256 cams with 16 valve stock ECU

[Hald]

Good day everyone!
Bought 256 HKS cams 8.1 lift for my bluetop, can you advice me timing adjustments for them? I will run them with stock ECU, or I can leave them at ziro?

[totta crolla]

They will run ok with stock cam wheels and ecu.
You will almost certainly need to adjust for correct valve clearance though.
Best cam timing can ideally be set up on a rolling road dyno using adjustable cam wheels.

[Hald]

I'v got adjustable cam gears, but maybe there's some known timing setups thet are best for thet config

[yoshimitsuspeed]

Set them by the cam cards unless you plan on getting it on a dyno to tune it.
Even if other people had success with different timing you can't know what will work with your setup till you can measure the results.

[Hald]

I can't afford dyno... thet's why asking advice here. also I don't have cam cards, and know nothing about them... mabe I'm asking silly question =) maybe some suggestions, or so,

[jdm86gtz]

I probably have this due to oldeskewltoy so you can thank him

[jondee86]

Run the cams with the factory cam wheels as HKS will have set the
knock pins to give the correct timing. If you want to install your
adjustable wheels, install the cams with the factory wheels, and
then swap the adjustable wheels in without disturbing the cams or
timing belt. Back the tensioner off and do one cam wheel at a time.

In theory, setting the adjustable cam wheels to zero should make
them exactly the same as the factory wheels. If they are not, you
will pick up the difference while swapping them in. Checking timing
with a degree wheel and a DTI would be better, but the above will
get you running.

Cheers... jondee86

[Hald]

jondee86
thx

jdm86gtz
thanks! now I should to learn how to use it =)

[totta crolla]

Once you have done as Jondee suggests above you can then index the adjustable pulleys with a marker pen or some such so that you can go back to a known reference point at any time.
Have fun adjusting the cam timing to get the power where you want it but don't forget to check your ignition timing each time you adjust the exhaust cam.
The article below should help somewhat and be aware of piston to valve clearance and ALWAYS turn the engine over by hand to check for any binding before trying to start it.
http://www.compcams.com/Technical/FAQ/LSAproperties.asp

[Hald]

totta crolla
thanks!

I have adjustable gears with mark tables, so marks will not be a problem.

[oldeskewltoy]

http://www.mr2oc.com/showthread.php?t=499258 - substitute your timing information for the KK108

[tiprock]

You will almost certainly need to adjust for correct valve clearance though.

imo probably more important than getting the cam timing perfect.

[Hald]

thanks guys! will learn new information!

[Hald]

Need help again...
Someone have cam cards for TODA 256 7.9 cams? Can't google it...

[oldeskewltoy]

Need help again...
Someone have cam cards for TODA 256 7.9 cams? Can't google it...

[Hald]

oldeskewltoy
yay, many thanks!!

[Hald]

Hey guys!
I found thet I have 66 degree overlap on my cams and stock gears. Is it good or there are some better overlap value thet can give good hi rpm power and don't loose too much low rpm? What overlap can you advice?

[yoshimitsuspeed]

Overlap is only one piece of a complex puzzle.
For example the 20v goes into high overlap cam timing in the middle RPM like 2500 to 6000 or so then goes into the low overlap mode in the higher RPM because the intake valve staying open later allowing more charge to fill the cylinder is more important than the cam opening earlier for more scavenging.
When you can change cam size you can get both and this will allow for better cylinder filling at high RPM but when you are not changing the cam but just the timing then you have to factor how you are effecting valve opening and valve closing.

[Hald]

Hey guys!
Can overlap of 66 degree be a reazon of unstable idle?

[oldeskewltoy]

Hey guys!
Can overlap of 66 degree be a reazon of unstable idle?

Overlap: It's an important function in valve timing because the exhaust gases flowing through the exhaust valve and manifold help draw a fresh charge through the intake valve into the combustion chamber.

This would mean the point that the exhaust valve closes, and the intake valve opening.....

referring to the Toda cam chart..... exh closes @ -1 degree, and the intake open @ -.5 degrees

How do you have 66 degrees of overlap with 256 cams???

[jondee86]

Overlap is the result of where you set (advanced or retarded) your cams.
It is not a tuning target as such. You can have the same amount of overlap if
you move both cams forward or back the same amount, but the end result in
terms of engine performance will be totally different.

HKS set the valve opening and closing events to give the best all round engine
performance with standard camgears. It just so happens that this resulted in
66 degrees of overlap. On a MAP sensored engine the idle can get a bit unstable
due to the reduced manifold pressure that results from longer duration cams.
This can be fixed by adjusting the ignition timing and raising the idle a little.

I haven't worked with an AFM sensored engine, and in theory they should be
less sensitive to cams. Check and reset your ignition timing first, and if need
be use the idle air screw to raise the idle 100rpm. You may get a tiny amount
of lope, but 256 cams should idle pretty much like stock.

Cheers... jondee86

[Hald]

dunno, I'm not good with this charts....

[jondee86]

How do you have 66 degrees of overlap with 256 cams???

From the HKS cam card, Intake opens at 36 BTDC and exhaust closes at 30 ATDC.
These are measured at 0mm valve lift, whereas the Toda figures are measured at
1mm valve lift. Comparable figures for the HKS cams at 1mm valve lift are 2 and -4
which means they are 2 deg short of overlapping at that lift.

Kind of a strange way of charting things

Cheers... jondee86

[oldeskewltoy]

How do you have 66 degrees of overlap with 256 cams???

From the HKS cam card, Intake opens at 36 BTDC and exhaust closes at 30 ATDC.
These are measured at 0mm valve lift, whereas the Toda figures are measured at
1mm valve lift. Comparable figures for the HKS cams at 1mm valve lift are 2 and -4
which means they are 2 deg short of overlapping at that lift.

Kind of a strange way of charting things

Cheers... jondee86

Need help again...
Someone have cam cards for TODA 256 7.9 cams? Can't google it...

understood.... but OPs post previous to his 66 degree question was asking about the Toda specs... and the Toda specs don't have a 0 degree point of measure.

[Hald]

Found where was a problem... Misstake with adjustable cam gears and wrong ignition timing