Zedyone_kenobi

Yes I checked valve lash. Nothing is crazy out of whack or lose. Hard to say for sure, as it was not hot and it was not cold. More warm. But the feeler gages felt within the realm of acceptability. I have a dizzy in there with a working vacuum advance. It is just plugged up. When I get her running tonight hopefully (I installed the carbs last night) I will be able to play with timing again with AND without vacuum advance. On top of that I have another OEM distributor that has not been recurved with a NEW pertronix, new cap, and new rotor, and new wires, I may swap that in, set it 5 BTDC and give that a try. I will flush out the ignition part of this thoroughly by the end of this weekend. Although, keep in mind, I already swapped dizzies with somebody else and this problem still existed. So this is one last ditch effort to run this to ground on the ignition side. While I know no two engines are the same, but many other people have run without a vacuum advance and high static initial timing without any issues. So part of me thinks this is something more clever. A leak down test will give another data point, as will the vacuum readings

UpDATE: Had a talk with Dizeasedz and he suggested I do a leak down test. I have acquired a leakdown tester today and will try to get that hooked up tonight to see what I find. PS-It was great talking with you Guy. Thanks for all the VERY helpful advice on the engine build. I will be in touch soon to discuss that further.

I will be interested to see how this one compares to the one I am running. Thanks for that. I had forgotten about that post from a while back. I will see if I can get a picture of the weights stamped inside as soon as I can.

I have a 71 240Z an this is not the OEM distributor to my knowledge. My car came with a D615-52 which is currently on the car (but recurved from www.advanceddistributors.com). I have no idea what this came from. It was an ebay find that was just too inexpensive to pass up. I have ordered a new pertronix to put in it and new taylor wires to keep for another build I have in mind. Which year, make model came with a D611-54. Any idea?

I have an infrared heat gun that I use to measure, well anything from the temperature of my grill, to the air coming out of my vents. My question is with your heat shield under those triples is there enough room to touch the pipes. I mean I guess there is since you did it, but VERY cool Nice use of science. I agree with steve, time to buy another diagnostic tool!

Thanks Adam, I am not even running my vacuum advance at this point. I am relying totally on mechanical advance. Well I got my carbs back last night, and I plan to put them to the test. After I get the car back together and I do all my other trouble shooting, if it still does this I am going back to timing. I picked up a newly rebuilt D611-54 single point distributor. I ordered a new pertronix, more new wires (I wanted red ones anyway), new cap, new rotor, new vacuum advance and will try timing from scratch again. I know that distributor is not OEM for my car, but it should work well enough.

could have been an impurity in the metal that caused a local weak spot and then it lead to fracture. But I can forward this pic to some of my NASA failure engineers.

more importantly, VTO should buy these and make a replica in 15" sizes we can buy at an affordable price. I LOVE these rims, but the cost is just too high for my car.

Thanks Blue. I have acquired a very nice OEM distributor and will be swapping mine out with it. I have taken it on good faith that it was curved correctly and maybe it is. I am going to build up a whole new distributor with a new pertronix system and see where we go. I am currently STILL waiting on getting my carbs back. THey have been shipped apparently. I did run a jumper from my battery straight to my coil before and the problem still persisted as I thought the stock tach was doing something crazy. I am getting 13.2 volts to the coil if I remember correctly. for all intensive purposes this still looks like a smart vacuum leak, but I will be darned if I know where it may be. I still have to try to get a full suite of readings from my vacuum gage after I get the carbs back. Then hopefully somebody can do the same and we can compare. I will take a look at the links you posted Blue.

Thanks Andy, but I have a 71 240Z. I cannot imagine why it would be any different though

Datsun is only being released in three other markets not including Japan or United states. So it is really a non starter. They will not release a BRZ competitor in the united states. Personally I have been a dedicated Subaru guy for the past 11 years. So it would be a BRZ or nothing for me.

Well congrats man! I am always happy to hear a problem resolved. I am still trying to fix my issue, but I have jumped my resistor and still have my weird issue. Best of luck man!

