I was taking vacuum advance off the carb, and someone told me to set my timing using a vacuum guage. I do have light advance weights on my HEI, yes. Are you using "ported" or "manifold" vacuum to the distributor? "Ported" vacuum allows little or no vacuum to the distributor at idle. I've read a LOT here about people saying (for a variety of reasons) to connect the distributor vacuum advance to manifold vacuum rather than ported vacuum. When I got my RRC with the Chev the local V8 gurus said to get the vacuum from the manifold for ign advance for lpg, rather than the port on the carb above the butterflies, which I have done ever since to get more advance at idle. Lets take a moment to understand vacuum advance together. The Broncos run best with timed/ported vacuum as was mentioned. We know that at WOT we lose almost all vacuum, so the vacuum advance is no longer in play at WOT. It is above the throttle plates and does not have vacuum at idle. Several years ago the line i am using msd 6al box and the intake to a vacuum advance auto parts. The curve should be complete (fully advanced) by 2500 RPM. If you engine will run well with manifold vacuum, great. (duh) But as the engine cranks, it will start to pull vacuum, and if the throttle is closed manifold vacuum will start to pull in advance where the ported won't. Also, in these diagrams "10-20-40" and "10-25-45" indicate FSJ's, while "80" indicates a CJ. Whenever the hell I get mine running, I am planning to hook up the vacuum in the stock configuration, with a ported vacuum switch. A vacuum constriction device (VCD) is an external pump with a band on it that a man with erectile dysfunction can use to get and maintain an erection. I know the fwd 4cyl's aren't the same engine but i think their distributor will work, check for length etc first. if you are using manifold vacuum to the distributor's vacuum advance canister, it is way-over advancing the ignition timing at idle, making it run rough. For the heck of it, I ran a tee-ed hose w/fitting from both carbs to the distributor vacuum advance unit (I thought it would look nice). It is an aftermarket Chevy 350. Find ACCEL HEI Adjustable Vacuum Advance Canisters 31035 and get Free Shipping on Orders Over $99 at Summit Racing! ACCEL adjustable vacuum advance canisters for GM HEI are designed to give you instant horsepower and throttle response. You can also use the Powerfire Distributor Vacuum Advance Lockout kit which allows you to remove the vacuum canister for aesthetic purposes: 1. Dui distributors no vacuum signal at the carburetor must close adequately for a little bit of these cams. Excessive pinging will require a deeper look into your ignition timing and/or mechanical advance rates. c) Use a 5/32” diameter vacuum line from the bottom of the throttle body to the vacuum advance canister on the distributor. Hydraulic and Air clamps,power supplies and fixture accessories designed for all your workholding needs. Some cars did use full manifold vacuum to the distributor, but most don't. With ported there is no advance at idle. Make sure your vacuum is connected to the time port on the carb and not manifold vacuum. I ended up connecting it to ported side and it made driveability much better. I'm at 12* initial, 32* total, about 10* vacuum advance. I may look for a way to the locked out HEI and retard the timing just for starting. If left alone it is preset to run like a stock HEI distributor with vacuum advance. It is designed to work in Mozilla Firefox 6. I recently tried using ported vacuum off the MC2100 carb, and it seems to improve the bottom end power, possibly at the expense of the top revs. the vacuum canisters do come with different springs in them; some heavy some light. It provides maximum spark advance while preventing detonation or "pinging". Ported vacuum may add an off-idle hesitation, as the vacuum advance has to suddenly re-adjust the distributor when the throttle is depressed, and that takes a fraction of a second to happen. Bronco Tech - Archives. And they like the vacuum advance engaged at idle. I have always run my engine ( 350 SBC ) HEI distributor with base timing set at 14 deg at idle with vac advance disconnected, 20 mechanical advance ,with 10 deg of manifold vacuum advance. Ported vacuum hose to manifold vacuum advance below the retard that t on my hand vac to manifold vacuum hose hook your distributor timing. hello everybody, with my vacuum advance plugged, i have my initial timing at 18, then when i hook it back up it goes to 44, i run manifold vacuum for advance, does that seem to high, will that cause idle problems?. Mallory Part # 8548201C Trigger Style - Magnetic Advance Type - Vacuum & Mechanical Cap Style - Male / HEI Gear Material - Steel Ignition Box Required - No Housing Material - Billet Aluminum Housing Finish - Polished Shaft Diameter -. I just checked an old Canadian Service Data Book and it shows spec at 8 BTDC which would be ported. 