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brokebolt

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Posts posted by brokebolt

  1. I was looking through a plumbing book and ran across this the other day and I thought I'd share some info.

     

    Standard auto hose to -AN hose equivalent:

     

    1/8 inch = -2

    3/16 inch = -3

    1/4 inch = -4

    5/16 inch = -5

    3/8 inch = -6

    1/2 inch = -8

    5/8 inch = -10

    3/4 inch = -12

    1 inch = -16

    1 1/4 inch = -20

    1 1/2 inch = -24

    1 3/4 inch = -28

    2 inch = -32

     

    Another method to convert -AN size to S.A.E. is to remember that -AN number represents 1/16 inch:

     

    For example: -8AN = 8/16 inch = 1/2 inch.

     

    -AN Thread sizes:

     

    -AN size = Metal Tube O.D. in inches = Thread Size and Pitch S.A.E.

     

    -2 = 1/8 inch = 5/16 - 24 S.A.E.

    -3 = 3/16 inch = 3/8 - 24 S.A.E.

    -4 = 1/4 inch = 7/16 - 20 S.A.E.

    -5 = 5/16 inch = 1/2 - 20 S.A.E.

    -6 = 3/8 inch = 9/16 - 18 S.A.E.

    -8 = 1/2 inch = 3/4 - 16 S.A.E.

    -10 = 5/8 inch = 7/8 - 14 S.A.E.

    -12 = 3/4 inch = 1 1/16 - 12 S.A.E.

    -16 = 1 inch = 1 5/16 - 12 S.A.E.

    -20 = 1 1/4 inch = 1 5/8 - 12 S.A.E.

    -24 = 1 1/2 inch = 1 7/8 - 12 S.A.E.

    -28 = 1 3/4 inch = 2 1/4 -12 S.A.E.

    -32 = 2 inch = 2 1/2 - 12 S.A.E.

     

    -AN size wrench size to S.A.E. wrench size (if you use a standard S.A.E. wrench don't over torque the fittings):

     

    -4 = 9/16 inch S.A.E.

    -6 = 11/16 inch S.A.E.

    -8 = 7/8 inch S.A.E.

    -10 = 1 inch S.A.E.

    -12 = 1 1/4 inch S.A.E.

    -16 = 1 1/2 inch S.A.E.

     

    My copy has plumbing "shadows" so you can match up the actual fitting to a "picture" for fast identifications for both -A.N. and N.P.T. But if you have a set of calipers or a steel scale handy you can also measure them just as quick. Hope this helps.

     

    Found this on the web, not sure how true but shows some standard metric to S.A.E hose sizes:

     

    4mm = 5/32 inch

    5.5mm = 7/32 inch

    6mm = 1/4 inch

    8mm = 5/16 inch

    10mm = 3/8 inch

    11mm = 7/16 inch

    13mm = 1/2 inch

    14mm = 9/16 inch

    16mm = 5/8 inch

    19mm = 3/4 inch

    50mm = 2 inch

    57mm = 2 1/4 inch

    64mm = 2 1/2 inch

     

    One more thought on fuel pumps:

     

    Your pump must be capable of maintaining the

    minimum GPH at working pressure under all conditions

     

    HP divided by 2 = lb./hr. (pounds per hour)

    lb./hr divided by 6 = gallons per hour required (min)

    Multiply GPH by 1.15 for safety factor

     

    Example: 600 HP divided by 2 = 300,

    300 divided by 6 = 50

    50 multiplied by 1.15 = 57.5 (minimum gallons per hour)

    (This formula is for gasoline only.)

    • Like 1
  2. I don't have a direct answer to your question...

     

    My advice would be to get a good book, like "How to Build & Power Tune Weber & Dellorto DCOE & DHLA Carburettors" by Des Hammill. Excellent book for the dollar and readily available for like 20-30 bucks. Worth the cost for sure. You can find this book on Amazon or other online book sellers. You should be able to source this from your local book store as well. I like this book because you still can find copies, it covers both Weber and Dellorto carbs so if you upgrade, you can still use this book (He, he!)...also a car club library would benefit from this book as it covers both carbs. Their are many other books that are available, this is just one in an arsenal of good books. This site also has loads of help, and tips for Webers. Search "Weber" and you'll find a whole pile of discussions.

