remote starter switch 4 tuning valves

[vvurdsmyth]

I tune the valves HOT at .006" (been doing that with all the 2002s I've had), but with the '86 E30, connecting the remote starter switch to the starter doesn't turn over the motor; any way of connecting it to turn the motor over...?

[Tom D]

off hand i'm not sure of the correct way, but if you read through a ETM, which can be found on-line, i'm sure it's quite easy.

[draccent]

22mm socket and a 1/2 inch breaker bar works pretty well....

[nick325xit 5spd]

Just put it in 4th and push the car back.

[thejlevie]

I don't have a reference with me at the moment, but from memory if you adjust the valves hot they should be set to 0.012". Cold, you can set the intakes at 0.006" and the exhausts at 0.008" if the head is in excellent condition. Otherwise intake and exhaust should be set at 0.010" cold.

When I adjust valves I use a 22mm wrench on the crank bolt.

[Helion42]

Cold, you can set the intakes at 0.006" and the exhausts at 0.008" if the head is in excellent condition.

I've never heard this, and if my engine can handle it I probably would like to tighten the valves a weensy bit. What defines the head in "excellent condition"?

[Tom D]

…. if my engine can handle it I probably would like to tighten the valves a weensy bit.

actually you probably don't. what would be the reason for a tighter clearance?

for daily driving you would want to increase the valve lash. this acts in the same way as cam timing and will give you more torque in the lower rpm range. if you're looking for higher horsepower and spend a lot of time in the upper rpm range, then you would what them tighter.

[uberpanzer]

There is a way to jump connections in the diagnostic port. Don't have the pin numbers in front of me, but you can find it online. It supplies power to the starter without supplying power to the fuel pump. Just don't have it in gear. I have a switch with two 'pins' on the end of wires in my big tool box for exactly this. Just need a momentary contact type switch and enough wire to have it where you can reach it from where you're standing while doing the adjustments.

[Tom D]

^^ 11 and 14, at least for the 325i

http://i764.photobucket.com/albums/xx288/tomrd/pinoutdianosticport.png

[thejlevie]

I've never heard this, and if my engine can handle it I probably would like to tighten the valves a weensy bit. What defines the head in "excellent condition"?
One that has been recently rebuilt.

[T77911S]

actually you probably don't. what would be the reason for a tighter clearance?

for daily driving you would want to increase the valve lash. this acts in the same way as cam timing and will give you more torque in the lower rpm range. if you're looking for higher horsepower and spend a lot of time in the upper rpm range, then you would what them tighter.

you have it backwards.
if you make the valve lash tighter, the valve opens sooner, advancing the cam timing which moves the power band down in RPM range.

if you can tell the difference between .006 and .010 in performance, you are a better man than I.

it would be interesting to know, but .006 to .010 lash would likely be less than a degree.

[Helion42]

One that has been recently rebuilt.


you have it backwards.
if you make the valve lash tighter, the valve opens sooner, advancing the cam timing which moves the power band down in RPM range.

if you can tell the difference between .006 and .010 in performance, you are a better man than I.

it would be interesting to know, but .006 to .010 lash would likely be less than a degree.

I thought that is would respond like tomD was saying, that it will give a little smoother power and better breathing at higher RPM. So I should just leave it at the cold .010?
I just finished rebuilding it, and had the head polished and ported and all, but the rocker arms are probably what I'd be worried about. The head has about 10k miles on it I believe, but if by rebuilt you mean new/uprated rocker arms then that's a no. The car as a whole will be daily driver, but I'm talkin about tuning it up for sporting.

[Tom D]

…...advancing the cam timing which moves the power band down in RPM range.

…...if you make the valve lash tighter, the valve opens sooner which moves the power band down in RPM range



while your logic at first glance might seem correct, i believe you are not getting the big picture.

the first statement is correct. advancing the cam will move the power band down in the RPM range. however,

for more torque you do not what to necessarily open and close the valve sooner, but rather LATER AND SOONER. to do is you need to reduce the duration and the overlap of the intake and exhaust valves. by loosening the valve lash the valves will open later and close sooner. that will shorten the duration which in turn shortens the overlap.

think of it this way.

if the engine was a very slow revolving machine, lets say 100 rpms, then you only need to open the intake on the downstroke of the piston and open the exhaust on the upstroke. actually, since there is almost no piston movement in the last 15° of crank rotation at TDC and BDC, it would be better to open the intake at 15° after TDC and close it 15° before BDC, same with the exhaust. this results in 150° of duration and 0° of valve overlap, but because the engine rotates so slowly there is plenty of time to fill and empty the chamber.

