manifold vaccum for vaccum advance ?'s

[Bulldozer]

Google it and you should find a You Tube video that will show you step by step.

times 2 man, there are a bunch of videos , step by step

 

[pjc360]

i dont have a leak down tester, but i do have a compression tester. Acouple of my friends work at mechanic shops, i will talk to them about doing a leak down test and a compression test, depending on how much they wanna charge me to do it i may just let a shop do it.
If the trouble is in the cylinder heads, would it be cheaper to have a shop pull the cylinder heads fix whatever it is and then put the cylinder heads back on, or would i be better of just getting new cylinder heads?

 

[pjc360]

I'm thinking the piston rings are fine , because i had an old LA 318 that had real bad piston rings and everytime i fired that thing up blue smoke would come flying out the exhaust and blue smoke would be coming out the exhaust while the engine was at an idle.
My 360 magnum does not do that, it only has the smoke coming out the exhaust when i'm driving it relatively hard and i back off the throttle real quick. It seems strange to me that when the truck is in park and i run it up to 4000 rpm and back off the throttle no smoke comes out the exhaust, but smoke comes out the exhaust when i'm driving it? whats the difference there? is there more vaccum present when i'm driving vs being in park? And is it valve guides or valve seals that let the oil thru when you back off the throttle?

 

[TrailBeast]

BTW a miss will cause the engine to smoke, and more after deceleration.

Dammit, I said I wasn't having anything to do with this thread and now you guys made me.

 

[Oklacarcollecto]

BTW a miss will cause the engine to smoke, and more after deceleration.

Dammit, I said I wasn't having anything to do with this thread and now you guys made me.

I said that too and now look....... :banghead::banghead:

 

[pjc360]

ok, i'm taking it to a shop then because i dont know how in the hell this engine could possibly have a miss?? Brnad new distributer curved and phased. Brand new cap and rotor brass contacts. Plug wires are fiarly new borg warner select 7mm's, plugs are fairly new ngk v-powers and i have triple checked my firing order it is correct.
And when you drive it there is no miss at all, i can go all the way to 6000rpm and it dont miss a beat???
But while its at an idle, you can hear the thud thud thud out the exhaust, i'm really starting to think this broken intake manifold stud has aot to do with whatever the hell is going on with this thing.
I will set up an appointment with my buddys shop to have a compression test and a leak down test done. And i will go from there, depending if everything checks out good? then what could be causing this engine to smoke when backing off the gas? bad valve seals or valve guides? or both? I just read that the valve guides and the valve seals can be replcaed with the heads still on the engine. I guess i will need to get a second opinion on this.
Maybe i should get the broken bolt out, then get a new intake manifold gasket, get the broken stud drilled out put a new bolt in it, bolt the intake back down and if i still have this thudding out the exhaust issue and smoke coming out the exhaust when backing off the gas i will have to think its ehter valve guides or valve seals then, correct?

 

[pjc360]

I will post the verdict of my compression test and my leak down test when i get it done, but i will post it in the small block engine section and i guess we can go from there. This guessing game is driving me nuts. so i aint even looking at the dam thing untill i have a compression test and a leak down test done, wich will most likely be on monday.

 

[jos51700]

So i just bought a brand new one that was already curved and phased to my engine.
lol

There's no way you can "buy" a distributor curved for your engine unless someone installed on YOUR motor and tuned it. Mail order? Not tuned for your motor. No way, no how.

There are several articles on ported vacuum advance from Mopar Action and Mopar Muscle. All say that ported vacuum advance is necessary for proper street performance. Richard Ehrenberg said that properly set up vacuum advance will increse FE by 30-50%. Enough to justify the time to get this right. I have run up to 60° total adance (initial+mechanical+vacuum) with no detonation on a 9.8:1 CR 340 with a 284/484 cam. Hooking up to manifold vacuum will only increase vacuum advance at idle beyond what is desired or needed to run the engine properly.
Good Luck!

