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Anybody tried a DGAV?


seattle smitty

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Some Weber thoughts, in search of opinions:

32/36 Webers came in DGEV (electric choke) and DGAV (water choke), it appears.  Years back, I acquired three used DGVs, two electrics, one water.  Put one electric choke carb on an '86 Dodge Colt Vista, and have just rebuilt the other electric carb to go on a beat-up '81 720 Z-22 I am trying to get roadworthy.  But I have this third 32/36 with the water choke, and wonder why it might not be just as good as the electric choke  .  .  .  if not better, because slightly simpler, with no electical connection whatever.  Anybody have experience?  Not a big deal, and electric chokes are pretty reliable (frankly, I like a manual choke, but I am very old, and something of a Luddite),  but I've never heard anything pro or con on the water choke.

Is there a best place (always means good plus cheap) to get a DGV tuning kit (jets, et al)?  I'll check Redline otherwise, unless someone has something to say on this.

I'm going to carve a Weber-to-720 adapter out of aluminum, I guess, though I do have a chunk of phenolic about an inch thick which might hold coarse-thread studs well enough  .  .  .  let's see, I suppose I could press and Loctite in some Keenserts (threaded inserts)  .  .  .  .

One thing I've never liked much, though I will use one temporarily as a means of getting the 720 going, is those little rectangular chromed foam-element air cleaners that are standard for DGVs.  In my opinion, the standard big round-and-low air cleaner housing having a long snorkel with a thermostatically-controlled flap-door that admits hot air for warm-up, then switched to OUTSIDE air for running was one of the best simple inventions in auto engine history.  In this case, I am lucky to have good welding skills to adapt the base of the factory Datsun air cleaner to fit atop the Weber,  having done the same for my Vista, years ago. I could also add a second snorkel, if the first seems like it would be restrictive (not likely for a 720 driven by a slow old man).

Edited by seattle smitty
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The manual choke version is by far the simplest design, but the electric choke DGV is the most reliable of the auto-choke varieties. One feature of the water choke version that I've never been a fan of is that you're running hot water to the carb. This hot water may actually be cooler than the heat coming off the exhaust manifold (on an L series) when the engine is hot, but I've never tested this. I do know that running the water cooling through the L series intake manifold does in fact cool the intake charge. Another aspect that I do not love is that you've got water running through your carb, and I have seen porosity kill them.

 

As far as the air cleaner is concerned, I too like to adapt stock air cleaner housings to the DGV. Below is a pic of one I built for my A powered 320.

 

Datsun_320%20022%20Small_zps8xewyrp5.jpg

 

Datsun_320%20018%20Small_zpsb8ashrut.jpg

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Remember that these carbs have been used on SCCA Formula cars for years, so if you want some performance parts (non-original) for the DGV, try one of the racing parts suppliers like Pegasus Racing. Google search for DGV racing mods for info on how and what to modify.

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Good thoughts on why running (hot) water into a carb might not be quite desirable.

I knew a top local Formula Ford builder/tuner/racer who took my foam float and said, "I like your brass float better, but when I can't get those, here's how a modify a foam float,"  and proceeded to add a little weight to it.  I'm using that one in the carb I've built for the 720.  I'm not interested in anything like "street performance" for this vehicle, but I'm expecting to have to do some re-jettiing as I dial-in this carb, the spare jets and other parts I had to put in it being a somewhat random assortment.  Somebody here, maybe you, Stoffregen, listed the jets and such that come on the carb for generic applications stating that they would be a good place to start and probably pretty close to what one would end up with on a well-sorted-out stocker, so I have that written down.

David Vizard, in his book on carburetion, says tests show that the best shape for an air cleaner happens to be the one we usually see:  large in diameter, and not very tall.  He is also a big advocate of K&N filter elements.  With the number of dyno pulls that man has done in his life, I tend to trust his judgement as being based on real, expensively-obtained evidence.

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Lets see...

 

Run a wire from the ignition to the electric choke.

or

Buy hoses and clamps and plumb water lines to and from the water choke into the thermostat by pass system assuming you have this system like the L series. Or find some other hot water source on the engine and find another way to return it to the inlet of the water pump so it will circulate properly.

 

 

.... don't rush me.... let me think.. hmmmmmm

.

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Oh, haw haw haw.  Now cut me some slack, Mike. The car, the wretched pile of steaming dog-doo that is temporarily serving me while I get my 720 going, is a '90 Geo Metro, which has about the most flurgenurshun electricals going (or often not), with an electronic TBI controlled by a computer and a million sensors.  This heap is making me allergic to anything electrical right down to two D batteries.

Edited by seattle smitty
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Manual are alright, I had one on my '71 521.... but you have to develop a sense of just how much to set it to, based on the outside temperature and how cold the engine might be. An auto choke does this accurately for you. (once set properly) Then remember to turn it off when warmed up. One good thing about a manual choke is if you leave home and immediately go out on the highway before it warms up you can shut it off and save gas.   

