Stanley

I'm not seeing a huge amount of excitement here about Seafoam. Also, the dread I had about carbon build-up from running rich for a few months evaporated an hour ago when I pulled the spark plugs. Yesterday I swapped the SM's for some modded N-27's, opened the gap on the crappy old points a bit so it would start, set the mix 2 1/8 turns down and checked the flow, and drove to Gardena in 2nd gear to pick up some lube for the points cam, then over to Torrance for some groceries. The engine temp got up to halfway on the gauge which almost never happens (have some cooling system mods for summer trips through Blythe). Had to stop three times to lower the idle, which I'd previously raised so it would keep running with the no points gap shituation. Each time I noticed how hot the engine was. Almost burned my hand adjusting the idle. Couple times it crapped out and died, I realized it would keep running if I pulled the choke way back. So today I found (after an hour of searching) a new set of Nissan points and the feeler gauge. After installing the points still had some daylight left, so checked the plugs. Amazing. They were all spotless and new-looking except some grayish lean-burn stuff on the ground side. After seeing the plugs fouled for months I couldn't believe it.The sooty stuff on the insulator I could never reach with the wire brush was all gone. Maybe the lean condition 2nd gear run cleaned out the engine. Think I'll richen it up a little though.

My 240z has been running rich for a while. The replacement cylinder head was sparkly new-looking when installed 6 or 7 years ago. Thinking about running a spray can of Seafoam through the SU's to clean up the top end. Read some threads on this site about it but they don't mention using the spray type. Seafoam site recommends using spray type except for professional applications. I guess I'd do it by spraying into one carb about 15 seconds and switching to the other one for 15 seconds etc until the can is empty. Not sure I want to do this but read mostly good reviews of it.

Fan shroud. MSA carbon fiber works good but 2-piece would be handier. Maybe oil cooler for Palmdale. Nice cam cover. Is that powder coat ?

Looks like there's a hole in the weld where the rusty old stock tailpipe meets the new muffler. That's the worst welding I ever saw. Sorry if you welded it yourself. Whoever did it should practice a lot on some old parts before welding for a customer. I noticed my truck backfiring through the tail pipe after a small hole rusted out in the header about 10 inches from the exhaust port. Cause and effect maybe, but I don't understand t how a hole in a header would cause backfire.

It wouldn't run with the modded SM's so I put some modified N27's in today. Still wouldn't start. Since it ran with them before figured it must something else. Had a look at the points, they were rather played. The points cam was worn down, not enough gap. Bumped it around until it was on the cam and opened up the points a bit. It started right up and ran great, except for overrun when I shut it down after a drive. Tomorrow will install a new set of points and set the dwell with the meter AFTER I get some points cam grease. Maybe the modded SM's were OK. I'll try putting them back if it goes lean. Idle was set high couple days ago so it would run. I forgot to readjust it, so today it was way too high once the engine warmed up. Maybe the cause of the overrun.

Modded my SM's today. Measured a new set of N27's and compared to C.O.'s numbers on this thread. One of his numbers looked like an outlier so I used mine. Also one of mine looked like an outlier so I used his. There's a better way using statistics and curve matching software, but I wanted to get it done today. Only planned to modify the first two stations anyway, to equal the N-27's so they might work better with the Hitachi nozzles. Pulled an SM and put it in my drill, used the edge of a piece of used 320 grit with a credit card as a backer. Checked it at station 1 with caliper set at 0.0950, and station 2 at 0.0940, (not that I trust the numbers in ten thousandths place) took about 5 or 10 minutes each to get from 0.0990 to 0.0950. Used some 1000 grit for a few seconds to shine them up. Unintentionally took station 3 down a little too on both needles. Only 1/4 inch from 1 to 3. It runs, will test and tune tomorrow.

I heard the opposite: that rich mix causes popping in exhaust and lean mix causes popping through carb. But the cam might have something to do with it. Race cars always seem to be popping on deceleration.

No ? I saw an official-looking "no Jake Brake" sign on a big downgrade there in 2001 but maybe it was a concerned resident that put it up and not D.O.T.

Jake Brake. Illegal in Oregon.

I don't understand that, maybe someone else does. I meant the end that goes into the banjo, not the part that contacts the float. There was a different type that was used for a while, I haven't seen one though.

Suggest running hoses from the vents on the lids to some containers so gas will go there if it overflows. Make sure it's not overflowing before the test drive. I run the vent hoses to a couple of empty plastic Shiracha bottles lodged under the master cylinder. I leave them there so I'll know if they ever overflow. The rubber tip of the needle valve needs to come to a sharp point or it might not seal. If it's rounded get a new one. While it's out maybe give a blast of carb cleaner out through the banjo bolt, in case there's gunk in there. Also If the float isn't sitting just right in the bowl, especially if the fuel level is set too high, or if the float is tilted up, it can stick against the side of the bowl causing overflow.

