timing

[jon_570]

is there a way to change the timing in a 4AFE....just to give it a lil more power.????if so does neone have like a step by step process on how to do it..???thanks...

[ghost_ryder35]

more power... LOL... um rotate the dizzy, but remember when you advance timing you should run a higher grade gas have fun and dont advance it to much, make sure to check timing with a timing light.

[fistofmeat]

rotate the dizzy? what do you mean?

[Flashmn]

You wont really get more power from upping the timing, you might get knock though.

[Bitter]

Originally Posted by Flashmn

You wont really get more power from upping the timing, you might get knock though.

i have to disagree.
i added 5 degrees timing and felt a marked increase in low end power. the F head design is very knock resistant as well, the combustion chamber is very compact and actualy most of it resides in the dish of the piston. with 15 degrees of timing 89 octane should be safe, but i run 93 since its not that much more cost than 89 and i've done a little more than just advance timing.

by advancing timing you're trying to put the LPP (location of peak preassure) closer to 14* ATDC where the angle of the rod, piston, and crank will transfer the most of the downward push into rotary motion. starting ignition a few microseconds sooner on a A-F engines wont do harm as long as you keep an eye on the plugs for any signs of knock. timing is set at 10* for emissions, to reduce the formation of NOX. however in my state my car isnt subject to NOX testing, only HC and CO.

signs of knock you can read on your spark plugs are
1. they'll be alot whiter than normal
2. you may see small speckles on them

if you see either of the above step up a grade of gas or turn the timing back. DO NOT adjust your timing without a timing light.

[Flashmn]

i added 5 degrees timing and felt a marked increase in low end power. the F head design is very knock resistant as well, the combustion chamber is very compact and actualy most of it resides in the dish of the piston

Dont lecture me about a F head, theres nothing in them that I dont know.

As for looking at sparkplugs for knock, you wont see signs in them. Only thing you might see is that your electrode porceline is starting to glaze, even then the signs arent gonna be very visible. Granted when you blow off the electrode from the plug you'll notice the signs.
Modern gasolines with their chemicals will almost always have a whitish tinge to them, even then you cant look at timing much, only thing you can judge from plugs is when and if you know your plug temperature range is correct, then you can have a sort-of indication on the mixture, however stock heat range plugs arent always the best bet.
I'm running 2 numbers cooler plugs on mine, however mines a forced induction engine.

But unless you really crank up the timing you wont achieve any ground breaking hp levels or gains and that again is risky, theres always a limit for octane.
we've gone through the whole range of distributor adjustment, we didnt get knock at a detrimental level, however you really wont find power if you adjust it too much.

Also keep in mind that the F-engine has vacuum adjustment as well as mechanical advance, whilst the FE has electronic adjustment from the ECU.
What happens is that vacuum advance will keep the advance up in no-throttle and part throttle, where as the RPM increases, throttle opens the weights will advance it more.
So as your base timing is about 10BTDC with the hoses off, your total advance is along 16degrees. Now you mess with the base timing you're gonna have more idle timing, but you're also gonna have alot of timing in the WOT area and thats when you're gonna have problems.
So when you say you advance the timing 5degrees, your static timing will be around 20BTDC, not 15BTCD, because of vacuum advance.

[Bitter]

sorry, i was only speaking of the FE, not the F.

when i said whiter i meant brand new clean white after 1000+ miles can be a sign of slight detonation, the sudden spike of heat and pressure burns off any deposits on the porcelin. also you can read the ground strap and electrode to see if you're burning too hot.

if you're getting worse detonation you'll see small sparkles of aluminum on the plug and in the exaust runners. when i initially advanced my timing it was at school and the asshole teacher wanted to let other students play with my car as well, so somehow i ended up with nearly 20deg advance! it ran like that, on 89 octane, for almost 2000 miles. all the while i was chasing a fueling issue or an air leak because my plugs were so white and hot looking, finally i got down to the only issue being ignition timing, and when i checked it sure enough it was way over advanced. when i put it to 15 like it was supposed to be it runs like a champ and idles smoother than it did at 10, accelerates more smoothly, and feels like it has a smoother torque curve than it did before.

[Flashmn]

those small sparkles of aluminium are from your pistons, if you have sparkles on your plugs, you're already suffered engine damage.

I had my car going pig rich, to the point it almost stalled when you pressed the gas, yet my plugs where whitish with a brownish tinge.

[Bitter]

Originally Posted by Flashmn

those small sparkles of aluminium are from your pistons, if you have sparkles on your plugs, you're already suffered engine damage.

I had my car going pig rich, to the point it almost stalled when you pressed the gas, yet my plugs where whitish with a brownish tinge.

yea i know what the sparkles are i need to do a compression test, but its not running poorly so i dont think i did any serious damage. its the last time i let anyone else fuss with my car at school, thats for sure!

i'm willing to bet the speckles of aluminum are from the top edges of the piston, thats the most logical place to get detonation damage since its the most exposed part of the piston.

[jon_570]

my motor as it is now..a 4afe..knocks if i use 87 octane gas..i use 89 as of now and it doesnt do it unless its bogged down..

[Bitter]

Originally Posted by jon_570

my motor as it is now..a 4afe..knocks if i use 87 octane gas..i use 89 as of now and it doesnt do it unless its bogged down..

and you havent fiddled with it any? likely culprits are...
incorrect plugs (too hot)
carbon deposits in the combustion chamber, they heat up and stay hot creating 2ndary ignition sources which can cause knock.

check/change all your plugs and try a topend cleaner.

[TheOtherCarolla]

Mine seems to like the stock timing setup the best. I don't recall what it is off the top of my head, but when i threw the head back on, i did it all to factory specs to make sure it ran right, and everytime i changed it, it didn't respond well.

[jon_570]

Originally Posted by Bitter

and you havent fiddled with it any? likely culprits are...
incorrect plugs (too hot)
carbon deposits in the combustion chamber, they heat up and stay hot creating 2ndary ignition sources which can cause knock.

check/change all your plugs and try a topend cleaner.

havent fiddled with it none..the spark plugs are the ones that came with it stock..i have tried seafoam..trice..the first time ALOT of smoke and the second tims just a lil..so it cant be THAT dirty...

[Flashmn]

Modern gasolines have cleaners in them and they dont make carbon deposits. thats more/less a thing of the past.

[Bitter]

Originally Posted by Flashmn

Modern gasolines have cleaners in them and they dont make carbon deposits. thats more/less a thing of the past.

it depends where you fill up at, Mazda was having a hell of a time with their 2.5 V6 getting clogged up with carbon, eventually they and other makers went onto certify ONLY certain gasoline brands as "Top Tier" fuels, which means they have the correct amounts of additives as needed by the automakers. typically 7-11, walmart, flying J, and grocery store gas stations fuels do not have these additives and do not meet the 'Top Tier' specs for fuel quality.
http://www.toptiergas.com/
http://www.toptiergas.com/deposit_control.html

i know it looks like a bunch of hooey put on by some fuel makers and auto makers, but its honestly not. I've talked to GM techs who've pulled heads on motors still under warranty and found carbon deposits that were causing detonation. perhaps in finland (and europe in general) they have stricter fuel standards.