Niall.b

what would the symptoms of the cams being a few degrees out, either advanced or retarded

tabetha

If you are on standard cam pulleys then it would be impossible to be a few degrees out as each tooth is 9.47 degrees, ie 360 divided by38(teeth).
This is a hell of a lot it would be doing anything from being completely flat to spitting flames, you would know.
What is the problem, as it is so easy to just look at cams and check.
tabetha

Niall.b

on verniers and flat would be a good description. think im going to have to get my dial gauge & degree disc out

tabetha

I would, make sure the basics are right first.
When I bought an auto sierra before my cos, the belt(pinto) was just one tooth out, it was like driving a 1L car not 2L, I checked the belt timing whilst looking for the lost power, corrected it then intended to drive up the road to try it, I literraly got 15/20 feet, the difference was obvious.
Previous owners firend did it as he serviced all the taxis, quality job if he can't get it right on a pinto!!
tabetha

IANS2RST

iTrader: (1)

check the actual ignition timing as it is very easy for the aux pulley to move when changing the belt altering the position of the dizzy

IANS2RST

iTrader: (1)

also have you just added the cams? if so what is the rest of the engine spec?
standard cams are good for 400bhp changing them even if the timing is spot on they can feel very laggy until they hit the power band
a bigger turbo will make this feel even worse

OldDan

Custom valve cut outs on the pistons

foreigneRS

doesn't affect ignition timing

if your figures are right, that is 9.5 degrees of the cam, but only half that of the crank, so not all that much in reality

IANS2RST

iTrader: (1)

how does it not affect the base ignition timing as the aux pulley drives the dizzy????????????

foreigneRS

because the distributor is only a distributor of the spark - the timing of the spark is done by the ecu based on the signal from the crank position sensor. don't you know anything about engine management systems?

IANS2RST

iTrader: (1)

yes but as a base setting the distributor needs to be in the right place
or why would the distributor be adjustable?.
the ecu controls the advance & retard it does not move the starting point, how can it? it needs a point of reference hence when you look at the manual for changing the timing belt it tells you to align the marks on the dizzy
from what your say if the timing is controlled by the ecu it could alter the timing to compensate for the rotor arm pointing at number 2 cylinder when no 1 is on its firing stroke.
haveyou ever done a timing belt on a cossie? do you just not bother lining up the the marks on the aux pulley or the dizzy when you time it back up?
bet it runs great

foreigneRS

that is only so that the rotor arm will be in the right place to distribute the spark from the king pin to the correct lead for each cylinder

there is absolutely no need for the distributor to be adjustable - it is just fixed like that as that was how it was done on that block before with a conventional distributor with points etc.

the distributor also contains the phase sensor so that the ecu knows where in the 4 stroke cycle it is, as the crank shaft position sensor does not tell it that. but that does not affect the ignition timing.

i've done plenty of timing belts, and of course i line it up correctly - but i understand what i am doing and why, not just follow a manual

you can't educate me about how it works. if you knew enough about it you would not come out with your last sarcy comment - it will either run or it won't. it will if the rotor arm lines up sufficiently, and it won't if it doesn't

i'll tell you again, the dizzy position has NOTHING to do with ignition timing - it is done by the ecu from the crank position sensor. it knows that there are 4 teeth on there and how fast it is turning so knows the time interval for each degree of crankshaft rotation.

tabetha

9.5 degrees not all that much!
It is a collosal amount in cam terms.
When you do the belt timimng is is vital to set the lug on the crank pulley on the very edge of the pointer almost, BUT NOT, past it to set the rotor arm DEAD CENTRE, as spark is not generated until lug has moved OFF the CPS, and the filed has collapsed, easy mistake to make, it will put the PHASE out of line and you will have a lot of coughing backfiring the more revs you use.
tabetha

foreigneRS

anyway, to answer the guys question - it depends on the cam profile, but yes it could feel flat

