cfm carb for Buick 350...places sell 600 and 650...is that enough?

Ok I'm glad that were all good. I know there are a few different ways to check for a vacuum leak. I just spray a little carb cleaner you just got to be smart with it try to keep it away from the exhaust. A safer way is to use propane enrichment. Get a small bottle of propane the one you use for soldering get a tip with an on off valve but no built in igniter slip a piece of small vacuum hose over the tip (you may have to use an adapter to down size the hose) Engine running turn your propane on just a little and point the hose any where you suspect a leak (carb base plate, intake /head, any vacuum nipples, brake booster. if you have a leak you will here the engine idle up when you hit it with the gas. I would keep the vacuum gauge connected because the needle will also rise.

 

I wouldn't suggest propane as it is flammable and the best results would be something that will seal up leak as with a solid liquid would do.

 

I thought using a flammable liquid would be a bad idea too but what do I know, I thought checking for a good spark might be something to look at since it looks like a lot of other things were checked and so far the man still has a problem with the motor, but our new 20 year mechanic just could not believe that it was suggested. :blast:

This is one of the reasons I do not like to post on here that much anymore, someone always has to pick at your suggestions. I don't care, my car runs 11's or 13's just depends on how I want to run it, I have it figured out.

Gary Farmer and Larry should get OP figured out, It actually should be done by now but is not. I thought the OP had a new carb from Cliff, if so it should be fine if the correct specs on the car were given to him. This was the reason I went with checking the ignition system and you might as well check it all while you are there, including good spark.

Mine will shoot lightning bolts 1/2 inch from the spark plug wire to ground. When my coil was bad it would shoot sparks but the car would not start. The spark was about 1/8 to the ground. Put a screwdriver in the spark plug hole of wire and have someone crank over the engine to see how good the spark looks. I do run a MSD system and this is all different than stock so you may not get the same results as I did.

Just forget I said that it is a crummy suggestion anyways, right?:idea2:

 

Propane enrichment is what is used by dealerships tune up centers... I have personally used it even when I was younger I worked for precision tune it was part of the training along with all the scopes and analyzers I believe on one of the machines it would prompt the tech to use the gas as it was checking emissions it was to aid in finding a lean skip. You need a gas or something that will burn that is what makes the change in idle so it can be determined that's were the leak is if spray water or wd 40 or something like it is not going to affect the idle. I wouldn't be spraying anything with a sealer in it around the Carb. Like everything under the hood you need to be care full. I am totally not bull sh***** on the propane it is what it is

---------- Post added at 09:08 PM ---------- Previous post was at 08:58 PM ----------

Hey Fox's den I issued an apology to any one I have offended. But I think I owe you a personal apology I was having a bad day/days but it's no excuse I was out line and acted like an ass. Please accept my apology

 

No such thing as a solid liquid, and the propane used is not a liquid it is a gas. I know it might sound dangerous but its just what is used I wish I had a better answer. Now what is probably more dangerous is using carb cleaner but I'll bet if you were to poll local service stations, garages, dealerships you would find they all do it. Common sense don't spray it on your exhaust (But I'll bet you that it evaporates before it catches fire) Also I'm not talking about empting the can just misting an area.

 

Apology accepted brother we are all crazy on here. I guess if you have used propane with no problems it will probably work, you would know about it since you are a mechanic and have been doing it for years. :beer

I don't think carb cleaner is a good idea either, besides the chemical is strong and may cause other problems. I wonder if a can of air would work.

 

I'm sorry if it has already been suggested before I could have missed it of forgot it But if you don't have any luck with the timing and can't find a vacuum leak maybe you could borrow a Carb. Off of something close to stock if not stock. Now I'm not talking about a Carb from someone's basement that might have ran good back in ??? I am always the guy that says don't just go throwing parts at it but in this case if you have access to one for the 10 min. it takes to swap it and another 10 min road test its worth a shot. Even if it's not correct for your set up like say a performer or a holly I'm not concerned about how much more or less HP it makes it is just a control using a (Known Good Carb) This would put to rest any and all chances it is the Carbs fault. If you find the Carb to be bad then get another 4GC or what ever you like (I'm not getting into the whole who makes a better Carb debate) Wow did that get ugly.

 

I suggested propane to check for vacuum leaks pages ago too...but whatever works.

Something's not jiving and until OP can get the time to check things we're just inflating the thread with suggestions he may not even need just yet.

Let's give it some time and see what Jason can come up with, then we can work from there.


(stock Buick 350 should idle at around 550 RPM with 20" or more vacuum) If it's idling at 700 and there's only 17", sounds like it could very well be a leak somewhere, and you're not supposed to use the metal intake gasket with the TA intake. TA recommends using composite gaskets for it, so that just may be the problem.