     

    If you're going to be a triple carb owner it would greatly behove you to learn how to work on your own carbs. Most speed shops charge by the hour and like any business you get what you pay for. Tuning these carbs are "relatively" easy and tear down and cleaning is "relatively" straight forward. A good resource like a car club accompanied with a book can greatly help you along that path of ownership. Also note that most people these days are leaning towards EFI for the ease of tuning, and most carb guru's from back in the day, are getting up in age and might not be interested in helping a newbie. Just my $0.02. Best of luck.

  3. Weber DCO = 12 mm X 1.5 mm threads

     

    Dellorto DHLA & Mikuni PHH = 12 mm X 1.25 mm threads

     

    Solex ADDHE = 9 mm X 1 mm threads

     

    Russel, Earls, Aeroquip, and even no-name brands (like Jegs) all produce -AN to metric fitting and all the -AN plumbing your looking for. Use the list above for your particular carb, then choose your -AN size: 8-AN, 6-AN, 4-AN; etc.

     

    Search Summit Racing dot com '-an metric' and you will find an extensive list and descriptions to build your custom plumbing.

     

    EAR-9919DFGERL Earls part number, might be the cheapest way to connect and -AN hose to your carb, just at 10 bucks. The swivel (EAR-949092ERL) might be as cheap but I always worry about fuel leakage. The carb doesn't move so I see no need for the swivel. Your call. But hose can flex a bit and they usually don't leak, unless they rub a hole. In that case your in trouble eitherway...

     

    Best of luck, and post some pics when your done. Happy parts hunting.

  4. The insert type you will still need the "tabs" that hold the horn in place; two should be used per horn, four per carb. Extra cost not addressed in the original post. The flange mounted version will fit any side draft, Mikuni/Solex, Weber, Dellorto, or O.E.R., etc. Because of the "universal" fit, you will see most air horns are of this type. The insert type will be a smoother transition from the horn into the inner venture (auxiliary venture). Mikuni/Solex did this with an insert that fit over the inner venture and butted up to the outer venture (choke). Honestly, I really don't see that your going to "gain" that much performance using the insert type vs. the flange type. Horn length and horn shape play a much bigger role then insert of flange mounting in my humble opinion. Longer horn is like a longer manifold, better for street use. Wide opening on the horn is better for air draw. A rolled lip at the horn inlet seems to the the accepted superior design or a donut ring on the horn inlet...if that makes sense.

     

    Honestly, this is why I prefer the Dellorto carb. The inner venture has the insert that the Mikuni/Solex units had in two pieces, slap on a horn and your golden. Also, no gasket for the Dellorto carb on the auxiliary venture. Try changing the choke while the carb is still mounted on the manifold, and attached to the engine in the engine bay. Not that fast and not that easy. Just my rant of the day!!! (And yes, I know Weber didn't use a gasket.)

     

    Factor in the tabs, recalculate and then compare cost vs. performance. Either version should bolt on and work. Hope this helps. Happy wrenchin'!

  5. I'll just add to the list. Mikuni is the shortest (note picture above) I've seen and it is stamped with the letters that spell the name, in the example the letters are painted red (nice touch). TWM, Cannon and FET also stamp the letters in the casting. SK Racing uses a steel acid etched placard like you might find on the door jam of most cars. Redline has it scripted on the bottom and Lynx has no markings that I recall. The real issue with measuring the manifold length is the head mounting surface isn't on a parallel plane as the carb mounting surface. So the two mounting surfaces don't run parallel to each other. For example the Mikuni measures 75 mm on the top and 68 on the bottom. So, I will give you the measurements from the top of each mounting flange of the manifold (not inside the hole where it bolts to the head but above it) for standardization and also note other things (like truing) will change how this measurement is interpreted. I will also include millimeters as we are working on Metric cars not American iron. My side drafts are stamped in millimeters not inches, how bout yours?

     

    Cannon, Redline and others like the one that I have heard called the Nissan/Datsun motor-sports intake which is stamped with a 240Z in the same location as the Redline script, are all the same casting, or really close to it. TWM, SK Racing and Nissan Comp are the same with some differences and FET is really close to the same length as the TWM but has a nasty twist like the Mikuni version. Rebello is correct the longer runners are better for street use, all out HP go short with the Mikuni but good luck finding anyone that will part with one. So the best solution is the TWM as it is a nice hybrid version of the two manifolds and has no massive twist and is readably available as of lately...but haven't checked in a while.

