chickenman35?

Anyway, I cleaned 6 of my plugs (black as HELL) and now the car runs smoother. No more backfiring. But now (of course there's a but) the car hesitates, all around. I think the primary jets are too big. It’s not the shooter as much, I don’t think. The hesitation is all around and steady, i.e. too rich I think.

 

I took out the 66 prim. and put in 64's. And I also changed the shooter to a 32. now the car backfires through the exhaust with huge hesitation WTF!!!

I'm about to buy another car

 

Man, I'm not trying to start a fight, or a flame war, but seriously maybe you should look into getting an edelbrock.

 

so his car can be about a second slower in the quarter..... sounds like a good deal

 

double post....

 

LOL a second lower in the quarter who you kiddin ..lol..thats funny thou thanks i needed a good laugh today

 

Yes there it is, the holley is ***. THe holley is the best. Bullsh*t. It isnt. You couldnt pay me to put a holley on my street driven car.

 

by the way, if you think it'll make a second higher in the quarter, then you sir are a dumbass.

 

yeah dude, edelbrocks just rock, thats why i see so many edelbrocks at the track

I just took my edelbrock 1405 off and replaced it with a demon 750, and the difference is night and day. its not even comparable.

Given both carbs were out of the box, and the edelbrock was probably a bit small for the engine, the difference shouldn't have been as big as it was.

And keep in mind that he has a mechanical secondary carb, and switching back to vacuum secondaries would be a big drop in performance.

I've seen too many people switch from edelbrocks to holley/demons and/or vacuum secondary to mechanical secondary, and not see big performance gains.

And never seen one edelbrock do better than a holley/demon

So i don't see any reasons why trans88 should go out and spend $250 to buy an edelbrock carb so he'll have a slower car, just because he is having problems getting it tuned.

 

every one has a preference on carbs but edelbrock isnt a bad carb ive owned holleys quadrajets and edelbrocks and id have to say that if i were building a car for the track only id go with a holley but for a daily driver thats going to the track on the rare occasion id have to say run an edelbrock and then you dont have all the jetting issues and problems adjusting everything on a holley ..and ive never had a problem with a edelbrock cutting performance at all you must have had done something to it or hooked something up wrong to have one be that low on performance especially considering you can get the 750 for such a good deal nowadays and have it run right outta the box like a holley youve had to adjust to the hilt to make it run right ...but anyway Trans_AM_88 has a holley already and he is wanting to adjust it so i wont waste any more time talking to people that are mindset on hating edelbrocks for no apparent reason except they had 1 and had a bad experience with it hell if every one that spent the hours upon hours upon hours workin on holleys and just went and bought an edelbrock and a calibration kit they would have it all done in a matter of a hour and be out enjoying their car instead of tuning all day and night trying to keep it from backfireing .....

the statement above was my opinion and doesnt matter to me if anyone else cares so please ignore me if you want or be open minded about stuff and check em out ...its worth a try ....

with that said enjoy tuning and good luck hope you get it figured out man



not trying to be an azz but by going from a 600 cfm to a 750 cfm you should expect to see a great deal of performance gain if you didnt they your engine is crap

 

I already said that the cfm increase in my case was a large difference, as well as going from vac. sec. to mech. sec.

The edelbrock was hooked up right, its just not as good of a performance carb as a holly-type.

And as far as holley's being hard to tune, i can't justify it on personally experience, but my demon ran right straight out of the box, and after tuning the idle mixture screws, it pulls even more vacuum than my edelbrock did. Runs great.

It's still all personal preferance, an edelbrock can make a great carb.

I just found it funny that your guys answer to this guys tuning problem was buying an edelbrock.

 

oh yeah an edelbrock can and is a great carb so is a holley for that matter a quadrajet can be also if new and the right cfm for the engine...but ive went thru the nightmares of trying to tune a holley before and have even had one taken to 4 different mechanics and had it tuned or adjusted to work properly and within a week there was something wrong with it ..lol..but thats my experience with a holley ive tried atleast 4 different ones for street apps and ive had no luck all of em were brand new out of the box and would run for a while then crap out ..lol...just my luck but the edelbrock never gave me a problem ive had 3 now on 3 different cars/engines and never had a problem i ran one for 80,000 miles without a single problem is all i was trying to say i should have worded it different i guess but myself dont care for the holley as stated before unless on a strip only app .....

hey not trying to start a war here ...
but um where did you post anything to be relevant to the thread to begine with except to jump in a start an argument ...lol...

