Tuning issues.. Jake can you advise?, advance curve or jetting (that is the question) Options

[brant]

I finally got my latest project running but not well enough
I need to do a little tuning...

its a 1.7 motor with a cam (don't know the specs of the cam) from the previous owner
I can get leak down/compression, but don't have them at this moment.
I also don't know the compression, but it is mild... probably stock

the P.O. claims it was rebuilt and I believe it
I took all of the tin/push rod tubes off, and it looks to have been rebuilt with out worn/shot stock cam lobes and with lifters showing no significant wear
doesn't seem to burn-smoke or leak any oil at this point.

Its running 40mm dual webers, currently testing at 3300 foot altitude
(motor came from a running car at about 5500 ft)

I rebuilt the carbs and the jetting is:
-28mm (chokes) main venturis
-2ndary venturis 4.5
-main jets 115
-air jets 200
-emulsions F11
-acc. pump ball jet 50
-acc. pump towers 50
-idles 50
I've never carbed a 1.7 before

The motor came with a 009 distributor and points
I ditched it and put in a L-jet 914 (1.8) distributor with points, blue coil, and no retard/advance lines hooked up
the cap/rotor/plugs/wires are all good-new

car idles smooth, pulls fine from standing, and then stumbles mildly from 2000 - 3000
the car clears out and runs great at 3000 or 3100rpm
timing is currently set at 29degree's, but this is my norm for altitude.

dad and I are in disagreement about the cause
he thinks its too rich for the tiny motor

I think its a distributor curve issue

Jake, do you know?
I have a Djet distributor available easily... or could put the 009 back on... or think maybe I should buy an 050 somewhere to see if the curve is actually the problem

We discussed buying 110 mains also to play with it...

thanks in advance for any advice from the guru's out there
brant

[brant]

what is the prefered and affordable (not mallory) distributor for carbed street cars...

my last carbed 4 was electromotive, and before that in the 80's it was an 050. I thought I heard that the 1.8/ljet had a good curve.. but I'm not so sure now.

[McMark]

A stumble from 2k to 3k indicates an issue with the transition from idle jets to main jets. I'd guess pulling back a size on the mains. But I'm not the carb guru that some people are.

[Jake Raby]

If this persists a change of emulsion tube to an F7 may help... BUT thats usually a band aid for something else thats wrong..

[tat2dphreak]

I'm no where NEAR the guru Jake is, but your carb specs are similar to my 2056... which I got the carb-tuning for from jake...

I'm running
32mm vents,
125 mains,
f11 emulsion
60 idles
200 airs

that is what jake suggested for a stock-cammed 2056..

I agree with McMark,

I'd maybe kick up the vent size and mains.
I'm guessing 30mm, and 125 mains
because there's a 'gap' in between your idles and mains right now...

I THINK you can either increase the idles or mains to fix your issue, you might want to do both in a smaller increment tho... gaps are bad, if I understand it right, you are stretching the limits of what the idle jet can put out, so it cuts to a lean mix, then you get a lean mix starting the main jet, so my thought is if you increase both a little, you should get a smoother transition because the idles aren't being stretched as much, and your mains should start a little richer... meaning no 'lean' gap.

I could be off the mark or over simplifying it tho..

[Gint]

A stumble from 2k to 3k indicates an issue with the transition from idle jets to main jets. I'd guess pulling back a size on the mains. But I'm not the carb guru that some people are.

(IMG:style_emoticons/default/agree.gif) But I'm certainly no expert. Looking forward to more responses to this thread though. (IMG:style_emoticons/default/icon_bump.gif)
Easy enough to throw in idle jets one size up and try that out. If nothing else it may clarify the direction you need to go.

This post has been edited by Gint: Jun 9 2009, 05:59 PM

[r_towle]

Leave the vents at 28mm
step up the idle jet first..then change the emulsion tube to the F7

The other thing to do is contact aircooled.net. They have a real world list of known setups for webers on type 4 motors from all over the country at different elevations.
Just be nice and buy your parts from them...
Call and get an answer...email and you may not.

Rich

[brant]

its easy to flood it out at starting and the plugs certainly are not lean looking....

