New Engine - getting it dialed in

[Hatracks]

So I am getting to the point where the car is extremely drivable and getting used to the nuances of dual carbs. Some background and a couple of things I want to check:

Engine build:
1679
rotating assembly w/ lightened flywheel and kennedy stage 1 balanced as unit
ACN L3 heads
1.1 rockers
Webcam 218 grind type 1 cam with 108 LC
1 3/8 merged header/J pipes
Dual 40 IDFs w/ 28 venturis, 115 main 180 air 50 idle
034 SVDA


The engine runs great and is lightening fast through 1st and 2nd gear and liked to shift into third at about 4500 rpm, you can really hear when you tune for best lean idle on 2-4 cylinders but on cylinder 1 i cant really hear anything and i have it set to 1.5 turns out from lightly seated.

The car runs really well but I am a bit scared I am partially running on 3 cylinders. I have compression and leakdown tested and they are good and today will pull that side again and double check the jets are clear and put a new gasket on (last time I reused the gasket) along with checking the #1 plug for fouling. I have the snail type sync tool (BK Model) and when the car is set at a 750-800 idle all 4 barrels are pulling around about 4 on the tool and idle set scews are about at a half turn (maybe 1/8th more). Fuel pressure bounces between 2-2.8 at idle and at 3000 rpm is right at 3 and the timing is right at 7.5 BTDC.

Anything else i need to check or just quit worrying and drive it?
_________________
73 Super Build

[Danwvw]

Everything sounds about right although the Webcam 218 is kind of for a Bus engine used that way.
It seems that these engines when you go to dual carbs IDF's or DRLA's they tend to Idle on 3 cylinders some of the time. They should Idle on all 4 though smoothly it's probably the Idle circuit for that cylinder has a little air leak somewhere so gas does not get drawn up at idle. What kind of carbs are they? With the Dellortos it's usually a clogged Idle jet. Do the spark plug wire remove one at a time at the distributor test at Idle each time you change something to see if that was it.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Hatracks]

[Danwvw]

I think the Webers did not have the clogging Idle jet problem so bad like the Dellortos. But yeah, I fired up my Webcam 118 Cam engine below for the first time in months the other day and got it idling good and warmed up then revved it a few times then It would only idle on 3 cylinders. I started cleaning Idle jets. And it would change which ones needed cleaning after each revving. I think in my case I had some dirt in the carbs and revving disturbs it.
Some tools I use are the Dwell Tack timing light to read RPM's and the IR Lazer thermometer to measure exhaust port temps and intake port temps. You can see how strong they are running on the cylinders to some extent that way. I have yet to buy and use a flow meter.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Hatracks]

[Danwvw]

Sounds like it's running on the Mains then ok on number 1. That means the plug is not fowled. Although carbon on new plugs can still be a problem at idle.

I just have not played with the Webers and I know they have the jetting on the side of the carbs. My guess is it's a clogged Idle jet or an air leak somewhere into the Idle circuit of the carb. Maybe the idle mixture screw o ring needs grease.

Weber Idle Mixture Screw:

_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Frank Bassman]

Clogged idle jet. Take it out and blow it. Spray hole with brake cleaner. Try again.

Adjust each barrel idle MIXTURE until smoothest, fastest speed is reached. Do all 4 barrels. THEN, check throat to throat sync on both carbs and adjust with bypass screws. Repeat the idle mix adjustment.

This will be a circular process until you reach your desired idle speed. If your mix and fuel pressure is right your idle will be rock solid, will seemingly idle forever, and your spark plugs WILL look nice and white.

You may or may not be slightly lean with that jetting. If you run into idle clogging issues try 55 idle jets and adjust mix.

On an 1835 for someone I ended with 55/F11/120 and I THINK it was 190 airs but don't quote me on that. 28 mm vents. Baja extractor exhaust, 1 5/8 "

Hope this helps.

-Frank

-

[Hatracks]

Pulled the carb, blew it out and cleaned everything. Still would not fire on #1, yanked it again and this time replaced the idle jet with a spare and now it is firing on all 4 at idle.

I do not see anything plugging, or wrong, etc. with the idle jet i took out but for some reason the car doesnt like it.

Car runs well, in 3rd and 4th it likes to be kept over 2800 or its a bit sluggish if you come off idle/cruise. These cars really respond well to just a little bit of engine (and a whole lot of suspension work).
_________________
73 Super Build

[anthax]

Perhaps it could be the camshaft, that wakes up at 2800 rpm.
I guess 280 degree cam on a small engine eats up some low rev grunt.