 

I suppose I could send back my Holley to jegs and have them give me an edelbrock...I’m up for anything that will get me my power back I guess.

I have a freaking 1405 (converted to elec. choke) here at home, but it's old as hell (well it looks old). This carburetor ran pig rich as well on my car. However, I bought it used and I don’t know if the guy before me did some changes to it.


Is there any chance that there’s some sort of other factor that could be causing me all this trouble?

 

Go with what you think man. Some people love the holleys, I dont. I just dont like paying 300 bucks for a carb, another hundred to get it right, and then fiddle with it all the time. Just not my game.

 

I've been away for four days at a big race. ( Shattered the Hill Climb Record at Knox Mountain, BTW )

Sorry to hear that your troubles are still continueing. The backfiring out the exhaust is very strange. I think you have some other problems with this car other than the carb...in fact they may be causing a lot of the problems .

Before sending the carb back to Jegs try the following.

1) The catalytic convertor is hooped. If you are blowing out chunks, it may be horribly clogged. Cut it off and install a test pipe. Most muffler shops won't do this because of legalities involve and they will try and hose you with a new cat. But for testing purposes you can DIY. Buy a section of stright pie from your local auto store and a couple of " expander" sections to mate it to the ends of the vehicle exhaust. A couple of clamps and you're done. This probably won't fix the problem, but you must remove a clogged convertor before any meaningfull fixes can be made.

2) Beg, borrow, or steal known good working carb from a friend. Try it on your car. See if that helps. Don't bother with some grungy old carb that is just laying about. You may be adding more problems.

3) Thoughly check the whole ignition system. Make sure that you don't have any crossed leads. Check the inside of the distributor cap for any signs of " carbon tracking " this will look like tiny pencil lines from the center carbon button out to the outer contacts. If you see this then the spark is "cross firing" and the distributor cap is junk. Check for any melting of the plastic around the center button. ( Usually only happens with high energy coils or ignition boxes such as MSD or Crane. You need a special low resistance button. )

Check the condition of the rotor, top and bottom for cross tracking. If you find a lot of " rust " colored powder on the underside of the rotor this can indicate that the spark is encountering high resistance some where ( usually the plug leads) and is shorting out through the bottom of the rotor to the distributor shaft. Again...rotor is toast.

Check the mechanical advance mechanism. With the rotor on you should be able to twist the rotor freely ( clockwise I believe ) in one direction about 20 degress. It should " snap " back quickly when releaded. may need a shot of WD40 or " Move-It " to free things up.

4) What type of ignition leads do you have? A good quality spiral core wire such as MSD or Moroso Blue Max is all that I will use. Some of the stuff on the market is junk ( Taylor and cheaper Accel brands come to mind ). Carefully inspect the wires for any signs of burn through. Pay particular attention to the connections at the cap terminals and at the spark plug. look for any signs of corrosion or shorting out. If everything passes a visual inspection, then grab an ohm-meter and check each wire for resistance. Spiral core wires should be less than 500 ohms resistance. Carbon core wires should be less than 10,000 ohms resistance. Carbon core wires are particularily bad for " braking down " and having high resistance. I have seen some Brand new wires....straight out of the box .... with over 100,000 ohms of resistance ( Cheap Taylors ). This will cause instant cross tracking in the distributor and hoop the cap and rotor.

4) Borrow a known working ignition coil from a friend or buddies car. This could be your #1 cause for mysterious backfiring and other problems. A bad distributor coil can drive you nuts. It is often intermittant and causes several problems. Backfiring or missing amongst them. Guess how I know? Just had one go bad on me at the Knox Mountain Hillclimb. Fortunately I had a spare and fixed things in about 10 minutes.

The backfiring out the exhaust is unusual. However, a bad coil can cause this. That is why I'm suspecting it. A bad coil can cause various problems...such as rich running, missing under load and backfiring through carb and exhaust all at the same time. Could be your culprit......

5) Check again for vacuum leaks. they can be in the strangess places.

6) Reset you timing...try a different timing light ( Sometimes the simplest things: rolleyes: ) 12 deg BTDC should be fine.

Now if after trying ALL of the above remedies and it still backfires out the exhaust and carb then you may have some mechanical issues with the engine. If you have a flat tappet cam in your crate motor then the lobes may be going flat. I highly doubt this as you likely have a hyd roller cam in that, which are virtually bullert proof.

