madkaw

Any links to threads showing this process? I would be very interested in doing that later.

Thanks for the insight Tony and FI is in the future, but I want to say I've done triples! I'm awaiting a return call from Todd. He left a voice mail suggesting I remove the jet cover and try it again, not sure what that does. Of course I'm on a train and try anything right now- plus my car is still on jacks awaiting my Cibie headlights to arrive and to install. At this point I probably need to drive it to see what it does or does not do.

Pete, I stumbled upon a very clean e-31 if you need one-- very clean! I'll add that I would have voted for the 25ett

Did you disconnect the cables and checked to make sure the linkage is not binding? The linkage piece that connects to the bottom of the jet nozzle utilizes a special washer that allows them to pivot. If the washer is not there or the wrong one the screw will tighten down preventing rotation and freedom of movement.

I concur on the main air jet thinking, but I obviously have a lot to learn. An added note; every once in a while my flakey wideband works and I saw decent AFR's at idle with the 65's, but it still stumbled to death . I need to go back at it with fresh plugs and an open mind. If it wants bigger main air I'll get it. I will eventually get back to Todd on this, but his info usually comes complete with a lecture;)

Okay, got some 62.5's and some 65's today. Didn't even bother with the 62 at first, just threw in the 65's. Engine ran a bit better, but still fell on it's face with 2 turns out. Wouldn't idle with just one turn Now I'm pulling out my hair thinking I still have other problems and I don't have anything else to try. When I received the carbs it had 2 sets of main air jets, 180 and 200's. I have been running with the 180's so I decided I would try the 200's. Wouldn't you know it raised the threshold of the stumble by atleast 1500 rpm, and I can about save it with a little more throttle. I ran out of time to do more troubleshooting, but the larger main air did help! Thoughts?

I should have stated that I already replaced them. When I pulled these out I thought I had found my issue and got on the phone and ordered new ones. The new pilot screws went in with the 60 pilot jets-but still too lean. I have actually found several issues with these seemingly "new carbs", but I think I do have a very nice set.

These are the ones that came out.

63.5's and 65's are on the way! Last trip around the block was an embarASSing barrage of coughs and sputters and I thought I was going to have to push the car up my steep driveway

Schneider 274f I believe-480 lift 270/270 Then you throw in dual 50mm exhausts Larger valves Mild port Unschrouded chambers and notched bores I don't know if there is a way to guess, but just try different sizes Sidenote; Just got off the phone with Todd and he made a general statement that the smaller carbs usually wind up taking bigger pilot jets then say a set of 44's. He also believes I should just get out and drive it since a no-load scenerio sitting in the garage might be decieving. Maybe, but I know that an engine shouldn't die under no load just acclerating the throttle in the garage either, and my garage is to steep to be screwing around with a car that stalls. So I have the next 2 sizes coming And Tony, as far as timing I am running 20 initial and 37 full

Yes, 1 turn= 360 degrees, so 2 and 1/2 turns =900 degrees My car will not run with just 1(360 degrees) out-not even close. 900 degrres out gets a nice idle, but that's it. The throttle opens into the progression hole area and it's done(dead) 57.5 is a bit arbitrary, but a lot of threads where guys posted their pilot#'s , they weren't to far off or smaller. Todd at Wolfcreek thought I should be "in the ball park" My wideband O2 sensor is a bit erratic, but when it is stable, it is showing lean-like 16+ As far a booster venturi's-I might need to school myself on that subject-I'm not sure what you are exactly refering to. Time to search, though it sounds like that is not my issue.

Was that a L24? Did you exhibit my symptoms with the smaller jets? I have seen sizes all over the place, but usually smaller then 60. I guess every engine is very different! Learning about Mikuni's the hard way I guess.

Okay, I'm still having the dead spot. What I have done is: Removed carbs and checked and cleaned accelerator circuit-all carbs are firing a steady pee stream with the slightest of throttle movement.(pumps set on middle hole) Blew air and carb cleaner thru the pilot circuit and I can feel air coming out of all pilot holes-idle and progressive holes. Installed 60's pilot air jets-seemed to best around 2.5 turns to 3 Sprayed carb cleaner around while running-no significant change All O-rings were in good shape between carbs and intake Removed ALL sources of extra vacuum-brake booster and PCV and removed vacuum log-plugged intake Can get a very smooth idle-even down around 800rpm. Engine will rev-up nicely, but still will die doing a very small, steady opening of the throttle. I even threw the 57.5's back in, no real change. I pulled the plugs after all this horsing around and some did show rich. It was kind of odd-1.3.6 were cleaner then the other 3?? My wideband is a bit sketchy right now, I think I need a new sensor. Most of the times I had the best idle it was showing lean. IT was a challenge to get it below 14 and then it seemed to load up trying to get it any richer. By then I had 3 turns out on the pilot. So if I had a vacuum leak somewhere, would I still be able to get such a smooth idle? I have searched at many set-ups and you rarely see over 57.5 on the pilots, so why would mine be the exception. Would bumping up to a 62 make that much of a difference? Tony, recurving the dizzy would be required to get past this point?