This guy here nailed it.

ok, i'm taking it to a shop then because i dont know how in the hell this engine could possibly have a miss?? Brnad new distributer curved and phased. Brand new cap and rotor brass contacts. Plug wires are fiarly new borg warner select 7mm's, plugs are fairly new ngk v-powers and i have triple checked my firing order it is correct.
And when you drive it there is no miss at all, i can go all the way to 6000rpm and it dont miss a beat???
But while its at an idle, you can hear the thud thud thud out the exhaust, i'm really starting to think this broken intake manifold stud has aot to do with whatever the hell is going on with this thing.
I will set up an appointment with my buddys shop to have a compression test and a leak down test done. And i will go from there, depending if everything checks out good? then what could be causing this engine to smoke when backing off the gas? bad valve seals or valve guides? or both? I just read that the valve guides and the valve seals can be replcaed with the heads still on the engine. I guess i will need to get a second opinion on this.
Maybe i should get the broken bolt out, then get a new intake manifold gasket, get the broken stud drilled out put a new bolt in it, bolt the intake back down and if i still have this thudding out the exhaust issue and smoke coming out the exhaust when backing off the gas i will have to think its ehter valve guides or valve seals then, correct?

How does it have miss? Well, you followed this Don guy's advice, and he's a f**kin' retard handing out advice that probably damaged your motor. Did you EVER go back to the PORTED vacuum, like it's supposed to be?

Here's the deal:
Vacuum advance is an economy feature only. It's NOT supposed to be in action at idle, Therefore you use PORTED vacuum so it's not working at idle, and the vacuum advance ONLY works at cruise. At Wide Open Throttle, there is NO (or very little) vacuum, and no vacuum advance.

Repeat, it SHOULD only work at cruise, and by plugging into manifold vacuum, you screwed up and made it work damn near all the time.

If you hook it up to manifold vacuum, it's advanced at idle, and that advance only goes away at Wide Open Throttle. In other words, when you plug the vacuum advance to manifold vacuum, it's WAY too advanced, and you've probably hurt a piston, or rings, or maybe even damaged something else from hideously over-advanced ignition. Tell Don to bugger off. I mean it. He lacks a fundamental understanding and I don't care who he is, it's fact.

April 2000 Mopar Action, as well as others, covers this in depth (I'll scan it and send it to you if you PM me your address, it's literally right here on my workbench.) It's easy, no fancy carbs, no "Closing the throttle" BS, no four-corner idle, nothing. The above information holds true for any carb, from one to two to three to four barrels. Vacuum advance is on the ignition side, no carb work anywhere. No rich-this or lean that, it's timing.



And for the record, you won't be changing valve guides with the heads on the motor. Just the valve guide seals.

 

[jos51700]

you can fix the guides yourself with the heads on the engine.

I'll send $500 to the charity of your choice if you post how to do this on Youtube. Flat-rate mechanics everywhere will be able to send their kids to college.

To the OP...I'm betting that you (besides having the timing JACKED), have it tuned way rich at idle. Because you said that after a test drive it idles great for a minute but then starts mis-firing, I'm guessing that it's loading up the plugs from running rich, and after 30-45 seconds of that abuse, they start fouling out, causing your misfire. Then a drive cleans 'em off until the next idle session.

Take your vacuum advance line, plug it, cap it at the carb, and do your compression and leakdown checks. If everything there checks out (I hope it will, but over-advancing ignition can do a lot of damage) then tune your carb and get it right.

THEN leave it be, set your timing right, THEN hook up the VA and get it right.

That's what I would do, anyway. And if it's burning oil, get running right first. Burning a little oil isn't the worst thing in the world and I have had a few that burned oil until mechanical issues were resolved (I won't say what, because then you're going to miss the point).

Prioritized?
Carb.
Timing.
VA.
Oil burning.
In that order.

If it were mine.

 

[Lonewolf3165]

You failed to mention(unless I missed it somewhere) if it's an electronic distributor or points. I'll assume it is electronic since nobody "upgrades" to points. Popping from the exhaust sounds like combustion in the exhaust system. Probably not caused by the vacuum advance since it only adds advance to the timing & popping in the exh would be more likely a retarded timing situation. Not likely in this case. What type of ECU are you using? Is it compatable with the dist or is it functioning properly? I'd get a hold of a dwell meter & check the dwell on it. If it is too severe it will cause the popping you describe & cause the coil to get hot. I'd also make sure your not confusing the popping with a misfire. That too would cause the exhaust to become overly rich & then combustion could start in the exhaust. Do a power balance test on it to be sure. Also check you manifold vacuum with a gauge & see if it's steady & how many inches @ idle. Post your results here & we'll go from there. Good luck.

 

[Lonewolf3165]

my vaccum gauage moves around a little bit, it does not stay steady while at an idle, wich i have been told indicates a vaccum leak, i'm wondering if it is too small of one to really change the idle when spraying carburetor cleaner on it.