However, I'm really thinking that you have a couple of finicky problems that are hiding and making you think that the carb is junk.

Try things in a logical order. Do try a different borrowed carb and especially the coil.

Diagnosing from a distance can be really, really difficult. I'm hoping some of this helps.

 

ok, what if i just buy a new MSD vac advance dist, new cap, coil, rotor, wires, spark plugs, and trade in my holley for an edelbrock.

 

I would say go for it, because I am an edelbrock person. I like them. From the sounds of your problems, if you switched to one you would probably like it too. But be careful, I'm sensing a flame war, there are a lot of holley ***** here.

 

well i figure at least this: if i do purchase the above items, i will have replaced the ENTIRE ignition and fuel delevery systems. if that doesnt solve my problems, then my they lie elsewhere.

im not even going to screw around with cheap parts either.




Edelbrock Performer Carbs - 600 cfm, Electric Choke
Item # 350-1406 Item Total: $265.99

MSD 8.5mm Red Super Conductor Spark Plug Wires - w/HEI Style Distributor Cap
Item # 121-3559-9 Item Total: $69.99

MSD Billet and Pro-Billet Distributors - GM Pro-Billet, HEI with Coil & Vacuum Advance, (5)(6)
Item # 121-8365 Item Total: $329.99

MSD Ultimate HEI Kit for GM Ignitions - Ultimate HEI Kit, GM
Item # 121-8501 Item Total: $137.99


Order Total: $803.96


minus $250 for the holley i'm going to send back.

yes?

 

Don't forget the Catalytic convertor. It is hooped from your description...IE: chunks blowing out. Must be changed. All that raw fuel going through it has surely ruined it.

The thing I'm concerned about in buying all the new parts at once is, what if it's something really simple and cheap like a bad coil or something that you\we may have overlooked? I'd hate to see you waste your money...it doesn't grow on trees.

That's why I suggested the step by step approach as I outlined and hang onto the Holley until you are Absolutely certain that it is defective.

Have you looked at the ignition yet? Have you tried replacing the coil with a known good unit? The joy of HEI is that they are so plentiful and so universal that you can grab one from any GM HEI unit and slap in in for testing. Borrow a coil from a friends, Dad's , neighbors car . Heck they're cheap enough... buy a stock HEI coil from your local jobber.

That backfiring out the exhaust is really strange. That bothers me... backfiring out of the exhaust usally is not something that can be caused by a carb. Can you provide more info on this? Is it a big backfire or just a little pop or sneeze? Does it occur under light acceleration or heavy? Is it under deceleration? Backfiring out the exhaust is usually caused by unburnt fuel in the exhaust system. Usually caused by a weak or crossfiring ignition system if under acceleration. Backfire under decel can be caused by air leaking into the exhaust system. IE: Leaky header gaskets or some other leak in exhaust system that lets air in.

Did you find any evidence of crossfire in the cap or rotor? What barnd of ignition wires do you have now?

IMHO..the wires are a good investment. The Pro billet distributor and MSD Ultimate HEI are not required unless your distributor is worn out. BTW...if you do decide to buy the MSD Pro Billet distributor I do not believe that you will need to buy the Ultimate HEI kit, Part # 121-8501. The Pro Billet already comes with an HP performance HEI module. Edit: Confirmed . The Pro Billet #8365 already comes with these parts ( High output coil and HEI module ) installed. http://www.msdignition.com/dist_5.htm

If your original distributor is in good shape then I would suggest just buying a good cap and rotor. Standard Blue Streak makes an excellant heavy duty line. Has the suffix " X" added to the part number if memory serves me correct. The Jacobs super dooper HD Cap and Rotor is nothing but a Standard Blue Streak HD model with the brand name ground off. Plus Jacobs charges about twice what you can buy the actual Blue Streak part for at youir local jobber.

Then buy a Crane HI-6 Ignition box with PS91 coil. The Crane units are far superior to the MSD 6A-X series. Much more reliable as well. MSD cannot compete with the features and relaibilty of the Crane series until you get into the MSD Digital series...and these are much more expensive than the Crane units ( which is also full digital ). Again...only if you current distributor is in decent shape. And really...the only thing that can wear out in an Electronic distributor is the bushings...and that takes forever.

