swapped my 750 eddy for a 600 and.....

[shadango]

Hey, just thinking....

If I were abel to uplaod a videoclip of it running, would that help at all?  maybe just hearing it would help?

Then again maybe not.....

[72bluNblu]

A video might help!

I wouldn't mess with drilling the primaries until I had played with all the other stuff, jets, rods, etc. The 600 should be about the right size, you should be able to dial it in without any drilling.

What do the spark plugs look like? The vacuum seems really low, either you're off on the mixture quite a bit or you've got a leak somewhere. Mine pulls like 15" hg at idle in gear. Have you checked/replaced any of the carb gaskets? Also, what manifold is this carb on? I made the mistake of putting my Carter AFB (pretty much identical to a performer) over an open plenum intake without a 4 hole spacer...DOESN'T WORK. Pretty sure the performer's are the same way, the bottom of the carb has to be up against a 4 hole style inlet/spacer to block off all the appropriate ports. Otherwise you get a massive air leak.

[quagmire]

If you only have 5" of vac in park, you have problems.  That will make the metering rods stay up and cause all sorts of running problems.  Unless you have a monster cam, something is going on.

[shadango]

I am going to try the lighter rod springs next....

The thing is: I may very well have a cam.

The carb is sitting on top a square bore edelbrock performer manifold...supposedly a match for the carb...

But now, wait a tick......72blue --- wondering if you arent onto something with the "4 hole spacer"....

All I have right now is the carb, the square bore gasket and the manifold....the install manual doesnt mention this unless I missed it....

I have tried the mixtures up and down, timing up and down.....still wants to idle really low...

[shadango]

Also, what manifold is this carb on? I made the mistake of putting my Carter AFB (pretty much identical to a performer) over an open plenum intake without a 4 hole spacer...DOESN'T WORK. Pretty sure the performer's are the same way, the bottom of the carb has to be up against a 4 hole style inlet/spacer to block off all the appropriate ports. Otherwise you get a massive air leak.

OK..followup....The manifold just says "performer" on it with a bunch of numbers....but looking at the edelbrock site it looks most like the "rpm", from what I can recall. Its divided down the middle...





so I dont think I need the 4 hole spacer....BUT....

The carb instructions says the following is needed for installation:

":Divided Square-Bore Heat Insulator Gasket #9266 for dual-plane
(stock or Performer series) manifolds. May be used in place of
Square-Bore Adapter Plate #2732 on some Edelbrock manifolds."

here is 9266




Now, all thats on the car now is the square bore gasket in this picture, not the metal spacer........



Could the lack of that division in the gasket be the issue here? And how do I know if I need the spacer?

 

[73Chally]

I missed the 5" vacuum.  That is a huge problem.  I'm pulling around 15" with a slightly hotter than stock cam in my 440 6 pack.  I would say you have a major leak somewhere.  That would definitely kill your idle and performance.

[quagmire]

I have a decent sized cam and still pull 13" in gear, granted mine is a stroker but you'd have to be running a race cam to idle at that vacuum level.  From what it sounds like your car runs poor but doesn't have huge amounts of lope like you'd expect if that were the case.  I think you have a big vacuum leak, a jumped timing chain, or other internal engine problems.

[shadango]

Well, I just got off the horn with edelbrock....

Basically, my carb is not gasketed right for one.......I should eiether be running the sqaure bore metal plate with two gaskets, OR the 9266 which replaces it and provides some heat insulation as well....

Gonna try for that.  He said that I should have been able to find that leak, though, by spraying carb/brake cleaner around.....but who knows.

Regardless, I am gasketed wrong right now so will stick a 9266 in there once I can get one.

He also told me to block the breather inlet with tape, etc.....then put my thumb over the pcv valve hole and if there is suction, that means I have an internal vacuum leak, like an intake manifold leak, or a cracked intake.....and that would cause this....so, like y'all said, possibly a vacuum leak.

Did a similar test before but didnt black both the pcv and breather ports..... wanna say there WAS suction at the breather whe ni put my hand over it....but again, the pcv valve was hooked up to the carb so that would proabbly affect the test.

