Zedyone_kenobi

Took the valve cover off and had a look around. Set it to TDC and peeked through the cam sprocket hole first. I took some pictures of it, but they did not come out. But the timing mark on the cam plate, is within the notch on the cam sprocket, and even though the number of which hole the cam dowel goes through is covered up, It looks like a number one is on top at TDC. But I can take more pics to verify. WHat I was wondering about, is I want to verify this is a stock cam. I have no reason to think otherwise, but it is marked E30 and has an orange painted section.. by the way, all lobes are smooth to the touch and show no signs of scratches or wear.

I will have to show you a picture of it. :stupid: OKAY: UPDATE with the wideband! Got the car warmed up. Verified pistons drop uniformly before I went out. CHECK. Checked timing, still at about 16-17 deg BTDC depending on where I position my head...but rock steady. Car started up and was running VERY smoothly this morning.. and as usual, had Zero issues driving around normally loafing around. I make some notes to myself mentally, as it is too hard to drive and write: 2nd gear pull - part throttle, tried this at 20% to 80% part throttle, same results as near as I could remember them... 2000 rpm----13.9 3000 rpm----14.5 4000 rpm----15.8 Popping started 5000 rpm----16-18 Popping too strong to continue at part throttle... I did this repeatedly with the same results So, next I kept the car in second and slowed down to 2000 rpm and went to WOT: 2nd gear pull - WOT throttle 2000 rpm----13.9 3000 rpm----13.8 4000 rpm----13.9 5000 rpm----14.0 6000 rpm----14.2 Well this seems to confirm what we already knew but now we have data...Just to reinforce this I tried another test. I put the car in 3rd gear, and did some 40-60 mph runs using various amounts of throttle input Every time I could get the rpm to rise under part throttle I had an accompanying leaning out trend until it started popping The same run under WOT, kept the A/F right at 13.8 to 14.2 My A/F at idle is 13.0ish So the same problems as before but with data now. :disappoin: Blue, do you still think slop in the timing set would manifest itself in this manner, where it would only be evident at part throttle. I do not see how my throttle position would effect timing, as that should just be rpm related. I am going to pull off the valve cover today and have a look see. I am also going to start seriously thinking about doing an SU swap out now as no amount of 'tuning' will fix this. I will also have at try Bonzi's suggestion.

No, not yet Bonzi. But it is on the white board in my garage under 'things I have not tried yet'. I write all this stuff down, and I try things when I can fit them into my schedule...Today I am off! Yeah federal holiday! So I will do many things today before it rains.

Well I made a movie showing my disassembly of the carbs, cleaning them, performing the drop test, reassembling them, doing the clear fuel line trick to get your float levels right, and starting the car. BUT it is 53 MB large and I cannot find a way to post it on the net. Everything tells me it is too big.

You could very well be spot on. I am going to pull off the valve cover Monday if it is raining and have a look around. I will also do the measurements you described earlier

Correct captain, I only get an imbalance when the damper valve installed. When it is removed, they THWAK together... It is such a fine adjustment that it seems crazy. They should not be that marginal. I and would wager that most of them are not. OR else nobody would ever get them to run right. Today I am going to reverify a lot of things and go for a drive with the wide band hooked up. Update today

That is a great idea Steve! Thanks!

did some digging, this is a 66 Duetto.... Pure pornagraphy. And my love affair with Alfas, continues...

I want to say alfa, but I am not sure... Can any of you guys help me out. That has to be one of the most beautiful roadsters I have ever seen.

Thanks for trying to help me avoid a rookie mistake though...

yessiree That is a fun 'personality' trait with SU's.

LeonV Make no mistake, I am going to buy a set of triples THIS YEAR. I dearly love playing with carbs, maybe I am a masochistic. I have always wanted a set, and after hearing Steve91tt's MIkunis, I am going to pick up a set of triples for DARN Sure. However, I still I need to fix this issue for two reasons. One, if I am to ever sell these SU's, I will want to ensure the buyer that they are perfect. And Two, before I go slapping triples on anything, I want to be sure the engine is healthy and ready to accept them. I found out the compression is spot on already, so that is good. I will get this problem nailed down soon. I would stake my OEM voltage regulator on it.

