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| Slant rpm https://www.slantsix.org/forum/viewtopic.php?t=4335 |
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| Author: | George [ Sat Oct 26, 2002 10:49 pm ] |
| Post subject: | Slant rpm |
My name is George, I have a 68 dodge dart, 170ci., milled head, 9.8 to 1 mechanical compression, stock valves and ports, mopar 2bbl intake, 318 carter carb (have tried 350 and 500cfm holley 2bbl), new airtex fuel pump, mopar electronic ignition with orange box, the cam is around .450 lift and 220 @.050 duration, new 340 valve springs, 30 degrees total timing, and a header. The problem is that it will not RPM past 4000 no matter how much I try, short of free revving. It does not surge like its running out of fuel, so I am a little lost. Its always been like this and I expected more when I recently installed the camshaft. Any and all help will be greatly appreciated Thanks, George did4nooky@aol.com |
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| Author: | Tim Keith [ Sat Oct 26, 2002 11:18 pm ] |
| Post subject: | Re: Slant rpm |
George, maybe you need to change the axle ratio? Either than, or find a long piece of flat highway. |
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| Author: | Doctor Dodge (Doug Dutra) [ Sun Oct 27, 2002 9:22 am ] |
| Post subject: | Re: Slant rpm & Cam centerline |
Quote:
: My name is George, I have a 68 dodge dart, : 170ci., milled head, 9.8 to 1 mechanical : compression, stock valves and ports, mopar : 2bbl intake, 318 carter carb (have tried 350 : and 500cfm holley 2bbl), new airtex fuel : pump, mopar electronic ignition with orange : box, the cam is around .450 lift and 220 : @.050 duration, new 340 valve springs, 30 : degrees total timing, and a header. The : problem is that it will not RPM past 4000 no : matter how much I try, short of free : revving. It does not surge like its running : out of fuel, so I am a little lost. Its : always been like this and I expected more : when I recently installed the camshaft. : : Any and all help will be greatly appreciated : Thanks, : George How was the cam installed? Did you degree it in or just line-up the dots? What is the installed centerline? Cam phasing on a 170 is important, the shorter stroke engine needs less cam advance if it is going to rev. Here is some info and there is lot's more if you search the messages for degreeing the cam, split overlap degree cam, etc. DD <A HREF="http://www.slantsix.org/cgi-bin/webbbs_config.pl?read=8961">http://www.slantsix.org/cgi-bin/webbbs_config.pl?read=8961</A> Cam Cards |
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| Author: | George [ Sun Oct 27, 2002 3:53 pm ] |
| Post subject: | Re: Slant rpm & Cam centerline |
The was installed 3 degrees advanced. I did degree it in with a degree wheel. I did figure one thing out today I replaced the fuel filter and it was kinda nasty, and gained 500 RPM so maybe there is a fuel problem. I am going to put a fuel pressure guage in the car so I can make sure I have fuel pressuse after the filter at high RPM. Quote:
: : How was the cam installed? Did you degree it in : or just line-up the dots? : What is the installed centerline? : : Cam phasing on a 170 is important, the shorter : stroke engine needs less cam advance if it : is going to rev. : Here is some info and there is lot's more if : you search the messages for degreeing the : cam, split overlap degree cam, etc. : DD : : <A HREF="http://www.slantsix.org/cgi-bin/webbbs_ ... ad=8961</A> did4nooky@aol.com |
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| Author: | George [ Mon Oct 28, 2002 12:26 am ] |
| Post subject: | Re: Slant rpm & Cam centerline |
The cam is installed at 107 degrees, and is ground on a 110. When I installed the fuel pressure gauge I turned it over to see how much fuel was being pumped and it looked very good. The gas tank and sender is new so I have the bad feeling that the rust is from the fuel lines themselves. I have yet to drive it to see about fuel pressure. Could 3 degrees advance be causing my problem? George Quote:
: : How was the cam installed? Did you degree it in : or just line-up the dots? : What is the installed centerline? : : Cam phasing on a 170 is important, the shorter : stroke engine needs less cam advance if it : is going to rev. : Here is some info and there is lot's more if : you search the messages for degreeing the : cam, split overlap degree cam, etc. : DD : : <A HREF="http://www.slantsix.org/cgi-bin/webbbs_ ... ad=8961</A> did4nooky@aol.com |
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| Author: | Al T [ Mon Oct 28, 2002 7:50 am ] |
| Post subject: | Re: Slant rpm & Cam centerline |
Quote:
: I have yet to drive it to see about fuel pressure. . .
Fuel pressure is only half the story because a restricted fuel line can build pressure at lower flow volumes. I think you might be more concerned about testing volume coming thru which is a better indicator of line blockage. While you are looking at the lines, any kinks or sharp bends? An 'oval' cross section of a line on a sharp bend has substandtially less area than a true round. ahtoews@shaw.ca |
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| Author: | bud L. [ Mon Oct 28, 2002 8:47 pm ] |
| Post subject: | Re: Slant rpm & Cam centerline |
Quote:
: The was installed 3 degrees advanced. I did : degree it in with a degree wheel. I did : figure one thing out today I replaced the : fuel filter and it was kinda nasty, and : gained 500 RPM so maybe there is a fuel : problem. I am going to put a fuel pressure : guage in the car so I can make sure I have : fuel pressuse after the filter at high RPM. If there is any kind of crack in the hard line or loose fitting fuel hose on the vacuum side of the fuel pump the pump will have a hard time pulling the fuel from the tank. If you suspect rust in the steel fuel lines, you might try running an old speedo cable(inside) like an auger thru the steel lines. It has worked for me. fglmopar@aol.com |
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