Timing question

[Swiftdoog]

I get it now.

One more thing, this just happens to cross my mind right now...

Could it be; even though I have installed the timing belt quite a few times but; could it be... that I may, just may slipped one tooth from the crankshaft? I did have the piston on TDC, but I checked that using a long screwdriver and seeing where the piston began to fall, then I backed to where the screwdriver was more at the top.

Could it be, just could... that I may have jumped one tooth? I mean, this whole problem maybe just that, what do you think?

[fixkick]

sure,
the belt can be wrong for many reasons.
keys bad (both)
belt loose, not tension-ed right at install time.
idler bearing bad, causing belt overheat and bam.
the idler index tab , not indexed right, per photos on my page, shows, its canted and then goes loose later.?

using tdc finder proves the crank mark. is right, and top cam cog mark is other, easy check.
as does this.

http://www.fixkick.com/t-belt/sneak-a-peek.html

[Swiftdoog]

Hey fix, good news, all that you said, I applied it and it worked , of course I did some minor tweaks to your advise.

    I just choked the nipple a little bit and indeed the advance now is slower, firm, but slower. I even removed the stops and now there is no ping. Is like the movement is more like a curve rather than a jump straight to a line.

Clever right? I now, it was easier to pinch the vacuum line, but I am no easy fix man, I like the hard way

[fixkick]

that can work
it's very very crude, but costs nothing,
it's and orifice, that delays vacuum
in this case, you delay vacuum so long that it never arrives, and then your right foot , ends the high vacuum and wins.
so is just a race between your foot and the orifice
way to go., nice simple fix.
thanks for sharing !!!

[Swiftdoog]

Back again with one detail... the delay is so big that letting off the throttle causes the timing to back down so slowly that on certain situations pushing the throttle will cause ping "again" :S (sometimes, not all the time). I grabbed the timing light and saw the damper indicator move so slowly back to 6 degress that it was amusing. Could I just unplug the vac advance until I find the right vac advance pot? Maybe advance the timing to compensate a little, all this with the vacuum advance disconnected.

[fixkick]

It be real hard to make the wrong part work correctly.

It is ported vacuum and the following features (factory tuning)
1: the Carb ported vacuum, is tuned for location and hole sizes. (in or near the venturi)
2: the vac, advance spring force is tuned (or in some cars this spring is in the distrib on the advancing plate)
3: the Vac diaphragm size.
4: and limiters. the stroking rod , has limits that can be changed, many limits stops are located on the advancing plate.
5: all the above tuned for transmission type. (many ATs or MT , usually this is by smog laws)
6: tuned for a working EGR or not. (many G16's ping with no EGR active)
7: and last, suzuki used different distribs in different markets, not sure why but did, and the VAC is diff, fit. "physical fit" making parts very hard to locate.

some brands of cars have 50 different vacuum devices, for engine sizes, 1 to 2+ liters. and different body weights(loads). some done for forced factory carb changes, (the seller stops making a carb, is one cause)
that is where EFI wins best, it tunes by simple table.

many guys with old cars , very old cars, that cant get the Vacuum advance to work correctly, due to gross head millings, (CR way too high and no high octane to match it)
They modify the advancing weights /springs, (lighter weights, or stronger springs or lil of both) Spark timing is a very very complex topic !
This is common on old race cars, where they only need advance at one speed around a loop track. (the methods and ways and means)
The advancing springs can not work very good, at all for engine load. as vacuum does.
so is a gross compromise, the centrifugal is RPM only, simple and effective for speed.
you can run all day with no vacuum advance, all you give up is that instant torque off the line. the VAC advance is LOAD sensing device.
no vac, no load, can be sensed, and there for no power off the line, no power when you need engine torque now, leaving you with one choice
that is to down shift and make the distributor spin faster, .
if you advance static timing ,that makes the engine almost impossible to start. after all it tries to start backwards.
think about that , the piston rises, an at say 15 to 20 Deg. BTC it fires way too early, and that fires backwards, see?
Ask old real HARLEY riders how that sends you over the handle bars,skipping step one,(retard lever)
your pinch vac tube, cause the Vac advance to work as an accumulator. (like battery or electronics capacitor holds a charge)

Back again with one detail... the delay is so big that letting off the throttle causes the timing to back down so slowly that on certain situations pushing the throttle will cause ping "again" :S (sometimes, not all the time). I grabbed the timing light and saw the damper indicator move so slowly back to 6 degress that it was amusing. Could I just unplug the vac advance until I find the right vac advance pot? Maybe advance the timing to compensate a little, all this with the vacuum advance disconnected. sure many have, power will lack.

