Ran the "low dollar 318" in the Duster today

[318willrun]

Add more accelerator enrichment to try and remove the stumble when accelerating (move the lever one notch closer to the carb)

Already moved the lever for the accelerator pump.

Is the Edelbrock a 1405 or a 1406? Have you swapped to heavier step-up springs? If you're running more than 14-15" of idle vacuum, the pink spring usually works well.

1405, haven't bought the spring kit yet.

 

[ir3333]

you probably posted it and i probably missed it
.. what is your timing initial,total and curve rate? ( all in @ what rpm?)

 

[Aaron65]

I think that if you're timing is OK, I'd start with the pink step up springs, and if that doesn't totally fix it, try a .031 squirter from a 1406 (if you can get one easily enough) and/or a pump assembly from an Edelbrock 800. They apparently push a little more fuel and are blue in color (I've read that part here and in a couple other places).

http://www.summitracing.com/parts/edl-1468/overview/

Additionally, there are some guys on here (if you do a search) who have fixed a secondary bog by making some basic modifications to the secondary venturi clusters. Good luck!

 

[318willrun]

you probably posted it and i probably missed it
.. what is your timing initial,total and curve rate? ( all in @ what rpm?)

initial is 21 and total is 39 right now. It feels really good there. I put two of the weak springs in there, so total is probably around 2200 (no tach). I'm not running a vacuum advance because of how fast the advance comes in.

I think that if you're timing is OK, I'd start with the pink step up springs, and if that doesn't totally fix it, try a .031 squirter from a 1406 (if you can get one easily enough) and/or a pump assembly from an Edelbrock 800. They apparently push a little more fuel and are blue in color (I've read that part here and in a couple other places).

http://www.summitracing.com/parts/edl-1468/overview/

Additionally, there are some guys on here (if you do a search) who have fixed a secondary bog by making some basic modifications to the secondary venturi clusters. Good luck!

haven't got the spring kit or anything yet. However, I did put squirters in from a 750 I got for free. I think those squirters were 32?? Can't remember exactly.....

 

[318willrun]

Some questions about the cam I used from folks. Here is the vacuum on it.

 

[AJ/FormS]

Are the secondaries fully closed?
IMO, the 21* of timing may be creating too much vacuum for the current step-up springs.They are not popping up fast enough. Easy enough to prove.

 

[318willrun]

Are the secondaries fully closed?
IMO, the 21* of timing may be creating too much vacuum for the current step-up springs.They are not popping up fast enough. Easy enough to prove.

Right now the timing is 20* initial, and 40 full advanced. But what's not popping up?? are you talking about the old eddy carb that was on there? Look at the video, it's a Holley Street Avenger now...

 

[AJ/FormS]

OH crap I thought I saw in the video, you pulling the secondaries closed by hand. And my brain got stuck on Metering rod carb. I didn't notice the timestamps, Sorry Will

With this type of carb setting up the transfer port sync is critical for tip in response. I'm pretty sure you know this.
Idle the engine up to 2000 rpm or thereabouts. Reset your mixture screws for highest rpm. If they do nothing, idle it back down 200rpm and try again. After you get that set, idle the engine back down to normal.If she idles like crap now, it's cuz the transfers are not right.
Or you can just flip the carb over and look.
IMO, it may be that the 20* initial is causing the sync to be off , and the transfers are drying up at idle.Then when you tip the throttle in they take a few microseconds to get going again. I see that all the time. The pumpshot without the transfers is just not enough.
There is a proof for this and it is right there in the video. Several times you tip it in from curb idle, and there is the stumble. But a couple of times you tipped it in from some higher rpm with the throttle not yet returned to curb idle, and then the stumble was reduced.
So, maybe you can humor me; reset the timing to 12 degrees, make sure the secondaries are fully closed,idle her back up to 700, and reset the mixture screws. You may have to readjust the accelerator arm preload to initiate the shot as soon as tip-in occurs. Now try it.
Or you can just flip the carb over and look.