     

    TWM = 110 mm/(4 5/16")

    Mikuni = 75 mm/(2 15/16")

    RS Compe = 110 mm/(4 3/8")

    Hayashi = ?

    FET Kyokuto = 104 mm/(4 1/4")

    Nissan Comp = 110 mm/(4 3/8")

    Shokei = ?

    Kameari = ?

    Redline = 140 mm/(5 1/2")

    Weber = ?

    Cannon = 141 mm/(5 9/16")

    SK Racing = 110 mm/(4 3/8")

    Lynx = 122 mm/(4 13/16")

    Off the wall no name that looks like a Lynx = 124 mm/(4 7/8")

     

    I need to add that these are not with a dial indicator on a marble slab, just a quickie with vernier calipers and a flat work bench.

     

    Happy measuring!

  6. I have the motor pulled and head milled...If the camshaft was not turned, nor the crank, the timing should be fine despite which notch the gear goes back on, right?

     

    I might be late for your project but here is my $0.02. The cam will have to be removed to mill the head so the cam timing is off for sure. The timing notches will need to be selected based on the amount of milling, with only 0.008" you might be able to re-use the same cam position if the head has not been milled previously and was close to spec before the start of this project. However, being that the position was not checked (or noted that it was checked) prior to removal then you may need to select one of the other two dowel holes that the stock cam gear has bored into the back of the gear (their are three total).

     

    If it were me, I would remove the front oil pan bolts, remove the timing cover, inspect the chain guides and tensioner (replace if needed), set crank to TDC using a dial indictor and cam wheel (if not available, then just guess), set cam to TDC using the middle cam gear dowel hole aligning the cam gear with notch on first cam tower, place head onto block, install chain aligning the cam gear with the crank gear and yes they have to match I always use the shinny gold links but you can count them if your unable to find them, install tensioner, check chain for slack, install both guides, install head bolts and torque, turn over engine with 27 mm (1 1/16" 6 point may fit) socket wrench and check for any problems with cam timing. Re-install all of the removed parts and hardware with new gaskets, install motor from where it was pulled...unless it was a junker/donor car...

     

    P.S. I have had no luck reinstalling the chain tensioner if the chain has slacked up enough to fully disengage the piston from the tension block. That is why I just remove the front timing cover...to prevent damaging the spring and causing more parts usage then necessary, been their done that!!!

     

    Happy wrenching.

  7. Yes, Fubarl33t that is correct.

     

    Weber DCO = 12 mm X 1.5 mm threads

     

    Dellorto DHLA & Mikuni PHH = 12 mm X 1.25 mm threads

     

    Solex ADDHE = 9 mm X 1 mm threads

     

    Any O.E. R. or SK Racing users care to post?

  8. ...I tried some advance auto parts wrap, and the stuff smoked like crazy, went darker and then caught fire when I held the motor at 3k...

    Wow!!! That would be interesting to see! Not that I doubt they caught fire just surprised they did!!! Very dangerous indeed!!!

     

    I have always used Cool It Termo-Tec Natural 2 inch wide header wrap. They make a copper and black version as well. I'm sure their are many others that will work just as well. But to comment on your experience, mine too went dark after a minimal run time, smoked for a while until they went dark, but no fire to report...yet. I don't DD the car anymore but the sport 600 motorcycle I did the headers on was used extensively without any problems. The real kicker on the bike was that if you run the pipe under the oil drain plug and the o-ring gets too hot and oil leaks on them, they tend to smoke more and longer... I'm willing to guess that's oil down there burning away though... "Use a Copper gasket next time, Copper..."

     

    Heat shields used in conjunction with header wrap should provide decent results. I've never used the thermo blankets or Heat-Safe products but I say give it a whirl and report back your experience.

     

    I like to take a more scientific approach to things, install a couple of remote temp gauges, like that which you might find at any home improvement store for measuring 'outside the house' temps, install several under the hood in various locations, drive the car around noting weather conditions and gauge temps in various driving scenarios (a buddy in the passenger seat helps) and then install one heat isolation item at a time, trying to repeat the same conditions each time. That should give you some 'real world data' that actually makes sense. And way better then slogans on the packaging that proclaims "Reduces under-hood temps by (as much as) 70%!!! *results not typical*"

     

    Just my $0.02

  9. ...Does that sound (like) a plan or a waste of time...

