After 9/11 I figured it was a good time to get out of NYC, at least part of the time, so I imposed on a friend in NJ and so I finally got the B20 back together and swapped it for the B18D. Since then, the motor has run great. I had to play with the float levels and adjust the carbs, but my mileage has been disappointing. Unfortunately I can't give you an exact mileage, as my speedo/odometer is disconnected due to leaky seal allowing oil to migrate up the cable, causing the speedo to race, so I disconnected it. But until then, it was terrible, and since I disconnected it I know that I'm filling it up more oftern than I used to.

In any event here's what the motor is. Input about further adjustments/mods, needle changes etc. are welcome, in fact sought after.

B20, new .15 over pistons/D cam and stock lifters (I can hear George wincing), E head with plugged injectors and rebuilt SUs with KD needles(I love SUs). I found a new non-vacuum distribtor, so am using that until I can get the 75 240 electronic ignition setup installed. Not that it matters but I also have an OD(jtype). That's the "given".

It starts right up even when it's been cold here in NYC, idles nice when warmed up. I can keep a quarter on the valve cover sometimes. Accelerates smoothly and has plenty of power around town and on the road. Seemed to be lagging some until I richened both carbs up 2 flats - helped a lot.

So (Rhys, I'm counting on you here) what're my needle options? I'm not a racer, rarely stomp on it even on the road, just looking for moderate power, and good mileage. I cruise around 70-75. Is asking for 30mpg on the highway too much?
thanks all

As with the other responses, sounds like you have a good setup. I always liked the KD needles for Canada. However, the ZH may work better in NYC in summer.
That's the easiest thing to try. Detonation is the silent enemy. Better to use a little extra gas unless you are sure you are getting the good stuff. Don't forget you are getting your numbers by guessing, and in winter weather. Do you have the hot air pickup box on the air cleaner or are you using the pancake filters?

I'm using a pair of aftermarket WEIAND filters. I describe them below in a post titled something like "Starved for Air?". I realized that they may not allow enough, or as much air as the correct thicker filters. Thought this might affect mileage.
I had tried to find one of the B20B plastic air filter housings as a way around the outrageous cost of replacing the stock air filters, but to no avail. I know a fellow up in Conn. who swaps out his thick pancakes for the B20B type box seasonally. The B20B rectangular filter is more reasonably priced.
The advantage to the WEIAND setup is that they use foam filters which are washable and replaceable.
Have to pull my gauge/speedo cluster and remove the oil that spiraled up from the OD via cable before I can monitor mileage accurately.

One other thing to check (or double check as I assume you have done so already)

Make sure the jets are perfectly centered. If they aren't, your air/fuel mixture won't be as fine or consistant, and it will have to run rich to run semmingly right. A couple thousanths off center can make a pretty significant difference...

-Matt

AM I wrong or doesn't an engine need 500 miles or so to break in after a rebiuld? On another note, recently I cleaned/repacked all the bearings front and rear and my highway milage improved.
--
patrick of montreal, '66/120, '83/245.

I just put a 73 B-20 in my 65 122 and I have the same problem you have. It runs great but the mileage is much worse than my old B-18. It has the two bolt SU's with ZH needles and obviously runs too rich as it starts up on a cold day with only minimal choke. When I adjust it leaner it starts to lose power.
Harry

The KD is the richest standard needle, on the whole it safer to start with too rich than too lean.

It is a fair assuption that if the car starts readily from cold without choke your base settings are too rich. Have you tried using the lifting pins on the carbs to gauge your settings. hen the carb is tuned right if you lift the piston with the pin the revs should rise momentarily and then drop. The engine should keep running at a slower idle. If the engine stalls richen up the carb opposite to the one you're lifting the piston on. If the idle doesn't drop lean the carb off. You always adjust the opposite carb to the ne on which you're using the lift pin.

The settings shouldn't vary drastically between the two carbs, if you end up with a final adjustment that differs by more than a few flats you have another problem.

Check whether your float level isn't too high. If you've moved to the later nylon floats without the metal arm you need the matching float bowl lid.

