duragg
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Posts posted by duragg
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No question about the tank. I drained it once, but will drain again and refill with 100LL Avgas and run the electric pump for a while while letting it drain out up front. Worst case I have a spare fuel tank, but not up for that job again.
I figured more for guys racing or running Triples daily in a more humid environment, might come in handy.
Aircraft carbs and fuel systems have multiple drains and water catches.
Just a thought.
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I've had a continual idle problem with my Triple Weber 240.
When I got the car I drained the gas tank and replaced the filters and rebuilt the carbs. But on a hunch I pulled them off again and the floats are full of water, or beer or pee or ...?
QUESTION:: Has anyone ever installed a float bowl drain system?
Those square covers on the bottom could be tapped and threaded and a simple drain and valve installed for occasional removal of WHATEVER might be settled into the bottom of the bowls. LOTS easier that removing, cleaning replacing.
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Interesting OD Green.
I am considering painting my project a traditional military OD, but non-metallic. All the trim will be (already is) powdercoat black.
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Front Camber Plates installed today.
Bought the plates from Arizona Zcar as I plan to use his suspension in this project. Nice stuff he has.
Cut out the hole to rough shape with Plasma Cutter.
Bend the plate to match the contour of the strut top.
Trial fit the piece in place
Align the plates. I bent a piece of aluminum to aid in alignment.
Mig weld the pieces in place and grind to look nice.
See the full restore log:
http://www.desertzassociation.com/forums/viewtopic.php?t=759
http://www.desertzassociation.com/forums/viewtopic.php?t=759&postdays=0&postorder=asc&start=15
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I'm having a heck of a time tuning 3 carbs on a Z that are all identical and have a fresh rebuild.
Buying used carbs from a variety of sources is guaranteed to be a hassle. You'd have better luck training 3 housecats to do tricks than getting carbs with varied backgrounds all singing the same song.
Maybe Mikunis are far easier than Webers?
But sounds like impending headaches.
GL.
TJ
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DCOE 40-151 carbs.
45F9 idle jets, car has a "lean pop" in cruise.
Throttle response is perfect.
Switch to 50F9s and Cruise "Lean pop" goes away.
But car hesitates on smooth throttle tip-in.
I tried 55F9s and the hesitation is way worse.
Back to 45F9s and the cruise lean-pop is back.
But the hesitation goes away.
Questions:
1) Should I try a different "F" number?
2) Does the "Air Bypass Screw" have any impact on this?
I was told the Air Bypass Screw is only for balancing one barrel to another. But nobody seems to know too much about these screws.
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Ok what happens is that Cylinder #4 (Fed from carb #2) doesn't make much power at idle, and sometimes it just misses altogether. You can tell by removing one spark plug at a time. THey all cause a change in the engine except #4, or wherever the rear barrel of that carb happens to be.
I moved the carb to Position #3 and the problem follows that rear barrell of that carb.
Adjusted the valves, checked compression cleaned the plugs etc.
The plugs are Bosch Crapinum... prolly need NGKs.
But just cant figure why that one barrell does so poorly at idle.
Carbs are rebuilt and I've tried lots of jets.
Pulls strong and tests clean at emission on the Mains.
But the idle circuit goes haywire after it sits at idle for a few seconds.
I think I will pull that carb apart again and check for debris or something weird. Hopefully I'd find a little piece of rubber or something in there.
Thanks.
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I suspect my #2 (Middle) Weber 40 DCOE isn't flowing right at idle, despite a rebuild and jet replacement.
What is the function of the thing called the "Exhaust Bleed" and can it impact idle running if messed up?
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Weber Idle Circuit is TRICKY~!
MAINS
I increased my Main jet from 115 to 120 and Air Corrector from 200 to 170. This makes it much more rich.
My Arizona Emissions numbers tumbled!
Loaded CO was 1 percent, increased to 1.8 percent (3.75 is limit)
Loaded HC was 600 (fail) , went to 320(pass) (limit 500).
Cool..., richer jet equals better emissions?
So I took my idle jet from 45F9 to 50F9 and then to 55F9.
I did this because my idle screws were like 3 turns out.
But each richer idle jet made a bigger bog on throttle tip-in.
With the 55F9s I got wiplash with each cruise throttle movement. Unacceptable
So I went back to my 45F9s and the throttle response is EXCELLENT.
But (crap)./.. the emissions went haywire.
50F9s got me 1 percent CO and 600HC
45F9s got me 8 percent CO and 1100HC (Progession ports prematurely exposed???)
I retarded the timing with the 45F9s and got 8 percent CO and 490 HC
Limit is 5 percent CO and 400 HC.
I'm begining to think the IDLE CIRCUIT IS CRITICAL...
Its like you HAVE to set the butterfly valves JUST short of the Progession ports... then NEVER touch them and find an idle jet that will work.