I was thinking it might be too rich for ameasly 1.7 (1/7th less displacement than a 2056?)

hmmm
I'll buy one set of smaller mains and if that doesn't do anything I can always bore out or increase the jet sizes myself to go richer

I'm thinking I may buy an innovate tail pipe fixture too and see what the guage says

do other people run the 1.8 ljet distributor with carbs?
should I try to hook up the advance side of the dash pot to a vacuum line?

Mike, do you have any spare 050 distributors that I could throw into the motor for a 5 minute test run to rule out the timing curve side of the equation?

Mike, are you running that mallory yet.. and what distributor did you have in it before the mallory?

thanks all
brant

[Jake Raby]

Kick its ass or it'll kick yours..
That said, the set up you have is stock for a 1600cc engine for a Fiat!! Those vents also work great on a 1600cc T1 and your 1700cc TIV..

UNLESS you have a worn cam, shot rings or glazed cylinders or a half ass exhaust.. The VERY FIRST thing that you do when tuning issues occur is verify the engine's integrity with a compression and leak down test- period.

With 2.5-3 PSI fuel pressure, float height set at 10& 23mm and the jets you have that engine should run great... The only change I'd make would be running a 220 air at that elevation

And remember that 95% of Carburetor issues are actually ignition issues...

When I learned about carbs there was no internet, no air fuel meters, I never read a book and no one taught me how the damn thing worked or what the circuits were.. I decided to kick it's ass so I threw changes at it, figured out how they responded to those things and won the battle.

That said IF this engine is using an 050 dizzy that IS the fucking problem. Remove it, throw it away and don't look back- they suck, always have and always will and I don't give a damn what people say that have a so called "positive experience" with them.. They are made for WOT running all the time. Most people that "think" the 050 works well have never experienced a properly set up alternative.. They set up retarded at idle and breed hesitations, flat spots and rich running.

Carbs are the simplest thing on this planet to work with, nothing is easier to understand on the entire engine IMHO...

[tat2dphreak]

if a mallory is out of the price range tho, then what? he's using an 1.8 Ljet dizzy right now...

009?
Djet dizzy? where do these dizzy's rank? sorry if I'm getting OT, but if it's ignition, what else should one try? I'm curious, because all I've ever heard is that 009 is crap, and 050 is slightly better, but still shit compared to the mallory...

[Kirmizi]

Brant,
I've been running the Mallory in mine since Feb and it's made a world of difference. Prior to that it was an 009 with Pertronix. Obvious, and I do mean obvious, change in performance. The engine now pulls throughout the entire rpm range. As I mentioned before, whenever I experienced any hesitation it was due to debris in one of the carb jets. 2-3k stumbling would have me checking idle jets first, but it's easy enough to pull everything to inspect.
Mike

[Gint]

Mike, do you have any spare 050 distributors that I could throw into the motor for a 5 minute test run to rule out the timing curve side of the equation?

Mike, are you running that mallory yet.. and what distributor did you have in it before the mallory?

thanks all
brant

I probably still have an 050 laying around here somewhere, but I'd have to find it. Of course you're welcome to use it if it will help your troubleshooting. Let me know and I'll see if I can dig it up.

The Mallory has been installed for a year or so now. Prior to that the zambeziteen had a 009 installed. You can borrow that too if'n you want. (IMG:style_emoticons/default/wink.gif) Hell, I even have a dual point 009 around here somwhere. Don't know who went to the trouble to make that thing up. (IMG:style_emoticons/default/laugh.gif)

The problem your having doesn't sound like ignition or advance curve to me, but whaddoIknow...

I did find out at C&C last Saturday though that Scott's 40IDF's as well as mine (I was shocked (IMG:style_emoticons/default/blink.gif) ) do in fact have a vacuum nipple! Both of them. I never could see this on a diagram, but it's there bigger than life. Yours might also. If so, you could add vacuum to your dizzy and get the additional benefits of vacuum advance curve to the 1.8 unit.

Call me this afternoon anytime after 3:00. (IMG:style_emoticons/default/wavey.gif)

[Gint]

(IMG:style_emoticons/default/icon_bump.gif) Hello Brant...

[brant]

(IMG:style_emoticons/default/icon_bump.gif) Hello Brant...

sorry for not calling
I'll call tomorrow if thats ok with you
after 3 good again?