 

The digital timing light says I am idling at 500 rpm. Is that enough rpm? Should I turn in the carbs idle air screw to bring it to 550?

At 500 rpm the initial timing is 2.3 degrees advanced.

At 2500 rpm the total with centrifugal advance is 22.8 degrees advanced

So centrifugal is giving me 20.5 at 2500 with out vacuum advance.

Can I hook up the vacuum and get a reading with vacuum advance?

 

If you are using the composite gaskets you have to cut the valley pan gasket to eliminate the ports and using the valley pan only to keep the oil off the intake. This is what I did with mine. You can actually buy just the valley pan from AMP.

The idle speed is all over the place depending on year of car or engine.

From my Chiltons manual, 1970 350 600rpm in drive auto trans, 1971 same, 1972 650/500. I would put it at 550-600 in drive and be done with it. After this, you adjust the idle mixture screws to obtain the highest idle speed possible, or the highest vacuum reading, then readjust the main idle speed 20 rpm higher, then readjust the idle mixture screws to reduce this 10 rpm to get back to the specified idle speed. Seems like a pain here for this I would put the idle at 550, but that is what the manual wants you to do. Besides, idle speed will not effect the bog situation going on here.

 

Yeah I should have added that part in about using the metal valley pan and cutting the ports away to use the composite. I knew that, but didn't say it. I guess I should stop assuming someone else knows what I'm talking about. It would certainly cause less confusion.

I just tossed down a number for idle. Anywhere from 500-600 should be fine for pretty much any (stock cammed) engine--wherever it runs best at.

Personally I like how a low RPM smooth idle stock cam sounds, so mine was around 500 RPM.

 

It idles fine in gear too, (even lower).

Timing at 3000 rpm is 30

One spring is blue, the other silver. (Crane kit)

I found the sheet from the crane kit, it says:

................................Full advance in
blue/blue...................3200
blue/silver..................2800
blue yellow.................2600
silver/silver.................2200
silver/yellow................1800
yellow/yellow...............1600

 

I like the 500 rpm too, that is what I would probably end up doing myself. I went back to the original post in the beginning and I thought it was funny how the link to the carbs said they are a direct fit, yeah if you have a TA intake but not the stock intake with the spread bore secondaries, this shows you how stupid they are.

They must think a 68 69 Buick 350 is really just a Chevy motor in disguise. The Edelbrock will not even fit the stock intake with out an adapter and that adapter makes it run like crap, I know I have another Buick 350 car that is just stock only and I have the Carter AFB that I had on the TA intake on the race car and I just could not get it to work on the stock intake car no matter what jet or rod combination I used. Q-Jet only for the stock intake. I rebuilt that Q-Jet and just put it back on the stock car. That was when I found out how much of a pain it was to take the Q-Jet apart to rebuild it. Glad I have that Holley on the race car.

 

While I had the dist off I put in a yellow spring to get it closer to in (30) by 2500. (blue/yellow springs.................2600)

But does this confirm that I was over timed when the vacuum advance was hooked up? I mean I am at 30 degrees at 3000 with no vacuum advance, in this test.

 

I agree with Smar, try bumping up the initial advance to 7* or so and I bet that helps (just loosen the dist.and give it ~ 10* twist in the direction the canister points & retighten). If it does help, you will know what the problem is at least. From the figures you given it looks like the timing is a little late. Of course you could just do it properly and follow Larry's timing thread step by step. But until you actually try something with the timing we won't know if that is the problem.

 

Vacuum advance will only work on a high vacuum situation,such as cruising,or idle. Vacuum advance goes away when you stomp on the gas peddle,because vacuum drops,that is where your centrifical advance kicks in advancing as RPM goes higher. Vacuum advance is for better mileage and drivability for a street driven car.

Your total centrifical timing should be 34-35 degrees coming all in around 2,500-3,000 RPM,checking it with your vacuum advance disconected. After that is setup properly,connect the vacuum advance and make sure that it doesn't advance it futher than the 34-35 degrees,if it does,you may have the wrong canister on it,but can be corrected to still use it by limiting how far it will be able to advance the distributor by welding the slot to shorten it to stop where it needs to stop advancing.

In other words,you don't want more than 34-35 degrees of advance with or without the vacuum advance hooked up.GL


Derek

Just read Larry's post,I like a little more advance,but listen to Larry and set it to 32 degrees.

 

So I can hook up the vacuum advance and read an accurate reading with the timing light?
Is this only relevant if I use a manifold vacuum source?

When hooked up, I have my vacuum advance hooked to ported vacuum so there is non at idle for me.