attacking a monojet

[boxer3main]

I forgot to take this thing highway to see if the bellow is back .this tells me it is rich enough.

it is indeed there. the let down is instant off..the long jet can't play games.

a new problem is in the cold. it did the opposite of warm up faster..the draft is even colder. I can pop thru carb if laying it on too fast.

I refuse to go all plenum under the hood like the old days..

a heat riser needed...
even the I-6 had a warm up time for this carb. all plenum under the hood to roast it in minutes.

the new gasket seems to be a cold one as well, no odors after shudown. As if the old gasket was some weird catalyzer.

valve noise is a lean condition coming back around to richer and colder. springs will take some time. this boxer has done this more times than nothing I know survives.


anyone play with CAI and carb..the heat riser subject? I need a simply clever idea.

I have a resistor on the fuel, and a partial draft under hood...not enough.



I was thinking of how the plenums worked. large area above carb, electrocutable, sloppy chamber of deadness. it is to keep the venturi happy..slow feed.
Above is a wheel bearing race on top of the float bowl cover upside down. it is nearly the same size as the barrel. I will put this in the intake tube, wedged ..this may fake a chamber like a plenum has, by sizing up the demand before it gets to carb...and leaving a slower space of the larger air duct that follows the race...I ponder it is over a foot after this race is wedged in to be the slow down.

I am avoiding heat riser as that sucks on city sewage, hondas an evos...and whatever else.

[boxer3main]

no vacuum valves, no thermal vacuum switch, nothing that will break to useless after finding it never worked. I want nature.
this is wheel bearing race with pc fan grate over it to screw it to plenum end. another freak fit..it is the exact same size. the race is heavy and the final size for barrel..larger by a small amount. the grate is to stop free flow. all stainless.

will it work? don't know yet.


overthunk? no.

a test ride. car will be sitting for a couple of weeks. would love to just pounce a 1000 miles into it. still stubborn cold starts. the cold cough did subside a bit. A good rain storm..could drive all day in it.
seems a world of crap in the oil side now..pcv may be releasing the monster that hung onto the carb. taking plenum apart to put in my gadget was no brain robbing odors.

stainless in the presence of air duct scare away many things. enzyme related. the little four banger is flowing too much to care about that anymore..but I still think of it.

[boxer3main]

there is not much else to conquer. stuff not mentioned was not important.

I may tinker with an engine oilpan heater, stick it on the air box. little stuff. The custom plenum stainless piece is to promote pcv inlet with carb gasses..else it won't get anything but arctica...10% humidity.
been there with more than this car. engineers know hawaii more than america. that is coincidental to..
oh nevermind.


first vid:
february 8 2012, the intake stuff. first looks.
I have to use music that does not get me into trouble. making my own loops is usually a safe bet.



last vid Apr 22, 2012



the driving clips or cold starts etc..showing errors along the way, as if to be immortally forever stuck there. those vids are deleted. people are stupid.


I was reading my local paper..internet is doubled for everyone in my locale. Here I thought the registry cleaner was giving me a faster net. thanks to "docsis 3.0"

anyway..my vids are actually wide screen 10mbit, panasonic ( good stuff), for several years I have been squashing them into a blur due to an insanely slow upload.
finding old settings.. I was even uploading sound at 256kbit in the past. I'll be back to that shortly.


this air/fuel stuff, seeming to be way overthunk to you?

changing plugs to hot the other day I noticed the intake valve open at the plug hole...between rocker ratio, solid lift, and an injection cam that has lobes looking like an egg..
the lift is over half inch. in the v8 world, well we know what this is don't we. to have a smooth idle..I must have done something right with a monojet and mismatched subaru parts.

manufacture ships easiest for themselves and a warranty. This is just another car going to a real runtime..who cares what power numbers are.

the fuel air subject gets much nerdier than me and this boxer.

