I have one of those actron point/dwell/rpm gauges which is what I use to check dwell and set the RPM, the needle did not move a whole lot I think it is more the video as I am using my Galaxy S3 to record the videos. The needle did move a little but it was never really more than 50 rpm at the most as I have the idle speed set at 700-750 rpm when I set it last so the in gear idle speed would be at I think it was 650 rpm is what I set it at in gear.






If you want I can take and get my gauge out hook it up on tach and crank the car up and let you see how the RPM is doing at full idle in park wouldn't be hard to do and I can upload the photo. Atleast that will verify if its wandering like the video sounds or if its just the way the video recorded the sound.

 

I don't think that is necessary. If you don't actually hear a fluctuation then there probably isn't a problem and it can probably be chalked up to the sound quality of the recording.

Re the 50rpm variance
if that's + or -, then I think that is excessive. For instance, if the target rpm is 700 and it varies between 650 and 750, I'd say that indicates a problem.
if that is a total sweep of 50rpm, target 700 and varies between 675 and 725, that's not too bad though you still might check things out.

The drop from neutral to drive is pretty good.

Another great tool to have is a vacuum gauge.

 

I have a vacuum gauge as well, I used it after fabricating hard lines for the Autolite 2100 to the double action fuel pump and back to the wiper motor. I can not remember what the vacuum was but I do know it was with in specifications when I tested it before the wiper motor but after the double action fuel pump.


I know a video is not needed but I would like to get this old engine running as good as possible so I did take a video. the video below starts off with the engine on a cold fast idle (was cold actually) and it is running at just over 1,500 rpm I need to how ever adjust this back down as I had the fast idle at 1,200 rpm but after installing the oil bath air filter I had to idle the engine up but forgot to turn the fast idle screw back down.


The slow idle speed is shown to be just under or just at 850 rpm. Later in the video you see it does bounce around a little as the engine warms up more and drops to around 800 rpm. But being honest it is more random than a steady surge up and down rpm wise it holds steady while the needle wanders just a little. This wander how ever is not more than 50 RPM at worse. In the video you can see its probably around 25 to 30 rpm. I also have to correct my previous statement I remember now after having the tester hooked up my idle speed in park/neutral is 800rpm roughly and in gear is 650rpm. Been months since I checked this so I was incorrect on the 750 to 600-650 rpm in gear.


The dwell, it registers at idle to be 29* and when racing the engine up some it drops to 28* and I believe if I were to race the engine up more it would drop to 27* but I was having a hard time reaching from the passenger side to the driver side to reach the throttle. I believe if I remember from my shop manual spec on the dwell is 26* to 28* which having dwell at 29* is 1* more than spec.


In the end if you believe this is a common sign of the dist being worn I have no problem replacing it but I will probably do it down the road as I don't drive the car and I gave up on my July goal of having her on the road. Texas is a pain in the rear for transfering ownership of a vehicle without a title so I will be waiting till after I move out of the big city to deal with more helpful people. Plus back on the topic of the dist, I had already planned on getting another dist as this one the dual vacuum can was replaced for a single vacuum can when the original Holley 4000 was taken off. I have the original intake and Holley that was taken off this car back in the late 70s early 80s that I planned on putting back on. I haven't found anyone selling not even on ebay just the dual vacuum can so I had planned on buying the whole reman dist and paying the core.

 

It looks good to me.

On the subject of the distributor, an Autolite 2100 must be used with a 1957 or newer distributor in order for the distributor to function correctly. From your description, it sounds like you are still running the load-o-matic (older than '57). That will cause problems that can only be fixed by installing the appropriate distributor.

 

Hey Rusty

One thing I've noticed on these is they won't idle smooth at lower RPM unless everything - timing, ignition, valves, compression, carb fuel mixture, vacuum leaks, etc, is up to speed or where it needs to be.

Spec is 550 for a M/T for example - once engine is thoroughly warmed up though - what's it idle like at 550 or even say 450-500 RPM? (just for test purposes) Steady and strong? Idle speed should always be rock steady regardless, on a stock motor at factory spec. An engine in poor tune won't likely idle at all at 400-450, but a solid motor will to some extent.

