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Small block tuning questions...carb, timing, ... #1223988 04/29/12 01:32 AM 04/29/12 01:32 AM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	I've got a 360 in my Dart, with Pertronix ignition, MSD 6AL, mild cam (Comp Cams XE268H), headers, Edelbrock Perfomer intake and Performer Carb (600cfm) ... a couple questions: From what I've heard, the Edelbrock Performer carbs are not the most popular... what would a reasonable alternative be? I'm on a budget, so no $1000 carbs or suggestions to switch to EFI.... Also, what should the timing be set at for this engine?

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1223989 04/29/12 02:24 AM 04/29/12 02:24 AM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	I'd start at 16 initial and about 34-36 total to be safe on pump swill. The carb, though not even close to my favorite, should be pretty snappy. It may require some jetting up or smaller rods in it.

Re: Small block tuning questions...carb, timing, ... [Re: RobX4406] #1223990 04/29/12 02:35 AM 04/29/12 02:35 AM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	OK thanks for the response on the timing.. I was getting a little concerned because the guy who's helping me with it told me that he had it at 36 total.. but when I googled what to use for timing on a 360, I found many responses that said to use around 4-6 degrees ... so I was wondering if he was just way off, or if something else was going on! As far as the carb is concerned.. carbs are voodoo magic to me.. when it comes to needles, jets, etc.. .I'm lost he's having trouble getting it to idle smoothly, and he's a "Holley guy" .. he thinks that there may be a problem in the idle circuit... not sure what's involved in fixing that.. a rebuild kit?

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1223991 04/29/12 03:18 AM 04/29/12 03:18 AM
Joined: Sep 2003 Posts: 1,168 Vancouver, WA MoparMarq super stock
MoparMarq super stock Joined: Sep 2003 Posts: 1,168 Vancouver, WA	Quote: OK thanks for the response on the timing.. I was getting a little concerned because the guy who's helping me with it told me that he had it at 36 total.. but when I googled what to use for timing on a 360, I found many responses that said to use around 4-6 degrees ... so I was wondering if he was just way off, or if something else was going on! Personally, I don't know jack about tuning either, but I suspect that the 4-6 degree number comes from the FSM, at idle, with vacuum line removed from the carb and plugged. The 36 degree number is (and others can correct me if I'm wrong about the vacuum line) when the engine is running at an rpm that allows the mechanical advance in the dist. to fully activate (somewhere between 2000 to 300 rpm) and vacuum (I believe) disconnected and plugged. Quote: As far as the carb is concerned.. carbs are voodoo magic to me.. when it comes to needles, jets, etc.. .I'm lost he's having trouble getting it to idle smoothly, and he's a "Holley guy" .. he thinks that there may be a problem in the idle circuit... not sure what's involved in fixing that.. a rebuild kit? Word is that Eddy carbs are very sensitive to fuel pump pressure (mine states 5.5 psi is ideal). Mine ran rich as all get-out at idle (I couldn't even breathe behind the car, eyes watering, etc.) and no amount of fiddling with idle screws made a bit of difference. Put a regulator (Holley brand ) on it, and already can tell the difference in exhaust CO and engine idle quality. Still not there yet, but yours might be similar issue.

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1223992 04/29/12 03:18 AM 04/29/12 03:18 AM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	IMO, total timing is the rotten and lazy way to time a street driven car. If you want it to be snappy off the bottom, get way more initial/idle timing on it than the factory recommended 4-6. Then limit the mechanical in the distributor to hit your total number. It requires a bit more work, BUT, the resulting idle quality improvement is night and day when done. I'll bet money that the initial timing is too low and causing the idle quality issue. Fixed a bunch of rotten running cars over the years because of just that issue alone. Carb issues that were really rooted in bad timing settings. And eddies are sensitive to fuel pressure as mentioned above. That engine should easily idle at 800rpm and 700 in gear with a little bit of chop to it.

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1223993 04/29/12 08:55 AM 04/29/12 08:55 AM
Joined: Jan 2003 Posts: 11,081 Berlin, N.J. A abodyjoe I Live Here
abodyjoe I Live Here A Joined: Jan 2003 Posts: 11,081 Berlin, N.J.	i agree. 15-17 initial and about 35 total is where that baby is gonna like. that cam should idle like a stocker. may hear the lope when cold but it should smooth out when warm. you'll most likely have to mess around inside the distributor to get the timing right but its well worth it. here are a couple article that should help ya out. It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt. www.MoparMisfits.com

