Hello together, i have just finished my ford model a hot rod project and due to engine problems i tried to find a good community which could probably help me Everything is fine with the car except the acceleration from the engine under part to full throttle. It is a bone stock goodwrench 350 crate gen1 with a edelbrock 600cfm carb with an electric joke. The engine idles fine and also respons good to throttle in neutral and park. It also cruises ok and seems to have enough power when the kickdown shifts back and you drive under high rpm (Altough it seems a little bit tired). The problem is when i am driving in 3rd gear the car accelerates under light throttle but as soon as i give it a little bit to much throttle it stops accelerating and seems to stay same rpm. I searched already in the web but many people have stalling problems and also bad idle which is not happening in my case. Thanks a lot Matthias
As an addition to my post above- I ran into a similar problem when I worked on a warmed up BBC that my buddy had put a smog era HEI distributor on. It ran great at 12° BTDC initial but went to over 50° all in and had zero power. The quick fix was a washer welded to the vacuum lever, to stop it at about 38°. It took a while for me to figure that one out, personally I rather use an old points distributor and if I can´t come up with a good set of points, pertronix is my choice.
If timing is OK, check the carb float level and the accelerator pump settings, does it max out to soon?
Hello, thanks for the fast answers. I had to borrow a more accurate timing light from a friend and checked timing today again. The inital timing was at about 10°.I disconnected the vacuum advance and plugged the line and the idle dropped to about 500-600. The timing was then about 10-20 degree behind tdc??? I set it then back to around 800rpm and 12° at idle. At 2800rpm it only advances to about 22° total. Therefore i think the advance from the distributor must be damaged, right? I can´t tell from the outside what kind of distributor it is and its a little bit tricky(not much space) to get it out but i will take it out tomorrow. We installed a pertronix 2 maybe we messed something up there? Is there a way to check if it works or not or is there probably something to be fixed easy or should i just go for a new distributor?
When you re-set the timing, did you do it with the vacuum line disconnected and plugged? That's typically the way it is done. Then hook up the vacuum advance and set the idle speed. Is your vacuum line hooked to ported or manifold vacuum? Dropping 20*+ of advance when you unhooked the vacuum line means you were running that many degrees retarded and that may be the reason why you are only getting 22* total advance.
i would set timing at 10-14 degrees at idle and 32-34 total all in by 2800 rpm,, bad torque converter will fool you acts pretty much as what you describe,what kind of trans? heavy car ? light car?
Yes i reset the idle and timing with the vacuum disconnected and plugged.(i used the manifold vacuum port). What´s strange for me is that with the vacuum disconnected and inital timing at 12° it only went to about 20-22 total advance at 2800rpm. @bobkatrods: It´s a pretty light car around 2600lbs and a freshly rebuilt th350 trans.
Right size carb for crisp street response. Depending on how your plugs read, the timing suggestions offered sound good. In a 2600lb car you should have Xcellent mid-range!
You haven’t mentioned which distributor you have, only that it was converted to Pertronix. Is it a GM style points or HEI type? Or it might even be an aftermarket distributor. Many GM style HEI’s will only give 10* of mechanical advance and that is what you describe- 12* initial and 20-22* total. Take the initial up to 22* or so, that might be too much and it might kick back against the starter, you might have to give it only 16 or 18* but if it will start take a short drive and see if the performance has improved. If it has then look into a mechanical advance kit that has weights with a different shape. Weights that can sling out more will give more advance. Lighter springs will only make the centrifugal come in quicker, your total centrifugal will remain the same.
No one's asked about gear ratio or rear tire diameter ? 3.07's and a 30" tall tire will give most any small engine fits..! Add to that, a stock..OEM style torque (low rpm stall speed) converter will make the off idle slightly sluggish Mike
Everyone seems to be focused on ignition and timing And there are a lot of smarts on this forum so I wouldn't think of arguing with my betters. But my first thought was the kickdown for the trans. I know you mentioned that you have that function in about the middle of your first post, but it has to kickdown for any degree of brisk acceleration over a lazy few miles an hour. If that's not happening you need to look there and make adjustments for less slack in the linkage or whatever. 90% of the time a problem turns out to be something simple, thank goodness.
Sounds like you've got the advance hooked up to manifold vacuum. There should be no vacuum advance at idle. Try setting it to about 36 degrees btdc (full advance - revved to around 3K) with the vacuum disconnected. Idle advance should then be around 10 degrees. The car should drive alright like that. If it does, find the ported vacuum spud on the carb and hook it up. It should run fine and you can fine tune it from there. Hope this helps, Phil
The OP states the biggest problem is in 3rd gear, probably moving 25mph or more, then steps in it, it does not respond. Neither ported or manifold vacuum is functioning at that time. I would look into advance mechanism in the distributor.
If your timing with the vacuum advance disconnected is 10 -20 degrees after tdc and you then set it to 12 degrees before tdc, I'd say you found your main problem. However, you could use an additional 12 - 14 degrees total. I'll bet it runs a lot better with the 12 degrees before tdc.
I had a similar problem. My engine idled great at 11 degrees before tdc, but only gave me about 24 degrees total timing. No power. Most engines like 34 - 36 degrees total timing. I just pulled my distributor apart and filed the slots for the weights out, so they could give me 36 degrees total timing. I generally don't worry about setting timing at idle. You can set a good digital timing light for whatever you want and then set your timing at full advance. But the distributor has to have enough timing built into it. Sent from my SM-G950U using The H.A.M.B. mobile app
you definitely don't have enough timing at 2800,,ck your mechanical advance is it stuck? power brake it,will it break the tires loose or just torque up?
Hello, it´s me again First of all thanks a lot for all the fast and good answers, I really appreciate it. I now redid the timing with the vacuum disconnected. I set initial timing to 12° at 600-700 rpm and it turned out that it goes up to around 28° at 2500rpm. I went then for a little test drive with the vacuum still disconnected and it feels like it gained 100hp . From standing still it brakes the tires loose and accelarates through all gears without problems. So also the midrange problem is gone. Now i tried to hook up the vacuum again on the driver side on the edelbrock 1405 but that gives me an inital timing of about 30-40° at idle, cant say it exactely because i turned it off as soon as i saw that its that much. I changed now the port to passenger side and hooked up the transmission on the driver side. At idle it now still have the 12° but will go up to about 45° at around 1000-12000rpm. So the questions now would be is that fast and huge timing advance normal with vacuum hooked up? Up to how much should it go, if so? Should i drive it simply without vacuum hooked up (think worse fuel economy, right?) Is it advisable to still buy a weight kit for the distributor to get it up from the 28 to the 36°, will there be a noticable power gain?
Back to my first post... You have the vac advance hoked up to manifold vacuum. It should be plugged into the ported vacuum at the carb. That will have no vacuum at idle as it is tapped in above the closed throttle plate. Once you find and connect to the correct port you'll be fine. regards, Phil
If your inital is 12, you may have a 20 degree vac can giving you the 30-40 degree at idle with the vac can hooked up . Nothing wrong with manifold vac source, but which ever makes your car operate the best. There have been bloody arguments both ways about ported/manifold vac source. I prefer manifold vac, and having more advance at idle. Like some mentioned earlier there are adjustable vac cans, or OEM specific degree cans. Ported vac will complete the combustion cycle cleaner, but at a higher temperature.
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