3 v6 edelbrock performer carb and hei distributor with vacuum advance. What trans do you have????. At this point the port is now connected to manifold vacuum and advance is pulled in. Ported Vacuum vs. If hooked to manifold vacuum, the EGR would remain open whenever the engine is running. Ahhh, this sounds like a conversation we had a short time ago, Ray. Now the timing question. At the center of our modern 289 is a Crane "Retro Roller" camshaft, a special 5. if you are using manifold vacuum to the distributor's vacuum advance canister, it is way-over advancing the ignition timing at idle, making it run rough. There are two types of vacuum sources that you should be aware of. Browse 1500 suburban impala for sale here. It provides maximum spark advance while preventing detonation or "pinging". I believe there is now a turbo specific Safeguard model which can handle vacuum advance. 10 degrees vacuum advance connected to manifold. This setting will produce 32 deg. Should you use Ported Vacuum or Manifold Vacuum?. This port is supposed to be 0 vacuum at idle and increase as you open the throttle (venturi vacuum) to advance the timing on the HEI distributor. Not running any vacuum advance is great for getting the basic timing settings dialed in, but running like that all the time will just cost gas mileage and probably engine life as well. This is the number of degrees of mechanical advance. "Manifold" vacuum allows actual manifold vacuum to the distributor at all times. but with an chevy HEI should i have the vac hose hooked to manifold or ported? i know with my old inline 250 it goes to ported. As far as vacuum advance goes, you want manifold vacuum. Are you using "ported" or "manifold" vacuum to the distributor? "Ported" vacuum allows little or no vacuum to the distributor at idle. Make sure your vacuum is connected to the time port on the carb and not manifold vacuum. Edelbrock is the most respected name in performance. 3 -With vacuum advance still disconnected I moved the gauge to manifold vacuum port and ran the mixture screws in to see what effect they had on vacuum. Ported vacuum hose to manifold vacuum advance below the retard that t on my hand vac to manifold vacuum hose hook your distributor timing. I have a 4 port thermal vacuum switch w/ a 2 blade electrical connector attached on right (pass) side on front of intake manifold. Typically a vacuum advance uses ported vacuum so there is no vacuum present at idle. Small Block Ford, Vacuum, Mechanical Advance. You can also try full manifold vacuum as some have good luck using full vacuum to the distributor. This is a version of emissions control; the ported vacuum allowed carburetor adjustments for a. Here is how I understand vacuum advance, correct me where I am wrong: As rpm's go up, ported vacuum goes up, manifold vacuum goes down. The vacuum advance is preset to 16º. I've always understood that ported was the way to go, but because of this thread and after reading up on it, I'm going to try switching to manifold vacuum for the vacuum advance and see how it goes. Some systems have a special temperature sensor on the engine to switch from ported to manifold vacuum if temps climb too high for this reason. I have had 83 305s and 350s. Glömt ditt lösenord?. I havent mess with timing or anything since I've put new carb on just swapped from ported to full manifold vacuum on distributorwith vacuum (unhooked) got 12 degrees at idle and 35 degrees at 4000rpm. Ok I'm confused about using port or manifold vacuum advance. Noticeable improvement in mileage. Car idles at 34 degrees and runs well. Shaft endplay is shimmed to. Manifold vacuum is the vacuum available in the intake mani-fold. The vacuum advance diaphragm and mechanism should be retained, and repaired if not functioning properly. 0L) and LO5 (5. Ported will give you no advance at idle but will increase the advance as the throttle is opened. Centrifugal or mechanical advance is controlled by engine speed - as engine RPM increases, so does mechanical advance, up to a point. Then I reconnected the vacuum advance. When the unit sees no vacuum, there is no additional vacuum advance. I tried the "Non Ported" vacuum hook up but couldn't get the idle down to where is should have been. I am getting that I should put the vacuum advance into a port on the base of a carburetor? I read that the HEI was actually. Running manifold vacuum to the distributor without the vacuum advance unit adjusted properly for it can cause an unstable engine idle leading to stalling. the vacuum canisters do come with different springs in them; some heavy some light. For example the line from the timed port on the carb goes through two of the switches as it did on the stock manifold to the vac advance. imantly 10 ° of advance. I think the second vac line is to retard the timing, however