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Our parents and grandparents and maybe great grandparents all somehow managed with manual chokes.  (THERE, gotcha back, Mike!!)

I'm putting this poor old ragged 720 back together with the Z-22 that's in it, but only on a temporary basis, so I can drive it while fixing something else (besides all the usual work/chores/distractions).  The cylinder bores are astoundingly bad,  yet the fellow from whom I'm getting the track back was an auto machinist, and he swears that he has seen lots of old engines handle this. I'm skeptical, and won't be surprised if there's a ton of blow-by, if it makes any compression at all.  Yet when I had the truck before, years ago,  it ran all right,  and nine years of sitting, with leaked coolant filling only one of those bores, can hardly have changed things a lot.  So if it runs as the machinist expects, if it runs as well as it did years ago, it will just emphasize an old opinion of mine:  gasoline IC engines can continue to run and do the job despite being horribly worn out.  

ANYWAY,  eventually I'm going to fix up the 720 as a keeper.  With a good engine rebuild.  Based only on previous exposure, I'm inclined to replace the Z-22 with an L-20B. What do you guys think?  It's going to be a hauler, not a speedster.  I gave the Z-22 head a valve-job. It checked out as flat, so it didn't get decked, and I didn't bother to clean up the ports and bowls because I figured i'd sell it later. Not doing this is strange for me;  as an old 2-stroke racer, I love to grind on stuff.  A pal still laughs about the time he came into my shop when I was grinding out the sharp edges in a brand new shop-vac, "porting" it.

Sorry, I'm old, and can't help digressing.  Tell me about L20B vs. Z-22, assuming you're starting from scratch to build a fuel-efficient, torquey truck motor.  BTW, are L20B's hard to find?

Edited by seattle smitty
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22 hours ago, Stoffregen Motorsports said:

Pretty easy to develop that sense. Listen to the engine and adjust accordingly.

 

Once started.

 

6 minutes ago, seattle smitty said:

Our parents and grandparents and maybe great grandparents all somehow managed with manual chokes.  (THERE, gotcha back, Mike!!)

 

They did, and also managed to live and work within a small radius limited by how far and how fast you could travel by walking, by horse or rail and live on a limited local diet that did not require refrigeration. Everything was much more labor intensive ... and you still can if you wish. There is a certain charm to a manual choke... you know... 'hands on' doing it the 'old way',  but I wouldn't convert an electrical one over to it. To me a manual choke is a theft prevention device. ?

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12 hours ago, datzenmike said:

  .  .  .  .  within a small radius limited by how far and how fast you could travel by walking, by horse or rail  .  .  .  .

.
My father twice (once with my grandfather, twice with little me) DROVE (no walking, horses, or rail) to and then up the Al-Can highway, in 1946 and 1951, thousands of miles when it was still all gravel, en route from Los Angeles to Anchorage, by way of Detroit.  With a manual choke, tee hee!! Sorry Mike, once started, this ribbing is hard to resist.  I should never have asked about that dang water-heated choke.  So anyway, what about the Z-22 vs L-20B if you are starting from scratch to build a keeper-motor for a keeper-truck?

Edited by seattle smitty
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Definitely a Z22 with an L20B head. Basically an L22B if there was one. Larger is always better. Compression with an open chamber L head is 9.84 so use higher octane gas to take advantage of the compression. You want everything above, below and in front of the iron block to be L20B. Only the block, crank rods and pistons are Z22. If I did this I would run a larger cam and carb(s) maybe R1 motorcycle or side drafts if available) and an L16 'cast iron header'. The Z22 would red line at 6500 vs. the L20B's 7K but who drives there anyway? The longer stroke and higher displacement will make you forget all about it.

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Hmmmm, interesting. And if I weren't so OLD, I might like to try a near-10:1 engine with water injection just to see what mpg I could get out of it.  I have a Pat Goodman water injector stashed (that means "Hid from myself"} somewhere that I bought in the late-'70s for a planned fuel-efficient 510 project. But I'm getting increasingly car-conservative, and lazy, therefore resistant to increasing my odds of occasional on-road surprises. Next, why cam-up a truck engine, Mike? And though a row of CV motorcycle carbs could be torquey and fuel-efficient, and wow the boys at the car shows, again, old and lazy and like the simplicity of the single little Weber. This truck won't be run every day, and then has to be very reliable.

I'm hearing myself say these things to you and thinking what a drag I've turned into, afraid of doing anything interesting!!  I better think on this.

Edited by seattle smitty
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Aw damn and blast, I forgot all about the opposite tilt of the two engines, which would mean a tranny swap to go with an L- engine. It would be a fair idea to go through a trans as long as I have the engine out, but it's chasing down all this stuff and getting rid of mine that is time-consuming, therefore a hassle.  

Maybe I am just wasting everyone's time here, very sorry about that.

 

 

 

 

Edited by seattle smitty
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