It's your money of course.... I'm just concerned because I know it's frustrating and you want to get it fixed ASAP. But IMHO.....I'd like to identify the cause of the problem rather thatn just replace everything at once in the hopes of hitting it with the " shot gun " affect.

In diagnostics, as with tuning, the Golden rule is: " Change one thing at a time". Just my .02c

 

Edit: delete post.

 

ok, I’ll make a delete pipe or something for the cat.

coil was replaced

the backfiring through the exhaust was just little pop pop pops with an occasional louder one (that's when
the cat came out). it happens through out the acceleration but I don’t think anything happens during deceleration. the header gaskets were replaced about 4 months ago.

cap and rotor are 3 - 4 months old; I have Accel super stock wires.

So I’ll pick up the wires, the ultimate HEI kit (so I can completely rule out any of those components).

Crane Cams has a few HI-6 Performance Ignition boxes (here) should I get any of the boxes over the normal one just for future purposes?

I’m not sure what the PS91 coil is for. does that replace the HEI coil-on-cap? also there are a few of
those as well (here). which one should I get?

 

The 6000-6400 Crane unit is the normal one for street and Race use. All of the other units have extra controls such as dual-rev limiterss for staging etc or timing retards. The 600-6440 is just a different colored case. Believe it or not color is a marketing decision. I attended a Crane seminar some years back when all of their boxes were Gold. They introduced a Blue colored box because apparently in some cultures, a gold color is considered bad luck....strange but true.

The PS91 coil replaces the in cap HEI coil. It is specially built to provide more spark energy, than a stock coil, when used with a Capacitor Discharge ignition box. A standard coil will work with a Capacitor Discharge ignition...but you will nor achieve the full benefits of the ignition system with a standard coil and the standard coil could fail prematurely due to the voltage and currents pushed through it.. It is generally best to use the recommended coil built by the same mfg as the ignition box.

The proper PS91 coil for your distributor is Part# 730-0291. The only difference between 730-0291 and 730-0191 is the color of the wires....nothing else. Chevy\Cadillac use Red\yellow wires and Buick, Olds , Pontiac use Red\White wires. Other than that they are identical...go figure. Edit: Note: Picture on Website is an External coil. Obviously in cap coils look different. Picture of in cap coil not shown.

Notice that a CD ignition ( Crane, MSD, Accel, Jacobs etc ) uses VERY high Primary voltages ...450 volts vs 12 volts. Current is much lower of course. But a proper CD coil is built to withstand this voltage and has a different " Turns Ratio " to maximise the spark.

http://www.cranecams.com/?show=brows...mber=6000-6400

The Accel Super Stock wires could be suspect. They are a carbon core wire. They have been known to have high resistance just like some of the cheaper Taylor lines. This can cause instant cross tracking in even a brand new cap and rotor. Just because the cap and rotor were replaced 3 months ago doesn't mean that they are OK now. That's why a physical check is necessary. Don't assume anything.

Ditto with the coil. The ultimate HEI kit would be a safe bet. You're getting a new Cap, Rotor, Coil and module. That with the new wires should eliminate any Ignition problems. Don't forget a fresh set if plugs. I prefer NGK or AC-Delco. Nothing trick necessary...no Platinum or Unobtanium fancy, smancy stuff. A new fresh set of plugs is cheap insurance.

Keep us posted ...Good Luck.

Edit: Spelling

 

Juat a thought.....Can you do a compression check and report back? Want to rule out all possibilities. A burnt exhaust valve or a broken\weak exhaust valve spring might cause some of the back firing out the exhaust. Best to be sure.

I'd still pickup the other items ( Wires and Ultimate HEI kit )...but a compression check is always a good indication of overall mechanical condition of engine ( in regards to combustion seal ).

 

sure i can do a compression check, but i need to get the car running first. so that means i have to buy the stuff, fix the car, and then drive it to school where my equipment is.

the reason why i wanted to buy a new dist. is so that i can rule out that possibly of a bad vacuum advance diaphram and/or the mechanical advance weights.

do you think my carb is defective?

 

You can check the vacuum advance with a piece of hose and suck on it. If it holds pressure the diaphram is fine. Has a pretty strong spring so you probably won't be able to pull it in with your mouth. A Mitey Vac ( vaccum pump ) would come in handy.

Mechanical advance weights are dirt simple. Check them with the rotor on as I described. If they're binding a shot of penetrating lube will free them up. $329.99 is a lot of money for something that can be checked and fixed in 5 minutes. And you don't have to drive the car any where.