that line has been disconnected from the christmas tree TVS valves (California has two) and directly connected to the carb. Test drive. Are you using "ported" or "manifold" vacuum to the distributor? "Ported" vacuum allows little or no vacuum to the distributor at idle. It also means less power, lower efficiency, and poorer driveability. In most cases, OEM used ported. BTDC, 36 deg. Manifold vacuum advance canister. The HEI was developed to run with ported vac in order to provide enough advance at heavy airflow to control emissions as mentioned above. The distributor vacuum advance mechanism used on this build was set for use with manifold vacuum and the centrifugal advance was curved for reliance on that source. Wires Features:. A couple that come to mind right away are some of the flat head v8 and the early VWs. If you do use vacuum advance you have two choices - manifold vacuum or a ported vacuum source on the carb which will do the same thing once the throttle is opened. If the EGR is functioning properly, the. Ported Vacuum. As the screws went in idle fell off so I had to adjust the idle linkage screw (which dramatically increased carb "ported" vacuum). The problem is that you have the vacuum line connected to a ported vacuum source on the carb. Didn't know that it increases advance at cruise until I read the above article. Set your motor up at 5 degrees of base timing on ported vacuum then apply port vaccum where vacuum advance is limited to 12 degrees to net a total of 17 degrees of idle timing. For the heck of it, I ran a tee-ed hose w/fitting from both carbs to the distributor vacuum advance unit (I thought it would look nice). Too much initial advance can also make. Remove screws holding. PhilC64 Apr 1, 2007. A lightly loaded engine can tolerate more spark advance than a heavily loaded engine, all else being equal. I've never heard or seen "vacuum advance only started being connected to port vacuum in the pollution control era" but I could be wrong. Going back to factory style, make an offer. The first way is for the car to have the base timing set high with manifold vacuum applied to vacuum advance. 538" and has both a full vacuum and a PCV vacuum port. The PCV is always to full manifold vacuum and should be a large 3/8" diameter port. The carburetor's vacuum advance port does not have vacuum at idle. Two Types of Vacuum. Then I reconnected the vacuum advance. This is why the OEM's always connected it to ported vacuum. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. As the screws went in idle fell off so I had to adjust the idle linkage screw (which dramatically increased carb "ported" vacuum). These steps will set the vacuum advance degrees up correctly to use full manifold vacuum, instead of the incorrect ported vacuum sourcing. During a recent internet search, I found dual-point, light beam, HEI, Hall-effect, and magnetic pick-up types. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15. Going to replace choke stat and recheck vacuum break adjustment. I figure some vacuum signal to the advance was being lost when the idle dropped when placed in gear with manifold vacuum. Wires Features:. Single Path SAE Ported/Manifold. It is an aftermarket Chevy 350. Hooking it up to manifold vacuum can over-advance the ignition and make it kick back at the starter in extreme examples. It had the 90's Holley FI system, which I replaced with a Demon 625 new carb and GM HEI. They are about as stout as the 8. 350 backfires through carb Hope somebody can help!Just rebuilt a 1972 chevy 350 with a new crankshaft,edelbrock torquer plus cam,torker manifold,holley carb, Money Making - Chevy 350 TBI - HEI Distributor Problem - Aftermarket Junk Distributor! - howto-make. If the EGR is functioning properly, the. I recently tried using ported vacuum off the MC2100 carb, and it seems to improve the bottom end power, possibly at the expense of the top revs. As for ported vs manifold vacuum, definately go with ported for vacuum advance. A vacuum pancake can increase Total Advance to as much as 60°! If under load, we start to hear engine knock, most vacuum pancakes have a set screw adjustment inside the vacuum port. One immediately obvious change was an increase in idle speed; I had to back off the idle speed screw. There is two ways to set up the vacuum advance which will effect the performance of this car tremendously. Timing Should be Set @ 32° Total @ 3,000 RPM With Vacuum Advance Disconnected. The Kit is supplied with Vacuum Advance Limiter, Blue Bushing and mounting screws. The best prices on 1500 suburban impala and other similar items. I am using manifold vacuum so it advances the timing at idle. Low manifold applications can run a vacuum advance to a timed port for cruise benefit but it will have zero affect at idle. ChevelleStuff. There are two types of vacuum sources that you should be aware of. Maybe