 

[318willrun]

OH crap I thought I saw in the video, you pulling the secondaries closed by hand. And my brain got stuck on Metering rod carb. Sorry Will

With this type of carb setting up the transfer port sync is critical for tip in response. I'm pretty sure you know this.
Idle the engine up to 2000 rpm or thereabouts. Reset your mixture screws for highest rpm. If they do nothing, idle it back down 200rpm and try again. After you get that set, idle the engine back down to normal.If she idles like crap now, it's cuz the transfers are not right.
Or you can just flip the carb over and look.
IMO, it may be that the 20* initial is causing the sync to be off , and the transfers are drying up at idle.Then when you tip the throttle in they take a few microseconds to get going again. I see that all the time. The pumpshot without the transfers is just not enough.
There is a proof for this and it is right there in the video. Several times you tip it in from curb idle, and there is the stumble. But a couple of times you tipped it in from some higher rpm with the throttle not yet returned to curb idle, and then the stumble was reduced.
So, maybe you can humor me; reset the timing to 12 degrees, make sure the secondaries are fully closed,idle her back up to 700, and reset the mixture screws. You may have to readjust the accelerator arm preload to initiate the shot as soon as tip-in occurs. Now try it.
Or you can just flip the carb over and look.

Well, I think I have to take the carb off to adjust the back secondary's. I'm not so sure right now there is a stumble. I've done some changes on it but because there is salt on the roads, I haven't taken it out. The eddy stumbled bad. I started with the engine around 14* initial, but it wasn't as responsive, and also the vacuum was low. It seemed to run the best around 20* initial. When I had it at the strip, it ran the best at about 40* full advance, no pinging or nothing. Remember, this engine has less compression than a factory 318 2bbl (which isn't much!). I say that because I removed the 318 heads and reinstalled them with a .050 thick head gasket, so I lost compression. Lower compression motors take more timing. I've done a lot of low compression motors (barely 8 to 1), and always they want more timing.
However, I'm always open for improvement.

 

[AJ/FormS]

Yeah, they crave timing.
It takes a lot of time for every molecule of gas to find a molecule of air to react with, when the pressure is that far down, and no help from the squish.
But the humor-me-adjustment was just to prove the t-port sync was off. After it's proved, you have to figure out what to do about it.
IMO there is no reason to run a lot of idle timing with a higher stall, if it messes up the t-port sync. I mean what's the point, if the engine is never pulling in that zone?I would just fix the sync, set the timing to whatever gets the sync done, then go mod the dizzy to get what you want when you need it,right? Yeah, I know those slots are hard to grind out,lol. But I hate a hesitation on tip-in,more.
But I could be wrong,too. Maybe that carb is just not a good match,or rather the primary size, for that engine.Maybe airflow in the intake is too slow. Maybe the fuel-level is a tad low.Or the water is too cold. If you had mechanical lifters I might add; maybe the lash is too tight. But I thought I saw it pretty clearly in the video.
Happy hunting.

 

[318willrun]

Yeah, they crave timing.
But the humor me adjustment was just to prove the t-port sync was off. After it's proved, you have to figure out what to do about it.

you very well could be right, this carb was on a 400 big block I had in a truck, and it worked flawlessly on that. I just put it on here, never did anything with the jets, or anything else. working with the weather, I'll get to more of in depth tuning.... after all, it's in the 318 race on my other thread

 

[rumblefish360]

318WR, on the Edelbrock carb, you said you moved the rod on the pump shot lever. Did you readjust the bend in the rod to deliver the proper amount of movement on the arm?

On the engine timing, 20* initial is a lot. Try backing down 5*'s to start. The small block lines about 35/36 max with vacuum advance, 52 total with the advance hooked up.

Your time and mph are super close to my '74 - 318 Duster. LD4B intake w/hookers and Jegs exhaust.
The gears were 3.21's on a stock tire.

I only spent a few more bucks than yourself.

 

[318willrun]

318WR, on the Edelbrock carb, you said you moved the rod on the pump shot lever. Did you readjust the bend in the rod to deliver the proper amount of movement on the arm?

On the engine timing, 20* initial is a lot. Try backing down 5*'s to start. The small block lines about 35/36 max with vacuum advance, 52 total with the advance hooked up.