I think this might be a good scenario to drive the car to school...whether it's back firing or running like a piece of C**p...and get some of the Teachers to look at it. Do that compression check and report back. Heck...get a buddy to drive you to your local jobber and buy a compression guage. Or borrow the one from school.

IMHO...from all you've been through, and from reading the thread thoroughly, I do not think the carb is faulty....per say. The #1 mistake you made was not checking the float level thoroughly. You had some trash in the Secondary needle and seat which was causing excessive richness...probably from the get go....but you started changing everything else ( in the carb ) right left and center before identifying the real cause. Not flaming you but just pointing out a basic error. You have to check the float level on any new carb as soon as you install it and unfortunately you did not do this till much later in the program.

Order the plug wires and Ultimate HEI kit. Do the compression check. Install fresh plugs. Baseline the carbs. Put the factory jetting back in the thing....#66 Primaries and #73 Secondaries. I do not think that #66 Primary jet are too big, especiially on a 350. Put the jets back to stock for now.

Accelerator pump. Blue cam in #2 hole should be fine for now. #32 shooter in Primary side should be fine. What is your rear end gear ratio? Auto or stick? You may have to put in a slightly bigger pump shooter if you have an Auto and tall gears...but don't do that yet.

Set the timing at 12 to 14 deg before top dead center at 700 to 750 rpm. With vacuum line detached. Make sure that you have no mechanical advance before 1,000 to 1,200 rpm. That will take care of the basics.

Then connect the vacuum advance to manifold vacuum and adjust your idle speeds and mixture settings. Read the links thoroughly that I supplied. A lot of good info there.

Get some help from the teachers at school. Do things in a logical manner and one step at a time.

If ...and only if you have checked and assurred that everything else in the engine ( Compression, ignition, wires, timing ) is 100% ...after all this and it's still running like a piece of garbage, then I would consider calling up Jeg's for a refund.

Wires and HEI kit are a good investment...everything else is just simple checking.

 

Ok here we go

• I’ll order the hei kit, wires and plugs.

• Install everything.

I’m not sure what you mean by the vacuum advance "holding" pressure. If I suck on it, what would happen? Should the car be running while I suck on it?

• Lube up the mechanical advance. Should I leave the weights in there for now?

• Take the carburetor off.
• Pull off the bowls, clean the **** out of everything.
• Reinstall all factory pieces.
• Replace the power valve with another stock 6.5" since I had 2 or 3 backfires through the carburetor.
• Install a 32 shooter on the primary side, leave the secondary shooter at 28 (right?).
• I’ll keep the blue cam on, in the #2 hole.

• Put the carburetor back on.
• Connect vacuum advance to manifold vacuum.
• Reset the idle screws to 1.5 turns out from fully in.

• Install fresh, brand new spark plugs.

Can I run the car with the catalytic converter on? I’m going to have to; because there’s no way I can work on the exhaust where it is in front of my house right now. ASAP I’ll get a delete pipe put in.

If the car runs well after that, then I'll order the Crane ignition box. Is that ok?

 

the car should be off and you need to hook a piece of vaccume line on it then suck on it really hard and hold it on the tip of your tongue and see if the pressure bleeds off or holds tight against your tongue thats the easiest way to do it .....if it doesnt hold tight then your diaphram is bad in the vaccume advance on your distributor....

 

Alright, this is what I ordered today:

 

You don't need the MSD HEI module. The Crane Ignition box takes care of that. With an external Ignition box the internal HEI Module is removed.

Make sure that the Cap comes with a low resistance button ( actually I think the PS-91 coil comes with one )

 

the ignition module underneath the rotor? i also realized that i'll need a GM HEI harness to hookup the box. i dont really like hacking up the wires

 

Yep....the ignition module below the rotor is no longer used with any external Ignition box like a Crane, MSD, Aceel, Jacobs etc, etc.

GM adapter harness a good idea. That's what I ordered as well. Makes things dead easy to hook up.

If you have an early distributor wuth 4 pins on the OEM module then the correct Crane part number for the adapter harness is #6000-6712.

More info here:

http://www.cranecams.com/index.php?s...s&lvl=3&prt=73

 

Well the harness had to be special ordered so it'll be here on Monday or Tuesday. I should have all my parts by then.

One thing though, lets say I replace all of the ignition system, but I leave the cat on. Will the car still backfire? Will it run decently enough at least so I can get it to an exhaust shop?