Not sure if you know how relays work, but if you don't----try the Daniel Stern lighting website(you know-the bad guy in Home Alone in NYC). He does a nice job explaining them and give you some hints to troubleshooting. I would pull the relay and my multimeter out and start checking voltages. Are you getting a trigger voltage?

I'm on here because I just drove my train to ST. Louis which is 250 miles away from my Z. I'd love to be home trying to figure out my triple Mikunis - but wait - the wife is off today so that wouldn't work either. So I guess I will just do some searching on this site and read all the reasons I SHOULDN'T pressurize the Mikunis later-I know you have a few Tony!!

Yep!

After re reading the thread, it's hard to believe you have had the same issue with two different cams. I'm with the float issue. Insufficient fuel in the bowls with show up under heavy loading, but otherwise drive decent. Maybe time to revisit the floats and bump them up a bit and check out the needles and seat closely

Maybe Childs play for Tony D, but for an average mechanic - very average like me, basic valve geometry is beyond my ability. Not that I don't understand that timing of the events is crucial, but to dial in a cam without specific details to go by- no way. Maybe Ray can do that and I am under estimating his ability, just thought I would throw it out there.

I guess I am still confused on how you set up or dial in a cam without a card? What numbers are you referencing? I wouldn't even know where to begin without the card in my hand. Any numbers in a FSM for a stock cam wouldn't work for an after market cam. Most cams, if not all that are sold are usually dialed in using measuremnts based on .050 lift on the valve. Nissan used an arbitrary number like .020 or .025 lift to dial in there cams in any published numbers. I remember reading this from a Racer Brown article. As far as the statement about the L24 not coming on until 4k rpm, My engine feels very strong(torquey) starting at 2k. In fact I am always impressed at the amount of low end grunt the little booger has. Maybe I haven't driven enough Z's to make that statement, but I feel power is very even across the rpm band-and the dyno showed that. Anyway, I realize it's frustating, hope you find something.

I have reread the instructions for the speedi sleeve and they recommend using Loctite 209? I think they meant Loctite 290, which is the green loctite. I think a liquid type sealer would be best in this close tolerance situation, even though I'm not sure if I classify the green loctite as a sealer. The description by Loctite does say sealer/thread locker, so I imagine it would do the job. I guess you would pay hell getting it off if you ever had to!!

Well my first attempt at the speedi sleeve was a failure. I did get a set of mics and checked the size and it was in the limits of the sleeve. The instructions stated to use a non-hardening sealant on the ID of the sleeve before installing-and I think that's what did me in. It took too much force to install the sleeve and I bent the flange on the sleeve trying to get it on. I used permatex #2 non-hardening, but I think it was too thick even though I thought I put it on thin. This caused too much interference and too tight a tolerance for the thin flange. So I guess I will order another one-maybe two just in case. I am having the worse time with something so simple as the rear main. Any suggestions? I thought about preheating the sleeve with a heat gun to give me wiggle room, but not sure if the sealant would like that. Maybe a thinner type sealant?

You need to check all aspects of your ignition. Heaving loading at low rpm will put a large load on your ignition and will show a weak coil or bad wires. Have you checked your charging voltage? Weak spark will exhibit your symptoms.

I have a 280zxt flywheel and PP set-up on my L24. All was good until the last time I did a rear main seal change. At that time I had the flywheel modded for a hall effect sensor and had the flywheel rebalanced. After putting the car back together, it seemed that I had more vibration than usual. I blamed this on a possible bad balance job on the flywheel. Well since I had to pull the motor again because I didn't fix the rear main seal(this time it's getting speedi sleeve), I looked over things carefully. I noticed that of the 9 bolts holding the PP, 3 of them were shorter, by maybe 1/8" or so. So I guess I mixed up some hardware when reinstalling? I am pretty sure these should all be the same just for the reason of balance. What do you guys think;would 3 odd bolts actually be felt as an imbalance? I've scrounged around my hundreds of bolts and can't seem to come up with the other 3. Anyone run into having to replace these bolts and can tell me where they might have gotten them locally?

Neither-you want 3.5psi. Maybe 4psi at th most, so you will need a regulator

You mean the pilot jets? The first post I said 57.5. It might be the case that they are the wrong size, but I need to get other things squared up first. I am going to replace the intake gasket to assure no vacuum leaks. I did take the carbs off today and watched the accelerator pumps in action- and there wasn't any on one port. Another nozzle was spraying weak, so this was obviously effecting transition. My floats were also rich, but not sure if that was hurting me at this point.