Your time and mph are super close to my '74 - 318 Duster. LD4B intake w/hookers and Jegs exhaust.
The gears were 3.21's on a stock tire.

I only spent a few more bucks than yourself.

answer your questions in order:

1. I did not bend the rod on the eddy. Maybe I should have.
2. I started out at 14* initial. went up from there, because it ran better, idled better, performed better and had better vacuum. Same with full advance, started around 35* but it performed best at 40*. Remember, I have less compression than a stock 318 2bbl, and low compression motors love timing. I have not run a vacuum advance yet.
3. I'm sure with headers, 3.21 gears, and no stumbling I would have been at 97+ mph, which is plenty good enough to go low 14's (with a stock converter).
4. Because I was trying to stay under 500 (which I did), I didn't cut the heads. I felt cutting the heads .030 to get back what I lost on the head gaskets would have been big to this car, and low end torque.

 

[rumblefish360]

answer your questions in;

4. Because I was trying to stay under 500 (which I did), I didn't cut the heads. I felt cutting the heads .030 to get back what I lost on the head gaskets would have been big to this car, and low end torque.

Huh? Ummm, I asked
1 question. But this reply, #4, is a understood well know and the reason for the thread. I only mentioned I spent more. Nothing more, nothing less. Just sayin.

 

[318willrun]

Huh? Ummm, I asked
1 question. But this reply, #4, is a understood well know and the reason for the thread. I only mentioned I spent more. Nothing more, nothing less. Just sayin.

Oh, I know, just chatt'n ......
I really put no time into it last summer. Super busy.... like all my summers! LOL. I'm entering this in the 318 race in my other thread, so I have to get the stumble out. I think this race will be a blast.
ATTENTION 318 owners: any interest???

 

[rumblefish360]

Oh! I'll have to check it out.
Excellent!

 

[AJ/FormS]

By any chance, did you verify your TDC mark? I agree that 40* power-timing is a lot, even for a very low C/R engine. Keep an eye on your plugs,for detonation tell-tales. I wouldn't be able to hear it over my exhaust.
>Even modern EFI engines run a ton of idle-timing, but the second you touch the throttle it starts dropping out fast. Put a scanner on your factory injected car and see it in real-time.
An .050 gasket only adds 2.5cc to the total chamber volume, over an .039er, 4.9cc over an .028. Going from an .028 to an .050,this would drop the Scr from 8.0 to 7.64,about .036 point.
>At 8.00 Scr the 318 might make a 7.0@135psi Dcr
>At 7.80 Scr, she might do a Dcr of 6.88@131psi.
>At 7.64 Scr, she is still at about 6.73@127psi
As to Dcr;That's about a point to a maximum of a point and a half below optimum.(optimum being about 8.0 with iron open chambers).
As to Scr she's about 2.3points low
That factory 240* cam does a pretty good job of keeping the pressure up.So if your engine is cranking over 127psi,there's still hope for her.

 

[318willrun]

By any chance, did you verify your TDC mark? I agree that 40* power-timing is a lot, even for a very low C/R engine. Keep an eye on your plugs,for detonation tell-tales. I wouldn't be able to hear it over my exhaust.
>Even modern EFI engines run a ton of idle-timing, but the second you touch the throttle it starts dropping out fast. Put a scanner on your factory injected car and see it in real-time.
>Even at 7.8Scr, that teener would have a Dcr of 6.88@131psi. That's only a point to a point and a qtr below optimum. That factory 240* cam does a good job of keeping the pressure up. A .050 gasket only adds 2.5cc to the total chamber volume, over an .039er, 4.9cc over an .028.

I did not verify my TDC timing mark, other than when the #1 piston is up by "eye" (when I had the heads off), the mark was at TDC. But that could easily be a couple degrees off, I know.
There is a picture of a plug at the beginning of the video, if you stop the video at 19 seconds you can see what you think. I personally like a "cardboard brown" color on the porcelain. Keep in mind, I didn't change the jets or nothing, just went on the car....

 

[AJ/FormS]

Mr. Wallace thinks 140 psi is 8.25Scr,7.25 Dcr; That ain't so bad.