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Weber 38 Won't Run Right :(


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I finally got my car back together after overheating it.  I ran it up and down the street on my old 32/36 to make sure it ran right and then swapped on a 38 I got from ebay a while back.


The car is a 76 california car with petronix ignition, no emissions crap, tube header, 292 regrind from IE and it runs pretty good on the 32/36, but feels like it runs out of air at high rpms.  


The 38 will start and I got it to idle, but driving it is terrible. It has power off idle and then immediately falls flat and struggles to rev.

I currently have 142 mains, 185 air correction, and 45 idle jets.  It is idling ok at about 1 3/4 turns out.

I set the float height to 41 and 51mm which made no change.


I ordered some jets, but I feel like it should be running better on the jets that are in there as they seem to be in the right range.


Do I need to get a different fuel pressure regulator? I'm using the mechanical fuel pump and the regulator that was hanging off the 32/36.


I checked for vacuum leaks and couldn't find any.  I tried retarding the timing and that made it run a bit better..


Any ideas?  I'm getting pissed and I might just put the 32/36 back on for now but I've spent 2 days working on this and I'd love to get it working right.




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142 main jet seems really small you should jump up to 155-160 and a 195 air correction also try a 4.0 aux venturri you should be able get all that stuff cheep on ebay

142 main jet seems really small you should jump up to 155-160 and a 195 air correction also try a 4.0 aux venturri you should be able get all that stuff cheep on ebay

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With every solution comes more problems.  The engine is running well, but I blew out my third guibo since getting the car a year ago.  I replaced it again and this time I shimmed the transmission up a bit to try to eliminate the slight angle I had in the drivetrain.  Now my shifter tower rubs on the driveshaft occasionally making a terrible noise.  I lowered the trans halfway back to where it was and I'm still getting a bit of rubbing usually when I shift.  Is this a common problem?  Anyone know what can be done aside from lowering my transmission back down?


Second problem, more worrying, is that at high rpms (over 5000) I'm getting a steady plume of blue smoke.  I rebuilt the head 6 months ago and had no oil burning problems until i overheated it not long ago.  This seems like oil getting past the rings?  I had the head surfaced and used a new head gasket, did I screw something up?


If it is the rings, I probably will just burn oil until the spring when I can commute on the motorcycle and afford to have the car taken apart for a while.  Is it worth the extra $400 for IEs 9.5:1 pistons or should I just re-ring it?  Is there significant performance gains to be had or should I save my money for more guibos  :P

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142 main jet seems really small

I was switching between a 135 and a 140 when I had one on... and that was 'a little lean, a little rich'


Before you tear the motor down, unhook the crankcase vent tube.

If that cures the smoke, then you just need a different way to vent the crankcase.

It needs quite a bit of 'breathing' room- I've made small changes that have lead to puking 

huge quantities of oil from a solid engine...


Try checking the side- to- side on your trans, too.

It makes a big difference in how things flop around.

And a 320i trans mount helps, too.


Finally, guibo quality's been really variable lately, with

some brands being a lot more fragile than they once were.





"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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