Dual Weber IDF 40s, Carb Rookie question... Options

[malcolm2]

2 filters? The middle canister is a filter. I got rid of it. I went with a FI filter, same sized inlet and outlet. Perfect fuel line fit. Use shouldered clamps. Easier to see when the filter is fouled. The metal can? Not so much.

"Product images are representative only..."

IIRC I did not get the clear filter. I do know that all the clamps are "permanent", if you will. Not the screw type, nor do they have the shoulders.

I like the FI filter idea. I have a few of those packed away for the 914, so it would be good for the Bus and the 914 to use a few interchangeable parts.

Yeah in high school, I had a bug with a metal can. Out of the blue it would just stop running..... I would wait about 30 minutes and it would start and get me where I was going. Eventually I figured out that the metal filter was clogged up and you could not see it. Sh*t never changes.

[r_towle]

I used two filters on my race car because the tank was toast.

I use one on either side of the fuel pump (because filters are cheap)
the inlet filter between tank and fuel pump is a race filter, can be taken apart and cleaned. It has a stone??? in it with tons of holes used as the filter.

That was the one that I kept having to clean.
a new tank fixed my issue, but I left two filters in place because it protects the fuel pump...

I can fix any issue on the side of the road by cleaning up that race filter with some carb cleaner.....so I like that.

For the OP
Carbs do not (aside from the accel pump) squirt fuel.
Fuel is sucked into the engine by the motor, via the carbs.

So, your adjustments are three.
One, the size of the Venturi really matters...the smaller it is, the faster the suction velocity. Standard Webers are all wrong when we buy them.
Get to the 28mm vents before you get super frustrated.
It will always be a bit sluggish without doing that first step.
It will run, it can be tuned...but it will always be meh.

Suction matching on the engine is dependent upon the intake and exhaust valves being identical in adjustment over all 4 cylinders.
If one of them is wrong (one of yours is wrong...I can hear it) then the suction on that cylinder will be different from the other three.

Get the valves perfect.
Take your time....and get used to doing it.
Its not a terrible job if you learn the easy way to get it done.
I think (maybe) Cap'n Crusty did a write up on how he did it in the Classics forum here...at least I hope that still exists (RIP Cap'n)

Idle jets...
Pretty simple jet, but its the one that does a lot of the work.
Perfectly tuned at idle matters a ton.

Mains are just flood gates, when you need them (high rpms) and you won't feel them....idle is the key jet.

the Access pumps are typically setup wrong from the seller
The floats are typically setup wrong from the seller
The jets....remove and verify each on (there are tiny numbers on them)

Trust but verify.


Rich

[914werke]

Not to hijack the thread but has anyone see these installed in their Webers?

[nditiz1]

Rich, I just check 3 sets of my carbs. All of them have that missing. The one set that I run on test engines runs fine without it.

[914werke]

Ya Ive never see it before & they are installed in a set of Italian 40's Im restoring.
It plugs a opening ..for some reason?

[sportlicherFahrer]

I believe that piece is a float bowl vent that was omitted on Webers made outside Italy. No big deal if removed. If it's not plugged, it's probably okay to run as is if needed.

[malcolm2]

Pulled the plugs and did a compression check before i adjust the valves.

Plugs were BLACK. Got pix if we have any plug readers in the group.
1-2 were super black and dry.
3-4 were not as black and looked wet

Compression was
1. 100
2. 110
3. 120
4 115

Will adjust the valves again, re-check compression add some low mileage plugs and pull the carbs to verify settings and check for clogged jets and float height.

Might take a day or so, damn real job is calling.

[Superhawk996]

Pulled the plugs and did a compression check before i adjust the valves.

Plugs were BLACK.

Black = way too rich

Definitely verify float level as 1st step.

You won’t end up with black plugs from clogged fuel Jets but could occur due to clogged air correction jets and/or air passages.

install new plugs, then go back to basics: setting idle mixture, balancing airflow, and synchronization.

[malcolm2]

update......

I have chromoly push rods and swivel foot adjusters. I have been told to adjust valves as follows.

ROTOR BUTTON pointing at #1 Attempt to rotate the swivel foot on I and E adjusters for #1. Grab the rocker and pull outward. Listen for a slight rattle.

The object here is ZERO LASH.