Best of Luck buddy! And I do love that 912, such a great car. Like so many before me, if I ever sell the Datsun, I will be getting either a GTV or a 911

I have been considering getting my engine rebuilt just to freshen her up, and I have been considering only going with Rebello. But if Datsun Spirit does good builds, I can consider them as well. Any body hear of how their engines stack up? Again,I am looking for a mild rebuild, not a road racing scorching road terror

Keep in mind folks that the front body work you are running makes a huge difference in what size tire you can run. Lazeum's car looks awesome with that air dam on it, but I could never get away with a 225/50 on my stock valance with my car sitting on tokikos springs and struts. I rubbed with 205/60's, so I had to run 195/60's. (15x7 0 offset rim) I may be able to get away with 205/55's, but it will be crazy close.

Isn't this the same car that was at a Mecum auction a while ago and the bidding got up to 45k and it did not meet the owners reserve!

Thanks very much sir. I certainly appreciate it Steve, I will be in touch. The next time you hear from me though may be to help me take off my hood! HAHA When I get the carbs back, I will report back in. I will look into another completely stock dizzy as well. I have time on my hands just sitting around waiting for carbs!

Steve we can try if you have a spare set of carbs, I will get an extra set of insulators

The reason I am hesitant Steve is two reasons 1 when I pulled the carbs off my intake the first time the gaskets on the insulators came off in pieces, if that happened to your car you would be in a tight place since yours is a daily driver 2 I really do not think its the carbs any more. I realize I need to try another pair for completeness. But I think the results will be the same Blue we swapped dizzies and coils Steve's dizzy had another pertronics as well Carbs will be here next week hopefully the troubleshooting can continue I am going to focus in great detail for vacuum leaks in strange places

Well I fully expect the problem to exist, since technically nothing has changed. My plan of attack starts off in data collection and then moves to vast sweeping changes. First I am going to run the car with 0 changes from how ZTHERAPY gives them back. Report back Second Hook up vacuum gage inside car and see what vacuum is doing while the lean out phenomena occurs. Report back Third Spray carb cleaner all over intake while running to try to spot leaks or cracks. Report back If all of that does nothing And a set of seemingly good carbs do not fix it I am going to go crazy I am going to pull the head and send it to Rebello for the works E31 setup. I am going to install a new oil pump new timing chain, new tensioner , new balancer, new crank gears , etc. I will get it running with my SUs, them slap on some webers or Mikunis Yes I am serious, yes I am ready to spend money. Mark my words, I will fix this

Nope did not want to bug anybody, but I really do not think its the carbs My carbs are on their way back. Ztherapy said they were set too lean but everything else is fine. I will gladly pay shipping if anybody wants to loan me some GOOD carbs

Does it backfire through the carbs or from the exhaust

UPDATE Form those that still care, The great folks at Ztherapy called me back and Steve in then shop installed the carbs on his shop car and Said the air fuel was set too lean by a turn and they liked 3.5 turns out on his car but they experienced zero popping at any rpm. He will look at floats tomorrow. So, the million dollar question is still what would cause leaning out at part throttle that we have not already covered. The last piece of data left is vacuum readings over the rpm band.

The issue seemed to come up around the 8/71 time frame. If you have an A type 4 speed, your tunnel will need some work, or you will need to get creative with your shifter. If your car came with a B type (late 71 and on) then your tunnel will probably be okay. I cannot vouch for the console cutting. I have a Type A in my car and recently had a chance to drive a B type 4 speed. GREAT GOOGLY MOOGLY, the shift action in that thing make mine feel like it was floating in jello. What an incredible difference in feel. I have resigned to the fact that when and if my Type A goes, I will put a fresh B type in there, as my car is a 7/71 and it is close enough to the time when Datsun did it, that I really do not care. 4 speed to 4 speed, should be a clean swap. I will have to fight the internal demons when it comes to cutting the metal in my unmolested 71.

Chris, when I pulled out my ITG's, they were pretty well deteriorated, and looked NOTHING like the pictures. If you still want the air horns you are welcome to them though.