     

    That actually sound like a solid plan. Removable and well designed. Cost vs. performance, would seem to be inline,

     

    ...I know the right persons to have this done for the right kind of money (a little to none)...

     

    I bought a Mikuni Manifold that had a very similar set up for a Turbo. The manifold block (vacuum log) was only a few inches long though, but it was a square block and had a round bore in the center. Longer would be better, like stretching the entire length of the intake runners. It didn't use banjo bolts but tomato, tamato...

     

    ...I want to make a heavier linkage using 10 millimeter rose joints just to make it more solid than the 8 m.m. i have now...

     

    Beefier linkage is always a plus. I can't stand that stamp steel junk they include with the Cannon manifolds. I like to use 3/16" heim joints for the carb link arms, lots of adjustability and very beefy, and 3/8" as the risers for the throttle shaft rod. I had a Lynx manifold once years ago, and if memory serves me they are only missing the bungs on cylinders one and five. Is that correct? Mine too had those stupid plastic heims, fortunately for me the threads were all stripped out and I was forced (not reluctantly by the way) to replace them with all steel units... and I too stepped up the throttle shaft rod size. That really is an odd location for the throttle shaft. TWM, Mikuni and others got it right by stuffing the throttle shaft towers close to the carb mounting flange. Hey, those look like a set of Dellorto DHLA hidden under those triple bore throttle bodies. What are those throttle bodies from anyhow? What's the bore size? Do share.

  10. LOL :lol:

    No smog stuff on my SU's

     

    Thanks alot for your explanation, the car is for street only, so i guess i can take advantage of a balance tube, the thing is that my manifold (Lynx witch i have found out is not the best)have a crappy linkage, i'm welding on 3/4 inch aluminimum towers, being that the present linkage is attached to a row of bungs and it is located 2 inch to low and 1 1/4 inch to close to the head, now after relocating the linkage, i will have those bungs avalible and got the idea of connecting the runners with a hollow aluminimum bar, mounted with banjo bolts to each runner, then on that bar i could drill and tap for brake booster and even crank vent, but before going in to all this efford, i needed to know, if it would be worth it.

     

    Chris

     

    Honestly, unless your doing all the welding yourself, the cost might outweigh any benefit you would gain, in my humble opinion. As far as addressing your engine vacuum issues, an aftermarket vacuum system would be the best solution to evacuate the crank case of spent blow by gases and such. That would also be the most expensive option aswell. As far as making a vacuum log (as those EFI guys like to call them) then you can make one relatively easy as long as you tap each runner and pull vacuum from each runner to ensure no lean cylinders. That could get messy real quick if you were burning up parts. As far as welding up a manifold, you sure could do that but I wouldn't expect to see any real improvements except at maybe idle. The firing order may not lead prudent to having enough time to smooth out the idle across all the cylinders. It wouldn't hurt anything, maybe performance but other then that, as long as the welds were good and no leaks... give it a rip and try it out. Haven't seen anyone do this... yet.

     

    I might consider welding bungs on the remaining runners and simply running a vacuum log with hose fitting from each runner. If it doesn't work out like you expect you can always plug the bung holes and your only out the cost of adding the additional bungs. Or maybe spray some "juice" in those runners and scrap the vacuum log idea altogether. Your call.

  11. This might be the stupid question of the day, but i like to know if it will be a good idea to have a balance tube on the triple manifold or not, i have searched but not fount anything useful.

     

    Chris

     

    Some Cannon manifold have the balance tube bored clean through, others were bored only on the ends between the the fifth and sixth holes; some also had it on the front one and two holes. Others I seen have not been bored at all between any cylinders. Mikuni used a plate that sandwiched between the carb and the manifold and had a cut out between the bores on the same carb, unsure what they came from. FET made a manifold that has a balance bar on all six runners with several taps on the bar. The Mikuni manifold has bungs on each runner so you can add a small block manifold with tubes. The benefit would only be at idle and low speed operation. At W.O.T., or close to it, you're drawing way more air though the bore of the carb then you ever could through the balance tube. Yes, the benefit would be a smoother idle and low speed operation but that really would depends on the engine set up, cam, etc. If it idles rough with no balance tube it's gonna idle rough with one... just not as bad. If your looking for a smooth idle then a triple set up isn't the key, the carb is "on" for one pulse and then "off" for five. The SU's have an alternating pattern of "on", "off" that with the balance tube have a very smooth operation and idle due in part to, what I would consider, a huge internal volume of the stock balance tube. And it makes a great place to stuff a bunch of smog junk...