Bentley says to start at 1.... rotate rotor CCW to 2, then 3 then 4.


I have gone around the engine 3 times. ALL EIGHT valves allow the swivel foot to rotate (spin) and the only click I get is if the rocker moves side-to-side. I also have solid aluminum spacers with 2 warped spring washers so there is just a bit of room for the rocker to move side-to-side.

Let me know what you think. I will go around once more.... maybe video the fun and report back here.

[nditiz1]

Sounds fine.

I usually see if I can spin the pushrod and have no movement of the rocker, but your method seems to work as well.

The goal of lash is for expansion of the aluminum pushrods during run. Chromoly do not, or maybe extremely little. .006/.008 for aluminum .000 for chromoly.

[r_towle]

So, I am lazy and I hate getting up and down 50 times.

Jack up car
Lower car so one wheel is resting on a 6x6
Put car in 5th

Rotate the wheel like reverse
This spins the motor forward

A valve on each side of the motor will be closed (bottom of the lobe) at the same time.
The lobe that is shared will always have one valve open and one closed.

Hard to explain but you can adjust one valve on both opposite sides of the motor at the same time.

Let me find his thread.
Found it

http://www.914world.com/bbs2/index.php?showtopic=28758

[malcolm2]

So, I am lazy and I hate getting up and down 50 times.

Jack up car
Lower car so one wheel is resting on a 6x6
Put car in 5th

Rotate the wheel like reverse
This spins the motor forward

A valve on each side of the motor will be closed (bottom of the lobe) at the same time.
The lobe that is shared will always have one valve open and one closed.

Hard to explain but you can adjust one valve on both opposite sides of the motor at the same time.

Let me find his thread.
Found it

http://www.914world.com/bbs2/index.php?showtopic=28758

I have done it 4 times.... even getting up and down only four times. All valves allow the swivel for to spin but give no rocker movement.... all 8 are on zero lash.

Pretty much did the cap'n crusty method.

I do not feel like these valves are out of adjustment. What else can you suggest to determine if they are out of adjustment.

I did take a video of each cylinder.... I am attempting to meld the 4 videos together. Maybe it will work, maybe not. If not I will post 1 video as all four result in the same thing..... swivel foot spins with the valves closed. Glad to try something else.

[nditiz1]

Who said your valves were out? I think someone mentioned to check they are in spec.

You should be fine, continue on to adjusting the carbs. Maybe we can vid chat and I can dump all my carb knowledge.

[malcolm2]

A couple folks mentioned valve noises, now after checking them, I can believe that it may be the side to side of the rockers. That is really the only clicking I hear with these chromoly push rods.

Damn if I can remember if there was a reason.... Something came with the solid spacers and some washers. I see that I was not consistent with assembly of the washers.

They are all taking up the same amount of space, wonder if it matters. Maybe I should add more washers where I am getting the most side to side noise on adjustment??

hard to see, but IV has 4 washers in the middle. III has washers spread out. same deal on the I II side. Not consistent with the washers for some reason.

[nditiz1]

No that all seems fine. I didn't hear anything abnormal from your video except it was not running optimally due to the carbs.

The spacers will be different due to how much the valves were clearances on the sides ( I'm assuming Tabari? did them) you try to get slightly off center from the valve so it spins the valve as it hits it instead of exact center.

[porschetub]

No that all seems fine. I didn't hear anything abnormal from your video except it was not running optimally due to the carbs.

The spacers will be different due to how much the valves were clearances on the sides ( I'm assuming Tabari? did them) you try to get slightly off center from the valve so it spins the valve as it hits it instead of exact center.

(IMG:style_emoticons/default/agree.gif) many don't check this and its essential for good valve sealing and wear on the stems.

[malcolm2]

Heads are Camper Specials from Type4store.com. They did the valves etc… as well. All the innards are from them. Cam, lifters, bearings, push rods. Probably other stuff I can’t remember.

[r_towle]

After you have done this adjustment, did your compression test results change?

[malcolm2]

I did not adjust any valves. I checked each valve several times using the method described about and once using the cap’ns “rocking” method.

Each check resulted in zero lash.

[nditiz1]

Was this a newly rebuilt engine?

Compression test should be done on a warm engine. Also, I rarely do compression tests anymore even on unknown engines. I get more info from leak down tests.