[fixkick]

see this.
all you need is in this one clear 3d graphic, this is timing, seen in a much more clear way.
this is the magic curve in all cars today, they burn 20% less fuel doing that, and more power, matching that un-wasted fuel.
what you ask is what happens if you take that left lower point and lower it to zero. (vacuum hose dropped and plugged)
there is only one answer, the low end power will be weak and fuel will wasted.
if you set static too far advanced.?
what happens
see the top RPM advances here (mountain top), you then get them into the illegal zone, ping zone. so now you need , high octane fuel. to do that. (burns slower it does, that fuel)
my lawn more has 3d curve that is pancake, flat line, no dynamic advance at all and sends most the fuel , out the exhaust, but if keeped at a constant speed, this can be tuned, one speed, one load.
Cars are very dynamic bests, driver and hills. so we need a dynamic spark machine,. or power lacks and fuel is wasted.

[fixkick]

btw this curves sits on top of static advance.
so if at 10 D. BTDC then add 10 to all numbers on left side of graph.

[Swiftdoog]

VACUUM ADVANCE UNIT SUIT MITSUBISHI LANCER CB CC 4G15 1.5L DISTRIBUTOR T6T87372

This one looks almost like the one I need, except the rod is bent, but I am looking for this part around (Mitsubishi seems to be more popular here, even than Chevys and Fords), if I find it I will see if I can straight it or cut and solder and test (don´t want that thing breaking at 2000 rpm)

[fixkick]

there is nothing more complex, ! Called engine tuning....
engine CR, that be first if not at spec. all is wrong ! 2x both the CR and the quench, areas... PING city, unless high octane fuel is run.

on cars with custom carb's like this car ,the carb and the spark are tuned together on a dyno ( takes weeks of work, lacking this dyno mach.)

in a factory car, the carb is already tuned and all you need to do is get the spark right matching that stock state of fuel flow. (called spec)
in this case it's the 2 fighting each other.

case in point, the advance is based on , fuel air ratios. if rich? the flame font is slow, if lean the front is faster. so spark is timed to MATCH THE CARB.
not the other way. (or pull out hair)
lean burn loves to ping, so, we avoid that.

btw, Suzuki dont make distributors, they do spec them and MiTsubishi makes them or Denso to their spec. (gear fit and advance spec)

when you are parked, and in gear, and slam down the throttle what happens?
the CARB goes super rich, this is a special feature of the carb, all carbs do that.. and can be very crude.
but it will go from 14.7: 1 AFR to 12:1, rich (best example)

this very rich fuel mix, allows a burst of more power, 12:1 is max power, 14.7 is min fuel , min smog. see?

so many race engine run 12;1 all the time, (not indy,500 or where fuel waste is an issue)?
but max power is great for driving from say 0mp to 20mph, (any time you accelerate the fuel goes rich, so needs advance NOW not 3000 rpm later)

this rich fuel burns slower, a slow flame front it's called.
and needs longer time to burn that fuel, it's so slow, and if not its just blown out the exhaust tips.

this is what vacuum advance does, its advances spark at that burst of vacuum at the calibrated carb port, (my guess, long long missing, now)
Centrifugal advance is easy, see? it just RPM, but vacuum advance is the most complex topic there is.

that is because it has many parts that must work together, as ONE. (and are spread out) case in point, I bet your vacuum is dead wrong....
it's not just a part thrown on a car, sure if stock an sure if 1 stock part added, but yours is anything but stock.

one could just not run Vacuum advance at all and just use lower gears.
but with a A/T you have no control its calibrated for a stock car, that you dont have.
in 5speed STICK, 1st gear take off will be weak but...
but once moving you can run 1st gear longer, and shift later, SO you get the benefit of the Centrifugal advance, say up a hill.

I'd hate to see you import expensive parts only to learn that your ported vacuum is dead wrong for any suzuki distributor.
can be.
its ported vacuum and that too, is complex. the diameter of said port and exact location are critical to the feature.


I have no secret suzuki list for what real mitsubish partnumbers were used, sadly








Suzuki Swift 1995
Carburetor with a Weber 32/36
G16 16v 1.6L ,
Automatic F3A