If the distributor is worn excessively, it will not idle smooth at factory spec. An engine that won't idle right won't run well at speed, either. A new dizzy unit will make a tremendous difference in idle and all around performance and driveability if this is the case. Old units not only wear out, they become erratic or kind of "intermittent" even - gummed up, and won't advance or retard smoothly. Wandering idle is one symptom of excessive wear.

600 RPM or thereabouts is right in the "sweet spot" where a stock Y Block motor sounds best, I think. The "one potato two potato" lope, is music to my ears. (Ok, I'm weird) This is where ears are better than a tach maybe. Speaking of, have you adjusted the valves lately? That's a lot of clatter, even for a Y block. Or maybe it's the nature of the recording itself. Search out Walt Nuckels and his Y block adjustment method. Real slick! Hope this helps.

 

Yes, the dist is a '56 Load-O-Matic that had the dual vacuum advance can replaced for the 2bbl ingle vacuum advance can.


What kind of problems would this cause? I hate to purchase a '57 and up vac/mech advance dist now considering I planned on throwing the Holley 4000 and original manifold back on, I just left the 2100 on cause I know those good enough to adjust them to get the engine running good then swap it over to original and then reset everything.


the needle is the same reguardless if I turn it down to 500 rpm or up to 650 rpm while in Park/Neutral. the only thing is theres a vibration you feel in the steering wheel and if the door is open you can see the door is gently going up and down as the car is vibrating as a whole. this only happens if you have it in gear. If you come out of gear to bring the RPM up everything smooths out again.


I believe it is a product of the video recording, I did hear one make a little noise but the video makes it sound like every lifter is rattling. In person that is not the case. I adjusted the valve train twice actually. Once was done when rotating the engine by hand the second time was using a remote starter. the second time actually took and stayed I think I didn't get it right the first time.

 

The vacuum signal that the distributor requires (and the Holley 4000 provides) is totally different than the vacuum signal provided by the Autolite 2100 and most newer carburetors from 1957. This means that your advance does not work properly.

I'm not well versed about how the load-o-matic functions. It seems like there was a great article about it in Y-Block Magazine in recent years, but I can't find it. If you run ported or manifold vacuum to a load-o-matic distributor, I think what happens is you get full advance immediately and it drops off as vacuum decreases, pretty much the opposite of what you want. Do you have an understanding of how advance curves should look? Put the timing light on there and see what's happening.

The 1957 and newer distributor will work with the Holley 4000 and is actually a great upgrade because it uses mechanical advance. The vacuum advance on the '57 up distributor is really for economy and is not required for the engine to run well but you can use manifold vacuum for that and it works just fine.

 

Ah ok that makes sense, I wonder if its possible to install a newer style vacuum canister and the advance operate as it should. I really don't know how they did this set up but I do know how a advance curve looks I can pull out my test light one day and see what advance is at idle, 1,000 and 1,500 rpm just to get an idea of what the advance is trying to do.

 

There is no vacuum canister you can put on a load-o-matic distributor to make it work with a new carb. You must install the newer distributor if you want to have a properly functioning advance curve with a newer carburetor.

 

I will be giving a try what a old timer at work told me. He said it in his opinion sounds like the idle mixure is not set right. Told me to put the car in drive and adjust the idle mixtures.


I will give that a try after all I have to adjust the fast idle speed down anyways so doesn't hurt to give it a try, will also try it on my mercury before I install the new dist I ordered yesterday for that engine.

 

Use your vacuum gauge to set the idle mixture. It's not required, but it really helps to also be able to see the result that even a slight turn of the needle can make. It'll never be audible hardly or visible on a tach, but it will show up as another 1" of vacuum.

Give the throttle a quick blip between adjustments to clear the carb, and wait a few seconds for the adjustment to take effect. Ensure initial RPM is set to spec and then adjust RPM up or down as required after mixture adjustments.

