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| Car seems to bottom out. https://slantsix.org/forum/viewtopic.php?t=48526 |
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| Author: | Brussell [ Fri Apr 13, 2012 6:42 pm ] |
| Post subject: | Car seems to bottom out. |
Hi, I have a 225 in my 67 valiant. If I put my foot down the car will get to 2800rpm, put it down a little more and the car just doesn't go past that. Should I put my foot to the floor? or what could be causing this. 350 holley, 2.5" exhaust with pacemaker headders, new ignition system, msd blaster coil, Apparently it's had a port and polish job, says the local mechanic (Not convinced of this). Is this me being overly cautious and I should just plant my foot? (This is after it's warmed up btw). or is this just because the motor is old? etc Thanks! |
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| Author: | ceej [ Fri Apr 13, 2012 7:14 pm ] |
| Post subject: | |
How is the carb set up? What Power Valve? Do you know your cruise vacuum, and do you know your idle vacuum? (Idle in gear if Automatic.) Does the carburetor have the original metering block? Air bleeds differ and will determine how much fuel flows as compared to air flow through the carburetor. There will be a number stamped into the metering block. How is your accelerator pump set up? Pump cam color and shooter number? Sometimes you will need to remove the pump cam to tell what color it was. There are two screw holes in the pump cam, note which one is used. Have you mapped your timing curve? CJ |
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| Author: | Brussell [ Fri Apr 13, 2012 7:24 pm ] |
| Post subject: | |
Carb was bought online, I said the application was for a 225. So I don't know any of that. I don't have access to a vacc gauge for a while money is tight. Following your train of thought I'm thinking you mean that at 2800 rpm and beyond the correct air/fuel ratio isn't getting through? I'll check for vac leaks. And no I haven't mapped the timing curve, something I need to do. I have never done a distributor re curve etc. Thanks! |
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| Author: | ceej [ Fri Apr 13, 2012 7:42 pm ] |
| Post subject: | |
This was a new carb? If so, it probably came with a 6.5 PV. Check this prior to buying anything. The number may be hard to decipher. There will be a 6 and a 5 somewhere on the PV. It's not together. You can try a patch by bumping the number up. Chances are, your not getting to the power valve early enough. The 6.5 starts to enrich the circuit at about 6.5 inches of mercury. (HG) Try something in an 8.5 to start out. If that doesn't do it, bump up to a 9.5 and so forth. You cap out at 10.5" HG with high flow power valves. There are dual range PV's that go to 12.5" HG, but are expensive, and likely won't perform well. Not enough fuel flow for the application. If it performs well with the 8.5"HG Power valve, you can work the other way. Try a 7.5 to see if the car works well. If it does, this will help to maintain cruise economy better. I think you'll end up around 9.5 personally, but that's dependent on cam selection and so forth. With an OEM or mild build it's likely. While you have the metering block off to check the PV, check the main jet sizes, and report back here with what size PV and jets are in there.Check the number on the metering block, and so forth. Let us know what's in there prior to ordering parts. Double check float level any time you pull the fuel bowl off, and be careful that the accelerator pump linkage is correct when you reinstall. When reinstalled, double check the accelerator pump clearance. This is critical to avoid pump diaphram damage. CJ |
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