GM thought that idle quality (always a problem on FI engines) would be better with ported vacuum advance, but it wasn't, and the '64-'64 FI engines got full manifold vacuum advance. Vacuum advance connected to manifold vacuum port, not ported port. I want to hook it up for better mpg. Set your motor up at 5 degrees of base timing on ported vacuum then apply port vaccum where vacuum advance is limited to 12 degrees to net a total of 17 degrees of idle timing. They also say the vacuum advance for the distributor needs to be connected to ported vacuum. Larger initial advance numbers produce a slightly more fuel efficient idle, but may make the idle unstable and result in higher emissions (this is why most engines use the no vacuum advance at idle). PART# 84281 Be the first to write a review. Gentlemen, Below are my thoughts only as I do not wish to get into the ported/manifold vacuum debate/argument-IMO Jbrake57 POSTED-" i have a 1957 f600 with the original 272 stock motor (rebuilt) and i put an hei distributor on it a buddy had one new and he gave it to me. dmhines, Apr 27, 2005. Seems to me that if you are using the U. And they like the vacuum advance engaged at idle. The top bushing was sloppy and you couldn't set the pickup gap right. So it’s just a matter of experimenting. These steps will set the vacuum advance degrees up correctly to use full manifold vacuum, instead of the incorrect ported vacuum sourcing. Turning it in (clockwise) will shorten the stroke, which limits the advance. Looking to buy Straight 6 Engine? We feature a huge array of straight 6 engine and other relevant listings. In an engine that does not have an EGR valve, combustion chamber temps want to be high, but not to detonation levels, as EGR engines are. if you are using manifold vacuum to the distributor's vacuum advance canister, it is way-over advancing the ignition timing at idle, making it run rough. You will probably need to drill the primary throttle blades so you can get your curb idle in the lower 1/3rd of the transfer slot travel. Ok I'm confused about using port or manifold vacuum advance. I believe there is now a turbo specific Safeguard model which can handle vacuum advance. Buy right now. When the unit sees no vacuum, there is no additional vacuum advance. There are two main sources of vacuum. I prefer ported vacuum for vacuum advances and try to limit them to 50 degrees total (this includes initial and centrifugal advance). usually in the back or front of the Carb. If it's possible (yea, "feasible") to use a vacuum advance for cruising, yet have the vacuum signal DIE instantly, as soon as the throttle blades open, I'd like to try it. WEBER carburetors do not have an effective ported vacuum fitting and do not work well with vacuum advance type ignition distributors. Super burly and only 8mm. Even if your car's vacuum advance is working properly and holding negative pressure, there could still be a problem with the vacuum signal itself. your vacuum advance should hook to the outlet on the carb that sucks when you rev the engine, not to one that sucks at a idle. 10° initial timing at idle should provide this total. 10 degrees vacuum advance connected to manifold. On pre HEI cars, the vacuum. Do I take it off of the base of the carb or the manifold port? It is a 350 with sportsman II heads, edelbrock performer series cam and manifold and carb. One of these band-aids was "ported. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15. As for trying ported or manifold vacuum. WEBER carburetors do not have an effective ported vacuum fitting and do not work well with vacuum advance type ignition distributors. On my Impala's old setup, fuelie heads and Comp XE274 cam, I had the vacuum advance connected to manifold vacuum and it wouldn't idle. They used ported advance exclusively, no mechanical advance at all. Includes: vacuum canister with unique adjustable vacuum diaphragm, three sets of advance weight springs, 3/32" Allen wrench, and instructions. Vacuum advance timing uses a manifold vacuum that reacts to the rotation of a position sensor mounting plate located in the distributor. If you engine will run well with manifold vacuum, great. Maybe GM thought that idle quality (always a problem on FI engines) would be better with ported vacuum advance, but it wasn't, and the '64-'64 FI engines got full manifold vacuum advance. HEI Vacuum Advance question. manifold vacuum is the right way. Super burly and only 8mm. install the vacuum advance to the port that is signaled or right above the throttle plate. This is with the idle screw backed all the way out and I verified the pedal is not hanging it up. When your turbo/supercharger beings to produce positive manifold pressure (boost) the vacuum advance immediately. Most of the adapted carbs below will also have a ported vacuum port available. When I pull the ported line off the vacuum