now if you have an engine turning at 6000 rpms, you need to fill and empty the cylinder much faster by increasing the volumetric efficiency and this is done by introducing valve overlap. by opening the intake valve before the exhaust valve closes, the intake charge is pulled in by the momentum of the exhaust gas leaving. the intake charge will also help clean out the cylinder of any exhaust gas. the exhaust valve will open before the piston reaches BDC on the power stroke and the pressure left in the cylinder will help by pushing the exhaust out the valve even before the piston does.

still with me? this is why a mild cam with 264° of duration will idle nicely (low rpms) and behave well in daily traffic, it is a good compromise between low speed torque and mid range power. a wild cam like a Schrick 336° will not idle very well if at all, but will create big HP at 8000 rpms.

so if you don't want to change your cam and don't have adjustable cam gears, then you loosen the valve lash for low rpm torque and tighten the lash for high rpm horsepower.

edit; the same goes for spark timing. if you have a very slow revolving engine then in theory you what the plug to fire after the piston gets by TDC, but because the flame front is so slow you advance the fire a few degrees (8°± BTDC at 700 RPMs). that way by the time the charge actually ignites the piston has gone past TDC. at higher engine speeds you have to spark the plug as much as 40 degrees before top dead center.

[T77911S]

i cant believe you actually wrote something that long thinking i am going to take the time to read it when it is about something that you nor I will EVER be able to tell driving the car.

although it does have me interested in how much valve lift per degree of crank rotation.

[Tom D]

i cant believe you actually wrote something that long thinking i am going to take the time to read it when it is about something that you nor I will EVER be able to tell driving the car.

actually i wrote it so folks have a better education of how things work. if you choose not to read it, then that's your business.

if you have become familiar with my posting then you have also come to realize that 1) i am not a kid and have quite a bit of life experience behind me and 2) i have formal technical educations in many different fields (meaning that i actually went to school for this stuff)

one of my teachers was fond of saying this and i took it to heart. turns out he was right on the money.

"He who knows how, will always have a job. He who knows why, will always be his boss." Francis 'Chick' Marino

so Mr. T77911S, what's it going to be? do you want to be a leader or a follower?

[T77911S]

for more torque you do not what to necessarily open and close the valve sooner, but rather LATER AND SOONER. to do is you need to reduce the duration and the overlap of the intake and exhaust valves. by loosening the valve lash the valves will open later and close sooner. that will shorten the duration which in turn shortens the overlap.

.

alright, i read this much. but you should tell people the correct stuff.

reducing valve lash does NOT change duration and overlap. it ONLY changes cam timing and by at the most .004 which is what, less than a degree of crank rotation. again, you will never know the difference.

now you could tighten the intakes, and losen the exhaust, but that is not what you said, and once again, you will never be able to tell.

[Tom D]

reducing valve lash does NOT change duration and overlap.

sure it does. having a bigger gap between the cam and the rocker means the the rocker will stay off the ramp for a longer period of time and probably more importantly, it will not lift the valve off the seat as much. so therefore the valve's travel is shorter and will open later and close sooner. that means the duration has been reduced.

as far as real world feel, well i doubt that in daily traffic with a 3K pound car and 150 HP you would notice much difference and in all fairness to me, i never said anyone would. i was just questioning someone on why he would want to close as opposed to open the gap on a daily driver.

but, i also ride motorcycles and when the weight to horsepower starts looking more like a high performance race car, then yes, i can tell the difference.

one more thing, i never said anything about .004", i am only explaining what happens when you open and close the valve gaps.

[T77911S]

yes, you are correct, i was trying to leave work in a hurry, i did miss-type. changing valve lash WILL change duration and overlap, but my original point was that you had advancing and retarding backwards, AND that this is such a small change that i can't believe you advised this for a performance gain, and its not the first time you have said this.

your quote:
"for daily driving you would want to increase the valve lash. this acts in the same way as cam timing and will give you more torque in the lower rpm range. if you're looking for higher horsepower and spend a lot of time in the upper rpm range, then you would what them tighter."

i go back the master, thejlevie, set the valves at .010 and be done with it.

my reference to .004 was based on the max jim said he would tighten up the valves, based on .010 being the standard.

[Tom D]

fair enough, i think we just went over everybody's head anyway.

this is not something i made up, but rather something i first saw when working as a ISMA pit member in the early 80's. when i asked the crew chief what his reasoning was he in turn suggested a book to read. apparently this is an old racer's trick of 'milding' out or 'heating' up a cam to suit a particular race track.