No! Unstable vacuum is an indication of valve trouble. As in a burnt valve. Since you hear it out the exhaust, my guess is that it's an exhaust valve.

 

[pjc360]

Wow after reading all of this i'm considering just buying brand new cylinder heads...... It kinda sucks, but if i caused alot of damage by running too much advance at idle. The ignition module i am running is just a car quest brand module, its the higher ignition line module not there red boxed garbage.
I was wondering if maybe the ignition module could be at fault for the thudding out the exhaust issue. I have a mopar gold ignition module, but it states that it is to be ruced for racing only... I am thinking tommarrow i will plug in th gold box just long enough to determine if the thudding out the exhaust while at an idle will still continue.
I really hope i didnt do too much damage to my cylinder heads? Like i said it never smokes when first starting it, and while its in oark i can run it up to 4000 rpm and back off the throttle and it doesnt smoke then ether. It will only smoke out the pipes if i am driving it and i'm around 4000 rpm and then back off the throttle?
since it only smokes when (driving) is that a another clue to point towords it being something? Like valve guides or valve seals? I'm going to schedule an appointment to get a compression test and a leak down test.I will then go from there, thats about all i can do at this point, that and change the ecu over, but i doubht thats going to take care of my smoking out the exhaust issue. Thts the one i'm most concerned with right now. Lets say i did mess something up in the cylinder heads like valve guides or valve seals, would i be better of just cutting my losses and buying a new set of cylinder heads? i am really interested in these iron ram cylinder heads. Unless the valve guides and valve seals can be repaired fairly easily? I dont know if it would be a better idea to replace whatever i hurt in my current cylinder heads or if it would be a smarter idea to just get brand new cylinder heads? Since the engine never smokes upon start up thats giving me hope that i didnt hurt the pistons or the piston rings. and its making me think something in the cylinder heads went bad and thats why i'm getting the smoke out the exhaust when i back off of the throtte.
But the leak down test and compression test should answer some questions. Once i get it done i will post the results in the small block section so you guys check them out and then point me in the right direction for the next step i should. Thank you everyone for your responses truely do appriciate you guys's help.

 

[toolmanmike]

Here's another FABO member that "Don" has gotten to. Stay away from this guy and his ignition systems.

http://www.forabodiesonly.com/mopar/showthread.php?t=199504

 

[toolmanmike]

Here's another explanation of ported vs. manifold vacuum. Another thing to check is spark plugs and their heat range. I had a similar popping/engine miss sound with my 273 and 3 heat ranges hotter plugs took care of the problem.

The mechanical advance is adjusted for high load WOT conditions. Under light load, part throttle conditions the manifold pressure is lower so volumetric efficiency is lower so the cylinder pressure is lower so the fuel mixture burns more slowly. This means you need to light the mixture sooner so you reach peak cylinder pressure at the ideal time. This is the purpose of the vacuum advance. The lower the load is the more it will advance the timing. Vacuum advance will improve gas mileage and drivability of a street driven car. A lot of guys think a vacuum advance hurts performance, this is not true. The vacuum advance is entirely independent of the mechanical advance. They are two separate systems that perform two separate functions. The mechanical adjust timing based on RPM where the vacuum adjusts timing based on load. Under high load, WOT, performance conditions there is almost no manifold vacuum so the vacuum advance does nothing. The only time the vacuum advance adds timing is at part throttle, low load conditions when there is manifold vacuum. So unless you race at half throttle a vacuum advance will have no effect on performance. It will however improve part throttle drivability so unless your car is a 100% race car I would recommend running a vacuum advance.

