You had vacuum on the ported vacuum port because your throttle transition slots were exposed. You had the idle screw so far in to run at a normal idle speed due to the timing being off. That was evident by how much your idle speed increased by turning the distributor. Good vid.
Thank you so much for this video. I couldn't for the life if me figure out why my 67 buick skylark 340 wouldnt run right. Shop manual said set ignition timing to 5°. After I did that, it would backfire out the carb, it would run like crap. I thought I had mechanical issues. Did this procedure and it's running amazing now. Sits at about 15°, smooth as glass now. I've only messed with new school. You explained what to do perfectly. Thank you!
@@jamiepatrone834 what he is doing at the ending, he adjusted timing for best vacuum, but that detonated under hard ecceloration, so he backed the timing off.
I like video just cause it's well done! It's not that highly modified. The cam may have a higher lift but from the idle it doesn't sound lumpy at all. Total timing should be 36 -38 degrees for a small block chevy. 40 -42 big block. Be careful. Looks like it's way to advanced. Shouldn't be starting that way. Thats a big flag, to much timing when it tries that hard to start. Good luck!
I used a recurve kit and limiter plate in my mopar 383 distributor. What a difference in off the line power! I learned quick that the car manual timing setting is for and distributor springs (recurve ) is for the safest and most economical. Amy change to an engine , even a small change in a stock engine constitutes adjusting the timing. It doesn't have to be an internal change either. A different distributor is a must to adjust timing. The performance distributors come with different springs and ive read that its usually the heavier spring that should be swapped out to bring in all the timing at a lower rpm. Dont set it to factory, but to the way the car runs best I dont know what the previous owner did to my 71 383 because i bought it that way. I have 14 degrees in the distributor (set it this way by using a limiter plate). I put a lighter spring in (recurve it) so all the timing comes in at about 1800-2000 rpm. (The weights in the distributor sling out at 1800-2000 rpm. My initial timing at idle, is 20 degrees before top dead center. Thats a Total of 34 degrees overall timing. What a seat or the pants difference ! Im still learning about carburetor tuning so ill be tinkering with that to see if i get more improvement. Great video!
For a relatively small discussion this one has an amazing amount of misinformation. Setting timing with a vacuum gauge may have been good enough in the pre-50's era when nothing made much power but it's a different story today. First of all you need either a dial back timing light or a crankshaft pulley marked in degrees to about 50 degrees. The most important number is total mechanical advance which is determined by revving the engine past the point at which the timing stops advancing. For a smallblock Chevy, or Ford for that matter, it should be 36 degrees, plus or minus 2 degrees and it should be all in between 2500 to 3000 rpm. This is, of course, which the vacuum advance disconnected, and will give maximum horsepower. If the timing continues to advance beyond 3000 rpm the distributor needs to be recurved with lighter advance springs. Once you set maximum timing you check your advance at idle. As long as it is somewhere between 8-15 degrees and the engine starts easily you're fine. The next thing to do is connect vacuum advance. Some engines idle better with ported, others direct manifold. The ONLY difference between the two is at idle. The instant the throttle is opened they are exactly the same.
Good video. Rule of thumb: Turn the distributer until the maximum intake manifold vacuum is reached, then turn the distributer back so the vacuum decreases by one inch. Lock the distributer down. See, you didn't need a timing light. Also, after 2 or 3 weeks of running this set up, you notice the engine is now misfiring at over 50 mph, remove and sandblast the spark plugs and reinstall. If the misfire is now gone, replace the spark plugs with a set that is one heat range hotter to burn off the excess carbon that was fouling the plugs.
I use the vacuum gauge to set my timing. I move the distributor until I achieve my highest vacuum reading. I turn off my motor and restart it again. If it starts up right away. I leave it. If it studders like his restart. The timing is to high. Lower timing down and restart the motor again. If it starts up with no studders, you are good to go. If it does studders, reduce timing even lower until it studders no more.
It pings because you have too much mechanical advance in the distributor. Total advance = base + mechanical. If you increase the amount of manifold vacuum, those Vette brakes will have a much better pedal. Good luck.
Thanks for posting this. Im new at carb tuning. My f100 has hard starting issues. I have no vaccum leaks but it will only fire right up if the choke is fully closed when cold. When hot i have to manually open the choke all the way then it fires up. If i dont open the electric choke fully when hot it will just crank. Is the problem at the electric choke? Also, In traffic i lose Rpms and it stalls too. I have edlebrock 650 carb
It sounds like the choke needs adjusted. I think the reason it loses rpms and stalls in traffic is because the choke isn't opening (at least not all the way) and it is not getting enough air, in other words it's running rich. Here's a video that shows how to adjust it. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-QbRKe8q4LmY.html That guy is in southern California so he leaves a little opening for the choke. In Ohio, I try to adjust it when the engine is cold and the temperature is around 50 degrees. Then I turn it until the choke just closes all the way. That has always worked for me. If turning the choke isn't moving it, open the throttle to relieve the pressure from the linkage. That should free it up.
@@fun-cars Thanks for the reply and vid! I will give it a try. I noticed I have the most consistent starting without the air filter on. So it really leads me to believe something is choking out the engine literally.
@@fun-cars I was able to adjust the choke it was stuck like you said but I tapped on it lightly with a hammer then use channel locks to loosen it up. I was able to make the adjustment thanks
@@dreamingcode Awesome. I was thinking of telling you this before but I didn't want to make things too confusing but, the air cleaner should only be tightened firmly but not too tight. Tightening it too much can warp the shape of the air horn and cause the choke to stick. It's possible somebody did that in the past. Hopefully, now that you got it loose, it won't stick in the future.
