC to 1?

I'll get it out this week.

I agree. It looks like the concentric grooves were filled to maintain alignment and to prevent the aluminum mounting flange from sliding up and down the tube (left/right relative to cars direction).... not to prevent rotating.

BTW your Z looks great!

At idle, the only places for air to pass to the cylinders are: On Carbs: 1. Idle enrichment screws. If these are open too much or if the idle jets are too large (have too much air and fuel passing through large drillings) 2. Throttle plate air bypass (built into 40DCOE 151 and 45DCOE152 carbs). Early carbs like your 40DCOE 18's may have holes drilled in throttle plates. 3. Twisted throttle shafts (one plate closed but the other is partially open...usually on early carbs with brass rods). On Intake: 1. Poor sealing between carb and manifold (loose hardware where softmount grommets/thackery washers are located). 2. Poor sealing between head and manifold. 3. Air leak from brake booster. 4. Other (such as you PCV fitting). What are your idle jet sizes? For a next step, I would recommend that you check for all of the manifold leaks then if no leak is found: Keep push rods off and, with engine running, start turning in idle enrichment screws in to full stop then back out to 1/2 turn (gentle pressure at full stop is fine). For early DCOE's like yours, the taper on the idle enrichment is rather abrupt so a small turn lets a lot of air and fuel pass. Most early carbs work between 1/2 to 3/4 turn out. Yours at 3/4 are way out there. Read this if you want your head to hurt: http://240260280.com/Tech/Carbs/Weber/DCOE Theory Operation and Tuning.html :)

Thanks. Great info. Can you disconnect the push rods to make sure the throttle plates are at full stop? This could be the issue. Once you get the carbs air balanced and a nice idle, then you can attach the push rods to verify the same air flow( i.e. the push rods are not pushing at idle).

Can you write the full tipo and no for each carb like below? For your fast idle issue, set the timing at 15 degrees at idle, disconnect the push rod to each carb then start closing each throttle plate using the idle stop screw on each carb and see if you can get idle down. (this is a quick check). For next step: You will need to report idle jets and set idle enrichment screws our same amount then measure air flow in each throat. btw is your engine stock 2.4 with stock cam?

Get the electrical then valve lash, and timing set first then focus on the carbs. First some questions: Do you have a sync tool? Is the manifold and linkage in good shape and solid with equal length push rods? What is type and serial number of each of the 3 carbs?

Here is how the pros fake the gap. Bondo and parallel blade.

Or drive it out then re-insert

Fashion a small crowbar like piece of metal with flat blade end ground narrow to push pin.

If you jet without an air filter, then add one that is restrictive, it will act like an old fashion choke and move the manifold vacuum further up the throat of the carb and cause richness. Make sure your filter flows freely and check a/f after adding.

Yes, extra to be trimmed. Those pics are of initial fitting.

Black Dragon Kit on Jan 71

AKA "soft mount": Rubber O ring insulators between the carb and manifold. The carbs are then secured with either bolts passing through rubber grommets or thackeray washers.

I think a 3.364 gear would be great in a Z used for long trips (like going to Zcon in October).

I think this is a little optimistic. Maybe the goal was to get 200kph at 12 o'clock position?

But how hard is it to **** up a rotor.... the easiest thing to make on a car? It is made with one metal, on tools that have been around for hundreds of years, it has no moving parts, yet they turn it into a polished turd by making it look like a rotor but use the worst steel known to mankind. The only lesson I learned is that the crooks at Napa sell $15 to $70 rotors that are all the same Chinese $^!#. None are worth buying.

Possibly but when you get things manufactured in China, you generally need to QA every item to ensure quality. Who can do this? It is usually statistical samples that are required to maintain quality.... and unless you have boots on the ground who can not be bought or tricked and can take truly random samples then you are screwed as the manufacturers will play the tricks to cheat. The first rule of doing business is to know that lying is OK. The second rule is that certifications, qualifications, and any quality document is either forged or a rubber stamp. When this crooked system hits your raw materials supply chain, you get steel screws in the first batch then white metal in all the rest until you complain.

I think it is both but more China itself. I used Chinese kit when I worked for a Chinese company and the metal in their products made for the Chinese market and rest-of-world market was pure crap: stripped threads, no reinforcing, "soft" bolts, chromed EMF edge shielding that crumbled like snow when inserting a circuit pack. My friends in China only bought non-Chinese produced goods when possible.

Kats, @moelk made very nice speedometer face plate reproductions on this thread:

Fred you are lucky. Falling cars from crap metal ...cripes! I'm going to start logging this crap on a web page. The problem can easily be fixed by having the crap vetted on entry into North America... effectively a "quality wall". China manufacturers must pay for quality and health and safety officers who are North American citizens who vet every shipment. If China won't do QA and H&S in China then we should do it here on their dime to balance fair costs of real manufacturing and protect ourselves at same time. I hate China crap every time the temp drops near freezing and the Garmin GPS power cable in my car freezes solid.... great Chinese fake rubber at its best.