[boxer3main]

the red is where it is not the same as mine, all else is good enough for explaining.
the accelerator pump shares main well (the last real revision of common sense), those are the monojets to go for. I know 1976 onward is a sure bet. else..adjustments don’t even matter. it will be a single digit low teens mpg hog. There is an obsolete versions to everything.


adjustable part throttle metering orifice. Yet another description of the extra hole near main jet. A real desire to leave that far open gets a performer..but yet again makes it a hog after vacuums are happy, engine warm. I found keeping it tight and make the carb earn the path will get a real stoich like modern (ie: 1.8 liters should be 30 something mpg). My own is 1.5 turns out..and may tighten it by end of summer. No monojet has clean paths. Make it earn them to be real. (example: The 4.1 L should be middle twenties mpg – do not stop letting it cough until it is there.)

a last trick for that hole, is sticking a pipe in the same size (press in some copper or whatever) and raising it up if you know the carb is clean. on my own, the jet is raised.. so I may use the little pipe that came with the chevtte and raise to .25 off the float bowl floor, and trim from there. I need the summers long day ride to finalize these little things. I treat a carb like welding chores...as long as it is 56F at a low temp at night. that needs middle of summer here.


all else is simply clever. for real tight stoichs, little engine..raising the jet, return line, and little float (old brass for monojet if you can’t find a chevette version) is a real runtime.

for the sharing main well accelerator pump..I had a friend who analyzed my 1974 chevelle, and he got excited about that...funny, at the time, I called him a nerd. that one move double and triples mileage..makes the main well gain pressure to seat a jets path to running tight. That is where I learned about the part throttle adjustement getting uncapped, and screwed right in to 1.5 turns and letting it have no more. (my chevelle was middle twenties mpg)


I'd really scrap the other monojets unless preservation of exact oem build for your classics year is the goal.
on multi carb gurus, they can take those pumps right out, even the metering needle. there is ways to hack old to new. the real line drawn is seeing if it has a stainless barrel..no stainless? its a scrapper.

[boxer3main]

the coffee jug and lid is made of HDPE. High-density polyethylene.
I guess I used the highest grade gasket available at big big cost.


they make gas tanks for cars out of the same stuff. any hardening is hydrogen leaving. wherever it is squashed between bowl cover and float bowl is where gasket stays soft. it digs into the little ridges monojet uses. never moves. kept a memory as I poked and peeled. no stickiness.

also..it proved the old gasket, a tar like covering..that one was very very bad, it may have even been toxic. almost holding my breath taking bowl cover off, expecting that horrifying brain stabbing odor..there was none. the new gasket also kept it worlds cooler. An inert you just know is there content.
if this gasket proves to be too thin , or not strong enough, other plastics include any oil jug, or even coolant. all reusable. pluck the top off and play with jets all I want.

I wanted to see how the coffee lid gasket did, and if idle air hole got filled in by squish.. i am going for very tight, as the gasket is a plastic trait.

the gasket swelled up (I don't mean the material, I mean it moved the gasket upward like a balloon) and hardened around float bowl needle, fuel pressure/moving is much bigger than I thought. wow. return line reason infinite..

all else is perfection. I trimmed a little more at idle hole.

an odd thng to take note of (they all do this, guaranteed)

I installed main jet and needle, they weren't exactly aligned. today it is perfection. did it all on its own overnight...the jet moved to the needle. not the needle to the jet. I bet its a power valve electrode gain and loss.

ready to go. engine sounds bad.. but I got fuel air...

..and engine may not be done of course, big changes can rumble any engine.

I am so very curious about the 115mph marker and beyond. the spongy four cyl feel has a climb. the boxer is like that.

[boxer3main]

on the original attempt at a return line, this was before getting it at the bowl, I found this check valve in a vacuum line. Gas proof of course. works on low psi. less than a pound. Car ran with it. the error proved to be return line needing to be after the float bowl gains priority, not before.

I thought it may be too big of an opening. not acting as a regulator enough. I added some piping I found in the chevette carb. pressed in, then quickly lit with a bic. this should restrict it to just right..been messing with different sizes. A .035 mig welders tip is in the return line now, and the bowl gasket told me it is still getting quite a pile of fuel in a hurry...freakish.

this will do it. Still no regulator needed.

seems as though, I am tuning this into a two barrel with no needles on the jets. more than a coincidence. that is what kind of carb was in it.

this will also add one way into return..can't surge back at the carb.

This photo captured all the intersections of the fuel lines going by each other.
check valve restricted, installed into return line. I found it acts like it is starving more than before. although a whiff of fuel goes with it when the hesitation happens. An emulsifed odor, not a straight shot leaky one. This is good news. my carb tuning nose tells me. I am assuming it is choking on aerated lines. I blew into return line and found that the .035 did not fill it, it gave it an air bubbled spray. Not check valved, it sucked this back into engine when it needed to. I am forcing the hard line fuel now. Something is much tighter with the gasket for float bowl..just going to force a runtime. I wonder if this tortured monojet ever ran proper, tight into its channels. the float bowl gaskets are freaking terrible. it is all there correct now, plenty of fuel. engine sounds terrible. needs an oil change. the front side of carb has control valve for vent can hooked up at carb, and the top vent that would normally return under full vacuum into the air duct (slow that crazy function down).