Too much idle jet and the Progeression ports are too far away and cause a lean miss.
Too lean idle jet and response is good but fuel flow is hideous.
Am I going crazy?
I am going crazy!
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I've been using Pierce Manifolds for all my Weber jets and tech help lately:
http://www.piercemanifolds.com/
I spoke with them for about 30 minutes today, described my problem and he recommended some jets to try.
Very easy to deal with.
TJ
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Thanks. In fact I have that thread printed out and carry it around in the car with me when I drive it..
TJ
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1973 240z with L24.
Carb question, is this jetting wrong?
Triple 40 DCOE-151 carbs.
Mechanical and electric pump at 3 PSI
Headers (wrapped and blanketed) to Cherry Bomb and out, nothing else.
Rebuilt all 3 carbs with Weber kits, new needle valves and new floats.
30mm chokes.
50F9 idle jets.
115 Main Jet
F11 Emulsion tube
200 Air corrector
Idle needle screws 3 turns out!
Carbs are sync'd perfectly with the $50 airflow meter.
Occasional lean pop.
Stumbles on throttle tip-in at speed.
Plugs are very light in color, if not white.
Idle mixture screws are 3 turns out to get smooth max rpm
Power trails off after 5000 RPM
Adjusted all valves to book spec.
Fails Arizona emissions with high Hydrocarbons
Loaded CO is like 1% and idle CO is similar.
36 degrees of total advance, no vacuum advance.
Replaced entire ignition system.
With the mixture screw 3 turns out and the plugs white I think its time for fatter jets. Any recommendations on target jet sizes?
Tj
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Ok, forgive me a minute.
First an update on my Triple Weber troubleshooting and setup.
Then some emotional comments about carbs.
{1973 240z with L24, 5sp, Triple DCOE 40-151s with 30mm chokes, 50F9 Idles and some other jets I can not remember exactly which now..., headers, a glasspack and thats it. I bought it this way... just a toy}
I bought this Z as a fun driver while my '72 is in restoration.
It barely ran. I rebuilt the carbs, replaced the entire ignition system verified compression, timing, vacuum leaks etc.
One of the most critical things I learned from this experience is to properly "seat" the jets in the Weber DCOE carbs.
1) "I THINK" the Weber jets should be "lapped" into their seats with lapping compound to make a perfect seal. (I didn't do this, but would next time).
2) "I THINK" the Weber jets should only be lightly installed in their carriers prior to screwing down, and let the "screwing down" function set the final height of the jet.
I have never worked on carbs before this, so forgive me if this is old news, but I never read about it anywhere. I don't claim to be an expert of any sort, just a fan of Triples and finally got mine running smooth and even.
After many long days I finally got these carbs all flowing equally at idle and pulling strong (at least to about 5k, will worry about the rest next week.)
Other observations:
1) Linkage is CRITICAL. MUST have linear arm throw.
2) THROTTLE STOP... let me tell you... if your throttle pedal stop is not correct and you jam the Weber arms into their stops while racing... you will get an incurable high idle and trash all your idle speed settings.
Make for darn sure you throttle pedal hits the stop before your Weber arms hit their stops and bend and f00k it all to hester.
3) My cylinder #2 wasn't firing, the other cylinders were all a "5" on my synchronizer and #2 was a "2.5". I took it back apart twice and reset the butterflys and everything else. Finally I went after the "Air Bypass Screw" and at about 3 turns out the cylinder started to run and makes a "5" on the synchronizer like the rest. Perhaps the shaft is bent? The shaft was sticking too, which I cured (mostly), but still maybe an incurable problem due to worn carbs.
Triples are a hoot to drive. They talk to you very clearly and have a wonderful sound and feel. Sometimes it seems like max power is not gained at full throttle, but at partial throttle until the engine is ready..
At certain RPMs you can go to full throttle and get an "rrrrrroar"
or back off to about 80% throttle and get an "rRRROAR" that will crescendo to a full blown WAIL at WOT screaming down the interstate. You have to feel for the sweet spot a bit and it is very rewarding.
Fuel consumption: I have gone through 2 tanks of fuel and barely driven the car 50 miles. I hammer it quite a bit. They go through a LOT of propellent at WOT. Perhaps I need to work on the mixture more. But I don't think Triples are for you if you have a problem with fuel consumption.
Timing: This motor runs at about 30BTDC advance at idle and 50BTDC at 3000rpm. I have verified #1 TDC corresponds with the timing mark. It runs and pulls good and doesn't ping. Damper bad? Dizzy slipped a tooth? I have no idea, but I know it runs good with timing that seems too much to be true, so it probably isn't true. I've checked with my timing light and a "Snap-On" timing light and got the same number. This is the next project.
Nite.