  12. But I'll do my best to answer some of your questions.

     

    The F11 is richer then the F15 within the same series. The F15 is missing the lower Air Bleed holes in the E-tube. Other then that they are "cut" the same. This is why Weber is so confusing, and why I am not a fan.

     

    You can always use the smaller choke with either combo you select. The choke will increase the Auxiliary venture velocity, might be a better choice on a daily driver.

     

    All around I would use the second set of tuning parts, you might be richer at idle but more fuel means less risk of burnt engine parts. You might waste fuel overall and lessen your performance gains but in the end fuel is almost always cheaper then a teardown and rebuild, time and parts wise; especially on a daily driver. Just my $0.02.

     

    Happy tuning.

  13. Not a huge fan of chrome, function before design. Also would those air horns fit between the inner finder? For that price I would seriously consider a EFI ITB set up. Just my $0.02.

     

    My triples arn't cool, they're gangster because I have a blow thru setup =P...

     

    Gangster = Blown? Good to know!!! So that must make me just cool.

     

    but the sound of triples..

     

     

    Those are Mikuni/Solex PHH 50 mm's? I think so!!!

  14. Off topic but I do have a Mallory 6AL (very similar to the MSD version), which wire is it? I've never noticed such a feature. It could be very interesting!

     

    I am not familiar with the Mallory stuff, but the MSD manual states:

     

    "When using the WHITE wire to trigger the MSD, install a switch across the magnetic pickup VIOLET wire to ground. When the VIOLET wire is grounded, the vehicle will crank but not start. When using the mag pickup to trigger the MSD, install a switch to the WHITE wire and the other side to ground. When the WHITE wire is grounded, the vehicle will crank but will not start."

     

    So you could control this with a relay, toggle switch or other means but the principle remains the same... theft deterrent!

  15. The other option for cold starting an engine equipped with a carburetor(s) is to add an electric fuel pump and a electronic circuit like that found on modern EFI cars where you kick on the electric pump when the ignition is 'on'. You will need to install a crash isolator switch (technical name maybe wrong). This prevents the car pump from running if involved in a collision or vehicle roll over. Safety first!

     

    What PanzerAce says is correct and will work well for bone dry bowls.

     

    Kill switches are always a great theft deferent. The MSD 6AL Ignition box has a wire for just that purpose.

  16. Well this sure spans the globe. Japan to Canada to France and back home to my state of California. Nice to see (or hear from) the Z community around the world.

     

    Ya, old school is awesome (some will argue), triples are even better (IMO). Fuel bowl evaporation will occur on any carb set up, EFI is best for cold start.

     

    As long as the pressure is set right and you don't suck the fuel bowls dry on hard, long accelerations then, ya, bolt up that old mechanical unit. I had issues with the stocker I had mounted up due the later problem. You can always add a second electronic pump back at the tank to help eliminate this problem (I did) but you will need a regulator somewhere in the system to prevent over pressuring the needle and seats in the carb bowls if you decide to use one of those electronic units alone or with a mechanical unit.

     

    I run my Dellorto's (basically the same carb) at about 5 P.S.I. with no issues. Yes, set the fuel bowl levels per the specs (most manuals will give you a spec). Do run a return fuel line if you can regardless of how you get the fuel to the carb bowls, and a pressure regulator can be had at just about any auto parts store in the USA for about $20.00. If not here is a link to a source or reference for a cheapy I've used in the past for $24.95 USD.

     

    http://www.summitracing.com/parts/SUM-G3131-1/

     

    If link don't work search SUM-G3131-1 at Summit Racing dot com.

     

    PanzerAce is right on the money about 15 seconds of cranking until fuel reaches the bowls using the mechanical unit. Electronic is just a tad faster, but not by much from my experience.

     

    Happy motoring with that old school mechanical fuel pump.

  17. if its sitting at idle for more than 2-3 mins i can see the primary throats lined with fuel and it starts to choke and will soon die.

     

    part throttle they run just fine but my eyes burn like hell and it smells of unburned fuel. under WOT it sounds like its drawing enough air but its sluggish and gutless.

