My 318 dyno results

-
So this is what my choke looks like.

choke.jpg
 
olei said:
How come you want me to take out initial timing, but add VA? I can't see it making any difference in the end?
Also, wouldn't connecting it to my manifold vacuum just make my idle quality worse, due to my lumpy idle (making timing jump up and down?).

It's not the air gap. :)
Click to expand...
Simple
Mattax (well said IMO) already gave an excellent argument/explanation for reduced idle timing. More VA will make that up as soon as you give it light throttle.
Most engine I have worked with like well over 42 degrees of timing at 2000, to say 46*@2400 for cruising,( and even up to high 50s with aluminum heads and lean-running). I really like the Big Vcans with 22ish degrees in 'em. That means the power timing in that zone has to be reduced to run with those. So if you take say 20 from say 44 then you need say 24@ say 2200, for power timing.
Yeah, you can run a smaller can and more centrifugal, but then you lose the Part-Throttle advantage.
Like when on the choke. At this time with a cold engine, it's almost impossible to have too much advance. So if you set the initial to say 16*, and run 1* per hundred rpm, then at a warm-up speed of 1500 rpm, the best you can have is say 16+ 7 =23* ..... but a 22* Vcan would about double that, and so smooth her right out :) . But wait! With all that advance, maybe you can reduce the warm up speed. Say to 1200. The mechanical might be 16+ 3=19, and maybe the Vcan loses signal and drops to 11, so you still have 30*!
But when you put it into gear, maybe you lose 2 mechanical,and so 28* may remain, and as you gently take off, 11* more will jump in right away for 39* now, and increasing by 1*per 100 rpm as you drive away. By 2800 most all the timing will be in, and so now it could be as much as 36+22=58*.
Iron headed engines usually don't like this much, this early, so I put a two stage curve in,to limit the curve at about 2800, and then I bring in the last 4 to 6, at some later rpm that the engine is happy with. This would drop the PT timing at 2800, to say 52*...
2800 is my chosen 1-2 shift rpm. Not every engine is happy with 52*@2800PT, so for those, there are plenty of Vcans to chose from....... or used to be,lol.
 
Last edited:
1800 converter is STOCK for a Chrysler.
 
I changed my initial timing to 16 degrees, total timing 34 degrees at around 3300RPM (still also have the vacuum advance hooked up). You guys are right, it seems stronger. When I now blip the throttle while in gear, it doesn't drop as low on RPM as it used to. I will do more testing later.

I still have my cold weather/engine hesitations though. I believe there actually is a sealed off adjustment screw for limiting the travel of the pull-off piston, I will have to take a closer look.
 
Last edited:
olei said:
I changed my initial timing to 16 degrees, total timing 34 degrees at around 3300RPM (still also have the vacuum advance hooked up). You guys are right, it seems stronger. When I now blip the throttle while in gear, it doesn't drop as low on RPM as it used to. I will do more testing later.

I still have my cold weather/engine hesitations though. I believe there actually is a sealed off adjustment screw for limiting the travel of the pull-off piston, I will have to take a closer look.
Click to expand...
Air gap adjustment, with the engine running, is by bending the rod. But this assumes the engine has enough vacuum to actually pull it open,lol. The screw you see hiding down there is for adjusting the fast-idle speed while on choke and specifically after it has been "tapped down"

Go back to the pic in post 51. You see that little tang where the choke coil anchors on? Attached to it is the vacuum pull-off piston.Engine vacuum is supposed to suck the piston down the barrel until it bottoms. This sets the initial air gap to spec. If your engine doesn't like it perhaps because of the timing, or T-port sync,or the float-level, or for whatever reason; then you get to adjust the gap, by bending the rod.
If the choke time cannot be made long enough with the existing heater element, then you have to reduce the voltage to it. But really, a little timing retard and a little more fuel in the low-speed circuit,usually gets the job done.
 
Last edited:
AJ/FormS said:
Air gap adjustment, with the engine running, is by bending the rod. But this assumes the engine has enough vacuum to actually pull it open,lol. The screw you see hiding down there is for adjusting the fast-idle speed while on choke and specifically after it has been "tapped down"

Go back to the pic in post 51. You see that little tang where the choke coil anchors on? Attached to it is the vacuum pull-off piston.Engine vacuum is supposed to suck the piston down the barrel until it bottoms. This sets the initial air gap to spec. If your engine doesn't like it perhaps because of the timing, or T-port sync,or the float-level, or for whatever reason; then you get to adjust the gap, by bending the rod.
If the choke time cannot be made long enough with the existing heater element, then you have to reduce the voltage to it. But really, a little timing retard and a little more fuel in the low-speed circuit,usually gets the job done.
Click to expand...
That rod is pretty solid. It's not the fast-idle speed screw I'm talking about, look here (almost to the bottom); Adjusting Automatic Chokes: A Semi-Universal Approach

And regarding a little more fuel in the low-speed circuit, is what I have been wanting to do, increase the IFR.
 