You're probably thinking, "Sure there is no manifold vacuum at WOT but aren't I supposed to use ported vacuum for the vacuum advance." Hold onto your hat, THEY ARE THE SAME THING! Except ported is shut off at idle. There are a lot of misconceptions when it comes to the ported vacuum source. After hearing 20 different theories I decided to hook up two vacuum gauges, one to manifold and one to ported, then drive my car and watch it. I found out they are the same, except the ported is shut off when the throttle is closed. Even then I had a hard time convincing guys so I hooked up a couple MAP sensors and a throttle position sensor to a data logger and recorded them while driving then dumped it into a spreadsheet and made a chart. As you can see, there is a direct relationship between throttle position and vacuum. When the throttle is closed vacuum is high, when the throttle is open vacuum is low, and ported vacuum is the same as manifold except when the throttle is closed. So which one do you want to hook it to? I prefer manifold vacuum. This pulls in more timing at idle which is good since there is virtually no load. Your motor will idle smoother and cooler with the extra timing. One night I was at the drags and my car was running hot in the staging lanes, I swapped the vacuum advance from ported to manifold then it would idle all night at 175°. Believe it or not the purpose of ported vacuum is to raise the temperature at idle, to lower NOx emissions. If you're like most hotrodders that is of no concern to you. If you have a big cam with a choppy idle then a vacuum advance hooked to manifold vacuum can really help. It will idle smoother and requires less throttle to maintain speed. Often a big cam requires you to open the throttle so far that the curb idle adjustment needles won't work. Hooking the vacuum advance to manifold vacuum will allow you to close the throttle some which may be enough for the idle mixture screws to work. Someone told me he noticed less dynamic braking with the vacuum advance hooked to manifold. I didn't notice it on my car but it makes sense. If the motor is running more efficiently with the added advance it will make a less effective brake. So which should you use? Try both and see which you like best.

 

[OldmanRick]

Here's another explanation of ported vs. manifold vacuum.

Thank you for posting that Mike. I personally don't care which source ya'll use for your vac advance, i'm happy with what i do. But there were some posts earlier which really made me have to bite my tongue.

 

[toolmanmike]

Here's another explanation of ported vs. manifold vacuum.

Thank you for posting that Mike. I personally don't care which source ya'll use for your vac advance, i'm happy with what i do. But there were some posts earlier which really made me have to bite my tongue.

I agree. Really there is no proper answer. Each engine has different timing needs. I think I'll play with mine this morning to see if there is a difference. Mine seems to like a lot of initial advance and runs cleaner when I give it that. Manifold vacuum may help that. I notice that mine runs hotter with less initial and ported vacuum. Manifold vacuum may help that too. As to what is causing the popping noise in the original post, I don't have a clue. Could be something as simple as spark plug heat range. That fixed mine. tmm

 

[OldmanRick]

I agree. Really there is no proper answer. Each engine has different timing needs. I think I'll play with mine this morning to see if there is a difference. Mine seems to like a lot of initial advance and runs cleaner when I give it that. Manifold vacuum may help that. I notice that mine runs hotter with less initial and ported vacuum. Manifold vacuum may help that too. As to what is causing the popping noise in the original post, I don't have a clue. Could be something as simple as spark plug heat range. That fixed mine. tmm

I posted early here and tried to convey to the op, if it was ok and you changed/touched "X" ( dizzy, ign.wiring, plug wires, etc.) and have a problem the you have to look at "X" as the source. Then other issues slowly surfaced and it kinda got out of control after that.
I like vac adv on engines that produce 12" vacuum or more. Anything less i do away with it. I figure the cam, converter and gearing required to make a engine like that work well kinda throws economy out the window anyways. Not recommending anything, just what i do.
Good luck with your experiment, never hurts to try something. I actually get enjoyment out of tinkering.

 

[Bulldozer]

I'll send $500 to the charity of your choice if you post how to do this on Youtube. .

yes its a chevy..same principal ..and i meant seals not guides, im pretty sure you knew what i meant, and i fixed it

[ame="http://youtu.be/ob_4-F-m1FI"]302 Found[/ame]

 

[Bulldozer]

Prioritized?
Carb.
Timing.
VA.
Oil burning.
In that order.

If it were mine.

how can you POSSIBLY tune a carburetor if the timing is not dialed in and you have an ignition miss? please do enlighten me
vacuum leaks
TIMING
THEN CARB

in that order

 

[Oklacarcollecto]

ok, i'm taking it to a shop then because i dont know how in the hell this engine could possibly have a miss?? QUOTE]


This is the wisest thing you have said since this thread started. You are obviously in way over your capabilities and are taking a lot of chances with destroying a prefectly good engine. More parts you don't need will just throwing more money away. Find a real pro that knows these engines and take it to be repaired. Don't take it to a ricer shop either.

Here is a question that you should be posting... "Does anyone know a good Mopar mechanic near Drummond, Montana".

 

[pjc360]

I'm not in montana right now, I will get a compression check done and a leak down test done and let you guys know whats up. I'm not even going to mess with it much more untill i get that done. I will try swapping plugs and ecu to see if that helps with the miss. but thats about it.

