"Bandit" (2bandit)
06/27/2014 at 21:18 • Filed to: Emma
2
15|
"Bandit" (2bandit)
06/27/2014 at 21:18 • Filed to: Emma | 2
| 15 |
For some reason the timing on my engine goes way out when the engine heats up. The car runs great for 1/8th of a mile and by the time the choke opens and engine heats up the engine is really rich, shoots flames out the carb, and won't start. Help?
Jeff-God-of-Biscuits
> Bandit
06/27/2014 at 21:19 |
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Must be the paint job... None of us have seen it so it can't be ruled out!
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Jeff-God-of-Biscuits
> Bandit
06/27/2014 at 21:21 |
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Stuck float in the carb?
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Bandit
> Jeff-God-of-Biscuits
06/27/2014 at 21:24 |
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I doubt it, I just rebuilt the carb and put in a new float.
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Jeff-God-of-Biscuits
> Bandit
06/27/2014 at 21:26 |
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Jetting maybe? running too big a main? Is this a new problem since the rebuild, or did it just start up after it had been running a while?
ZiptieMcBumper
> Bandit
06/27/2014 at 21:32 |
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Off the top of my head:
Fuel could be vaporizing out of bowls when hot (probably not it, but I start with the most easily explained things). EDIT: sorry, didn't read that part about running rich.
Check your amp draw when starting cold vs. hot.
Headers can cause heat soak in the starter. I've heard about people using aftermarket starters, but I don't know a lot about them.
Birddog
> Bandit
06/27/2014 at 21:33 |
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It sounds like your vacuum advance is either malfunctioning or it's not on a timed port. You're too advanced.
Have you tried running it without the vac advance hooked up?
Are you running a Q-Jet?
camaroboy68ss
> Bandit
06/27/2014 at 21:50 |
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The advance on the distributor is not working it sounds like
BrianNutter
> Bandit
06/27/2014 at 21:50 |
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have you physically checked timing before and after? A chrome distributor clamp needs all contacted surfaces to be sanded rough.
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Bandit
> Birddog
06/27/2014 at 22:22 |
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Yes a qjet
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Bandit
> Jeff-God-of-Biscuits
06/27/2014 at 22:23 |
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I've never run this carb before the rebuild. All hardware is stock 78 sizing.
Jedidiah
> Bandit
06/28/2014 at 01:09 |
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If it really is a timing issue, then your vacuum advance could be bad.
Could also be a distributor issue. Did you change the advance weights in it at all?
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Bandit
> Jedidiah
06/28/2014 at 01:13 |
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I haven't really touched the distributor, I got it new a year or so ago.
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Jedidiah
> Bandit
06/28/2014 at 01:20 |
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Is it stock spec or is it aftermarket? You need to put some weights that match factory specs if its aftermarket.
Did you mess with the air/fuel ratio (two screws on the front of qjet on each bank)? On an Oldsmobile (800 cfm version), they should be 4 turns out.
I highly recomend this book if you are going to be working on qjets.
!!! UNKNOWN CONTENT TYPE !!!
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Bandit
> Jedidiah
06/28/2014 at 01:43 |
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I was just given that book! I am around 4 turns out or so.
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Jedidiah
> Bandit
06/28/2014 at 01:57 |
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I just got that book recently. It is the absolute best for Rochesters. They are great carbs; no point swapping them if you know how to set them up.
Does it ping under acceleration or run-on when you shut it off? If you have advanced the timing any, set it back.
Stock cams in an Oldsmobile have 4 degrees of retard built into them. I don't know what it is on a Pontiac, but I wouldn't advance it more than 4 degrees past stock while your testing things.
Set it to about 12 deg BTC at ~1000 rpm or 16 deg at ~800 rpm for testing and see if it clears it up.
Try sucking on the end of your vacuum advance to test if it is bad. Your vacuum advance should be connected to a vacuum tee coming off the carb. Don't run it off of manifold vacuum.
If your choke is sticking; it might mess up the air/fuel ratio and make it run like shit. Make sure the choke plate opens fully.
Are you still running the EGR? If it is malfunctioning, it can mess up your A/F ratio.