quad weber help

two89w · #1 (**permalink**) 04-02-2002, 02:25 PM

i got my car back a week and a half ago,it really was crisp on the throttle screamed through the rev range(now, i know it may just have been the this time drive thing) but it has really gone off ,still got power but it just doesnt lite the tires in 2nd and third like it did the first couple of days,its been getting progresively worse,it has quad 44mm idf webers,does or has anybody out there had this or a similar experience

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427Aggie · #2 (**permalink**) 04-02-2002, 03:39 PM

Best person to get involved her is CalMetal....the IDF's are a little different than the IDA's that I have.

It would help to know what type of engine and then what size main, idles, e-tubes, idle holders, chokes, and air correctors you have on the carbs....

Where did you get your car back from? Did you just put the carbs on and have they been tuned? Have you check the sync on the carbs and are they all the same (the IDF's should have an adjustment screw that will allow you to get the barrels exactly the same on the sync).

All of these we will need to know then we can figure things out.....

Ohh have you pulled the plugs to make sure they aren't fouled? Let me tell you mine have been a trial and error bigtime to get them close to right and I have probably $1000 in jets and crap.

Matt - I am slowly learning alot about these things...helps when you take them apart 20 times....

BrianPaul · #3 (**permalink**) 04-02-2002, 04:26 PM

Matt,

What is your set up on your Web's? Jets, Etubes, chokes etc. I have a set on my 428. Runs great on the test stand, but, I have not got it in a car yet. mine are as follows.

40 mm chokes
65 idle
120 holder
160 air correction
160 main
55 bypass
F7 etube
D&G needle valves

What specific problems have you had?

Brian Paul

Bob Putnam · #4 (**permalink**) 04-02-2002, 04:46 PM

If you're not experiencing backfiring or popping back through the carbs, I would look at other engine functions, like timing, spark plugs or valve lash.

Or maybe the tires are getting broken in and you're getting used to the accelleration.

cobrajeff · #5 (**permalink**) 04-03-2002, 04:54 AM

Check your throttle linkage to be sure you are still getting full throttle. I have had occasion where a lock-nut (which must not have been tight enough) has allowed a piece of linkage to slip, or, a piece of linkage that is weak or in a bind may bend, causing you to lose full throttle opening.

Brian -
I'm not a Weber expert, but I'd suggest you may want to try some larger air correctors (like around 200) on your engine. Most set-ups I've seen have the air correctors several sizes larger than the main jets.

regards,

Jeff Burgy

BrianPaul · #6 (**permalink**) 04-03-2002, 07:47 AM

Jeff,

The 160 correctors was on the advice of the guys at Pearce Manifolds. I agree. they are too small. I am putting my original 205's back in and then going to wait to drop the engine in the car. According to "The Book", correctors should be double the number of the mains. i.e. 160 main = 220 corrector. Actually it is, after all, magic and we haven't figured out the trick!!

Brian P.

Cal Metal · #7 (**permalink**) 04-03-2002, 01:10 PM

Bob Putnam has some good advice here. Check the timing/valve lash, etc. Also, the suggestion regarding a linkage check is a good one. Often times these carbs are blamed for things for which they are not responsible. It would seem peculiar to me that the carbs would be running good one day and poorly the next.

Spitting and popping back through the carb is a sure sign of a synchronization problem. This doesn't appear to be the case here. If you tend to peter out at top end--everything other part of the range being good--your air correction jet is too big, braking the mixture flow and over emulsifying (lean).

two89w · #8 (**permalink**) 04-04-2002, 01:11 AM

it didnt just get worse over nite it was over a week,i has some sock type foam air filters on it for a few days it started to miss a little bit so i took them off and its never really been the same again,it must be running rich cause i can go out and start it now stone cold and just drive it up the street like its warm,will restrictive air cleaners effect webers ??

Cal Metal · #9 (**permalink**) 04-04-2002, 10:22 AM

It is amazing that the car ran well with the foam air cleaners. They normally restrict the air flow so bad that the engine runs richer than an industrial furnace. What fuel pressure are you running? Remember to keep at 3 lbs or below. Again, I would really check timing and valve lash for starters. Throw the foam elements away.