It should give reasonable fuel consumption with an ignition setting of 10 degress BTDC. By going to more you can get a better idle on a hot cam, a D should idle pretty nice though. The problem with going too far is that at idle you only get partial cylinder filling. If you boot the engine from rest you will get detonation, and you can't hear it. Ideally you need to check the full total advance your ignition settings are giving you. Much more than 39 to 40 degrees and you can do damage.


Regards


Pete

What I meant by starts easily in the cold, was that I have to use the choke, and fully, but it starts easily. I push the choke in as it warms up. If I go off the choke immediately after starting, it'll die.

Yeah, that's how I adjust the carbs - pin up - adjust alternat carb.- speed drops off 100-150(?) rpm. Get them both even. I'm a pro at this part. (I'm on my second unisyn in 30 years) Now, I guess I tended toward lean, because with tight carbs/engine, you can lean it out so that speed drops but it doesn't die, and that ends up being too lean when driving. 1-1/2 to 2 flats down (richer), it still drops, but dosesn't starve when you put your foot in it.

Float level may be the issue though I was pretty careful setting that (a stack of feeler gauges), but it may still be too high. There's an earlier and later, and maybe even later spec. I think mine's set right.

As far as timing, for this block/E head and D cam, 10 is the spec, just that I'm using carbs instead of FI.

Weather permitting I'm going to recheck all this over the weekend.

Right now, seems like float level could be the culprit. If it's too high, then it seems that there'd always be an excess of gas available, no? Lowering the float until the engine seems starved (all else staying the same) might be be the ticket. It's just a hassle to keep pulling the float bowl covers and tweaking the stainless strip on the plastic float.
Just realized that maybe grose jets (float valves) probably mess with the fuel level, not because it's not shutting off at the same level, but because of the nature of how the valve actuates. I should probably go back to regular float valves first.

Normally if the carbs start flooding the idle 'll go to pot. It's worth pulling a piston out of the carb and having a look down a jet. If the level is significantly high you'll see the petrol right up in the jet.
You won't get proper economy until the engine is fully run in.

Regards

Pete

I realized that the WEIAND airfilters I'm using on my 3 bolt carbs may be too small (surface area). This could account for the engines apparent thirst, though I'd used them on the previous engine (B18D).
These were an aftermarket(IPD) alternative to replacing expensive 3 bolt filters (20 years ago?). Sorta like the bottom half of a K&N - metal disk with holes and a lip, a quasi hemispheric plastic cage which supports a foam disk (5/8" thick). There's a chromed, expanded metal lath type grill/cover and a retaining clip. The advandage is that you can clean replace the foam (I just slice up grey foam on a bandsaw and cut out circles). WEIAND filters no longer available. But, this may be faulty thinking (you're using just ANY foam??), and I hear the rest of you saying spring for the K&N filters. My reluctance to do this has to do with the crankcase ventilation from the valve cover to the front carb. K&N's don't accomodate this. So, I'm spending $80+ for the be-all end-all of filters and then drilling and soldering a tube onto the nice, flimsy, chrome housing? I'd rather make a pair up myself out of bronze and just buy the filters. Anybody else interested in a set? Can one just buy the proper size filters from K&N, and fab the housings?

If your timing is retarded the engine will run smoothly but hotter (probably
not noticeable this time of year) and with less power and poorer mileage.
If you are driving fairly fast, the mileage will be really bad. Try setting
your ignition to about 20° btdc and see if it helps. If it kicks back a lot
against the starter you've probably gone too far.
--
George Downs Bartlesville, Oklahoma

Per spec, I've got it set at 10 degrees. Doesn't run hot at all, though as you say it's winter up here. The B18 behaved the same temperaturewise - always a little on the cool side. I guess I could try advancing it a bit and see what happens. When you say 20 degrees, that's dynamic, at the same 750 rpm?
Any other needle recommendations? Do KD needles pass an exceptionally large amount of fuel at mid-to-full throttle? Could this be a needle issue? Guess it makes sense to play with the timing first.