     

    off idle to WOT it just pops up the carbs and spits fuel back up and out.

     

    http://i43.photobucket.com/albums/e355/raceme54/240z/DSC02155.jpg

     

    Love the pic. Classic.

     

    I would say the needle and seats are not properly sealing due to the verb-age that you see fuel lined the primary at idle. The carb will meter the fuel at the same rate at idle with all things being equal. A rising fuel level will introduce more fuel as time elapses. Check to make absolutely sure the needle and seat are indeed sealing. A electronic fuel pump is great for this. Hook it up and see if the fuel bowls flood with the engine off. This is also a great way to set the fuel bowl floats as it is static and not dynamic testing. You can also see if your fuel pressure is holding constant too if you use a fuel pressure regulator.

     

    Weeping needle and seats are a problem with any carb, DGV, SU, side draft... any carb that uses a needle and seat. If the needle and seat do not seal and the consumption of fuel at idle is too little then they will over flow into the carb choke. Also make sure the cam, and ignition are timed correctly to the crank. On a new rebuild it is possible that it is not correct during the assemble process (I rebuild a distributor once that was 180 out. But I swore it was correct. It was not.). Just cover your bases with a simple check at TDC to ensure your engine is 100% correct. Easy to do. Worth the time to check this vs. trouble shooting a carb by far.

     

    Use a return line too, as if you do not, then as the engine idles the fuel pressure *can* rise due to lack of fuel consumption and increase fuel pressure due to natural pump pressure rise. If your using a stock pump best bet is your pressure will remain constant as it is spring driven after it reaches maximum resistance.

     

    To answer your direct question it sounds rich at idle. Those other conditions point me in the direction of incorrect timing of the cam to crank.

     

    Happy wrenchin.

  18. Why would someone copy the manifold and then move the runners? Not only does it not make sense to do that, it would also be a lot harder than just doing it right the first time. They would have to stretch the balance bar on one side and shorten it on the other side to do what they did, and then presumably they'd have to change the direction of the runners slightly to get everything to bolt to the head. I'm convinced that what I had was a Cannon manifold, not a reproduction that went to great lengths to screw up.

     

    Well... I really can't say why the manifold is in the condition it is. I didn't make it.

     

    If this was a copy do you really thing that they were experts given the condition of the manifold (as you described)?

     

    If this was an original manifold do you think Cannon would allow that to pass Q.C. looking like that (as you described)? I sure hope they had better standards than that.

     

    That is why I was leaning towards an amateur job with less then professional technics and experience.

     

    But in the end having not seen said manifold, I am mealy speculating.

  19. Namor, new to the site? I see only two posts, and you joined on June of this year. I would like to take this time to join Phlebmaster and say to you "welcome sir".

     

    I would also suggest you hook up with a local speed shop. Google search you zip code and "speed shop" for some locations near you. Any shop that sells MSD or Autolite can get just about anything you need, they are a local Jeg's or Summit parts house. If you spend a few buck on performance parts like fuel pumps or plumbing parts, those guys usually don't mind talking (bragging) about the stuff they have worked on/built/crashed/sponsored.

     

    They are a plethora of 'real world' information, especially when you start modifying stuff. Most of them aren't snobby about the hot rod you choose to work on, as long as your wrenchin' and having fun (and spending cash in their shop). They can help you with hose/tube/fuel injector size and type selection and usually have the stuff in stock. I have found they are a bit more cash but with shipping/handling it usually is a break even proposition for small jobs. Once you build a rapport with them, they seem more eager to help your project along. Progress for you, means dollars spend to them... and in this economy fun projects take a back seat to "food on the table".

     

    As for your direct question, unless your building an all out race car, stock might be the best way to go when you factor in cost/time modifying, 300 H.P. might be the upper limit for stock lines. Usually for the street your just taching it through the first few gears anyway and most of the time you live below 3k on the tach. It really depends on how big and bold you plan on building that L-28ET, what future upgrades and what you plan on using it for. But that is just my $0.02.

     

    Here is a good article written by Drax240Z. He seems to be on track:

     

    http://forums.hybridz.org/showthread.php?t=115904

     

    Happy motoring... eh, wrenchin' in your case.