IANS2RST

iTrader: (1)

what like your sarcy comment, why do tuners alter the dizzy to give the correct base setting when about right will do.
I have offered something for the the guy to check which from my experience would cause some of the symtoms he has listed. up to him what he wants to do.

foreigneRS

if you have paid a tuner to twiddle the distributor base of a cosworth you are a bigger fool than it first appears

on a cosworth, the position of the distributor base has nothing to do with ignition timing so you are not telling him about something that could affect his engine at all

on other engines from the early 20th century, you are definitely right

IANS2RST

iTrader: (1)

as i said up to him wether he wants to check it or not.
I've had a couple of cossies with the same symtoms and the ignition timing was the cause

foreigneRS

ok then, i must be completely wrong how was your timing 'fixed'?

IANS2RST

iTrader: (1)

each to their own, it worked for me & i've tried to help.
this is exactly attitude why I did not renew my trader status & havn't even bothered to sign up as a gold member.
i may not know everything there is to know about engine management systems as you obviously do I've offered advice & all I get is sarcastic comments & called a fool.
perhaps & i could sign up to your engine mangement & how to be a sarcastic prick course?

foreigneRS

tabetha

ForeignRS is talking NONSENSE.
The position of the dizzy is absolutely critical as it can cause and does cause CROSS FIRING, if not correct, a very WELL KNOWN problem, but easily overlooked by even very experienced people.
The dizzy does not JUST deliver a spark, it tells the ECU what phase it is in, one reason is because it has a phase sensor, get this just one tooth out it will be horrendous, despite the fact that the rotor could be aligned on the edge of the arm, wit the scribe mark.
This was something I was discussing very recently with STU from MSD, which is the reason for my CLEAR ADVICE, handed to me by someone I certainly trust to know.
Unless we all want to wait for ForeignRS to tell STU about setting up engines, I am sure he would be interested, as would others, no one ever has seen it all with engines.
Being roughly in line is NO GOOD it needs to be as I said, otherwise it will inject fuel at the wrong time/phase as it gets the signal for phase too late.
The ecu is NOT clever enough to understand this.
tabetha

IANS2RST

iTrader: (1)

what I've been saying from the start but I think he too far up his own arse.
obviously has a cossie ecu that can hop out from behind the dash with a spanner to adjust the base timing

foreigneRS

i have never known anyone be so useless as to get the dizzy position so wrong that it causes a problem. maybe they were using laserline tools

if you really understand it, you would know that you don't need to align the dizzy as shown in the manual as both the inner and outer parts can be turned

IANS2RST

iTrader: (1)

but they still need to line up you fool
yes you can put the dizzy in any way you want
yes the aux pully can be in an position you want
BUT the the marks on the dizzy need to align with the rotor arm

this you think doesn't seam to matter and a dizzy has no affect on the ignition timing
as i keep saying the ecu needs a starting point it can't work out where the dizzy is itself. it use the phase sensor to do this but this needs to be in alignment with the shaft.

grow up and accept you're talking bollocks

foreigneRS

i'm talking bollocks

and now i'm grown up

tabetha

Pity stu does not read this!!
I think you/we need to give up on him as a lost cause, it is obvious they don't fix the phase sesnor in a certain way just for fun.
tabetha

foreigneRS

stu does read this forum when he has time and may come across this thread

my understanding of what IANS2RST was saying in the first post of his on this thread was that swinging the dizzy would change the ignition timing in the same way that it would do on an old engine with a distributor that has the coil trigger inside. that is certainly not the case and what i said is true - the ecu sets the ignition timing based on the crankshaft position (knowing which of the 4 lugs is TDC at the right time in the 4 stroke cycle from the phase sensor)

i completely agree that getting the position of the phase sensor wrong will change the point in the cycle that the ecu thinks the crankshaft is in, but i don't believe that anyone has ever got it that wrong, and even if they have it would not cause an engine to just feel flat as the poster describes his symptoms.