vacuum retard
06-04-2005, 04:39 PM
#11
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RE: vacuum retard
You are close.
Vacuum advance controls timing relative to the "load" on the engine. A less dense mixture (no load like idle or cruising down the freeway) burns at a different rate than a dense mixture (romping down on it for quick acceleration or climbing a grade). That is why we need vacuum advance.
*******EDIT******* (sorry man, meant to put in the vacuum retard)
YOu are very close on this. Depending on the eingine load and temperature, vacuum retard will retard the timing enough so that the entire fuel charge isn't burned, thereby cooling the combustion chamber and reducing NOx (which really is bad by the way)
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Centrifugal advance controls timing based on RPM. Given a specific burn speed of the air/fuel mixture inside the combustion chamber, you need to light it off sooner if the RPMs are higher, because the piston is physically moving faster. Like if someone is walking by you and you want to say hello, you would start your conversation later then if someone was running by you.
If you are keeping everything stock then I would dial in the distributor as it was meant to be (to include the vacuum retard). The whole engine is designed as a package to work in unison. That means the cam, head chambers, exhaust, carburetion, intake manifold, ignition needs each other to be in optimum adjustment to perform to it's best.
If you are changing things like intake, exhaust, carburetion, cam, etc. then you want to look at it as a whole package. Just like the original engineers did. You may find that for what you are doing a complete distributor change is required. The absolute best thing you can do is find a local dyno shop. Stop by and spend a little time picking their brains and then get your car on down there, once you get it close. Not only is it way fun, but man do you ever learn a lot! These guys are really good, and you can literally see what effects what.
HTH,
Vacuum advance controls timing relative to the "load" on the engine. A less dense mixture (no load like idle or cruising down the freeway) burns at a different rate than a dense mixture (romping down on it for quick acceleration or climbing a grade). That is why we need vacuum advance.
*******EDIT******* (sorry man, meant to put in the vacuum retard)
YOu are very close on this. Depending on the eingine load and temperature, vacuum retard will retard the timing enough so that the entire fuel charge isn't burned, thereby cooling the combustion chamber and reducing NOx (which really is bad by the way)
************************************************** ****************
Centrifugal advance controls timing based on RPM. Given a specific burn speed of the air/fuel mixture inside the combustion chamber, you need to light it off sooner if the RPMs are higher, because the piston is physically moving faster. Like if someone is walking by you and you want to say hello, you would start your conversation later then if someone was running by you.
If you are keeping everything stock then I would dial in the distributor as it was meant to be (to include the vacuum retard). The whole engine is designed as a package to work in unison. That means the cam, head chambers, exhaust, carburetion, intake manifold, ignition needs each other to be in optimum adjustment to perform to it's best.
If you are changing things like intake, exhaust, carburetion, cam, etc. then you want to look at it as a whole package. Just like the original engineers did. You may find that for what you are doing a complete distributor change is required. The absolute best thing you can do is find a local dyno shop. Stop by and spend a little time picking their brains and then get your car on down there, once you get it close. Not only is it way fun, but man do you ever learn a lot! These guys are really good, and you can literally see what effects what.
HTH,
06-04-2005, 06:40 PM
#13
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RE: vacuum retard
ORIGINAL: Soaring
Yep. Very good infomation Scott. But I think this is just a tad over the head of the original poster. She basically needs to know how to hook up her vacuum line from the intake to the distributor.
Yep. Very good infomation Scott. But I think this is just a tad over the head of the original poster. She basically needs to know how to hook up her vacuum line from the intake to the distributor.
Man, I almost miss having a mechanic for a boyfriend.
06-05-2005, 01:25 PM
#14
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RE: vacuum retard
Yeah, to get the system back up to par, you would have to pull the distributor, etc. Most likely your mechanical skills are not there yet. It won't hurt it to drive it like it is, it will just not be as efficient an engine without it.
06-05-2005, 08:35 PM
#15
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RE: vacuum retard
ORIGINAL: angelsmith00
SO my vacuum retard is not needed? And should I check to see if my vacuum advance works?
I guess I'm just conufsed because my question was about vacuum retard and until Scott H. here, you all talked about vacuum advance.
Lemme see if I've got this on a baisic level.... Vacuum advance adjusts spark timing at higer RPMs, while vacuum retard sets the spark timing back to normal for emissions purposes?
SO my vacuum retard is not needed? And should I check to see if my vacuum advance works?
I guess I'm just conufsed because my question was about vacuum retard and until Scott H. here, you all talked about vacuum advance.
Lemme see if I've got this on a baisic level.... Vacuum advance adjusts spark timing at higer RPMs, while vacuum retard sets the spark timing back to normal for emissions purposes?
Depending on the year of your car, you probably don't even need the vacuum retard. It's something that's put on a lot of rebuilt distributors because they fit a large range of years and vehicles. Can you post a pic of the engine compartment of your car? Then we could tell you what needs to be where. Just an attempt to help
06-05-2005, 11:45 PM
#16
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RE: vacuum retard
pics of my engine... I think I did it right.