 

[pjc360]

lonewolf3165, at idle the engine has about 17 to 18 inches of vaccum and it will stay steady for about 3 to 4 seconds then drop about .5 inces of vaccum then it will bounce back to 18 and stay there for 3 or 4 seconds then drop down to 17.5 to 17 then bounce to 18 it just does that over and over with the vaccum gauge on it.
And for the record the vaccum was doing that way before i ever talked to don at fbo systems, that was happening when i first fired up the engine after putting it in the truck i bought. I didnt even know who don was at that point and never bought anything from him. So whatever damage that is was there before i aquired the engine.

 

[pjc360]

The main thing i wanna find out right now is where tht oil is coming in at. And lot of you have suggested the valve seals? Or valve guides, Some have mentioned pistons, but i dont think i hurt my pistons. i can start it up and shut off 10 times in a row and watch the exhaust and it never smokes upos start up. It only smoke when driving down the road relatively hard and backing off the throttle then the light blue smoke comes out the exhaust, and mainly only on the drivers side exhaust pipe.
I know the leakdown test will give more answers, but i have a feeling i will be replacing the cylinder heads. You guys gotta remember too this motor is 11 years old and my old man didnt exactly abuse it, but he ran it hard a fair share of times too. Granted he knew what he was doing when he worked on the engine, but he never really had to repair any hard parts on the engine its self. And this engine was fuel injected for most its life. My old man bought it as a crate hooked fuel injection too it and ran the crane cams fire ball ignition on it and ran it that way for 8 or 9 years.
The oil was always changed with synthetic and its always had premium fuel ran thru it, who knows maybe the valve seals or whatever is letting the oil by was messed up when i got the engine and i just never noticed it? But whatever it is, i will get it fixed.

 

[Bulldozer]

The main thing i wanna find out right now is where tht oil is coming in at. And lot of you have suggested the valve seals? Or valve guides, Some have mentioned pistons, but i dont think i hurt my pistons. i can start it up and shut off 10 times in a row and watch the exhaust and it never smokes upos start up. It only smoke when driving down the road relatively hard and backing off the throttle then the light blue smoke comes out the exhaust, and mainly only on the drivers side exhaust pipe.
I know the leakdown test will give more answers, but i have a feeling i will be replacing the cylinder heads. You guys gotta remember too this motor is 11 years old and my old man didnt exactly abuse it, but he ran it hard a fair share of times too. Granted he knew what he was doing when he worked on the engine, but he never really had to repair any hard parts on the engine its self. And this engine was fuel injected for most its life. My old man bought it as a crate hooked fuel injection too it and ran the crane cams fire ball ignition on it and ran it that way for 8 or 9 years.
The oil was always changed with synthetic and its always had premium fuel ran thru it, who knows maybe the valve seals or whatever is letting the oil by was messed up when i got the engine and i just never noticed it? But whatever it is, i will get it fixed.

i had an 80,000 mile 360. it never smoked. if youre puking any blue smoke, you are pulling oil past the rings, or the valve seals into the combustion chamber(s) and you will oil foul the plug(s). if it is misfiring from an ignition miss , then you would be pushing raw fuel out of the tailpipe(s) from the misfiring cylinder(s). a rich condition or unburnt fuel will usually show itself in the form of black smoke. by merely reading your plugs, you can find the cylinder(s) that are burning oil. they will be gooey black and wet. a cylinder that is not firing from an ignition miss will be wet with fuel and you will be able to smell the fuel on the plug.

 

[Lonewolf3165]

ok, i'm taking it to a shop then because i dont know how in the hell this engine could possibly have a miss?? QUOTE]


This is the wisest thing you have said since this thread started. You are obviously in way over your capabilities and are taking a lot of chances with destroying a prefectly good engine. More parts you don't need will just throwing more money away. Find a real pro that knows these engines and take it to be repaired. Don't take it to a ricer shop either.

Here is a question that you should be posting... "Does anyone know a good Mopar mechanic near Drummond, Montana".

Just take it to a shop that is known for being able to diagnose & repair dirveability issues. Chances are if you waste your time looking around for a guy who just knows old mopars you'll be probably getting more of the same as here. You may just end up with Bubba who used to work on his Duzder & dat ran good. Not much business in that anymore. Any good qualified technician with skills in driveability should be able to diagnose this in a couple of hours or less. I've been a foreign car specialist most of my professional career, now I own one of those so called "ricer shops". Muscle cars are my passion & hobby though, & I can tell you I've solved more than my share of problems caused & made worse by guy who were the so called "experts" on these older cars. It doesn't matter what brand of car it is the same rules apply to diagnosis & repair.
Take it to a qualified shop.