'72 three-screw roundtops swapped on my '73 car by the P.O. The sightglass is a pair of clear plastic tubes with metric fittings that screw into the drain plugs on the sides of the float bowls. I bend a piece of wire around the tube and hook it over a fuel hose or something so it doesn't flop down and let fuel run out. Fuel in the tubes rises to the height of fuel in the bowls. Handy for setting the floats. One of them has a slight leak so I remove them when the float adjustment is done.

Last time after I cleaned the spark plugs there was a noise when the engine started, coming from the head at hole 6. Wondered if something bent in the head from revving it up. Didn't drive for a few days. Today put a new plug in #6. The old plug tested more or less OK, ground side to threads intermittent or bad contact with meter. Did some tune, started the engine, it sounded fine, no noise at #6. What happened ? I guess the sound was a spark jumping but I couldn't see it and the plug looks OK on the outside. It was torqued to spec.

Guess I should chime in since I'm having the same sort of fun with carbs. Hope it will add some useful information but maybe not. I'd been running SM's with the mix nuts set 3.5 turns down to keep from going lean under load at low rpm's. Had to clean the fouled plugs every couple weeks. Got tired of that so two weeks ago tried moving the needles up in the pistons from stock position as far as they'd go, about 1/8 inch or one station. Set the mix the usual way and ended up with the mix nuts about 1.75 turns down. It idled great but wouldn't run well and didn't want to start, finally got it started and home. Checked the plugs, they were fouled even though I'd cleaned them before the "tune-up" an hour earlier. Had a couple construction jobs to go to, one 40 miles away, so rented a car, didn't have time to mess with the Datsun for a couple weeks. So yesterday cleaned the plugs again. Decided to lower the fuel level since I'd previously set it a couple mm above stock height (before installing the SM's). Pulled the air cleaners and discovered the probable reason it wouldn't start before - I had installed one of the velocity stacks upside-down, covering the vent holes. Today I hooked up the sightglasses. Got lucky and nailed the float setting where I wanted it first try. Set the mix by combination of methods including white paper towel at tailpipe, ended up with both carbs set 1.5 turns down. Started easily and sounded good at idle but drove around the parking lot a few times and it ran crappy. Richened it up a flat and made it to the store and back, not impressed with the lean popping though. I'll rich it up some more tomorrow and try again but I think I'm about done with the SM's. Think I'll put the N-27's in the drill and polish some off the upper-mid and top end zones instead. Or maybe polish off the first few stations of the SM's. Probably should have done that before.

What are you using for speakers ? I'd like to get away from stock speaker location, but maybe there's a small woofer that could fit there. I'm thinking under the dash, one on each side. Not trying for anything super loud, just loud enough.

Keep an icy drink in the ashtray.

Just keep the windows open and go fast.

Valve badly corroded and hose ends cracked on mine. It was leaking at the hose ends. My heater core looks new, guess the P.O.'s mechanic replaced that but not the valve and hoses, way to go.

Looks like the hose to the PCV valve is shot. That might cause a vacuum leak and interfere with PCV function.

A good radio wouldn't need as much antenna. Hitachi made some nice receivers back in the day, but maybe Nissan thought it would add too much to the price.

I like what you're saying. Are those Retrosound ones from MSA or the manufacturer's site ? What about the antenna ? The auto sound place charges $100 to install the retrosound radio and $200 to install the antenna. Don't know if that includes the antenna. They do it all day so I'm going with that. It would probably take me a week and I've got a job. 7tooZ, I'm not doing that but it's very cool. Maybe you'll show it off with some photos when done ?

Is there one? Saw the Retrosound at MSA site. It says it's got USB connection but doesn't say if it plays from that or needs an external player. If not is there a different one that fits the car and plays MP3's ? It also should have power antenna hook-up.

The radio antenna quit working last month. I'm getting a new radio as soon as I have time and they'll put a new antenna that works with the radio. So don't want to spend time and money to fix the stock one. Just want to be able to pull it up and push it down by hand for now. Seems like it should be easy but maybe not, so asking since it's not so easy removing and reinstalling that interior plastic panel. It's stuck in the down position, don't want to force it and break something.

Except for the popping, "can barely hear it" sounds normal for the radio. I'm done with the radio. As soon as I can find one that can play mp3's from a flash drive it's out of there. A new $20 speaker same size as original helped some. I thought if you put too much speaker on a weak radio it would cause smoke.

If you just loop it under the dash then hot coolant will recycle through the engine, raising the operating temp somewhat. Easy enough to lodge tapered rubber plugs or other restrictors in the hoses, though. If you test before installing the new valve and hoses, it might leak at corrosion pitting on the old valve, or at bad hose ends, before the core leaks. Wish my heater and especially defroster worked. Have the parts but dread the job.