timing and gap

H

havoline

Well-known member
been a while so am alittle unsure about things now but mass of same opinion will help me than any book lol.

My engine runs smooth. not getting the best gas mileage as I know it can be. Remember after getting the new pertronix ignitor in my car it went to 26 mpg in summer time on highway and 21 in city when driving with care. But a year and not driving the car and I know my brother messed with it but even though we never knew what was the timing on it cause the balancer was slipping for a couple of years. Installed a new one and checked my timing and at 875 rpm in neutral my timing is at 6 btdc. For getting best performance mainly gas mileage what would be the best timing set at what rpm??

Also I am still mainly running .035 gap on my spark plugs. I have pertronix ignitor, 40000volt coil and 8mm wires. with the best timing mentioned what would the best gap be possibly up to .04??? that wont hurt me right or be safe at .035??
 
For a stock motor 875 rpm in neutral would be a bit high for an auto set it idle rpm to 475 to 575 in drive with brake set. (vac. is plugged off) when setting the timing to about 10 to 12 btdc will be about right in your area. Than after you try that out you can always add another 2 to 4 depending on the fuel used and your driving style. Plug gaps of 0.44 to 0.46 should work.
 
my coil is pertronix. have had it for 6 years and am very happy old coil used to get warm when the car warmed up and would give inconsistant spark.

my car is mostly stock just the ignition upgrades and flowmaster exhaust. one day soon hope to have the fspp headers which will make everything sound really nice.

I have my engine idle that high because I have an amp in my car anything less especially with the lights on would be bad. my rpm does go down to 600 in gear so that is good then. trust me my idle used to be 1000. when it was rough. but my vacuum gauge I have in my car tells me everything and on average my engine is very smooth no irratic indications.

ok I will bring it back to 8 btdc and give the gap to .042 and see how that is. hope that will give me at least 1 more mpg on the highway to let me know I am moving in the right direction.
 
if you were getting an erratic spark, check all the connections to the coil, one problem i allways had was the magnets in the timing ring would fall out so keep an eye on that, i would get a new hi output coil, but it has to be a points coil, it can help with economy a little
 
no like in 2003 I was getting an erratic spark from the coil, the original coil that only punched out 20000 vs my current 40000 volts. my new coil since then never had that problem.

still so its a good thing to start out with resetting my timing to 8 btdc at 600 rpm and put the gap at .042 in to see what happens.


Right????
 
yes, 600-650 with it in gear, in neutral it should not go past 900, thats my prefrence anyway, any lower and i get a very rough idle and the engine stalls, 8deg is good
 
Howdy Havoline and all:

The stock specification for a 1965 200 with an automatic transmission is 12 degrees BTDC. 6 degrees is the setting for an engine with a manual trans. Is there a reason for being so conservative with initial advance? Are you getting any pinging in normal driving now? How do your spark plugs look? Have you fine tuned the low speed air screw on the carb?

Going from 6 to 12 degrees of initial advance will be noticeable- mileage wise.

Adios, David
 
Hello all. Just came back from the fabulous does forever car show. Was good. I have done quite a few things in the past year to my car with doing the tires, wheels, sound system mainly done by my brother bless him, brakes, weather stripping, and finally exhaust.

Having the new headers and a 6-2 to 1 single exhaust with a 2 1/4 tube to flowmaster muffler. Since doing the exhaust the cat behaves abit differently but I can still make a few adjustments. It's unconfirmed but my car may be doing less mpg than before where on the highway I was getting 25mpg. From my first fill up I lost 2. But a possible helpful solution is: my timing was set at 10btdc at 650rpm before exhaust and I have not changed the timing after the exhaust upgrade...perhaps changing that more would help? Recommendations and as to how much to say 12-14??

I still have pertronix igniter and 40000v coil and stock carb and plug gap at .045.

How are other peoples experiences with this exhaust upgrade? There is less drooning and a good distribution of sound throughout the car instead of just the muffler.

Should or could I open the gap to .05 but no more?


More opinions the better and if they all sound popular ones I will take that as facts ha ha. Thank you.
 
Yes with an auto trans your base timing should be set to at least 12 BTDC and you could probably add 2 more for 14 total as long as your not getting any pinging. You could try adding more gap maybe up to .060 go about .005 at a time and see how it dose, if okay add some more you will need to retune your carb each time you change something. :nod:
 
Thanks will give that a shot and see what the difference is. Maybe will put it to about 12 and make the gap at .05 for starters. I put too thin of oil in the car when it got hot so may put an oil additive since that might give me a little more compression pressure.

I have always been a little interested in getting a kn air filter. If I can get a extra mpg out of it I will take it.

Is it usual to adjust the timing after header installations? I hope it is.
 
