Need a crash course on Solex Carbs, Easy responses!! Emissions results here Options

[ninefourteener]

Ok folks..... these aren't quadrajets, Carter AFBs, or Holly's..... so I'm FAR from an expert on Solex Carbs. So hopefully, someone might know some easy tricks/adjustments to get this damn thing through emissions so far.

The 914 club was down yesterday, for far more important reasons....... and my heart goes out to ^Easton^ and his family.

So..... I found this website..... and adjusted my mixture screws as it said to do:

http://www.356registry.org/Tech/solex.html

What I've done, is adjusted all 4 mixture screws (2 carbs, #16 on the diagram) as far is as I could get them to lean out the mixture. The car ran great before, now its running really rough, and the idle is EXTREMELY low (like 3 or 400 RPMs).

I'm headed to the testing station today on my lunchbreak. If it passes, I'm tuning them back the way they were. If it DOES NOT pass....... I'd like to adjust them right out in the parking lot... and drive it through again.

Last time I tested, these were the results of my last emissions test:

Hydrocarbons (PPM) Carbon Monoxide (%)
Standards 800 8.0
Readings 3877 4.6
Result FAIL PASS

If adjusting the mixture screws lean doesn't work....... What's next???

Thanks for all the help in advance!!

Matt

[ninefourteener]

Bump....

Really need some advice....... anyone familiar with Solex Carbs? I'm headed to the testing station in under 2 hours!

[ArtechnikA]

you've got almost 4X (!) too much HC.

sounds like ignition issues, could be into lean misfire (actually *raises* HC...). try new plugs and make sure the timing is spot on or even retarded a bit from "normal."

what kind of cam you got in that thing?

idle jets way too big ?

[lapuwali]

Richen in back up. You're now so lean it's misfiring and lots of unburnt mixture is going right out the pipe. 3800ppm HC is unbelievably high. If an engine were tuned rich enough to generate that kind of number, you'd have clouds of black smoke out the pipe, assuming it even ran when that rich.

The other clue here is the relatively low CO number. Normally, both HC and CO go up on the rich side, and go down as mixture gets leaner.

Dial the carbs in until it idles very smoothly at 800-12000rpm. Now, lean out one cylinder by SLOWLY (1/4 turn, pause, 1/4 turn, pause) turning in the mixture screw until you feel and hear it start to run roughly. That cylinder is now lean misfiring. Richen it up again until that goes away. Note what the screw setting is now (number of 1/4 turns from lightly bottomed). Repeat with the other four cylinders.

To give you some idea of how dirty 800ppm HC is (and thus how much latitude you should have here), I've owned a number of cars with fuel injection but no other smog devices at all, which ran at under 200ppm HC (and ran very well).

[ninefourteener]

Actually..... I've put new plugs in it since the last time I tested it.. I forgot about that. Maybe that will help

I'm not exactly sure what was put into the engine... it was done by the PO just before I bought it. I knoe the PO spent over $4G just having the motor done..... and not that I have vast experience driving 914s, but my last one was a dual-Weber 1.7..... and it ran great.

This one is a 2.0 dual Solex..... the ass wobbles around at stoplights like it has a cam in it.... and it'll blow the crap out of my last one. In fact, it'll blow the crap out of my RSX...... in a straight line even. I don't think "stock" 4-cyl 914s are supposed to do that.

Wish I had a better answer..... I have the reciept of all the engine work done.. but I don't think the specifics are there.. Wish I had a better answer.

So retarding the timing might help if I fail again??

[ninefourteener]

QUOTE (lapuwali @ Jun 24 2005, 06:50 AM)

3800ppm HC is unbelievably high. If an engine were tuned rich enough to generate that kind of number, you'd have clouds of black smoke out the pipe, assuming it even ran when that rich.

Actually, the car runs fantastic (or it did when the carbs were tuned that way)... no black smoke, no backfiring.... no sputtering..... the car ran great!

Thats what kills me.... I feel like I'm screwing up my car just to get it to pass.

[redshift]

Wow... you got a cammer..

Yes, retard helps, but you gotta be close to matter..


