I was trying to check things out with the vacuum line and the first time I connected it to ported, it didn't change the idle a bit. Of course, it was due to the fact that I was filming it so I could show you guys. I left the hose connected and drove the car down the street and back, no fast idle. I pull back into the garage and the idle goes crazy. Not as bad as before but still over 1500 rpm. I would think that if the new can had a leak, it wouldn't do it (now) sporadically like this? I'm not posting the first video clip where it doesn't increase the idle as it's too long. The clip posted shows after I drove it and got back into the garage. In my haste to try and get the video I forgot to try manifold vacuum. Couldn't find a T to connect the advance and modulator as it is. From everything I understand I should be using ported vacuum for this can but I just don't get it. Maybe I'm just not used to it yet but it seemed like everything was really hot on the engine, intake was too hot to touch after a quick trip down the street and back? Never noticed that before, who knows.




'95 - I'm using a mechanical pump in the stock location and have 2 filters. First is a canister back by the tank and the other is an inline between the pump and regulator. I have the pressure set at 5.5lbs. I've seen electric pumps in both the front and back of cars, don't think it matters as long as it works right? I have one of those "glass" type filters that you're using but I myself decided against using it as there were a bunch of folks saying they're potentially dangerous should something hit them and possibly break the glass. I do like being able to see the inside of them though.


Got one fender on at least! Don't think I could've changed my mind more times than I did with these things. They are now painted (rattle can for now) the color I'm going with and have a coat of clear on them. Was a complete pain to have to straighten and weld the bottom of one, take the Z fender extensions off, pull my originals off my fenders, reinstall them, remove the running light lenses so I could black them out, remove the vents, de-rust all the brackets and reassemble everything. At least they're done. For now. The one fender (pic above) had what appears (from counting) to be 8 different coats of paint on it. On top of that, someone decided to shoot a BB gun at it and chip/dent the paint down to the metal. They are FAR from perfect, but sure do look better than when I got 'em. You can see the one in the "bonus" video clip just showing the Camaro outside and what it sounds like out of the garage. The purple thing is a paint brush that is functioning as a vacuum line plug in case anyone was wondering what that was.


http://vid1298.photobucket.com/album...psccod6oo2.mp4


http://vid1298.photobucket.com/album...pszqf2cial.mp4

 

When you have some peace and quiet, and a clear mind, read this: Timing & Vacuum Advance 101 -good article by GM engineer - 460 Ford Forum
It may take a while to go through, and for it to soak in.

 

I don't see a pump in the picture? I see a filter and regulator, but no pump. An electric pump should be lower than the fuel tank, and as far back as possible. It should also have a pre filter, and I run another filter after the pump, near the carb{s}. Electric pumps push fuel better than they pull fuel.

 

If you have your hose connected to ported or timed vacuum port, then nothing should change at idle when you pull the hose off. Manifold vacuum ports will get a leak when the hose is pulled and idle increases.
It sounds like you might possibly have an issue with mechanical advance hanging up, and not returning. Maybe check the weights in the distributor to ensure they're free and easily spring back when you open them.
And I agree with your comments on the glass fuel filters. I use the transparent plastic, or the metal filters. Beyond the glass possibly getting broken, the O rings in each end have been known to leak and spill gas on hot manifolds.

 

Thanks for the link Chuck, I've read that one several times over the winter actually sir. Appreciate you sending it though. While I do fully understand what the guy is trying to explain in that piece, it seems to me that it's more of an opinion (he says so himself) piece rather than the gospel. I've also studied several other articles about "Hot Rodding the HEI" and "Tuning Secrets" etc. and most all of the other articles recommend using a ported vacuum source. One other source (being yourself) just got done recommending I have the hose connected to a ported source also? The guy in that article sounds like he knows what he's talking about, however, he never even mentioned what the difference would be in off-idle timing using ported instead of manifold vacuum. I get that the ported vacuum came about as an emission control source and that it does nothing at idle, but why are so many other articles recommending to use ported vacuum with a larger cam if one should (per that guys words) absolutely, positively use manifold? I'm assuming it's got to do with where the initial timing setting is along with the centrifugal mechanism in order to get a good stable idle. What I gather from all the reading I've done is that the vacuum advance needs to be tailored to the specific engine, which is why I bought an adjustable can. I tried to set the advance to come in 2"hg below idle vacuum (which I saw 15"hg.) I'm not at all interested in a debate about this, but am curious what your reasoning behind the recommendation of using ported vacuum was and then sending me an article explaining the opposite? Do you use ported vacuum? I never understood the mechanics behind timing, total timing etc. before and spent a bunch of time trying to learn over the last several months. I really feel like I get it now, but that still doesn't help what's happening when I plug the hose into ported vacuum on my carb and the idle goes crazy! THAT'S what I'm trying to figure out right now. If I need to use manifold vacuum, I will. I'm not trying to argue that.


Vall, the springs/weights/mechanism are operating as they should sir. I understand that nothing should change rpm-wise when I remove the hose, but for some reason, mine is. I'd like to think that nothing else is broken or malfunctioning at this point. Don't think it's realistic that anything else is malfunctioning on the 3rd round of replacements.

 

yes I hear that thats why I may go ,glad to her you got your fender on ,I like the clear glass one, the plastic one I had turned this bad color orange black mabey I had some crap in tank now I have not had to clean that one yet ,I keep am extra filter with me ,an its also reuseable can be cleaned over an an over again ,yes I know the pump should push not pull ,I think moveing one of them is in there at some point ?hows your timeing set ,an the your air fuel mixture srew ,that's the one I don't like to play with ,just some ideas hope you get there soon ,seems nothing is perfect ,fix one thing theres another ,like little noice that only bother us no one else ,I think I blew a chamber in the muffler ,its all it could be spot weld break ,that pinging noice ,that's what I get for going with flow pro,though before the air shocks they did drag a bit ,got to get a set of flowmasters or cherry bombs full bore I think

 

I'll toss my 2 cents in on the vacuum advance topic.

Manifold vacuum will be a high vacuum at idle and no engine load. Ported vacuum will be low vacuum at idle due to air passing through the carb venturies being relatively low velocity. As engine RPM and engine load increase, manifold vacuum will drop towards ambient air pressure but ported vacuum will increase due to the air velocity through the venturies being much higher. This is vey you need ported vacuum for the vacuum advance on the distributor. As the engine RPM/load increase, the ported vacuum will bring more advance in. If you connect the vacuum advance port to manifold vacuum, it will start out with too much vacuum advance and as the vacuum decreases, the distributor will decrease the timing advance.

Ported vacuum is developed by the air passing over a small hole in the venturies. The higher that air velocity, the higher the vacuum developed(Low absolute pressure).

 

The old plastic filter turned dark because it was filtering junk out, and doing a good job. The glass filters are so porous that they allow large particles to pass through. They don't get full of crud, because it all passes through and ends up in your carb bowls, and passageways. A filter that stays clean is NOT a good filter, it's a bad filter!

 

Slow and steady.

 

I'll dissect your query's one by one (in bold). This is by no means an argument, nor is it to be an influence of one's opinion over another.

Extra credit....
Go back and read that article again. None of it is opinion, it explains just what is happening when and where with the timing and advance. It's how engines used to be "back in the day", before emissions took a front seat to performance.