I'm with Stan - new plugs, gapped at .024" but tighten the nipples finger tight plus 1/8'th turn. Let's not snap things off!
Someone please correct me if I'm wrong, but aren't stock plugs gapped at .028"?
I believe it is a range from .024 to .028, Al. I run mine at .045" on my crankfire, oh the blasphemy!
Danny - By the time I (and a bunch of y'all) thought of that I had already bought a new set. Too lazy to do it twice, I guess.
I found the old plugs last night, so they will go in shortly. Still haven't located the original distributor and might have gotten rid of it a few years back. I can't remember.
I believe it is a range from .024 to .028, Al. I run mine at .045" on my crankfire, oh the blasphemy!
Just looked it up in the orange Bentley manual (Beetle, Super Beetle and Karmann Ghia 1970-1979), Danny; .024" for carbureted and .028" for fuel injected engines. I only mentioned it because (iIrc) even the stock iginition system would support .028" and running at that gap was common practice, especially in modified engines.
A guy who knew a lot about ignition systems on the Samba suggested opening plug gaps until it started to misfire and then backing down one step as the way to find the biggest plug gap for any engine. He certainly knew more (not hard, as about all I know about anything electrical is you put your finger in the wrong place and it hurts!) than I did. If I get time I'll look for the thread(s) and post link(s).
And running at .045" isn't blasphemy, that's one healthy burn (and a wicked sprark)!
Thought for the day- So when is this "old enough to know better" supposed to kick in?
But.. But... Danny said to!
If I can find them locally I'll get some new ones, but I believe I had to order these. Meanwhile, switching back to the original plugs might get me back on the road.
And Lane, don't forget the anti sieze. My recent "R&R head to repair #3 spark plug threads"
using a Timecert cost almost 4 hours at $75 per. Ouch!
Maybe it's a pet peeve of mine, or maybe from hard experience, but here are some of the things I never re-use:
Gaskets - almost any kind, but I make an exception for O-rings. Paper, fiber, composite, no matter how good they look they never get re-used. Easy to re-install, but take HOURS to find a bad one.
Condensers - they're cheap and show zero indication of being good or bad
Spark Plugs (You can't tell if they're good or bad)
Points - unless they've been re-faced with a points-specific file and are not "blued" (indicating overheating and possible warping).
I'm beginning to include some fuses, since my eyes are getting old and I can't tell if they're good.
Brake Fluid if it's been sitting for more than a month
Transmission oil/Motor Oil - Never re-used. It's cheap. Rebuilding is not.
I'm sure there are more things that should be on here, but this is a good start.
All this is kinda like good wine - It's great in its first use, not so hot if it's been "recycled".
Four new plugs with tight nipples. Checked all other connections and checked sensor in distributor for looseness or signs of damage - no problems seen. Car started and sounded fine, so I though I had it solved. In the time it took to back the car out of the garage it started to miss intermittently. Took it for a short drive and the problem seemed to come and go, although it was never perfect. By the time I got back home the car would not idle at all. I have no more time to work on it until this weekend.
Where are you at checking things like fuel pressure, fuel filter, etc?
I have no way to check fuel pressure. I don't suspect this as the issue as the car will rev, but won't idle. The filters date from April.
Try the coil.
"I can try the old coil, but it would be a test only as I am pretty sure it was failing when I replaced it. Its failure mode seemed related to temperature so I should get a short ride in ok."
Isn't that the failure symptom you're currently seeing?
Does the coil you're currently using have a "Ballast Resistor" in it? If so, it is designed to give a much hotter spark (like 30%-40% hotter) when the engine is cold for better starts, and reduces spark voltage when it warms up, often within the first minute or less. Does this sound familiar? BTW: The voltage provided by the coil has NOTHING to do with engine temperature. The ballast resistor heats up as the coil is running and reduces voltage simply as a reaction to that increased in-coil temperature. 2'nd BTW: If your coil is mounted on the vertical face of the fan, right near the disti, it is subject to heat soak, especially in hotter weather. Try moving it to the Driver's inner fender wall with a slightly longer coil wire. That move usually cures premature coil failure.
Sounds like a coil would be a good investment, even as a spare for your road kit. As for that old one you removed before? Trash can it. You've already proven that it's bad.
Still noodling on this, minutes later.
Someone up above asked if the valves were adjusted properly - Leon, perhaps?
I would just check the valve clearance for that one cylinder, just to put it behind me.