The idea generally is to lean out the idle mixture as much as possible at a low RPM, and esp. note that the throttle plates will be completely closed at idle, with only T slot exposed. This means only the idle circuit is in play at idle.

 

I agree as well.........it may very well be more than fuel mixture adjustment (additional tuning required...including valve adjustment) but the FM would be my #1.

 

I will be doing that, I will disconnect manifold vacuum before my dual action fuel pump to get actual engine vacuum reading. I played with the idle mixture a little after I installed the air filter but not a whole lot.


I will try to do this this weekend if possible.




I do have another dist coming in for my 351w in my merc as she is pushing 200,000 miles and as far as I know never been replaced but the idle quality in gear is constantly floating around but runs great acceleration wise and I had to set my idle up to 750 rpm in gear cause the engine just didn't idle worth a damn it should be 750 with the A/C on and kicking the RPM up but base line idleshould be on that one a 500 to 600 rpm.

 

I went ahead and played with the carb adjustment today before the rain came in.


I hooked up my vacuum gauge to the metal hard line from the fuel pump to the wiper motor as it was easier than doing the other hard line at the carb since I wanted to ensure the air filter was installed for the adjustment.


I also hooked up my tach/dwell meter to ensure that I could adjust the idle speed if any changes came about.


Before I started at 850 rpm in park/neutral the vacuum gauge was pumping between 15 and 16 inches of vacuum and it was swinging back and forth which had me thinking at the time it was the vacuum pump on the fuel pump causing this swing.


I placed the hand brake on and put the car in reverse while the passenger side front wheel was chocked on the rear side. I then turned each idle mixture screw in till the engine started to run rough and acted like it wanted to stall out. I then took note on my snapon adjuster where the arrow was pointed on the **** and turned the idle mixture screw out 3 full turns. Did the other side the same way and the vacuum gauge when I checked it was holding a steady 17 inches of vacuum. The vibration that I was feeling in the car is 99% gone now and the motor was like a rock and was not moving while idling. I let the engine idle a little more and as the temp gauge got in the middle of the normal range a little vibration in the motor you could visably see came in so I turned out each idle mixture another full turn for 4 full turns out from wanting to drop dead and it seems to be running great. Still has a little vibration in the body but the engine has power doesn't feel sluggish and best part of all with the engine idling in gear with my wrist on the steering wheel my thumb is not vibrating like crazy. Still a slight vibration on my thumb but its not like the car has a hotrod cam in it resulting in a harsh idle.


I also released the park brake and touched the throttle a little and I will be damned if the car did not try with the low tire it had and climb up over that huge rubber wheel chock I got from Northern. Car always felt a little sluggish when you gave it throttle and it felt like you had to press a little on the throttle to get her to move she actually is very responsive now.


Best of all the idle speed is from what I can tell even more of a stable 850 rpm in park and 650 rpm in gear. I might idle her down just a smidge but I want to let her cool off and check the fast idle speed again just to be sure. I also have my vacuum wiper motor hooked up again I want to check to ensure theres not a vacuum leak there causing this issue.






Also I forgot to mention 19 inches of vacuum at idle in gear at 850 rpm and 20 inches at 1,000 and just blipping the throttle trying to get her to idle down before the adjustments the vacuum never dropped but shot up to 25 inches. So this fuel pump I rebuilt exceeds the 15 inch vacuum at 550 rpm spec easily so I am happy just need to buy a new vacuum wiper motor as this one you turn it on the wiper moves up a little then holds steady and you hear a hissing behind the dash.

 

The fuel pump vacuum line is not where you need to hook up the gauge. The whole point of that is to maintain vacuum during low vacuum situations so the wipers don't just stop.

Connect it to a proper manifold vacuum source and check again to ensure that you got the correct numbers. Maybe you can simply disconnect the fuel pump vacuum function and still use that line, but you need to make sure that the pump has no influence on the vacuum reading.

It does sound like you got it running better, though. If you really want it to run good, get that mechanical advance distributor.