 

You can run it safely to an exhaust shop. Cat is not causing the backfires.... so it should not backfire if you get everything else fixed.

One thing I was thinking about...sounds really simple but I've done it myself. Are you sure that you've got the firing order correct? It is really easy to mix a couple of leads up. Firing order for a SBC is 1-8-4-3-6-5-7-2. Particularily check leads #5 and #7 . very easy to cross these. Car will run, but roughly and it will backfire if two leads are crossed.

Also...use proper wire separators. Do not tie the wires together with zap straps like some people do. This can cause a " inductance " crossfire. You have to be particularily carefull with leads #5 and #7. It is recommended that you keep these two leads as far apart as possible. I run #5 through my wiring loom and run #7 behind the valve cover.

 

Got some of my stuff today. I'm not sure if they sent me the right PS91 coil though

edit: Damn, I ordered the wrong coil. Also, the coil does not include the low resistance button.

 

snip:


WRONG!!!....I think . Take a look at my manual:



Doesn't that illustrate that I need the module (see 'To GM Module')?

Here is my old ignition module and another cylindrical type thing (not sure what it is)

And here is my mechanical advance:



So can I keep the MSD ignition module that I ordered from Jegs?



p.s. I shot off a bunch of pictures on my carburetor, distributor and engine bay so if you want me to post them just let me know.

 

No...repeat NO...you do not need the GM or MSD module. Read all of the manual CAREFULLY. You are looking at the hook-up for a 6000-6713 adapter. You need to be looking at the instructions for a 6000-6712 adapter, which is the one I said to order ( 6000-6712 ) and hopefully you did order.

Edit: The 6000-6713 adapter is used for GM vehicles that have a computer and use a 7 pin module. The 6000-6712 is used for a 4 pin module, which is what you have, and hooks up in an entirely different manner....bypassing the factory\aftermarket module altogether.

 

With all these problems you've been having, have you checked your total timing? because it looks like your mechanical advance center plate is installed upside-down. (I had the same problem with my brand new summit hei distrib.) The weights should act upon the rounded part of cam, not the flat part. I doubt your seeing much mechanical advance with the cam installed like that.

 

Good eye!! Also looks like it is a POS aftermarket Cam and Spring set. The cm profile in those things are absolute junk. You are much better off with a stock cam. If you can find a Cam and weights from mid-seventies chevy trucks or a Caddy these have the most advance.

Also looks like he has very light springs in there which may be why his idle speed will not remain stable. Timing at idle is probably fluctuating due to the light springs.

 

Sorry to but in but I installed the lightest springs and it does make idle unstable. If wanting to use the light springs, time it with heavy springs first at idle and then remove and put in the light ones.

Also, Chickenman, what is manifold vacuum versus ported on the holley? Are you talking about the port in the back of the manifold, say the Edelbrock RPM, that the brake booster runs off?

 

In regards to manifold vaccuum...most carbs have a choice of Manifold vaccuum or Ported vacuum.

Manifold vacuum is taken from a small port located just below the throttle plate. This delivers the same vacuum levels as a fitting plumbed straight into the manifold, such as the one that the brake booster runs off of. Thus the distributor receives full manifold vacuum at idle.

Ported vacuum differs only in that the vacuum source ( on the carb ) is taken from a small port located just above the throttle plate. This delivers exactly the same vacuum as manifold vacuum..... once it is uncovered by the opening of the throttle butterfly. Thus you would see no vacuum at this port at idle, but as soon as the port is fully uncovered by the throttle plate you would see the same vacuum readings as taken from a " Manifold " vaccum port.

Some people have the misunderstanding that ported vacuum on a carb is taken from a port in the carb venturi and thus is controlled by venturi airflow. This is simply not true. Most carburators, be it a Holley, Q-Jet, Edelbrock, Weber or SU use this universal method of Ported and Manifold vacuum.

Manifold vacuum source from just below the throttle plate.

Ported vacuum source from just above the throttle plate.

I have never seen a carb that actually uses a ported vacuum source taken from the venturi area.

Edit: Spelling

 

ok, update.

i installed the msd ignition module, msd carp and rotor, new ac delco plugs, msd 8.5mm wires. the car runs smoother now and the idle is a bit more stable. i am about to set the timing to about 12 advance and check the plugs.


so far i havent gotten the fireball coil so im using an accel coil. no hi06 box either, because i CANNOT figure out how to use it without the ignition module.

