Carb adjustment

[oppositeLock]

I can't claim proficiency in balancing the carbs really well, but I've found using an STE SK Synchrometer works nicely. Certainly less restrictive design than a unisyn.

[Gregs672000]

I can't claim proficiency in balancing the carbs really well, but I've found using an STE SK Synchrometer works nicely. Certainly less restrictive design than a unisyn.

Agreed. I have a different version but they are much easier to use than a unisyn because you can leave it over the carb throat alot longer without restriction.

[DCooke]

Ok, so I re-adjusted the carb fuel mixture to the correct 0.087” and tweaked the idle for a good balance. Took it for a quick test drive and I could feel more pickup on acceleration. I’ll run it like this on a few evening drives and see how it does.

[Linda]

I like the ADQ needles that Keith suggests, also, Dave.
Linda

[guyatou]

Quick question: Does the "magic number" method work with the U20 engine as well? Is the magic number for those carbs also .087"? Looks like every reference I see for that method is for a 1600.

[Linda]

Since no one is answering .....
I would guess the U20 needs more gas, but at least you might start with the.090 setting in the Wiki and at least you would be EVEN. Then adjust if needed . If it seems good then check the numbers again. Kind of a hassle to take the domes off, then on, then off to check but that is the nature of fine tuning per this method it seems
Using the unisyn is the rest of it.
Good luck, and maybe someone with a U20 will post
Linda

[DCooke]

Ok, so I re-adjusted the carb fuel mixture to the correct 0.087” and tweaked the idle for a good balance. Took it for a quick test drive and I could feel more pickup on acceleration. I’ll run it like this on a few evening drives and see how it does.

Update: the weather finally turned sunny this weekend here in Chicago, so I got take the roadster out to a couple of local shows since my previous card adjustment. While the acceleration is fairly smooth, I'm hearing a bit of a "ping" when accelerating from a lower RPM, it does however go away quickly. The idle is also a bit more temperamental from a cold start even with the choke, not a smooth as it was on the first adjustment. I think its running a bit rich, but I do own a "ColorTune", so I'll dig that out & see if I can get a better overall adjustment with that process.

Regardless, this car still puts a grin on my face every time I drive it.

[Linda]

Might need a .086 etc adjust.
But would be interesting to see what the Colortune shows as currently set up.
Glad you got some nicer weather for driving.
Linda
Link for the Colortune people, great customer service
http://311s.org/phpBB3/viewtopic.php?f= ... 90359fee9c

[guyatou]

Thanks Linda! That's a lot richer than I've run it in the past, but it has a lot more power.

[Linda]

Maybe check the plugs , then dial it in from there?
I have run .086 but it is a bit rich too for my 1600..better than too lean
Linda

[msampsel]

I tried the magic number and then my wideband sensor showed me I was off.
Not sure how or if I deviated from the magic number method before I used the sensor.
I like the wideband sensor because I could test the mixture across all rpm under load. I am now pleased with performance.
Winds nicely up to 7700 or so RPM.

Of course you need a bung in your header or exhaust. And then a sensor/gauge. We have our toys ...
I guess I could measure the distance now and provide my personal magic number ...

[Gregs672000]

As the above post illustrates, every engine is different. This one is modified from stock as I recall, so what works well for him may be different for you... and why I Love the wideband...

[Linda]

Yes, would be interesting to get info on what the wideband " magic number" range might be.
Linda

[DCooke]

I dialed the mixture back a bit to 0.076 to see if that was better. I could get a better idle, but I could feel a little lack of power on acceleration. Still haven't had time to use the Colortune yet, should be interesting to see how that compares.

[DCooke]

Ok, so 0.076 was a bit too lean for my car, noticed some pinging at times on lower RPMs. I tried the colortune & could never get it to go to "bunsen burner blue" on idle, it was always orange no matter where the mixture was set at. I went back to the measurement method & set it to 0.080, then checked the colortune & still showed orange on idle, but went blue upon as I raised the RPMs. I'll take it out for a spin this week and see how it goes.