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1223994 04/29/12 10:26 AM 04/29/12 10:26 AM
Joined: May 2005 Posts: 416 Franklin Co. Illinois runinonmt mopar
runinonmt mopar Joined: May 2005 Posts: 416 Franklin Co. Illinois	My Duster is set up quite like your Dart (Comp Cams XE268H, headers, Edelbrock Perfomer intake) with Magnum heads (1.6 rockers) and Mopar electronic ignition. I use a 750CFM Holley 3310-2 I bought on E-Bay for $125. I had to replace the secondary float bowl and float,otherwise it was good and unmodified. Since DaveRS23 had used this on his Son's Scamp we had a place to start. The jets are #68,power valve is 9.5(that's not a typo. If the transition slots aren't uncovered too much there is no vacuum on the PV at idle) the power valve channel restrictions are drilled to .073" (#49 drill). Total investment under $250 including the Quickfuel kit. My initial timing is 16 degrees,total 35 a all in by 2400 RPM. It idles smoothly at 675 RPM. Acceleration is crisp and it pulls like a freight train. For the sake of fuel economy you may want to consider a 650 Holley or depending on your comfort level with the spreadbores a thermoquad. Ron In sixty-five I was seventeen and running up one-o-one I don't know where I'm running now, I'm just running on Jackson Browne-Running On Empty

Re: Small block tuning questions...carb, timing, ... [Re: runinonmt] #1223995 05/02/12 12:25 PM 05/02/12 12:25 PM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	Quote: The jets are #68,power valve is 9.5(that's not a typo. If the transition slots aren't uncovered too much there is no vacuum on the PV at idle) the power valve channel restrictions are drilled to .073" (#49 drill). Thanks.. but this is greek to me! ABodyJoe - those articles are pretty intimidating. Sounds like I need to take the distributor out in order to check how much advance is built into the distributor? Then there's all the options/variables with different springs to control the advance curve? Couldn't I just check the timing at idle, and then check the timing at higher rpm and see what the difference is in order to determine how much advance the distributor is providing?

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1223996 05/02/12 01:21 PM 05/02/12 01:21 PM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	Note the beginning number for advance and rev the engine up until it stops advancing. It may need to go above 4K RPM to get there. Subtract big from small and you have the mechanical advance in the distributor. It's not hard. There are 4 parts to it. Take one at a time. My suggestion. 16 initial, 18 mechanical so you end up with 34 total and have it in by 2500ish RPM (springs). Vacuum (fuel economy) is the 4th part and I never use it. I'm guessing you have a factory Mopar style distributor. They are tougher to limit and curve because you have to tear them all the way down to get at your advance mechanism. It's not hard, just takes time and some welding of slots.

Re: Small block tuning questions...carb, timing, ... [Re: RobX4406] #1223997 05/02/12 01:27 PM 05/02/12 01:27 PM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	Just checked and found that it has a vacuum advance on the distributor... not sure if that affects the process or not.. Anyways.. just pulled the plugs to take a look at them (we were wondering if we had a fouled plug due to it never being driven and only ever getting started for short periods). Here's a photo of the plugs.. they look ok to me .. but I'm no expert. Feel free to let me know if you notice anything.

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1223998 05/02/12 03:52 PM 05/02/12 03:52 PM
Joined: Aug 2003 Posts: 43,284 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,284 Bend,OR USA	What brand and heat range are those plugs? I would look at the idle vacume and see if the carb front metering rods are pulsating up and down in gear, you can do that by loosening the screws that hold the metering rod dooors down(on top of th ecarb. body besides the front venturis ), loosen the screws so you can slide the doors over enough to see the metering rod pistons are dancing up and down in gear or at idle out of gear. If they do you need to either change the springs under the pistons to a weaker set or snip one coil at a time off the stock springs one until the piston will say down at idle in gear. BTW I like to run between 30 and 32 degrees total timing on Mopar SB and I like to set the distributor up by shortening the mechanical advance in the distributor so it has close to 16 degrees(+ or - 3 degrees ) at idle in gear Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Small block tuning questions...carb, timing, ... [Re: Cab_Burge] #1223999 05/02/12 03:57 PM 05/02/12 03:57 PM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	Quote: What brand and heat range are those plugs? I would look at the idle vacume and see if the carb front metering rods are pulsating up and down in gear, you can do that by loosening the screws that hold the metering rod dooors down(on top of th ecarb. body besides the front venturis ), loosen the screws so you can slide the doors over enough to see the metering rod pistons are dancing up and down in gear or at idle out of gear. If they do you need to either change the springs under the pistons to a weaker set or snip one coil at a time off the stock springs one until the piston will say down at idle in gear. BTW I like to run between 30 and 32 degrees total timing on Mopar SB and I like to set the distributor up by shortening the mechanical advance in the distributor so it has close to 16 degrees(+ or - 3 degrees ) at idle in gear OK.. so when it's idling (or in gear), the piston should stay in the "down" position? I'll put the plugs back in and check that either tonight or tomorrow. I don't recall which plugs they are off the top of my head.. I can check them when I get home.. I want to say they're NGK.