Well, I guess I have a little home work.....LOL

I am really hoping to find a major leak.   I really dont want a cam that performs like this, if thats what it is....

It's the "other internal problems" that scare me.

[72bluNblu]

The gasket is a big problem. I ran into that twice, it needs the 9266 or a 4 hole type gasket, not an open plenum gasket. I'm guessing once that is done you'll be ok, it caused a huge air leak on my car when I had the open plenum. The intake is fine, that shouldn't be a problem. I had to go to a 4 hole spacer on mine because I had a single plane intake with no divider, you should be good with just the right gasket.

[quagmire]

Vacuum at the breather hole with the PCV hooked up is normal, and good.  Start with the basics, that carb gasket problem first and you'll probably be fine not needing any other work.  No need to start worrying yet until that is fixed.

[shadango]

The gasket is a big problem. I ran into that twice, it needs the 9266 or a 4 hole type gasket, not an open plenum gasket. I'm guessing once that is done you'll be ok, it caused a huge air leak on my car when I had the open plenum. The intake is fine, that shouldn't be a problem. I had to go to a 4 hole spacer on mine because I had a single plane intake with no divider, you should be good with just the right gasket.

I am going to hold you to that.   

Where did you hear/feel the leak? Externally?

Still, hafta wonder why I cant use the spray-cleaner test to find it...if its THAT big a leak, it should suck that stuff right in........

I just ordered it from Summit..should have it tomorrow but of course I am on my way out of town tomorrow evening for work.....

Its easy enough to change (famous last words) and I need it anyways.

Can someone confirm the "hand over the breather" test.....I did the test before, referencing it in one of my posts on the "scaled harmonic balancer"....when I did it before, I just pulled the breather and stuff my hand over it....it DID make a suction......did my not having the PCV valve block defeat the test?
*update*
I must have posted right as you were.....gotcha on the "suction with pcv hooked up is normal"...makes sense i guess......although technically isnt THAT just like a big vacuum leak?

[shadango]

Vacuum at the breather hole with the PCV hooked up is normal, and good.  Start with the basics, that carb gasket problem first and you'll probably be fine not needing any other work.  No need to start worrying yet until that is fixed.

"worry" isnt the word for it....I have been obsessed....

I just want my fish to run decent.......if it runs like a raped ape once I get this figured out, cool...but "decent" would work for me after all this!  LOL

What keeps running thru my head is how the seller said "The engine ran good when it came in..." 

And there was just the square bore gasket under the 750 when I got it....the carb was all hooked up, etc.....

The edelbrock tech said that there is nothing under the carb that has to be sealed etc...just leakage to the outside that is the worry....and I really do feel like an external leak THAT big should be obvious.....

But, like you said, hafta rule out the gasket I guess first......

[72bluNblu]

I don't think the spray can cleaner will work because it IS sealed to the outside, what you have going on is an internal air leak at the bottom of the carb. Not to disagree with the tech, it could be that the edelbrock is different than the Carter in that aspect, but going to a 4 hole spacer and gasket solved ALL the problems I was having with air leakage. It definitely sealed something up, and mine wasn't leaking from the outside. Also, the gasket I was using was the same around the outer edge, same thickness, everything, as the one I replaced it with, only difference was the open vs divided plenum. So there's no reason the first one should have leaked to the outside and the second one didn't.

Too bad you have to wait for the delivery! I picked up my gaskets (and even the spacer!) at the local Napa.

[shadango]

Ok, here is a video of my engine idling, in park and in gear.....

72blu, tell me if this is how your car ran with the bad gasket....

http://s349.photobucket.com/albums/q391/shadango_bucket/cuda%20video/?action=view&current=fishyidle01.flv

[72bluNblu]

A lot things could still cause that problem, but it seems like its acting pretty similar to mine before I swapped the gasket out. I also had zilch for vacuum, and it sounded a lot like yours. Probably as quagmire mentioned the metering rods were staying up because of the low vacuum condition. I know with mine neither the timing or the idle mixture screws did anything.

At any rate, changing the gasket will eliminate another possibility and is a pretty cheap fix to get you closer to solving the problem, if it isn't the problem outright. Personally I think your on the right track with the base gasket, that thing sounds awfully familiar.