The differences between needles are pretty small, and the basic mixture
is adjusted by the jet postion, which makes a LOT more difference than
which needle you use. What is accomplished by changing needles, then?
you ask. The needle profile changes the amount of mixture variation when
the carb piston is lifted, so if it gets richer too fast, then you need
a more barrel-shaped needle, and if it doesn't get richer fast enough, you
need a more trumpet-shaped needle. Unless you have a perfectly-tuned engine
and a pretty accurate way to measure how rich your mixture is, you would
probably not be able to tell the difference between needles.

I use the colortune device and still have a hard time telling any difference,
even using two of them at a time to compare front and back carbs. Other
problems, like jet adjustment, float level, clearance around the vacuum piston
and even vibration, seem to make a bigger difference than choice of needles.
BTW I am using KD needles. Usually I get good mileage, sometimes even with
a leaking carb, and other times I get bad mileage, but I don't think you can
pin the rose on your choice of needles.

If you have vacuum advance and set your timing to 10° btdc with the
vacuum disconnected, and then reconnect the vacuum, you have effectively
set it to about 20°. I set it to 20 on both cars, on the 164 without
disconnecting the vacuum, and on the 122, it doesn't have vacuum advance.
The big thing the vacuum advance does is to keep the engine from kicking
back against the starter. My 122 sometimes kicks back slightly but not
enough to keep it from starting. Once it starts it runs great, usually
starting in about 1-3 seconds unless the temp is below about 20°F, in which
case it might take 5-8 seconds. Thinner oil would probably help.
I do set the timing at idling speed, probably around 750-800 rpm.
--
George Downs Bartlesville, Oklahoma

Well...I'm afraid I really can't be much help with this one...sounds like you've got your engine set up pretty good, and running properly. All I can do is offer personal experience.

I've got a B20 in my '65 1800. The extent of the rebuild is unknown, but it has more power than any stock B20 I've driven...except maybe a '70 or '71 1800E or 142E. When that engine had less than 100K on it, and it was set up right, I would get 30mpg in town delivering pizza, and I got about 35mpg on the highway going from the west side of Colorado to Denver over the mountains. And I could light 'em up in third if I really tried (which I only did once or twice).

So...no, I don't think you are asking too much. But...we both like SU carbs (I collect them)...so we both know they are finicky. If the car runs right, starts good...I'd leave it. But that's just me. With more than 250K on my engine now, the great power/great mileage days are long gone. So I now settle for power. And the power is still great, but I only get about 15-20mpg in stop & go driving...maybe 20-25 highway. And I'm happy with that.

One thing to perhaps try though....have you taken it to an emmissions station for a test? That would be a real quick way to see if it's running too rich. Take it to your favorite mechanic and have them check the CO% and HCppm. They might even be able to suggest whether to lean it or adjust timing....or...?

If all else fails, try a 1/2" block under your gas pedal. You'll lose some power, but I bet you use less gas.

-Matt

Matt;

I'd be happy with that performance too (15/20 - 20/25)...checking the mixture at an emissions test station is only going to help if they have a dyne and can load the engine at speed while sniffing the exhaust...that's where Danny needs to see how the mixture is...and imho that's also the case with the colortune...without a dyne, it's just a toy which to check (for me the semi uninteresting condition of) idle...

Danny;

Have you tried driving in midrange and/or highway for a while, shutting down and pulling and checking the condition/color of spark-plugs...if you don't have access to a dyne, that's the next best thing...

I'll post metering needle data for KD, KX, ZH for reference shortly...are there any other needles that were used or that you need data for?

Good Luck, and please post your findings

Indeed, I'd agree that you would ideally load the engine to properly check the emmissions...but....

Here in northern Colorado, we gotta do emmissions tests yearly (or had to then), and at the time my car had the most power and the best mileage at the same time, it was passing 1988 vehicle emmissions standards which is better than I've ever had a carburetted B20 do. Not the best test admittedly, but helpful none the less if a dyno isn't available...

-Matt