M

[ArtechnikA]

you can 'take out' some cam by setting the valves really loose -- like 0.016".

that will reduce the lift and the overlap.

with a lumpy cam, you may just be SOL.
start looking at putting on cats...

[ninefourteener]

Well I guess if it fails...... I'll just turn the distributor a wee-bit to the left.

The car is idling really low right now though.. I'm not sure how much I'm going to get out of it and still keep it running.

[SLITS]

What happened to the 10% by volume alcohol added to the gas trick?

[ninefourteener]

QUOTE (SLITS @ Jun 24 2005, 07:35 AM)

What happened to the 10% by volume alcohol added to the gas trick?

I've done that as well...... with any luck... maybe that will help as well.

I'm leaving in about 20 minutes to go do this crap...... In my newly crappy-running 914.

wish me luck.

Dammit... this is bullshit.

[redshift]

Jees... g'luck..

At least it looks nice..


M

[lapuwali]

I misunderstood what you'd written. I thought the 3800ppm number was AFTER you leaned it out.

You need to make friends with someone who has smog testing equipment and tweak the mixture while you're on the machine. I'm still willing to bet that you can beat that emissions number handily and still have a very nicely running engine. Mark Henry, when he got a wideband O2 sensor, found that his tuned by the seat of his pants AFR was 10:1, which is very rich. When he tuned it down to 12:1, it ran even better. The difference in feel on the rich side of the mixture is fairly subtle, and it's very easy to overshoot the mark.

If you have it running so lean it's misfiring, your HC numbers will not go down. They may, in fact, end up being even worse.

If, while tweaking the mixture on the machine, you can't get a number that will allow you to pass because of that cam, then Rich is right about the cats. You'll need to rework your exhaust to allow one or two to be fitted. They won't live very long with mixtures that rich, however, and you'd have to either swap them with pipes after every test, or buy a new set every time. It would probably be cheaper to just install a milder cam.

[ninefourteener]

Dammit..... all that work and stress..

I drive it up there.. only to find out they are closed.

Turns out, they are only open 3.5 days a week..... must be nice.

The idle is so low right now, I almost stalled it several times.... especially after it got good and warmed up.

I'm gonna have to bump up the idle a little... I'm afraid if its really hot tomorrow morning (like it is now), I'm gonna stall at the testing station.

[IronHillRestorations]

QUOTE (ninefourteener @ Jun 24 2005, 10:12 AM)

The idle is so low right now, I almost stalled it several times.... especially after it got good and warmed up. I'm gonna have to bump up the idle a little... I'm afraid if its really hot tomorrow morning (like it is now), I'm gonna stall at the testing station.

Yes, just screw in the idle stop screws (same degree of turn each side) and raise the idle a bit.

[ninefourteener]

Well....... I have good news and bad news:

Good..... I'm DAMN good at tweaking Solex Carbs now.... because I've done it so damn much.

However.... there is no way in hell, or on God's green earth that this car is ever going to pass emissions.

I ran it through several times, richening, leaning...... The LOWEST I was able to get the HCs were down into the low 2000s........ but my COs were only reading .1, and the test was deemed "invalid" for a lack of a good sample.

Here's the good news though:

The LAST guy at the testing station told me that I could not get the suspension lifted on my plates until the car passed emissions...... but he worked for the DMV. Hell, thats why I was going through all this.

The guy I talked to that worked at the testing station (and is currently restoring a 1974 Ford) Apparently, the DMV and the EPA are completely different organizations, and rarely communicate with eachother.

If you apply to the EPA, for a "showcar" exemption, and provide all the necessary documentation (EPA form, pictures of the car, copy of insurance policy), they will send you a "showcar exemption".

Take the exemption form to the DMV, and they have no grounds to require your car to test on emissions, and no reason to withhold my registration.

Also, by doing this through the EPA, and NOT through the DMV (as an antique vehicle), then you get to keep the same plates!!!

Anyway.... thanks for all the help.... I guess I'm just not driving a very "ozone-friendly" car.

Paperwork goes out to the EPA today (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

Matt