Awk34

I haven't retried finding TDC on my new damper, but you can kind of see what's going on here: https://youtu.be/5KwKMwHtFMI?t=45

Here's a bunch of photos I took last Fall when I did a bunch of engine work (head gasket, seals, etc) PXL_20201201_005333745.mp4 PXL_20201201_005357207.mp4

It's hard to tell from the video, but I believe they are raised a bit. I'll get a better video or some pictures tomorrow. Last time I had the carbs apart It seemed like the butterflies were closing fine, but maybe I'll take them apart again to check. What should they look like when 'closed'? Should the butterfly be straight up-and-down, 90° to the intake? I remember them being at a slight angle to the intake.

The butterfly valve is closed. The throttle return springs are on. When I push on the throttle linkage, it'll rev even higher.

https://youtu.be/5KwKMwHtFMI I'm going so nuts with this thing. I tried spraying carb cleaner all around the intake area again and it didn't seem to make a difference in RPM, but there has to be an intake leak somewhere, right? The throttle is all the way closed. At this point I'm thinking it has to be something to do with the cam in there. It definitely seems like the previous owner put some sort of performance cam in there, but I have not idea what kind. In the video you can see the rear 3 exhaust headers getting red hot (timing, combustion in exhaust?). I tried moving the distributor in both directions (retarded, advanced), but it didn't seem to make much difference. At the end you can see me jump from a huge bang. I assume it was fuel igniting in the exhaust. At this point I'm so frustrated with this thing I'm considering just replacing the cam with a new one from MSA, or taking it into a shop so I can get some professional help..

I'm not sure but I assume they're original to the carburetors.

No idea which needles. Would I need to take it apart to check?

Okay, so i figured out why the sync tool was shooting fuel: the carb tuning guide says to plug all vacuum lines which were attached to the air box. I removed the plugs which i had put on the carb fuel bowl vents and it doesn't shoot fuel anymore.

I don't think so. When I manually move the float up while blowing on the fuel tube with my mouth, I can feel the valve close. I cleaned out the banjo and put new fuel filters in recently. The modified cam might make it want to idle higher, but not 1000RPM higher (I'd hope). "get your floats adjusted correctly" - any recommendations vs what I'm already doing?

So got to working on the Datsun again today. I'm still having the same issues. It will only start with the choke on a little bit, and it idles above 2000 RPM (it was 70℉ today). I followed this guide again (minus letting the car warm up first obviously): https://zcarguide.com/tuning-adjusting-datsun-240z-su-carburetors/. I backed the idle screws all the way off and then tightened them 1.5 turns, and put the carb jet adjust all the way up and backed it off 2 turns. After letting it "idle" there for a bit, I started noticing my rear few exhaust headers getting red hot, so I advanced the timing on the distributor, but this caused the RPMs to continue spiking up higher. After some more testing and shutting the engine down for a bit, I noticed fuel leaking out of the rear carb intake. My next step was to check the fuel float. The valves on both seem to close fine with the float up (blowing on the fuel tube). I recently bought a Float Sync on Ebay and decided to try that out. Watch the attached video to see what happened there.. (fuel shooting out) I'm running a K&N 81-0402 electric fuel pump. Other's have advertised it as being a drop-in replacement for the mechanical fuel pump (I think Motorsport Auto sells it as their electric replacement). I tried bending the tab on the fuel float up a bit, but fuel is still shooting up out of the sight glass and out the carb now. Any ideas? PXL_20210405_015735611.mp4

To close the loop on this, I got the new damper installed properly and all is good there! Thanks for all the tips/help. I ended up lightly sanding the inside of the new damper. It was still a very snug fit at the end, but I sanded it slightly more at the front to make sliding it over the crank key easier. I even put some red marker on the front of the key so I could definitely confirm it was still in place :) As someone noted, the new damper's belt groove is slightly smaller, so I went to AutoZone and got a new belt which fits better. I'm still having issues with my carbs, but that's a story for a different thread :) https://www.classiczcars.com/forums/topic/64813-l28-w-su-carb-intake-manifold-vacuum-leak

Yeah, I'll just wait until the brand new key arrives

Amazon to the rescue! Ordered a bendable magnet and was able to find the key and fish it out. It indeed dropped into the pan.

https://harmonicdampers.com/index.php?main_page=product_info&products_id=241

@Racer X Thanks! lots of great info in your post. You're saying to chamfer the keyway on the damper a bit to make it easier to seat onto the key, right? One other thing is that my new damper doesn't slide onto the crank very easily. I slid it on by hand as much as I could, and then used it's installer tool. Take a look at the side profile picture of my old damper. The previous owner did something wrong to that poor thing. I only discovered it when I was pulling the timing cover off for some other maintenance. That's one of the reasons I decided to go ahead and get a new damper.

No idea. I'm not the first owner. Good call, I notice that mark there on the right side of my picture now. I have a 2nd engine, I don't think it has a slinger either.

haha right, previous post had me confused

Ah yes, must have been removed to prevent getting oil on the windshield 😉

Those are both adjectives. Throw and sling are verbs 🙂 @Zed Head Why not. I ordered a couple.

I do not appear to have an oil slinger.

It's a relief to hear you say that. Do you have any tips on making sure the next one doesn't fall out when installing the damper? Is it a bad idea to glue it in place?

While pressing on a new crank damper, I heard a 'ping' and new it was that damn woodruff key. I pulled the damper back off and sure enough it was gone. I've searched all through there, pulled the seal off, tried digging around with picks and a magnet (although a large magnet on a straight stick, not the best tool for that) to no avail. I'm dreading the thought of having to disassembly the engine again just to get that damn key back. Do you guys know of another way? If it fell into the oil pan, should I just leave it there? Is it possible it fell into one of the oil pump holes? Please Help!

Right, I know the sensors don't give a digital signal themselves. I meant to ask how to get a clean signal for my digital ECU.

Yep, that's what I did to bolt it back on. I follow a similar sort of pattern as head bolts, alternated back-and-forth, starting from center.

Here's that new manifold gasket installed.