 

Crane seems to have complicated things with their new part numbering sysytems and WeatherPack connectors ( Plug and Go ). On the first page they have a notice that you should use a 6000-6400 Part number for the older 4 pin GM HEI distributors. ( No where is that listed on there on-line site... Grrrr ) On the other hand...read a little bit farther and you find that the 6000-6440 series can be used on the earlier 4 pin modules as well. Confused??? So am I...

It's no big deal...just confusing at first. My Crane is an older unit and did not use Weatherpack connectors....

Read page 10 on installing the Crane Box with older GM HEI ignitions with four pin modules. Then refer to figure 16 in the Instructions on Page 20.

http://www.cranecams.com/pdf/90006000e.pdf

You may or may not need the adapter # 6000-6712....I prefer it as it makes a solid snap lock connection rather than relying on spade terminals.

Here is what a 600-6712 adapter looks like. Go to page 8.

http://www.cranecams.com/pdf/90006400a.pdf

( Sorry. I've only got Adobe Acrobat reader. Doesn't allow me to copy and paste text or pictures. )

This is from an earlier design of the 6000-6400 without weatherpack connectors. But I think you can easily see how you adapt for use on the later 6000-6440 series. I don't know if Crane supplies the male WeatherPack connectors to attach to the 600-6712 adapter cable...but they are universal and dirt cheap.

Hope this helps.

 

Well I just bought the adapter cable to use with the MSD ignition module. Do you think I should go without the ignition module?

I checked the spark plugs and they are black again . I am running rich. Should I jet it down?


Edit: and is my mechanical advance screwed up?

 

Guess so..go down two sizes on the Primary. Make sure that float level is correct and holding constant. No gas dribbling out of boosters allowed. Read my previous post regarding instructions.

1: Make sure that the idle mixture is set correctly as well. Set it with a vacuum guage. Warm up the engine fully. Start with two turns out. Turn in 1\4 turn at a time. Watch the vacuum reading. If reading stays steady, lean out 1\4 turn more. Continue leaning untill vacuum reading just starts to drop or waver. Then stop. You can now go 1\8 turn leaner or 1\8 turn richer depending on what your engine likes.

2: If, on intitial setting ( two turns out ) the vacuum reading starts to drop as soon as you turn the mixture in...stop.... Return to previous setting then richen 1\4 turn. RPM and vacuum should increase. Richen 1\4 turn at a time until rpm and vacuum does not increase. Don't go too far. Once this point is reached, lean the mixture 1\4 turn at a time until vacuum reading just starts to waver as in step 1.

BTW...you cut off the upper part of the instructions when you snapped the picture. If the top part was shown it should have stated, in the left hand upper corner, that those instructions were only for GM HEI distributors with a 7 pin module. For Computer controlled distributors without vacuum advance.

 

I don't know....I don't have x-ray vision. Have you checked it like you've been asked? Seriously..you've got to take some initiative yourself. You've been given lots of suggestions...but if you don't follow them in a logical manner then we can't help you.

You've already been told how to check it ( in this thread )...NOW DO IT!! Lots of links and info supplied. It's up to you now.

I'm going away for a week. I expect when I get back that you will have thoroughly re-read this post and all the links....and have read your Crane HI6 instructions from front to back . You're gonna have the HI6 box in. The distributors gonna be all be set up and timed. Carb should be running lean and mean.

There is no " try" ...there is only " do". Now git out there and " Do" it. End of rant.

 

ive bought 4 edelbrock carbs and not checked the float on any of them and they fired right up and never had a problem at all . that weird ????but maybe i must have gotten lucky.. huh??

 

Yeah..I've done that to. But then I also had a pair of Weber carbs at $500 a piece. One was perfect...the other was miles out. It always pays to check.

 

yeah i guess it would suck to have it happen to ya for sure. guess ive gotten lucky

 

Dude, I have been taking initiative. I have been givin MANY suggestions (especially from you) and so far I've tried pretty much everything you have suggested. I've been doing this as logically as possible. Also, I have spent well over $500 on just your word alone. Don't go and say I haven't. You of all people should know that this crap is damn frustrating. On top of that this is my daily driver, so it's a real pain in the ***. This is my first real experience trying to tune a carburetor...

 

Trans_AM_88
are you and him related he sounds like your dad