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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7212
Location: Videbaek Denmark
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 Posted: Thu Dec 13, 2007 5:38 pm Post subject: |
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The float height is off, - most likely. Thats why the jets need to be so big.
What is your venturisize, main jet ? have you messed around with the main air jet ?
I have seen a couple (very rare though) 40 Solexés that for some reason just wanted like 0,10 - 0,15 larger main jets than all others on the same set up. Dont know why. It just is like that.
Also, where in the rpm range does it ping ? low, mid or high ?
T |
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Rowroy
Samba Member
Joined: November 07, 2006
Posts: 1012
Location: The ass of nowhere
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| Posted: Thu Dec 13, 2007 6:54 pm Post subject: |
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| Alstrup wrote: |
The float height is off, - most likely. Thats why the jets need to be so big.
What is your venturisize, main jet ? have you messed around with the main air jet ?
I have seen a couple (very rare though) 40 Solexés that for some reason just wanted like 0,10 - 0,15 larger main jets than all others on the same set up. Dont know why. It just is like that.
Also, where in the rpm range does it ping ? low, mid or high ?
T |
I never thought about the float height. I'm thinking the venturi size is 36 mm, but don't hold me to that. I'll have to re-measure, as my memory isn't very good.
I have not changed the air jet simply because I don't have any others on hand and the local VW shop doesn't carry them.
As of right now, my main jets are 152's. I'm thinking about stepping them up to 160's to see if that helps. The pinging starts ~2500 RPM's (about the time full advance starts to kick in) under a moderate to heavy load. I've backed the timing down to 30º (total) and I can no longer hear the pinging. However, I think I'm on the "ragged edge" of detonation.
What I plan on doing is to take the car for a nice highway ride for about 10 miles, then cut the ignition, pull over, and check a couple of the plugs to see if they show any signs of running lean.
I'm getting excellent gas mileage with my current set up @ 31 mpg (mostly highway).
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Suicide is man's way of telling God, "You can't fire me; I quit!" - Bill Maher |
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plantingchickens
Samba Member
Joined: July 28, 2006
Posts: 10
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| Posted: Tue Dec 18, 2007 12:48 pm Post subject: |
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Make sure you engine is cold before you start removing plugs, esp of your running a bit hot you dont want strip the threads, or burn yourself trying to get in there.
Just a safty precaution ^_^ |
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e85incallook
Samba Member
Joined: December 15, 2007
Posts: 26
Location: SouthCentral Kansas
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| Posted: Fri Dec 28, 2007 4:50 pm Post subject: So...what happened? |
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So...what happened?
I've read this entire thread and the problem is not solved. Please write one more reply and tell us what finally worked.
Thanks. |
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Rowroy
Samba Member
Joined: November 07, 2006
Posts: 1012
Location: The ass of nowhere
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| Posted: Fri Dec 28, 2007 8:24 pm Post subject: Re: So...what happened? |
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| e85incallook wrote: |
So...what happened?
I've read this entire thread and the problem is not solved. Please write one more reply and tell us what finally worked.
Thanks. |
Well, I ran down a desolate highway, cut the ignition, and pulled two of the plugs to check for a lean condition. As it turns out, it was running lean.
I stepped up my main jet from a 152's to a 158's (it was the next drill size "up" that I had) and noticed that the engine ran a great deal cooler (the oil temp was lower as well as the exhaust temp). I was even able to advance my timing back up to 30º (total). My mileage is still steady at ~29-30 mpg.
I've come to the conclusion that the the 9:1 compression may be a little too high for my combination. However, I think that I may have gotten around that with the larger main jets (having mitigated the detonation).
I just drove it on a 500 mile trip (with another 500 miler coming up on the 31st) and couldn't be happier with the performance and fuel economy.
The "acid test" will be driving around this summer when it's +90º outside.
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Suicide is man's way of telling God, "You can't fire me; I quit!" - Bill Maher |
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mharney
Samba Member
Joined: June 01, 2002
Posts: 8353
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| Posted: Fri Dec 28, 2007 9:11 pm Post subject: |
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You should be closer to a 145 main.. your floats..
Sounds like you used a 1/16" drill bit.
When your floats are wrong, as in what they usually are, fuel too LOW, it takes fat idle jets and big main jets to get the transition region rich enough to not run poorly. That said, it's amazing what kind of mileage you are getting. |
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Rowroy
Samba Member
Joined: November 07, 2006
Posts: 1012
Location: The ass of nowhere
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| Posted: Sat Dec 29, 2007 7:27 am Post subject: |
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| mharney wrote: |
You should be closer to a 145 main.. your floats..
Sounds like you used a 1/16" drill bit.
When your floats are wrong, as in what they usually are, fuel too LOW, it takes fat idle jets and big main jets to get the transition region rich enough to not run poorly. That said, it's amazing what kind of mileage you are getting. |
You know, I never did check the float height (and that was something that I meant to do).
Do you know of a spec for the float height?
These are the Solex DEIS 40's (similar to Kads . . . but different). 
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Suicide is man's way of telling God, "You can't fire me; I quit!" - Bill Maher |
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mharney
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Joined: June 01, 2002
Posts: 8353
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| Posted: Sat Dec 29, 2007 7:43 am Post subject: |
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Ah.. I had Webers on the brain for some reason, when I posted that. Sorry to confuse. Jetting could be different.
With Solex carbs and some others, if you don't know the float settings, a safe place to have the fuel level is where the float appears to be suspended level in the fuel. Stock Solexes are like this, if you measure the fuel height it generally turns out that the float is very close to level. This is crude, but with Solexes it is a little less critical than some others, like Weber and Dellorto.
The Kadrons do well when the fuel is about 3/4" from the top of the body.. this is also where the float is about level, provided someone hasn't gone about bending the float. Probably true with the DEIS as well. |
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mightymouse
Samba Member
Joined: May 26, 2004
Posts: 4220
Location: las vegas
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| Posted: Sun Dec 30, 2007 8:16 pm Post subject: |
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its nice to see how much help the forum can be when you have an issue isnt it. i just read the whole thread and was stoked to see all the good stuff. 
if i were you, i would pull it apart and put in a bigger cam. thats about it. looks like you have it dialed now. i think an engle 125 would be sweet.
looks like your on the right track with your carbs, im not too familiar with those carbs. but your story looks good. with more cam youll be able to run more timing too. i ran my 1679 at 10.5 to one for 10 years, and it had a 125 and i ran 36 degrees total advance. drove t everywhere, on 91 octane. later dave |
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