The going-faulty ballast resistor/coil could give misfires on one cylinder, but usually only if you had a weak circuit on that cylinder and you've already swapped out everything else in your secondary ignition circuit so a going-faulty ballast resistor should, theoretically, cause random misfires on all cylinders (and can really drive you nuts).
The fact that it's fine when you start it up and one minute later it starts misfiring tells me it's something temperature or run-time related and the only thing I can think of is that coil.
AND, I would probably try a different make coil, just for the hell of it.
Oh! and if you turn in the air/fuel mixture screw on the offending cylinder to all the way in, what happens?
There no longer appears to be a single offending cylinder, which is confusing. Perhaps that was a red herring. The old coil would run great for 30 minutes to an hour in the heat before it would cut out unexpectedly, bringing the car to a stop. The problem now seems to happen after a few seconds of clean running. Any reinstallation of the old coil would be for test purposes only, just to see if the symptoms changed at all. If so, a new coil is in order. If not, it's probably something else. If I replace it I will need another high energy coil to work with the distributor.
If this doesn't appear too be the problem I will check the valves.
Could this possibly be a fuel delivery problem.... The Aztec Attack collapsed a brand new NAPA fuel filter and the symptoms were roughly as follows.... Car would crank and run fine, then would faintly miss during acceleration.... Day 2, crank and idle fine, spit on acceleration and sporadic miss while trying to maintain speed... Things got progressively worse each day until I pulled the line from the fuel filter and checked the delivery voulume, which sucked.... Removing the line from the tank gave about a 6 fold increase in volume.... Installed new electric pump and filter... Problem solved... Just a thought.
Not pulling the tank without a good reason to do so. I am still leaning toward ignition, but a collapsed line or filter (internally as both are relatively new metal ones) sounds plausible.
New coil ordered, will be at parts store tomorrow. Fingers crossed.
The only other remaining ignition possibility is the ignitor in the distributor. At ~$145 I don't want to just buy one on a guess. If the coil doesn't fix it I will check it with the timing light for steadiness of signal. If that looks good I will investigate valves, etc. Leon Chupp also suggested collapsing fuel line or filter, but it doesn't quite seem like fuel starvation.
I had to go out and buy more popcorn . . .
And so how about a philosophical question at this point: Do we really need the Pertronix extra super duty high voltage ignition systems to make these engines go? I fully understand the need to go w/ breakerless (electronic) points, and have that in my 009 dizzy. But otherwise, the cap, wires and coil (blue) are "stock" to the best of my knowledge. So far, working fine. Maybe the extra high output voltage of the system here is causing a dielectric breakdown in the HV circuit somewhere so the plug at the end is not firing like it should?
PS: during my carb problems, while all was apart, I elected to install a fuel pressure gage, not because I thought the pressure was bad, but because I wanted to be able to tell everyone who said I might have bad pressure feeding the carbs what the pressure actually is. i.e., to be able to know for sure that this is not the problem. Cute little thing -- somebody looked in there recently and asked if I had a nitrous system. -??- Anyway, my electric fuel pump is working fine, and delivering the proper low pressure like it should. Maybe someday the pump will fail, and this gage will help me to know that. Meantime, it just hangs there. Lane's pump is likely doing fine -- but does he REALLY know that? See what I mean . . .
Re. the Pertronix fancy-shmancy ignition: Nope. I wouldn't do it again. I thought I sensed a bit more power and smoothness when it was new, but I am on my second or third coil and about to get another. This is the coil that Pertronix supplies with the ignition, not some mismatched thing from the local parts store. In fact, the system included all of the ignition with the exception of the plugs, and the original plugs seemed fine when I replaced them in the spring. In retrospect I don't think that the Pertronix system was worth the expense.
Re. the Pertronix fancy-shmancy ignition: Nope. I wouldn't do it again. I thought I sensed a bit more power and smoothness when it was new, but I am on my second or third coil and about to get another. This is the coil that Pertronix supplies with the ignition, not some mismatched thing from the local parts store. In fact, the system included all of the ignition with the exception of the plugs, and the original plugs seemed fine when I replaced them in the spring. In retrospect I don't think that the Pertronix system was worth the expense.
It's good to read your honesty above. I was reading this thread and started to wonder if the Pentronix system would be a good upgrade. Now that I'm upgrading to the 1915, I was wondering what I should do about the coil. Right now, the coil in my car is just an old non descriptive 'black' coil. Do I need to get something higher performance than this? Or do I stick with 'if it ain't broke?