When using a vacc gauge do you have to ignore timing marks on the crankshaft pulley is that right With my 289 standard if I use 12 degrees I’m slightly under when I turn the distributor and use vacc gauge I can get 20 tighten down check with timing light and I’m about 15 mil forward of the 12 degrees is this ok
The ported vacuum port only has vacuum once the throttle is opened. The manifold vacuum port always has vacuum when the engine is running. I believe all carburetors have both. In my video when it had about 3" of vacuum the throttle was probably slightly open.
I heard people talk about setting to the highest vacuum on a automatic transmission car by putting it in drive with someone holding the breaks. I usually just have it idling in park. What say you my friend?
My guess is that having the transmission in drive might prevent mechanical advance from kicking in. I don't think it would be much. To me, the most important thing is to eliminate any pinging.
@@fun-cars i get pinging mostly on something like when I hit passing gear of anything like that. I've tried a lot of things to eliminate it but it shows it's ugly head on hard throttle 😖
@@raymondmenendez6499 pinging is usually caused by too much advance. You might need to back it off a little or use a higher octane gasoline. A vacuum leak can also cause it because it makes the mixture too lean.
@@fun-cars been there, done that. 🤭. I even got some Octane booster to go along with the 93 that I'm using. I can't list all the things I've done/ tried. Besides a rebuild, but I'm worried about spending that kind of money and still have the issue. Thank you for your input 🖖
I don't know what brand I have (I can't look right now) but I don't think you need to spend a lot of money. I'm sure you can get a decent one at summitracing.com. Just read the reviews and you should be able to find a decent one. When it comes to vacuum gauges, the accuracy of the number isn't (in my opinion) all that important as long as it shows the changes in vacuum. Hooking up the tach depends on whether your car has HEI ignition or not. On HEI ignitions (usually '75 and newer) there is a square box with two terminals on the side of the distributor cap. You can see the square right at the beginning of this video at the bottom off the screen. One terminal should have a large wire attached to it (probably pink on a C3 Corvette unless somebody changed it) that provides power to the distributor. I believe that one will be toward the rear of the car as long as somebody hasn't installed the distributor wrong. The second wire should be right in front of that and dhould be brown.That is for the tach. You can remove that wire and use a short jumper wire with a female spade connector on it and connect your tach to it. Just replace the brown wire when you are done. If you have a separate coil (usually '74 and older) then you just connect the tach to the negative side of the coil. it should be marked but the other way of locating it is to find the small wire (not the one that looks like a spark plug wire) that goes from the coil to the distributor. That is the negative wire. My car is a '74 but I upgraded it to HEI. I hope this helps.
There are a few things that can cause pinging. 1. Using a lower octane fuel than the engine requires. If your engine has been modified to a higher compression ratio, you may need premium gas. 2. Vacuum leaks can change the air fuel mixture. You can find a vacuum leak by spraying carburetor cleaner around the possible leak points (base of carburetor vacuum hoses, intake manifold where it meets the head). If the idle speed increases, you have a leak in the area where you sprayed when the idle increased. If your headlights don't work properly, you may have a leak in that system. Power brakes being hard to press indicates a leak in that area. 3. Timing too far advanced. Adjust timing a little. Turn the distributor so that engine speed slows down a bit and test drive again . 4. Hot spot in one or more of the combustion chambers. Can be caused by carbon build up or something like a cracked valve that causes a thin spot that gets red hot and ignites the mixture before TDC (Top Dead Center). Yes,, I did get mine to stop by adjusting the timing. Good Luck.
Can you please help me by answering my question about my blazer 1973 with a new motor it won't you don't even talk about trouble st as ring a motor . So please h as ve something on a 350. Chevy blazer 1973
RU-vid didn't send me a question from you.. From this post it seems like you are having trouble starting the engine. There are two major reasons an engine won't start. No gas getting to it or no spark at the right time. The first thing to do is check for both of them. If you have gas and spark then it is likely timing. The first thing I would try is having someone crank the engine and turning the distributor while the engine is cranking. If you don't have a helper you can rotate the distributor as far as it will go in one direction (lets'say counter clockwise) and try to start it. If it doesn't start, move the distributor clockwise about a half an inch and try again. Repeat this until you find a point where it will start. Then tune the engine. If that doesn't work then the distributor might have been installed out of time. My channel has a video on how to do that. If you have any specific questions on anything, just ask and I'll try to help.
That engine was highly modified by a previous owner but I don't know what cam it has. Do you know what the timing spec should be? I tried using a timing light but it runs better after using the vacuum gauge.
@@fun-cars ya with distributor vacumm disconnected and plugged set timmong to 6° BTC. You can tell by the sound of the engine and your vacumm gague readings at idle that cam is not high lift or long duration and is pretty much a stock 350 cam. It does not even have a loppy idle
@@yezok01 dont know were you got that from,but any engine machined and cammed needs to start at 10,that 6 degrees from factory is also for all the emissions,if you check the rpm should also be 750 with the 6 degree,when you bore the engine and use a better than stock cam all the factory stuff goes out the window
Yep. The problem with this is that at idle with no load, the engine is going to like lots of timing. Then the problem becomes you'll have way too much timing under load and at above 3000rpm.