[IMG]local://upfiles/16347/98835F54E52F49B38E0ECC881270B56E.jpg[/IMG]
[IMG]local://upfiles/16347/B786343A9688416DB7EE529DCD50F845.jpg[/IMG]
[IMG]local://upfiles/16347/98835F54E52F49B38E0ECC881270B56E.jpg[/IMG]
[IMG]local://upfiles/16347/B786343A9688416DB7EE529DCD50F845.jpg[/IMG]
06-06-2005, 06:55 PM
#17
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Join Date: Feb 2005
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RE: vacuum retard
That looks like it's hooked up right, in fact, I don't see a provision for vacuum retard. What year is this stang? I noticed the EGR stuff is dn'd too, not like you need it anyway. If you want to test the vacuum advance, all you have to do is unplug it from the carb and suck on the end. If you can keep sucking then it's bad. If it builds vacuum and holds it, it's ok. You may also want to check the ends of the hose and make sure they're not loose, cracked, or brittle. If that's the case you can either replace it for about $2 or just clip an inch off each end if it's long enough. That's an exceptionally clean engine bay for a daily driver, great job!
So when are ya swapping in that V8?
So when are ya swapping in that V8?
06-07-2005, 12:43 AM
#18
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RE: vacuum retard
ORIGINAL: TBIAgent69
That looks like it's hooked up right, in fact, I don't see a provision for vacuum retard. What year is this stang? I noticed the EGR stuff is dn'd too, not like you need it anyway. If you want to test the vacuum advance, all you have to do is unplug it from the carb and suck on the end. If you can keep sucking then it's bad. If it builds vacuum and holds it, it's ok. You may also want to check the ends of the hose and make sure they're not loose, cracked, or brittle. If that's the case you can either replace it for about $2 or just clip an inch off each end if it's long enough. That's an exceptionally clean engine bay for a daily driver, great job!
So when are ya swapping in that V8?
That looks like it's hooked up right, in fact, I don't see a provision for vacuum retard. What year is this stang? I noticed the EGR stuff is dn'd too, not like you need it anyway. If you want to test the vacuum advance, all you have to do is unplug it from the carb and suck on the end. If you can keep sucking then it's bad. If it builds vacuum and holds it, it's ok. You may also want to check the ends of the hose and make sure they're not loose, cracked, or brittle. If that's the case you can either replace it for about $2 or just clip an inch off each end if it's long enough. That's an exceptionally clean engine bay for a daily driver, great job!
So when are ya swapping in that V8?
I was also wondering what the three little prongs in front of the radiator are for? It seems like the should be connected to something. is that the EGR you that was talked about?
06-07-2005, 01:52 AM
#19
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RE: vacuum retard
Wow!
I bought my 6 strictly because I am planning a V8 swap. My reasoning is that if I wanted a V8 mustang just like everyone else, I'd buy a V8 to start with.
But seeing as I'm looking more to old school looks with modern performance and convenience, I would have replaced most of what came in a V8 car anyways.
By picking up the 6 cylinder, I saved about $6K, I'm not messing with an "A" or "C" or "K" code car, and I can replace whatever I want without feeling like I've cheated on somebody
Bottom line, it's your money. Do what you want. Not what others tell you to do. Gees, next they'll have us all dressed in leather, riding Harleys and copping attitudes... oh wait there goes an accountant on one now
Your car would be sweet with a little 400Hp V8, AOD with a slap stick (for when the boyfreind isn't close enough to hit) Some nasty meats all around, and a kick butt audio/video/game system.
So what do you really want to do with Lucy?
BTW: that three prong dealy is a thermal vacuum switch. Probably runs the egr and if you've got it, vacuum retard (i'm not familiar enough with the 68). You're right it should be hooked up...if you wanted to be just like everybody else.
I bought my 6 strictly because I am planning a V8 swap. My reasoning is that if I wanted a V8 mustang just like everyone else, I'd buy a V8 to start with.
But seeing as I'm looking more to old school looks with modern performance and convenience, I would have replaced most of what came in a V8 car anyways.
By picking up the 6 cylinder, I saved about $6K, I'm not messing with an "A" or "C" or "K" code car, and I can replace whatever I want without feeling like I've cheated on somebody
Bottom line, it's your money. Do what you want. Not what others tell you to do. Gees, next they'll have us all dressed in leather, riding Harleys and copping attitudes... oh wait there goes an accountant on one now
Your car would be sweet with a little 400Hp V8, AOD with a slap stick (for when the boyfreind isn't close enough to hit) Some nasty meats all around, and a kick butt audio/video/game system.
So what do you really want to do with Lucy?
BTW: that three prong dealy is a thermal vacuum switch. Probably runs the egr and if you've got it, vacuum retard (i'm not familiar enough with the 68). You're right it should be hooked up...if you wanted to be just like everybody else.
06-07-2005, 06:36 PM
#20
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Join Date: Feb 2005
Posts: 120
RE: vacuum retard
I agree with what Scott H says, Lucy can be anything you want her to be. These cars are so freakin easy to work on it practically does itself (compared to new cars, and infinitely more so to 80's cars). That vacuum switch (3 pronged joker on your thermostat housing) is just for emissions crap... if your car runs fine without it then don't worry about it. A V8 swap is very, very easy to accomplish although a "proper" V8 swap is more involving. What I mean to say is that a lot of people will think it mandatory go run a 5 lug bolt pattern, upgrade the breaks, and change out the rear end. If you're swapping just the engine and transmission (not necessary if it's an auto) it can be done by a somewhat skilled do it yourselfer in a few hours as long as you have all the parts. I'd really reccomend picking up a Mustang Monthly and calling all the stores in it and ask for a catalog. Then you'll see exactly what's available for your pony.