advance canister (I'm 100% sure it's the ported line) I can feel vacuum and the idle will drop to 1000 RPM with it unhooked - can still feel vacuum at 1000 RPM. Right now you only need advance. Connecting the hose directly from the carburetor’s spark advance port to the distributor’s vacuum advance will make things noticeably more sprightly in part-throttle driving. This car has a Carter BBS carburetor, a 1976 distributor (the one for the 2bbl engine, with the good advance curves), and no EGR. Re: Nutter Bypass and Vacuum Lines I'll be glad to offer a fair and to the best of my ability an accurate reply to any questions that you have. This kit includes an allen wrench for easy adjustment along with instructions. It also means less power, lower efficiency, and poorer driveability. manifold vacuum source, but all the other vehicles that I've own/owned had use ported vacuum. I'm going to replace the brake booster, it's hissing audibly, as it turns out. Check this out, I love this little gem. After you get your Timing set, what is preferred, ported or manifold. Do I take it off of the base of the carb or the manifold port? It is a 350 with sportsman II heads, edelbrock performer series cam and manifold and carb. Using a ported spark advance will still allow the vacuum advance to do its job at steady cruising, but all of the benefits of idle cooling will be lost. It hooks to a vacuum port on the intake manifold behind the carb. It provides vacuum at all times when you are at no or little load which is what you want. Ok I'm confused about using port or manifold vacuum advance. Some people think manifold vacuum is ok because their car pings on ported but does not when hooked to manifoldthe reason is they are now using their vacuum advance as a vacuum retard so to speak and need to recurve the distributor or back off initial timing to get the proper overall advance curve. A vacuum pancake can increase Total Advance to as much as 60°! If under load, we start to hear engine knock, most vacuum pancakes have a set screw adjustment inside the vacuum port. Are you using ported or manifold vacuum to the distributor? Ported vacuum allows little or no vacuum to the distributor at idle. In the mechanical advance, the timing is done by the engine RPM, however in the vacuum advance the timing is instantaneous, as it senses the changes in the engine load at idle. Air valve vacuum The vacuum that. I know that it is not a head gasket I see no water in the oil, and I think if it were a bad head gasket it would run like crap. The selection of vacuum advance units for Ford and Chrysler is somewhat more limited, but. Re: 258 w/ HEI, vacuum advance issue? I don't know alot about HEI systems, but from what I understand they came in four, five and seven pin configurations. The best prices on 1500 suburban impala and other similar items. They used ported advance exclusively, no mechanical advance at all. Do I take it off of the base of the carb or the manifold port? It is a 350 with sportsman II heads, edelbrock performer series cam and manifold and carb. Maybe GM thought that idle quality (always a problem on FI engines) would be better with ported vacuum advance, but it wasn't, and the '64-'64 FI engines got full manifold vacuum advance. Mallory Part # 8548201C Trigger Style - Magnetic Advance Type - Vacuum & Mechanical Cap Style - Male / HEI Gear Material - Steel Ignition Box Required - No Housing Material - Billet Aluminum Housing Finish - Polished Shaft Diameter -. Just changed it from a vacuum advance. As for trying ported or manifold vacuum. idle advance: In MegaSquirt-II™ (or MicroSquirt ®), this is the advance at the idle rpm and MAP value. These steps will set the vacuum advance degrees up correctly to use full manifold vacuum, instead of the incorrect ported vacuum sourcing. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15. Engine without air cleaner. hero’s car didn’t have vacuum advance, that a street-driven car didn’t need one either. Set spark timing at 32 deg. For the heck of it, I ran a tee-ed hose w/fitting from both carbs to the distributor vacuum advance unit (I thought it would look nice). Vacuum advance. Using a ported spark advance will still allow the vacuum advance to do its job at steady cruising, but all of the benefits of idle cooling will be lost. As the name implies, vacuum advance works solely on a manifold vacuum and with the line capped, no vacuum is acting on the advance mechanism. If the timing curve required to match the changes with rpm can be achieved mechanically, then using ported reserves vacuum advance for lower density conditions. So I decided to try an experiment on my '73. This setting will produce 32º of total advance at wide open throttle. imantly 10 ° of advance. 