Ted
"If it ain't broke, don't fix it" should have been my motto.
I am also not a good spokesperson for Weber carbs as their maintenance requirements seem a bit onerous to me. A good set of rebuilt Dells would have been a better choice, I think. They seem less prone to dirt issues and when they do occur they seem more easily rectified. Or maybe an EFI system.
Or maybe an EFI system.
This system has its problems too. I struggled with mine (CB kit) for a couple of years, then, in frustration, pulled the engine.
The problem with EFI for air cooled engines is very few people know how to set it up properly and tune it. Henry, at Intermeccanica, tried with mine and was unsuccessful. So was the shop that built my engine. I'm hoping that my present mechanic is able to set it up so it finally runs properly.
I'm not impressed with the CB EFI kit and would not recommend it to anyone, unless they're very comfortable working with this particular system.
I highly recommend Mario at The Dub Shop to anyone thinking about converting to an EFI system. My old Speedster had a Megasquirt system that was easy to install and was up and running in a day. Tuning is done with a laptop and is so simple that even I figured it out. 
You can add crank-fired ignition as well and control it with the same Megasquirt controller and fine tune the ignition system.
I've not had an aircooled car in over a year now and am sure there's more out there today than there was last year but if you want something that works great and has great support, check into Megasquirt.
The Dub Shop system looks great but is awfully pricey. It's $2495 EFI only or $2995 with crankfire ignition included. I guess that's what small-batch manufacturing costs, but that's a tough one to justify at this point.
Wow - that is pricey. When I did my EFI conversion about 3 years ago, I ran the Megasquirt 1 (version 2.2) system and the total with crank fired ignition and all was roughly $1000.
I was lucky enough to sell my Dellorto's for $500 and my MSD ignition setup for $150 so it didn't hurt the pocketbook much and was the best move I made in the 11 years that I owned the car.
This is probably an "all parts included, just bolt it in" price, but it's still high for me.
Many may call this a step backwards or even lean towards Blasphemy but I wonder sometimes if it might be worthwhile to consider a center mount, single Weber 32/30 or something and get over all the linkage problems as well as the clogged jet problems too and whatever else. This comment is not directly related to Lane.
I know....dual carbs are cool, neat to look at and are really fun to tune. How much power would one lose going from dual to single ? Too much lost in the manifold runners ? Like crazy lots of loss ? Is it a matter of having the appearance of larger or smaller balls or what ? :-)
I've put about 30,000 miles on a Weber 32/30 over the last three years with rarely a burp. Kinda set it and forget it with half decent mileage too. The Megajolt ignition thing works well for me too. Still having trouble keeping windshields in the car though.....
Wow. That's kind of like Jerry McGuire and the mission statement. Somebody finally said it.
Don't want to hijack Lane's thread, but a single center-mount carb like the one you mentioned or a Holley 450 or Autolite 2500 would be perfect. Power loss would be minimal, IMO and jetted right it would be really minimal.
Apart from the "Macho-ness" of dual carbs on a flat four or trying to look "period correct", there really isn't any reason to run them.
Heck- I had a single 4-barrel on my Corvair powered dune buggy!
The only issue I can think of is availability of intake manifolds.
Aside from looking really cool, duals have some real advantages in carbureted applications. Cylinders burn an air/fuel mixture. Ideally, the fuel is completely atomized as it enters the cylinder. Anything that causes atomized fuel to drop out of the mixture and "pool" is really undesirable.
Fuel is atomized in the carburetor, and the change of state from a liquid to a vapor actually has a sensible cooling effect. Coler temperatures cause vapors to condense. The higher the intake manifold temperature (after the fuel is atomized), the better chance the fuel has of remaining vaporized.
In a dual carb application-- the intakes sit right on top of the really hot heads, and they pick up a lot of the heat. The intake runners are short, and pretty toasty. Tehy get hot enough that in some applications, guys will use a phenolic, non heat-conducting insulator between the intake (where heat is good), and the carb (where it's not so good).
With duals, the intake length is identical on all 4 cylinders and that length is more appropriately tuned to match the engine's power range. There are a lot of advantages.
In a single carb configuration-- it's a L O N G way from the throttle plates to the intake valves, and there's a lot of chance for the fuel to drop out of suspension. As I mentioned, the change of state of liquid fuel to vapor actually refrigerates the intake as well. Without heat from the heads, intake manifold icing is a big problem.