I will feel bad if I blow it..but a sacrifice had to happen. the gewkster hooked it up carzy. I am just getting it right the american way 25 years later. it is useless describing how tough that really is. if a chunk of valve breaks off and pulverizes the whole thing, I will laugh.
I got it to pop, biggest ever..this means moving more than ever. the vent can having a real function must be full of a change temporarily right now. the hesitation seeming a bit more elongated..but the engine climbs it. Something familiar about this..it will come to me. I know to just drive and run it. get some good oil in quickly. clean the reusable filter out...

edit: this did work. quick snap of reality in these retarded city streets.
Since this posting, I have found the brake booster is very strong.strongest I have ever felt. The guess about air holes for idle were correct,old bowl gasket could not do its job...for years and years. the hitachi was the same..but intermittent. the lucky seat to air loose must have been the lack of venting getting its way. So that is how the original setup did not become a complete bomb..only became a little one. An error got its way to correct when it needed to. I guess I deciphered the past with a current problem, building it on your own can do that. generalize 100 other cars with just one.

I got a whiff of the old gasket. that is some kinda power getting kicked out. off-idle to partial is existing. I give it a thumbs up..I am real curious about the other end. top end runout. Seems it is all there, thinking the needle over as much as I have. I am in a place that has 3 nanoseconds for error. People climb out of the woods to go through these streets of the only city. the accidents are funny when no one is hurt.
hesitating throttle is not an option. diesel thump of an old boxer to a scream not much heard of in the northwest USA woods wth lift kits and dangling EGR fungus.

how in the hell did they not see F1 in a self balanced short stroke, liquid cooled all aluminum boxer?
no rocket scientist needed.

just going to let it sit around, give it another long run again in coming weeks..funky thumpy sound the little engine makes... I love it.

[boxer3main]

getting into final things. green on the trees. above freezing (at night we still get frost into the morning sun)

time to get after little things.



the little hole that gets covered next to the pressure relief bolt, and glimpse of the spring. even on the old pump, the old line of where bolt ended showed how much was covered. this one ran perfect. the HG fail sent some casting sand into the shaft and it became sloppy. with stuff spewing everywhere, including out the oil dipstick, boiling..I could here fires in places that should not have had one. I pulled it into the garage on two cylinders and oil pressure at exactly 43psi..right by their book. amazing misproportion? no way. they need to do this for every machine.

I think the pump could do four v8s all at once.

oil pressure works via an external mounted trochoid. A robust one at that mention. I dropped the pressure relief bolt (it actually is a regulator) behind it is a spring and cup. I analyzed the old pump in the parts bin for the 100th time and still confuse myself without the manual right there with arrows and diagrams.
I found a problem with relief bolt that holds spring in, it takes up what would be on the backside of the cup. A little passage way partially covered by the bolt itself screwed in too far. I remember tightening that in a maine version of tight and killed the washer and dug into the pump hole. this means fluid motion going jerky, if that passage is too tight.

spaced the bolt away from pump more, gave it all the opening it is worth, this gave the fluidity I was looking for.

what does this have to do with a monojet? the pcv out the other end of our engine sucking on everything also pulses to whatever the pump is doing... more than the carb throttle. so, this is the last helper for that. next is just engine too old to run.

got a cold start by making choke tighter shutting. I forgot to monitor that as weather warmed up. Being so tight with fuel, I may have to do that several times again until june 21st.


no pops thru the carb, hesitating yes, but no pops. this means it is just shit that has to go. At least it is moving to the exhaust side after getting incinerated for whatever the fires worth. the wheel bearing venturi and pc grate did indeed resemble the plenum these run with a little more than what I had cramming wide open cold into it.

I have revived 21 years..but 25. this is new stuff, some of it. even anti enzyme in the coolant. All cold climate. alaska to maine. wow. the knowledge would leave engineers thinking the stuff they make is in fact a pansy...you tubers to go hug their mom like they do their honda...and put the overglorified flunk back in the effeminate mans closet.