Yes it could, but your stock timing specs with an auto should have been set to 12 degrees Before Top Dead Center, with the curb idle speed 485 RPM in drive this is where you should have started. With every mod the optimum tune will be a bit different and will need to be adjusted some. Headers and or a good free flowing exhaust system increase cylinder scavenging making the engine more efficient sometimes the carb may also need to be rejected a little richer too. So would adding a freer flowing air intake system. IE better air filter or air cleaner ram air system etc. :nod:
 
Well including what o have done with my car and I adjusted things making the gap at .052in and timing set between 12-13 btdc and its not helping much. Most likely what is happening is a back pressure issue since I only have a single exhaust still and same flowmaster as before but I use on the headers and the pipe after the headers is 2 1/4in Vs the 1 3/4in. If I went back to the exhaust shop nd put back on a 2in or smaller pipe would that help? I want my car to run good and for most part it has been doing that until screwed with making it work harder than it needs to. Would that mainly account for the bad fuel mileage? Also the car is having a hard time now since the header upgrade changing from 3rd to 2nd gear unless I really smash the throttle. No line leak.


Thoughts? Anyone else have this problem or is putting on a 300cfm carb the answer since it will more balance out the pressure and air flow in and out of the car? Not something I am wanting to do just yet since my carb autolite 1100 is still doing good.

These days I rather drive a good looking good sounding car that doesn't cost a lot to drive?

Santa sms to anaheim 21mpg with no real traffic and went only 62mph. Last year I drove from bakersfield to Santa ana and back at 25mpg. Same speeds.
 
I would not go to smaller exhaust again 2 1/4 should be fine. You should check your air fuel ratio many times carbs need to be jetted 1 to 2 sizes bigger after adding headers because they are too lean. Get the air fuel ratio right and your gas mileage will come back. :nod:
 
A bigger carb could help and if your still using the LOD (stock) distributor you should get a later one that has mechanical advance too.
 
well went back to the exhaust shop and had the main pipe that goes from y pipe to muffler from 2 1/4 down to 2 inch. so its 2 inch all the way to the tail pipe. around town it feels better. highway still issue mainly probably since the idle mixture stops working but thats normal.

so next step is to rejet the carb. I am using the autolite 1 barrel 1100. what size jet should I get? is there a specific kit or just the main jet I only need to change?

And if so is there a website and part number I can look up to buy or order??

In the far future I wont mind getting a D.U.I. system and chug the stock load o matic system. Currently have pertronix ignitor 1 and 40000 volt coil. running still .052 gap. Since doing all of this would a more exotic plug make any difference since I am using autolite cheap spark plugs??

Again main purpose is to have alittle more power but mainly have a dependable driveability. Owning these kind of cars in this day in age is a statement that style and desire and spirit can outlast the modern science based cars, and I want to keep doing that for as long as I can. It is still my first and only car and want to keep it that way. Good thing having a motorcycle helps ha ha.
 
There is a single jet in the fuel bowl and No way of knowing what jet you have until you open it up and check it. As to what you might need depends on the air fuel ratio that you have now and how far it is from ideal. Number of ways to check that, old school is checking the plug color, and new school using an exhaust gas analyzer, or an air fuel ratio gauge hooked up to your collectors. If you are too rich you can start with a couple jet sizes smaller. :nod:
 
Greetings...been a long time but been busy doing other things.

Spent the last week's getting my car for the car show in Anaheim next weekend.

Mainly interior adjustments...but did a big project by replacing the stock distributor with a new DUI system. Engine starts immediately buy I am afraid that's all it does. I haven't felt much improvement.

My overall goal has been to have best fuel economy and gain some power. Car feels like it is dragging something at lower speeds and it's really bad mpg in the city. I am lost in my decision making of what to do. Either I continue and hope a bigger carb will do the trick, update my autolite 1100 to a universal carb on classic inlines or rip out the headers and return to stock exhaust manifold.

I have been cautious all this time to do anything cause it is still my first car and has been for 15 years.
 
havoline":nwt8v3wm said:
Greetings...been a long time but been busy doing other things.

Spent the last week's getting my car for the car show in Anaheim next weekend.

Mainly interior adjustments...but did a big project by replacing the stock distributor with a new DUI system. Engine starts immediately buy I am afraid that's all it does. I haven't felt much improvement.

My overall goal has been to have best fuel economy and gain some power. Car feels like it is dragging something at lower speeds and it's really bad mpg in the city. I am lost in my decision making of what to do. Either I continue and hope a bigger carb will do the trick, update my autolite 1100 to a universal carb on classic inlines or rip out the headers and return to stock exhaust manifold.

I have been cautious all this time to do anything cause it is still my first car and has been for 15 years.
Click to expand...

Check your brakes for proper adjustment. Do the tires have the highest recommended pressure?
 
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