Last edited:
Well you're smarter than me;Wow, I had forgotten all about that.
I think I only ever saw that screw on a 41xx in a 60s grain truck.That's going on 40 years ago
To tell the truth, on a 4100 series carb, I have only ever had to fudge the vacuum break maybe once.
__________________________________________
My own 750DP carb has no choke at all, and I used to drive it from May long weekend to September long weekend, then pull it out and put the winter motor in. I sometimes stretched it to over 6 months.
I think DPs are like that;fairly rich on the low-speed circuit. They kindof have to be calibrated to a lower vacuum level than your Carter 2bbl,lol. My combos have all pulled from 8 to 12 inches at idle. This last one, with about 10, is right in the middle. You can fine-tune the idle vacuum,and the on-choke fast-idle vacuum, with timing and rpm.
To start it cold; I just mash the throttle a time or two, depending on the ambient temp, and hit the key. Then I babysit it for half a minute, with a blip or two,and that charges up my brake booster. Then she's ready to rock,almost. She takes about 3 miles to start warming up the aluminum heads. During this time the speed increases without my increasing the pedal, so I am actually backing out of the throttle every mile or so, to prevent speeding. I refuse to waste my money on speeding tickets. Since 1999 that car has never gotten a ticket for speeding. Other tickets yes,lol. After three or maybe four miles, she is ready to be abused.
 
AJ/FormS said:
Well you're smarter than me;Wow, I had forgotten all about that.
I think I only ever saw that screw on a 41xx in a 60s grain truck.That's going on 40 years ago
To tell the truth, on a 4100 series carb, I have only ever had to fudge the vacuum break maybe once.
__________________________________________
My own 750DP carb has no choke at all, and I used to drive it from May long weekend to September long weekend, then pull it out and put the winter motor in. I sometimes stretched it to over 6 months.
I think DPs are like that;fairly rich on the low-speed circuit. They kindof have to be calibrated to a lower vacuum level than your Carter 2bbl,lol. My combos have all pulled from 8 to 12 inches at idle. This last one, with about 10, is right in the middle. You can fine-tune the idle vacuum,and the on-choke fast-idle vacuum, with timing and rpm.
To start it cold; I just mash the throttle a time or two, depending on the ambient temp, and hit the key. Then I babysit it for half a minute, with a blip or two,and that charges up my brake booster. Then she's ready to rock,almost. She takes about 3 miles to start warming up the aluminum heads. During this time the speed increases without my increasing the pedal, so I am actually backing out of the throttle every mile or so, to prevent speeding. I refuse to waste my money on speeding tickets. Since 1999 that car has never gotten a ticket for speeding. Other tickets yes,lol. After three or maybe four miles, she is ready to be abused.
Click to expand...
When I start cold I hit the throttle one time before start, and usually she fires right up. But almost immediately it starts to surge and want to die on me (and usually does). I really don't want to wake up the neighbors in the morning sitting there and working the throttle for several minutes before taking off.
I do as well as you, need 3-4 miles to get up to temp.

I now have a (used) Quick Fuel Slayer 600 carburetor sitting here, that I'm interested to try on if adjusting the Street Avenger 570 pull-off doesn't work.
 
Many years ago, I was pulled over for a noisy exhaust, but the copper gave me an out (1975, when cops were still good guys). He said to fix it and report to the office on a certain date. I did that and passed.
What I had done was roll up some corrugated cardboard, about 20" long (going by memory) and stuffed it far enough up the pipes that he couldn't see it, without getting down on all fours with a flashlite. I was betting he wasn't gonna do that, and I was right. I kept the cardboards in there with nails, dropped in from the top which also could not be seen.
Of course as soon as I was out of sight of that copper, I pulled the nails, rapped the pedal and shot the cardboards out the back like a brace of canon.
That cardboard trick works pretty good.
 
Interesting thread and I have not had time to read in detail
but
heated ex manifold air to the air cleaner?
I do agree that this is tune first cam not likely the major problem
can you get Hughes to give the seat timing @.006?
did you degree in the cam ( I do need to re read the whole thread)
 
Alright, choke pull off adjustment was easy after all. I closed it down to approx. 1/4" opening, and cold starts are a bit better, but still not good. Will try to go tighter.

Wyrmrider said:
Interesting thread and I have not had time to read in detail
but
heated ex manifold air to the air cleaner?
I do agree that this is tune first cam not likely the major problem
can you get Hughes to give the seat timing @.006?
did you degree in the cam ( I do need to re read the whole thread)
Click to expand...
No heated air to air cleaner.
I did degree the cam, installed at 102 degrees.
 
Wyrmrider said:
can you get Hughes to give the seat timing @.006?
Click to expand...
You're a funny guy. That would be good but you know thye don't like to discuss that these days.
Actually I kindof did get that from them on the cam I bought. But it might have been before they decided to no longer post or discuss advertized duration. Maybe 2002-03 time frame.
Wyrmrider said:
heated ex manifold air to the air cleaner?
Click to expand...
That's a good idea.

What's the story on working with these Edelbrock RPM heads?
Do the combustion characteristics change going from to warmed up more than cast iron heads?
 