TJ
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I have the fuel pressure at 5psi now and will bring back to 3.
Valve clearance is good.
Car running a LOT better.
TJ
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Ok I fixed it.
I removed the carbs and cleaned everything up, but still popped at idle.
My friend Joe Moriarty (Owner of Total Seal Piston Rings) said it sounded like a "Lean pop" to him.
So I pulled the idle jets again and cleaned them double good again.
SEATING::::: I took time to remove the jets and seat them lightly into the carrier, then re-installed which allows the jet to seat better in the housing. (Is this common knowledge??? I'm new to carbs.)
Doing this cured the lean pop and they run good now.
I still plan to buy a slightly richer idle jet, and also get the service kits and rebuild the carbs.
Thanks for everyone's help, this was a fun adventure.
Tj
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Found this handy "DOS" based calulator for rough estimates on Weber jetting. I found this on the Alfa Romeo website.
It is designed for a 4 banger with double Doubles, so I just input 1600 as the displacement (2/3s of an 2400) to simulate an L24.
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Thanks:
I found the high idle problem when I took the carbs off to clean and check for vacuum leaks.
The throttle stop is mis-adjusted and when you slam the throttle down the throttle plate arm jams on to the full open stop and bends itself back a small amount. Then when the throttle goes back to idle the now-bent throttle plate arms keep the plates open a small extra amount to the point where the idle screw is all the way out and the plates are still way far open. Ok, fixed that.
For all the cleaning and checking on the carbs I did it doesn't change the idle pop at all. Its really only idle and just barely cracked throttle that it pops in all the cylinders. Not really out the carbs, just in the headers which are glowing red hot.
So the engine is either WAY lean or whacked out of timing, or stuck valves.
But it makes good power so I am not sure about stuck valves.
Gonna physically check TDC with a dial indicator today.
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So I bought a 1973 240z with Triple Webers to add to my 240z fleet.
Hauls arse at wide open throttle.
Triple 40 DCOE 151 carbs
Stock L24 block and head
poPs and pOps and POps at idle or high idle.
Fuel pressure is 5psi
Runs stock Weber horns
I put on a new distributor, rotor, cap, wires, plugs.
Cant tell much from the new plugs, they look ok, but have some oil fouling (worn guides?)
It has a Crane XR700 and I adjusted that and replaced the ground wire.
It has no vacuum advance, only mechanical.
I set the TOTAL advance to 32BTDC (maybe more
I checked all valve clearances and they are within spec.
I drained the fuel and refilled with 100LL Aviation fuel.
I sprayed vulcan death spray into the Triple carb intakes to try to clean.
I removed and cleaned all the jets, and checked the float levels.
I farked with every adjustment on the carb and...
..... it still poPs and pOps and POps at idle or high idle.
Pulls great at wide open.
Air Corrector Jet = 002? (or is that 200)
Emulsion tube = F11
Main Jet = 115
Idle jet says 45F9
I happen to run it tonight in the dark.
I cant get the idle down low enough, it wont go below 2500 once it is warm.
After just barely a minute at this high idle the HEADERS were CHERRY RED... GLOWING RED LIKE MAD HOT....
Perhaps a "lean pop" from too lean idle jet?
I see no reason why it needs to run red hot at high idle.
Seem like I am on the backside (lean side) of the Stoichiometric curve.
Do the jet sizes I found in these carbs seem out of whack?
Tj
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Forgive me.
You have exactly what I am looking for.
You are entitled for free beer for 3 days.
Thanks.
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Anybody with pics or experience of their installation of the "Rear Extension" frame rail option from BadDog?
I have my new floor pans and replacement frame rails in my shop.
Also have BadDogs Frame Rails: BEEFY.
And the Rear Extension.
Its the rear extension I am looking for feedback on the installation.
Tj
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Maybe I am nuts...
I am considering paiting my Z a real nice desert tan color with blackout trim. I don't see a lot of cars this color.
Stealthy here in Phoenix too...
But I need a way to mock it up and see what it will look like.
Does anyone have an outline image of the 240 I can modify in photoshop?
Tj
Weber jets??All who live for their triples please read this
in Nissan L6 Forum
Posted
When I jet-up to 50F9s or 55F9s and tune to eliminate the idle pop, I get a wicked head snapping stumble on throttle tip in...
So I got back to my 45F9s and I can mostly eliminate the stumble but I get occasional idle pops out the carbs (lean pop). This can't be right is it?
Do most people with Triples just live with occasional idle lean pops or a stumble on throttle tip in? Is it that freakin sensitive?
I suspect a lot of the stumble has to do with the throttle plates position in reference to the progression ports (NAPABill come back!). But when I adjust the throttle plates per the book or NAPABills suggestion I get a 2000rpm idle.
Gak.
TJ