Awk34

I like the radiator hose adapter option. I think the main downside to that is that it takes the cold temp of the coolant before the thermostat has opened. It seems like my best option will be to figure out the best way to use the old sensor the get the temp. I have a custom Speeduino ECU I'm building. I will eventually convert to EFI, but I'm doing everything piece-by-piece.

That's what I have I bought a new one of these: https://www.thezstore.com/page/TZS/PROD/16-7121 One hole is being used for the coolant through the carburetors. The other is for the stock temperature sender.

I want to get a digital coolant temperature signal to my ECU. Does anyone know of a temperature sensor that would work in the stock 240z sensor location? Apparently it's a M16x1.5 thread, and the only thing I can find to fit there is the original sensor. I haven't found any sort of thread adapters which I think would work there. I'm guessing my best bet is to use the stock single-connection sensor. I have a two-connection GM sensor with 3/8 NPT threads I believe, but I don't think I can get that to work.

I have the one mentioned in that thread on the way. If the gasket doesn't fix it, any other ideas? I need to double check that there was a leak around that area just to make sure I'm not going insane.

I gave them the P90A head casting number

You're right, thanks for linking to it. Hmm, I'm not sure exactly which gasket I got. It was provided when I bought my headers: https://www.thezstore.com/page/TZS/PROD/classic19d/15-6003CH

So I posted a while ago about some high idle issues I'd been grappling with. I still have a bit of an issue, but I think I've found where it's happening. I have a 240z with an L28 Engine block, a P90A cylinder head, and SU round-top carburetors. I took some pictures and videos of what's going on: https://photos.app.goo.gl/xft1yprkDfB7egaW6 I still have to dial the timing in. I think I might have a slight vacuum leak between the intake manifold and the cylinder head. I sprayed some carb cleaner around that area and the RPMs increased a bit. Is it okay that I have this intake manifold with the SU carbs on the P90A head? I've also removed the fuel rail and the mechanical fuel pump, and opted for an electronic one. It's currently a cheap K&N dead-heading pump. I intend to eventually change that out. In the photos you can see some studs/bolt holes, and how the intake lines up to the head. Is this head & intake compatible, or is the combo likely causing my leak? Other work I've done: swapped exhaust manifold for headers installed new MSA performance exhaust cleaned carbs, intake new MLS head gasket timed chain & cam according to Tom Monroe manual new oil pan gasket new valve cover gasket new oil pump, timed according to Tom Monroe manual Kameari distributor installed cleaned some carbon buildup on cylinder head Installed internally-regulated alternator new chain cover & water pump gaskets some more stuff I'm probably forgetting about I don't know what cam is in there from the previous owner, but it seems like it might be slightly aggressive. Would a cylinder leakdown test be a good idea? Would valve seals / seats cause these sorts of issues? Thanks in advance for any help!

This is with UV dye in the coolant under a UV light

Looks like a head gasket leak, huh?

I have it idling pretty well now. See the video linked at the bottom. I haven't taken the linkage off before, so maybe the previous owner assembled something incorrectly. Thanks, I'll take a look. I believe so, yes; the springs which return the throttle to closed after opening it? That's what I was sort of thinking. I haven't checked for leaks. If you watch the video below, you can hear a high-pitched sort of buzzing / sucking noise, so I'll have to figure out what's going on there. One of the problems I discovered was I just didn't have enough oil in the carb dampers. I made sure to fill them almost all the way up, and that made the carb pistons way harder to push up. I tried lubing the moving parts, which might have helped a bit, but I'll try giving the linkage a bit of a twist.