I have that vacuum port on this car also
which side of the dash pot do I want to hook it too?
(one hose barb is slightly bigger... like 3mm vs 4mm)

I think I'll stick a distributor in before I buy jets... (cheaper)
then I'll buy jets.. mains and idles
any local shops for jets around?
Is randy's VW still open?

brant

[Gint]

sorry for not calling
I'll call tomorrow if thats ok with you
after 3 good again?

I have that vacuum port on this car also
which side of the dash pot do I want to hook it too?
(one hose barb is slightly bigger... like 3mm vs 4mm)

I think I'll stick a distributor in before I buy jets... (cheaper)
then I'll buy jets.. mains and idles
any local shops for jets around?
Is randy's VW still open?

brant

No sweat. Today works. I'm cell-less until this afternoon. See my email.

I'll get a pic of one of my carbs or if we can meet up I can drive the 914 and you can see it for yourself. One of those vacuum ports on the dizzy can is for advance and the other is for retard. If memory serves me, advance pulls away from the dizzy and retard pushes. Based on the angle you can figure out which is which. Advance is usually the one sticking out the end and retard is in the side of the can. And then you can always pop the cap off and figure it out.

Randy's is long gone. Painter's will have some and even IPW has a selection. That's where I got my last set of idle jets a couple of years ago.

[tat2dphreak]

dunno about local, but I recommend aircooled.net fro jets, etc.

[brant]

Thanks to both of you!

Wayne, did you ever come up with any opinion about which "cheap" dizzy to use. I yanked the 009 since I've always heard so much bad about it.. I thought the ljet was better. But I might put the 009 back on just to see. I could try a djet distributor (I have) just to see also

obviously the mallory is best, but I'm wondering if something I already have access to is useable for a mild street car without spending money I don't have right now.

tia

[ME733]

Well you have recieved a significant amount of very good advise....So make a list of the best ones and proceed methodically.I would suggest that the person who stated that most problems just may be in the ELECTRICAL side of this issue is probably right on the money...AS an example (do you really want to tune your engine to accomodiate the other malfunctioning parts....GET down to the basics first....set the spark plug gap to .025-.;027ths of an inch.....make sure the CONDINSER is new,the points are properly set...016ths. and the lift block on the points is perfect, and the lobes are greased on the distributor shaft..no shorts from frayed wires.....excessive rotor to cap....gap will cause a miss,(flat spots)...and the RICHER the fuel mixture the more significant (problems) arrise.as the weak spark cannot fire the cylinder charge.....It might be that 29 is too advanced (for your elevation...air density)....try 27....and do your carbs have the short velocity stacks????a good direct air stream to assist the enrichment ventures with proper atomization of the high speed fuel mixture is critical....otherwise you will have fuel droplets(chunks) which will give the perception of a too rich mixture(plug check)....a new COIL may also be in order....etc etc etc ...you will resolve this issue faster if you ONLY make one change at a time and check the results.

[jmill]

The stumble is either ignition or transition issues. Can't help with ignition. Most carb transition issues are due to low float level. Check your float level. If your float level is low your mains will be lean and you'll stumble at 2-3K when you get off the idle jets. If your float level is good, like Jake said, the F7 will help richen it up at transition.

I don't think your rich. I'm betting if you step down on the mains you'll get a lean pop.

[tat2dphreak]

Thanks to both of you!

Wayne, did you ever come up with any opinion about which "cheap" dizzy to use. I yanked the 009 since I've always heard so much bad about it.. I thought the ljet was better. But I might put the 009 back on just to see. I could try a djet distributor (I have) just to see also

obviously the mallory is best, but I'm wondering if something I already have access to is useable for a mild street car without spending money I don't have right now.

tia

never a clear answer, but more options...
http://cbperformance.com/catalog.asp?ProductID=1477 was mentioned

as was the DIS-IX Distributorless Ignition System for 009 Distributor at http://www.compufire.com/vw-products-main.html

the last one seems interesting, but you still use a distributor like an 009 or 050 for the advance, so I dont know if that's really better? but someome said you can get a distributor advance changed by ??

of course, if it's that easy, why not take a good 009 and have someone fix the advance to be correct where it doesn't retard the 3rd cylinder? a cheap + correct solution is all we are looking for.