VW had the funky cross-over tube to keep the intake manifold from icing up. No decent sized exhaust has 'em. The EMPI 1-3/8" headers have provision for them... but the way they are constructed, they don't work most of the time.
It is hypothetically possible to have a bigger header fabricated with the provision for heat risers. While you are at it, you'll need to fabricate an entire intake system to match up to it. Don't forget that every stroker engine combination is a different width.
In an EFI engine, all of these issues with a single throttle body don't matter, because the fuel isn't injected until it's almost at the intake port (ideally). Actually, it actually works better with a single TB, because there is nothing to synchronize. But as Gordon pointed out, the existing end bells are pretty inadequate for 2L+ engines (from a flow standpoint).
The existing end-bells are the cat's meow on an injected, turbo motor, as the size doesn't really matter (the intake charge is under pressure).
So... in other words, the single-carb thing has been tried. It's a lot of work to get it to work right. When it does, it's really only fit for smaller engines. If you want to do that, I'd just get a modified Mexican Beetle injection system running MegaSquirt.
Duals really aren't that hard in comparison, and they make a LOT more power for the same amount of work. They're actually pretty hard to beat.
You make a lot of good points, Stan but your second to last paragraph is something I cannot agree with.
You know far more about engines than I do but please understand this. Some expert built me a 1915 cc engine near Baltimore and it came with a Weber 32/36 and it got me from Sacramento to Carlisle with nary a burp a couple of years ago with a lot of diversions along the way.
Not knowing any better, I later installed a 2,200 cc Soob engine with the same carb again center mounted. Strangely, after a very simple tune, it ran just as well for about 20 or 30 thousand miles without adjustment.
I did get an oil pressure sensor switched out in Vegas and a speedo cable replaced in Albuquerque on that earlier trip with the 1915. . From zero altitude in Cali to about 8,000 feet in Colorado and back down to Carlisle across the US.
A single, center mount 32/36 ( about $220US ) works, plain and simple. Different strokes for different folks. What do you really need ? It's up to you...a single Weber 32/36 can work easily but can you bear to open your hood and show it to the experts ????
Yeah, maybe it got lost in my verbiage, but the three most reliable, problem free aircooled engines I have ever had, all had single, center-mount carbs. One Autolite, one Holley and one Carter 4-barrel (on the Corvair).
All had intake pre-heaters (to Stan's point about icing), taken off of the exhaust pipes, not the heads. The 2-barrel versions actually produced noticeably more power than a pair of Zenith 36's I had been running before. Bolted them on and never again touched them For years.
but those were on a Beetle sedan or in Open rear Dune Buggies. Stuffing a single into a Speedster engine compartment is a challenge. It can and has been done, but those short/lower intake manifolds are really hard to find.
If I had it to do over again I'd go with a good set of reconditioned Dells.
I didn't have much luck with the two sets of Weber carbs I had on my older engines (40s and 44s), but ran a set of Kadrons on my old Beetle for 60,000 miles without a hiccup. I cleaned the air filters on a regular basis and had them adjusted every year or two...that was it.
Stuffing a single into a Speedster engine compartment is a challenge. It can and has been done, but those short/lower intake manifolds are really hard to find.
They are all over the Samba and dirt cheap for a Weber 32/36. They are no challenge to fit. Plenty of clearance.
You make a lot of good points, Stan but your second to last paragraph is something I cannot agree with.
You know far more about engines than I do but please understand this. Some expert built me a 1915 cc engine near Baltimore and it came with a Weber 32/36 and it got me from Sacramento to Carlisle with nary a burp a couple of years ago with a lot of diversions along the way.
That's great, Dave. In no way did I want to come across as saying it couldn't be made to work-- just that it's generally more difficult.
If I might ask-- did your 1915 have heat risers? Generally, if a single works well, it has a functioning heat riser set-up (since the intakes can't be heated from the heads as they are in duals). I know nothing about Subarus, so I have no idea why yours worked so well-- but I can say from the picture that the nice, short, equal-length intake manifold (made out of heat-transferring AL) had to help. As a total aside, I'd probably have done the same thing (at least initially) if I were doing a Subaru transplant. Did you use mega-jolt for the ignition, or some other package?
The ostensible purpose of my narrative tale was to explain how something as complicated and compromised as the dual carb set-up the vast majority of the hobby runs came to be the standard hi-po configuration. It does look cool but there are some solid reasons why it came to be preferred.
All that goes out the window with EFI. The preferred set-up there would be a single throttle-body, and injectors into the ports at the end-bells of the intakes.