1964 PLYMOUTH 1964 VACUUM ADVANCE V8. Rich woman looking for older woman & younger woman. Are these 4GCs supposed to have ported or manifold vacuum , mine has manifold vacuum, a little over 21 lbs of vacuum at idle hit the throttle vacuum drops off. Using manifold vacuum advance will add 10-20º of extra advance at idle and the engine speeds up a lot. d) On the left side of the base manifold (on factory TPI and ACCEL base manifold) a barbed fitting is located. For me, I found that ported vacuum works best with the motorcraft carb and hei distributor. 351C 4v with dual diaphragm distributor, distributor deceleration valve, and manifold vacuum; 351C 4v with dual diaphragm distributor, distributor vacuum deceleration valve, NASA Ram Air, and ported vacuum; 351C 4V with dual diaphragm distributor, distributor vacuum deceleration valve, Ram Air, and ported vacuum. It comes off the venturi above the throttle plates and is effectively isolated by the throttle plates from manifold vacuum, more specifically the throttle shaft as the defining point much like an expansion valve in a refrigeration circuit. The vacuum advance in this setup actually will trail off as vacuum pressure goes low and will increase advance as vacuum pressure, in the manifold, increases. Most carburetors have both ports. They switched the distributor over to a ported vacuum. The small one on the passenger side in the metering block is called ported vacuum. This is non-ported vacuum (it has vacuum all the time) - this is not appropriate for the vacuum advance. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15. The vacuum advance is preset to 16º. Otherwise you may get a loping idle. M4me quadrajet, today's hookup my. The HEI was developed to run with ported vac in order to provide enough advance at heavy airflow to control emissions as mentioned above. Yes, to start with I would hook up vacuum advance to full time vacuum and see how it idles and runs. Same question is, or a vacuum advance distributor cap, trucks suvs with vacuum. Hi all parts and road test. BTDC, 36 deg. However, I realized that my vac advance is plugged into Manifold vacuum (the port is located in the same place as the ported vacuum on a BBD, I made an assumption and put it in the wrong place, and didn't realize until yesterday. With this setup, vacuum is lowest at idle and it increases as the throttle is opened (completely opposite to manifold vacuum). In the vast majority of cases, the manifold may be installed without modifications, since the runner openings at he head flanges are already matched to all but the largest possible head flanges are already matched to all the largest possible head port openings. Vacuum advance’s purpose is to compensate for and engine’s LOAD. Vacuum advance; If this is your There should be a ported vacuum port on the right (passenger) side of the carb, toward the front and top. remove or bypass the resistor in the wiring harness to ensure the HEI receives 12 volts continuously. cruise rpm, the vacuum advance unit can only be allowed to pull in 16 more degrees of advance. 1966 Pony Welcome! This is a blog about my 1966 Ford Mustang. I may look for a way to the locked out HEI and retard the timing just for starting. Whenever the hell I get mine running, I am planning to hook up the vacuum in the stock configuration, with a ported vacuum switch. If you don't feel any vacuum pulling at your finger with the engine at an idle, you have timed/ported vacuum advance. They used ported advance exclusively, no mechanical advance at all. At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15. Is your carb stock, do you have a cto that switches between ported and manifold vacuum, if not which is feeding the advance? If the old distributor advanced ok then it is likely a bad advance module or a tooth off. I am pretty sure its not the cooling system 175 temp and a new water pump rad has been re-cored. The crane limiter plate, do not install it like crane says in their instructions. You can also try full manifold vacuum as some have good luck using full vacuum to the distributor. Sometimes with manifold you will get a slight sputter or bog when the vacuum advance drops out as the throttle is suuddenly opened. As you floor the engine while driving you loose vacuum and ignition advance which prevents detonation. I've never heard or seen "vacuum advance only started being connected to port vacuum in the pollution control era" but I could be wrong. Both ported and manifold vacuum will start with no vacuum advance, because there is no vacuum when the engine is not running. A properly curved distributor with vacuum advance hooked to a ported vacuum source will work just fine. Test drive. There are two types of vacuum sources that you should be aware of. Vacuum advance distributor hook up Click here about this distributor is for their distributors have a ported or retard the hei distributor ford 289-302 blue. 3 -With vacuum advance still disconnected I moved the gauge to manifold vacuum port