[boxer3main]

the people showing up for a street race illegal thread. got me thinking of inspection stickers, exhaust, tires..emissions, other legality.

although maximized in every way, the project in this thread is setup exactly like a singular fuel injected 1993 subaru loyale..with a mm or more gained in the right spots, and back to no computer. all natural.
compression way over the beginning, and a lift on the cam gained not really known. way more than a tenth. joking of .550 lift and a smooth idle..

I found many errors by manufacturing.

the vent can for example..it used to open at a certain temperature..and get hard sucked into the intake. that is not survivable in all scenarios ..when a heavy salt is dissolved on a moist day. I found a way to make a separater, like the air intake box does. a spot to pause, let the heavies fall. that is not only safer...this allows for vent to never stop functioning from startup to shutdown. no extra gadgets needed. they must have done the gadgets from factory making the cars run good while salesman and customer are around it.

nothing man makes is perfect. it is the dark side of deciphering the disappointment, simply setting up fuel air for modern use.

I even run a catalyst convertor that functions.

this setup is not only legal..it goes several steps beyond. fail proofing the old mistakes has been a blessing to take on. the extra power gained, is simply extra necessary.

if you want to go transcontinent 5 times with it..have at it.

I would love to try one of those machines that measure output levels to gain inspection. california crazy version.

funny enough. this car cannot do the sporty mufflers. the decibals could twitch eyeballs. the after twacks of letting off equally unpleasant. the ebay fart cans found on nearly every ricer F1 wannabe is not an option. I run a full chambered walker turbo muffler at $19.95, welded to stay together...my weld is probably the 200 dollars they are getting at magnaflow.

you have really built an engine, when the exhaust is a fight to keep quiet with normal stuff. the screws in the dash of your counterbalanced engine will let you know when you got it.

power numbers don't matter.

the output does.

[boxer3main]

I forgot to mention the jet differences, what was noticable.
the 80 jet needed a .25 turn in on idle screw. timing sounds advanced now..the pitter pattering tease. thta is its best idle. could be main jet ready to rip into a fuel delivery with enthusiasm. this is good news.

this may be the engines normal, it is old.

choking the cai by a few mm was the correct thing to do (the wheel bearing race and fan grate). normal carbs wide open no plenum or plenum on top of carb, use the choke venturi at the carb of course.. I turned the carb into two feet long...ice cold. Needed some extra think.


I also found the 3inch Hg number was a wide open throttle test by engineers. so 250 cfm is way under rated when you go beyond it with cool density.

it is no wonder I am reaming a #80 jet..going beyond normal numbers. (80 is supposed to be this barrels big one). finding the monsters they crammed to death on the 250ci engines was a tragedy. the giant jets belong on a propane setup or somewhere else.

a real shame what they did to this carb..rochester knew what they were doing. GM demanded it do something insane.



oil pump.
Here is the strangest error, more an anomoly. created a snappy twacker at the oil, along with pressure cap not spaced enough. Both sending units plugged in was not a good idea.. I finally plugged the little sending unit today (the left one in photo) with a hard steel plug. one less springy thump.I guess this was designed to ground one item as well. both units are 1 wire gadgets. The pump in car is baked, painted, very hard..can't be the slob of squishy japanese alloy they played with anymore (I love what I did to it).

I use pcv connections as oem type balanced. it works. nothing into atmosphere. the problem is oil system can encounter fuel system and try to own a squirt or two of throttle. thumpy little timers have to go...

I want modern. I am sure I got it.

this really does get precise.

[boxer3main]

I don't know why they call it the part throttle screw.



"the part throttle metering orifice” screw. I found the little chevtte carb had the same screw. no change n taper, threads, length. The chevette carb was brand new, so I took the screw out and swapped it into the car’s truck carb.

upon further analyzing.. I did miss something. the size of that hole in this chevette carb is at least 70% smaller than the one in the car now. I turned screw in all the way, let it out 1/2 turn. I used to have it at 1.5 turns. No leaks, I won't have to cap it. can get at it for future adjusting easier. no difference in runtime yet to notice. A longer run in coming days. something is stuck in something, valves rapping. This is even more MPG, the tighter I can keep the screw in.
I had an intuition that the truck carb unscrewed itself behind the permanent cap. after drilling cap to get at screw, I noticed it was way out. wherever the truck carb came from seriously must have been single digits mpg dumping fuel all over.(truck carb simply refers to the 250ci, the exact serial number for my carb puts it in a camaro straight six)

edit: the cold start. best one yet. that is about all I noticed so far. I did not go to full warm, or even drive..just cold start.