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1224000 05/02/12 04:07 PM 05/02/12 04:07 PM
Joined: Feb 2005 Posts: 28,312 Cincinnati, Ohio Challenger 1 Too Many Posts
Challenger 1 Too Many Posts Joined: Feb 2005 Posts: 28,312 Cincinnati, Ohio	That's the best damn pictures I have ever seen of plugs!! They look kind of sooty to me, rich? I hoping I'm not seeing pistons on those porcelains though?

Re: Small block tuning questions...carb, timing, ... [Re: Challenger 1] #1224001 05/02/12 04:18 PM 05/02/12 04:18 PM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	Quote: I hoping I'm not seeing pistons on those porcelains though? Huh?

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1224002 05/02/12 05:48 PM 05/02/12 05:48 PM
Joined: Sep 2011 Posts: 1,487 STL cdstl pro stock
cdstl pro stock Joined: Sep 2011 Posts: 1,487 STL	Quote: Quote: I hoping I'm not seeing pistons on those porcelains though? Huh? Read this: http://www.4secondsflat.com/Spark_plug_reading.html 1972 Cuda 340 4 speed, 2001 Ram CTD 4x4 6 speed, 1970 Duster 408 4 speed, 1996 Ram 5.9 2x4 auto, 1965 Coronet 500

Re: Small block tuning questions...carb, timing, ... [Re: cdstl] #1224003 05/02/12 05:58 PM 05/02/12 05:58 PM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	K... I read that.. but still don't understand what you mean by "pistons on the porcelains" ? Sorry.. I've never had to tune a carbureted engine.. so this is a learning process for me..

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1224004 05/02/12 06:02 PM 05/02/12 06:02 PM
Joined: Sep 2011 Posts: 1,487 STL cdstl pro stock
cdstl pro stock Joined: Sep 2011 Posts: 1,487 STL	Quote: K... I read that.. but still don't understand what you mean by "pistons on the porcelains" ? Sorry.. I've never had to tune a carbureted engine.. so this is a learning process for me.. Reread it towards the end, you missed this part: Shiny little diamond like deposits: It's too late you've already started to blow the pistons out of it. Start over from scratch, fatten the carb, back-up the timing and cool down the plugs. Now start a proper tuning procedure and hopefully you caught it before too much damage was done. 1972 Cuda 340 4 speed, 2001 Ram CTD 4x4 6 speed, 1970 Duster 408 4 speed, 1996 Ram 5.9 2x4 auto, 1965 Coronet 500

Re: Small block tuning questions...carb, timing, ... [Re: cdstl] #1224005 05/02/12 06:36 PM 05/02/12 06:36 PM
Joined: Aug 2003 Posts: 12,589 Sacramento, CA cal_gecko OP I Live Here
cal_gecko OP I Live Here Joined: Aug 2003 Posts: 12,589 Sacramento, CA	Quote: Quote: K... I read that.. but still don't understand what you mean by "pistons on the porcelains" ? Sorry.. I've never had to tune a carbureted engine.. so this is a learning process for me.. Reread it towards the end, you missed this part: Shiny little diamond like deposits: It's too late you've already started to blow the pistons out of it. Start over from scratch, fatten the carb, back-up the timing and cool down the plugs. Now start a proper tuning procedure and hopefully you caught it before too much damage was done. OK.. I saw that, but didn't see any reference to that on my photos.. are you saying there are metal shavings from the pistons on my spark plugs? Yikes

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1224006 05/02/12 06:44 PM 05/02/12 06:44 PM
Joined: Jun 2006 Posts: 5,166 CT GTX MATT master
GTX MATT master Joined: Jun 2006 Posts: 5,166 CT	Yeah, I kind of thought that I saw deposits on the top right picture, not sure which number that was, on my laptop. On another computer I don't see them though. Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street

Re: Small block tuning questions...carb, timing, ... [Re: cal_gecko] #1224007 05/02/12 06:49 PM 05/02/12 06:49 PM
Joined: Feb 2005 Posts: 28,312 Cincinnati, Ohio Challenger 1 Too Many Posts
Challenger 1 Too Many Posts Joined: Feb 2005 Posts: 28,312 Cincinnati, Ohio	Sorry I've been working away from the computer...imagine that. Pre ignition(pinging, knocking) can leave little spots on the porceline.(parts of the piston) But you can't read plugs after they have run for a while. Put some new plugs in it and do a accellation run somewhere and then shut it off and swap plugs in a parking lot somewhere. Then you got something to tune from, 8 fresh plugs that have only been under load once and then shut off before they can be tainted by idling. I think your rich at idling, just guessing? I'd give it more intial timing, which allow you to close down the carb throttle blades some and give you a stronger idle signal and better idle mixture control. BUT make sure you don't have too much overall/total timing so you don't hurt those pistons and rings from pre ignition. Coming out to North Highlands soon to visit family. Last edited by Challenger 1; 05/02/12 06:58 PM.

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