It seems like my L28 engine with SU Carbs wants to run away to high RPM at idle. I'm new to tuning, so I might be missing something obvious. The timing gun starts out at high hundreds of RPMs, but grows quickly to above 1200 or 1300 RPM, and I get spooked and cut the ignition. I've been using this as a guide for tuning: https://zcarguide.com/tuning-adjusting-datsun-240z-su-carburetors/ My fast-idle is backed-off, and it looks like the butterfly-valves are mostly closed. Both idle adjustment screws are backed off. I followed the guide to lift the mixture screws underneath the carbs fully up and then backed them off two revolutions. Choke is off. I noticed the mixture jets underneath the carbs might not be fully returning to the top of their travel, so the springs which pull them up might need to be tightened / replaced. I have 3-in-1 oil in the carb damper area. I haven't adjusted timing yet, but as far as I know that wouldn't cause this issue. Any ideas on what I could look at / adjust next? Is the oil that I used maybe too thin? Before I had some ATF in there, and it seemed like the pistons were way too hard to lift, but now I'm wondering if the 3-in-1 is too thin and they're lifting too easily.

I haven't disassembled the lower block yet.

Thanks for the replies. Actually all the head bolts and cam sprocket bolt were loose when I was taking the head off. L24 is punched in the side of the block. I have an L28 in the 72' 240z right now. I'll spray the cylinders down. I'm moving soon, which is why I took the head off (lighter to move around separately).

I got this motor free with the 240z I bought. After inspection, it looks like it sat in a mud hole for a few years... Is this a lost cause? Should I turn it into scrap?

Haha derp, okay gave it a 360deg turn and this is what it looks like now: https://photos.app.goo.gl/NnBwiLwbx2KAPU4o7, https://photos.app.goo.gl/q9gQSErUXPYjpVVz9 Thanks for the help thus far ?

Okay, I managed to get it to close to #1 TDC: https://photos.app.goo.gl/AcjWnUn1WbWCt2REA But this is what the distributor looks like: https://photos.app.goo.gl/d11xkbEXiagMp6sdA Something seems off here...

I forgot to mention earlier, I think I figured out the distributor pedestal mystery. It appears to me like the previous owner took the distributor out of an L24 engine and slapped it onto the L28 pedestal and engine. In one box of parts I found the transistor ignition box with all the wires cut. I flipped the pedestal around and tapped some new mounting holes: https://photos.app.goo.gl/Ln9hh2FvdabMKeiP6 https://photos.app.goo.gl/PnJSctfa4Qp9UrGa8 Why the P.O. would "downgrade" to the points dizzy, I don't know. I'm looking into upgrading to a new ignition at a later point. Another interesting tidbit: I just removed plugs #1 & #2, and it would appear that cylinder #1 is not firing, as the plug still looks brand new: https://photos.app.goo.gl/hgHEgfVZVgqBqDwa6 As I don't currently have a good way of turning the crank by hand, I've just been trying to eyeball things :'D I have a 27mm socket coming in the mail. The closest I have is 1" & 29mm deep, so I might just need to wait. Socket should arrive Tues.

Hmm that is a good insight. 'kickback sounds lean'. Today I did take the suction pistons apart and clean them, and put the correct oil in the dampers. I might look into how they might be getting stuck. I also bought the color-tune spark plug listed in that tuning guide, but haven't tried it yet. Maybe that will give some insight as well. Thanks!

Yes, same video. Link for context: https://forums.hybridz.org/topic/131555-help-new-to-me-240z-l28-wont-idle/?ct=1590465931 I've been having issues with the other forum, so I'm trying this one. I tried disconnecting vac advance, moving distributor to adjust timing, issue still occurs. It seems like something is vigorously stopping the motor from running, but I have no idea what it could be yet.

I started with this adjustment guide: https://zcarguide.com/tuning-adjusting-datsun-240z-su-carburetors/ I can get the motor to run for a bit, but then it suddenly will stop and spit fuel back out the carbs: I recently disassembled the distributor, cleaned everything, put in fresh points and some other hardware. I just bought a timing gun, but it's hard to check timing on one side of the car and start it on another, seeing as how it usuall doesn't run for too long. Has anyone seen something like this before? Other videos: https://youtu.be/jRxGxSqsDXw, https://youtu.be/4MFxvqKeHo0