  20. In my case it wasn't a matter of the holes being misaligned...the distance from the runners was VISIBLY off. You could see that the gap between the sets of runners was different...It could be that someone redid the casting along the way too (which would have been a good thing). The top and bottom halves were also not symmetrical on mine, the top half was situated probably 1/8" or 3/16" off to one side relative to the bottom. It's got the long runners which is nice, but the original Cannon casting that I have experience with is crap.

     

    I would guess from my summation of your description, that maybe you indeed did have a copy of on original Cannon casting. We (friends getting together, not business) used to do stuff like this for one-off parts, never for resale. If you didn't match the mold up correctly when you mated the two halves of the mold together, then yes it would misalign the top and bottom half of the manifold like you stated... that was all sand cast stuff not modern technics like today. Normally, however, you scrub any indication of the original manufacture (like a logo or the letters C-A-N-N-O-N across the number one, or number four runner) to prevent copy write infringement and liability on your part. I heard a rumor that the TWM was a copy of the SK Racing manifold, it does look similar to me...

  21. This applies to Weber's as well. I've seen mismatched webers cause nothing but idle/low speed issues due to progression holes being different between them.

     

    I didn't know Weber did this as well. Good to know. I am no Weber expert so this helps out a bunch, I do dabble with them from time to time. And yes, I agree with Drax240z, he is absolutely correct about causing issues... Dirt (straw, crud, debris, etc.) will cause issues too, gotta keep them holes clean!

  22. Is there anything I should look out for?

     

    Yes, you should look at the progression hole count and size, idle mixture screw type, and the idle air bleed type. Their are two types of both the last two and I don't know how many types of the first item.

     

    The first item is the progression holes, they are located under a slotted brass 'slug' (meaning it has a "-" {minus} on the head and uses the same type screw driver to remove it.) This slug is sometimes steel with a coating to prevent rust which may look gold-ish or at one time looked gold-ish in color and I have found is always a phillips head (meaning it has a "+" {plus} on the head and uses the same type screw driver to remove it). The 'slug' is easy to located in front of the idle mixture screw which is located toward the back side of the carb (where the butterflies are located on the carb body), on the top of the carb, located by the carb mounting surface to the manifold. Their are three bass things in a row on the carb. First is the accelerator pump jet holder the second is the brass slug and the third is the idle mixture screw. The hole count and size need to match. For example you may have a large hole and three smaller holes. I would not suggest you mix and match carbs of different progression holes, as it will effect the characteristics of the progression phase of the carb.

     

    Second their are two types of idle mixture screws. The first idle mixture screw is a fine thread if it is encased by the aluminum carb body. The idle mixture screw is recessed into the carb tower a bit. The other type is a course thread where the idle mixture screw is somewhat exposed and the tension spring is 100% exposed with no aluminum shroud around it. I guess you could mix and match these but I wouldn't suggest it, as the idle mixture may vary between the carbs.

     

    Third you need to make sure that they are either the non-adjustable air bleeds that have the air bleeds located in the carb body or the other type has the air bleeds on top of the idle jet like how Mikuni, Weber and others have done it. Locate the jet cover, usually black or orange plastic, sometimes aluminum, remove it, and pull the idle jet from the carb body. The idle jet (two per carb) is the smaller two of the four brass parts located under the cover. The other two are the main jet, E-tube and air corrections jet (or air bleed jet). Their are two ways to tell. First if their are numbers stamped on the side (like 7850.1), or second if you have two rows of holes drilled in the jet holder; one row above the threads and one below the threads, than you have the idle jet version, if not then you have the carb body version (no stamped numbers, and only a single row of holes drilled above the threads). The idle jet is located on the bottom of the idle jet holder on either version. The carb body idle air bleed vs. idle air bleed jet isn't an issue other than to make sure that you have three carbs that have the same type. If not, I do believe that the carb body is drilled slightly differently for it's passages and this may effect the idle characteristics of the two types of carbs. Not sure though, I have never mixed them before. I would not suggest it, as it may effect the idle and just off idle characteristics of the carb.

     

    If the tuning parts are not identical, no worries man, you can always pick them up from several sources, like VW performance shops and some still sell Dellorto parts. Dellorto DRLA and DHLA use many of the same parts. Auxiliary ventures maybe the hardest to source and cold start parts too. But you really don't need to use the cold start function for performance minded personnel.

     

    Happy motoring.

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