Captain, I have about 90% success in getting my pistons to drop reliably and steady. My procedure is as follows... 1) clean the parts religiously, meaning I clean the dome, piston, tube, check valve etc 2) Install them together on the carb dry. I ensure that both pistons rise and fall without any sticking at all and make that lovely 'THWAMP' when they hit down as close to the same time 3) I lift up the piston so the filler tube is level with the dome top as it makes it easier to fill. I drop oil into the tube...I have to do this as if I get any oil at all in between the piston tube and dome bore, the fall rates vary drastically, if I keep them clean they are identical. 4) Here is where it gets tricky. I screw in the little brass check valves into the top of the domes slowly. I then wait until the air bubbles have a chance to move out of the way and begin the drop testing. THIS is where my fall rates start giving me issues. THIS is when I get some minor sticking that I have to just play with to get rid of. I have taken both check valves apart and cleaned them religiously. I have measured them and they are identical as close as I can measure them with my micrometer. This last time, I knew that I had it a bit sticking on the back carb where it would fall 90% of the way down and then stop and then s-l-o-w-l-y go the rest of the way. This is no doubt causing my sloppy idle issue this time and I am not worried about it. MY SU experience now totally covers this. THe wideband just made the diagnosis that much easier. I already love it.....!! Just to recap, the piston sticking thing is not new, it is just taking more and more work when I get to step 4 above to get them to fall in perfect sync. Maybe I need to send my carbs back to Bruce and the Z therapy guys for some fine tuning. Just to make sure needle is not hitting the jet (I am rather sure it is not), but I will do the work without a needle installed, and that will allow me to see if it is the needle dragging or the check valve causing me grief. Since I can get it to fall perfectly without the check valves installed, I do not think I have any needle rubbing issues. I would think I could also use a black sharpy and color the jet black. Then do a test and see if any of the black rubs off. Alcohol will take off any extra marker residue. Steve, copy that on the stumble/lean condition, I am ready for that. When data and science come together, only good things can happen.

I am sorry Captain. I was in family time mode last night. I got all the parts safely tucked under the car, and the center console is in but not screwed together. I should have it on the road by Saturday. Monday will be a long data gathering day as I have off work and hopefully it will not rain. I will say this, at idle with the engine almost warmed up I was reading 15.1:1 at about 600 rpm. Then I blipped the throttle and it immediately started to stumble at about 450 rpm and wanted to die, but kept itself alive, but the A/F went to 19.7:1. I bet you a million dollars one of my pistons did not drop all the way down and I was starving it. They have been sticking more and more the more I take them apart and mess with them. Not sure why, as I have been careful and marked them F and B on all parts. But the carbs seem to be fighting me right now. They are getting tired of coming apart and going together so many times. But this little gage is awesome. Install was a snap, worked the first time. Just a lot of soldering to ensure good connections and a lot of heat shrink because I am anal. Again, I will try to get it completely together tonight, and on the road Saturday. But for SURE monday

UPDATE: My innovative wideband O2 sensor came to life today after work. I have it hidden in my glovebox. And it seems to come to life and read very quickly. I have not put my center console back together yet, but I will this weekend, and then I can take it for a drive. Updates to follow.

Carbs are like personalities. If treated properly, they are happy and easy going, more than delighted to perform. But when neglected they can cause all manner of weirdness. Sometimes, even when you think you are treating them well, they get all foul tempered... ask me how I know.

Those wheels are uber sexy.. nice job..and you are just feeling my crack like obsession I have now with Weber carbs

If you think it is your tach, run a jumper from your 12v source to your + coil terminal and unplug your tach. This takes the tach out of the loop. Did not work for me but good luck

O2 sensor bung installed. now to wire up my Innovative sensor and we can start to get some readings!

Understand completely. Like any data you have to know its limitations.

A glimmer of HOPE>>> I put my carbs back together (SM needles back in) with the only difference being that I put in some 10w-30, and she ran VERY well this morning. I was able to push her at part throttle easily to 4500 rpm, without the slightest hint of a pop. When I pushed it past that, I got some minor pops, but 10w30 did make an appreciable difference. I am taking her in to the mufler shop today to get the O2 sensor bung welded on and I will finally know where I am running. I am also going to do a full test on my brake booster check valve tonight. I will report back later... Having good O2 readings will be very informative and hopefully helpful.

LOve the car and the color. So that is what my silver Z would look like with no bumperettes on it the front. Interesting.. (scratches chin!)

I think the key to this is not to get stumped. I feel like my car is a patient on HOUSE, Some crazy ailment that I have to try half a dozen things to fix before some obscure thing triggers a eureka moment! Still I cannot thank everybody enough for their time and energy replying to my dissertation of a post!

The one for noise suppression at the coil is in fact removed. I will check to see if the one for the points has been removed, since I am running a pertronix.

NO we actually switched the entire cap / rotor / dizzy as a whole unit. I had already tried a new cap and rotor a while back. I did as much common sense trouble shooting as I possibly could in the past few weeks before I started this thread in frustration. I am winding down to the last few ideas that I can possibly use on the carbs. I have checked every measurement possible. The kicker is the part throttle nature of it all. What would cause this issue at part throttle but not at WIDE OPEN THROTTLE. The PCV and brake booster were not leaking. I thought maybe worn throttle shafts that at part throttle that allowed a leak (unmetered air) into the system at half throttle, but not at WOT. But the bearings Z therapy puts in should have eliminated that as a possibility. I need to get on the ball with the O2 sensor and stop messing around chasing my tail.