Mattax said:
What's the story on working with these Edelbrock RPM heads?
Do the combustion characteristics change going from to warmed up more than cast iron heads?
Click to expand...

When I hit the hiway with cold heads, I can always feel them come on line, when about two or three miles down the road, the car starts to surge ahead with no change in throttle setting. I often get about 2 to 3 more mph after the surge.
I painted my Eddies with three coats of Orange paint, in an effort to keep some heat in them.
This is also why I run them at a minimum 205*F.
Also why my WP is underdriven.
Also why I run; an all-steel, hi-attack angle, 7 blade fan, on a hi-flo pump,with a T-clutch which appears to keep the maximum coolant temp to about 207*F................... no matter what.
So,after the warm-up period, the window of cooling system operation is always between 205 and 207ish. That makes it easy to tune with fresh cold air coming down thru the hole in the hood.
Is this different than iron? IDK I haven't run HO iron heads.
 
Hughes has now relisted the 5.2 roller Whiplash camshaft, but with different specs. Wonder why?

Old spec (my current cam);
cam_card-jpg.jpg


New spec;
52whiplash.jpg
 
Last edited:
Just bringing this one back from the dead.

Hughes Engines changed the specs on the 318 Whiplash roller camshaft, because the idle was too rough with the 107 LSA.
 
olei said:
Just bringing this one back from the dead.

Hughes Engines changed the specs on the 318 Whiplash roller camshaft, because the idle was too rough with the 107 LSA.
Click to expand...

How's it been running the past few years? Lol. I wish I had seen this thread when it was still "active" I would have strongly suggested rigging up some type of warm-air intake for cold-weather driving. Even with the non-Air Gap intake manifold it will take quite a while for it to heat up as there is no exhaust crossover, the only heat it gets is from oil spraying on the underside (which also takes a while to get warm itself) and conduction from the heads which isn't great due to most of the contact area being separated by the intake manifold gaskets. You can do your best adjusting the choke, timing and whatnot but fact of the matter is, until the intake manifold gets warm there isn't enough fuel vapor and you are sending tons of unburned liquid fuel through your engine which is washing down your cylinders and diluting your oil.

I don't know many people with built carb'd engines without exhaust crossover trying to drive them in sub-freezing temps. I do it but most people here in the states put their muscle cars away for the winter and only drive them in warmer weather.
 
MopaR&D said:
I don't know many people with built carb'd engines without exhaust crossover trying to drive them in sub-freezing temps. I do it but most people here in the states put their muscle cars away for the winter and only drive them in warmer weather.
Click to expand...
Our winters can see 85 F here. Even back in Oklahoma it wouldn't be unusual to wear shorts on Thanksgiving or Christmas but the next day it's -14F windchill.

Wonder if the OP could rig up a dual snorkel air cleaner with 2 heat risers?
 
go-fish said:
Our winters can see 85 F here. Even back in Oklahoma it wouldn't be unusual to wear shorts on Thanksgiving or Christmas but the next day it's -14F windchill.

Wonder if the OP could rig up a dual snorkel air cleaner with 2 heat risers?
Click to expand...

That was my idea. I've run my Duster when it's 10 F and it does OK since the cam doesn't have a ton of overlap but would definitely benefit from a dual-snorkel air cleaner with hot-air intake until it's fully warmed up (open-elem. My truck's 360 has a Performer intake with stock iron heads but the heat crossover is blocked, that thing runs exactly how the OP describes when it's below freezing outside and it still only has the stock 2-barrel cam. I do drive that pretty often in winter so I think that'll be the one that gets a hot-air intake first.
 
My cam from Hughes is the "New" specifications that you've shown. However I bought it in 2015. I dynoed it in a 318 where it made 293 hp to the tires. That was with J- heads but otherwise similar set up as yours.
 
MopaR&D said:
How's it been running the past few years?
Click to expand...
Well, it hasn't. :poke:

It needs som work done to the frame, and I've started planning the restoration as well as other changes. I'm considering the Lunati Voodoo 20200710, 211/219 @ .050" and 112 LSA. 3.90 gear ratio is also a part of the plan.
 
olei said:
Well, it hasn't. :poke:

It needs som work done to the frame, and I've started planning the restoration as well as other changes. I'm considering the Lunati Voodoo 20200710, 211/219 @ .050" and 112 LSA. 3.90 gear ratio is also a part of the plan.
Click to expand...

Ah bummer. Well sounds like a good plan at least. I like that you're changing cams too, I've heard the Whiplash cams give good performance but if you're running it in cold weather the last thing you need is a lumpy idle and low/uneven manifold vacuum. I personally don't like the way they sound anyway, it's not the same lumpy idle as a "true" high-performance cam, sounds weird to me lol.

Also I still highly recommend making some sort of hot-air intake similar to the factory setups on 1970s Mopars. Your engine will thank you and you won't be going crazy having your engine run like garbage for the first 10-15 minutes after a cold start.
 
You must log in or register to reply here.
-

Back
Top