and ran the mixture screws in to see what effect they had on vacuum. Glömt ditt lösenord?. Ported vacuum delays the advance so it's not really giving any advance at idle, but starts advance as the vacuum comes up. I have some vacuum leaks, for sure. Not running any vacuum advance is great for getting the basic timing settings dialed in, but running like that all the time will just cost gas mileage and probably engine life as well. This is different from the included instructions. The Edelbrock 2101 Performer intake manifold is the right intake for torque applications, towing and low rpm performance. I finally finished installing my Langdon HEI today and fired it up this afternoon. I was taking vacuum advance off the carb, and someone told me to set my timing using a vacuum guage. advance will cause severe detonation but at full throttle, ported vacuum drops to zero (or very nearly so) as does manifold vacuum, so vacuum advance goes away and timing advance drops to 30 deg. I prefer ported vacuum for vacuum advances and try to limit them to 50 degrees total (this includes initial and centrifugal advance). For me, I found that ported vacuum works best with the motorcraft carb and hei distributor. See our vacuum ports. big difference with this set up vs stock. imantly 10 ° of advance. I tried the "Non Ported" vacuum hook up but couldn't get the idle down to where is should have been. It is an aftermarket Chevy 350. There are two main sources of vacuum. What happens when you disconnect and plug both vacuum sources? Most carbs have a vacuum port not familiar with the area bbs but if it is a stock carb mounted on a stock single carb intake it should have a vacuum port. Running manifold vacuum, the loss of advance when the throttle plates first open resulted in a bog and loss of power. Secondly, Once an engine gets below 8# of vacuum it's increasingly difficult to run a vacuum advance due to rough idle and low vacuum make it difficult to activate the canister. 1964 PLYMOUTH 1964 VACUUM ADVANCE V8. The carburetor's vacuum advance port does not have vacuum at idle. Try manifold vacuum and ported vacuum, use whichever one works best. The small one on the front is called manifold vacuum. Ported Vacuum. Going back to factory style, make an offer. When it comes to your Ford F-100, you want parts and products from only trusted brands. Both single diaphragm (with one vacuum port) and dual diaphragm (with two vacuum ports) advances were used depending on the type of transmission installed in the car. usually in the back or front of the Carb. It comes off the venturi above the throttle plates and is effectively isolated by the throttle plates from manifold vacuum, more specifically the throttle shaft as the defining point much like an expansion valve in a refrigeration circuit. I havent mess with timing or anything since I've put new carb on just swapped from ported to full manifold vacuum on distributorwith vacuum (unhooked) got 12 degrees at idle and 35 degrees at 4000rpm. Dui distributors no vacuum signal at the carburetor must close adequately for a little bit of these cams. Manifold vacuum is a direct connection to the intake manifold, and if the hose is connected to this port, you will have full vacuum in the line at idle. Ported vacuum Ported vacuum is just above the throttle plates and its reading is only about 1 inch of mercury with the plates closed and very close to manifold when the plates open. As the throttle opens during higher engine loads, the vacuum diminishes, enabling the timing advance to move back to the base, or original advance. Please remember, large cap HEI were designed for emissions use, not performance, and ported vacuum advance worked with an emissions engine that uses an EGR (Exhaust Gas Recirculation) valve only. With ported there is no advance at idle. The stock HEI uses a vacuum advance canister to further tailor the ignition timing. Chrysler used it with ported vacuum. The selection of vacuum advance units for Ford and Chrysler is somewhat more limited, but. Don't be baffled by the vacuum advance on your Pontiac. Manifold vacuum is lowest during acceleration and ZERO during WOTbut ported vacuum is zero at idle and increases with RPM because it is created by air rushing through the venturi of the carburetor and during acceleration the volume of air going through the venturi and it's speed is increasing thus making ported/venturi vacuum highest under conditions when manifold vacuum is lowest or zero. I tried the "Non Ported" vacuum hook up but couldn't get the idle down to where is should have been. Left it there for a couple of weeks to get a good, solid idea of the changes. There should be a vacuum line connected from the carb, or the manifold, to the vacuum canister. All engines should have vacuum advance connected to full manifold vacuum.
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