How to advance the camshafts PH3

20th February 2011, 17:46

Hi people,

well i had advanced my camshafts and my car was nice , going side by side with a Civic EP3 until 200km/h.

But now i ve put new pistons with cavities in the top.
So i've advanced more my camshafts... but now the car its falling behind the EP3.... did i advanced too much?

whats the best advance or how can i do it?

Should i put the old adjustment, and advance only a little?

another thing the adjustment should be more inthe camshaft from the admission or the exhaust?

best regards !! and thanks for the help

20th February 2011, 21:40

Just put it back to what it was if it was running fine... you never want it to early or it will start "pinking" It will inject the fuel and spark it before it's fully compressed everything at tdc.. Also let the new pistons run in a little more also before giving it full beans.

20th February 2011, 21:43

I would have the timing adjusted on a rolling road to be honest.

20th February 2011, 21:43

Yeh man, you NEVER thrash an engine after a rebuild.
If you do, you're wasting your money, the Pistons, Rings and bearings will be shot before you know it.

20th February 2011, 23:49

i had made 2000 kms before this

so now i want to get the best performance from my camshafts.
but i guess i had advanced too much..

21st February 2011, 12:27

How much did you advance by? did you advance the inlet and outlet?

I got told to retard my exhaust cam 2 degrees after fitting cams.. Not sure why

21st February 2011, 12:29

Yer been been told to retard the inlet cam abit before mapping as it helps it to ilde better before the map it sorted.

And to the OP question you need to get it on a dyno to get the best timing for them and the map corrected to suit.

21st February 2011, 17:45

if youve fitted pistons with cavitie's youve fitted low compression pistons..... boost pistons, if your not running some form of forced induction youll have made your car slower by lowering the compression ratio.....

21st February 2011, 21:17

Quote:

Originally Posted by blackie_2k5

if youve fitted pistons with cavitie's youve fitted low compression pistons..... boost pistons, if your not running some form of forced induction youll have made your car slower by lowering the compression ratio.....

yeah probably, but i can also give a better advance with nothing hitting in the piston.
my compression its at 11.5 bar at the cilinder.

Tomorrow i will ast to a friend with more experienc to advance the camshafts and see what it gets

21st February 2011, 21:28

O I think you have fitted low compression pistons, that compression you have is not all that great for a n/a engine.

Only 166ish psi, a vts normally is higher than that.

That could be your problem as that will not help a n/a engine having lower compression.

And would just keep moving the cams around, first get it on a dyno so you can see if moving the cams are gaining or losing.

21st February 2011, 23:19

Quote:

Originally Posted by blackie_2k5

if youve fitted pistons with cavitie's youve fitted low compression pistons..... boost pistons, if your not running some form of forced induction youll have made your car slower by lowering the compression ratio.....

If you are reducing the volume inside the combustion chamber then arent you going to increase the compression ratio?

Thats why people fit thicker headgaskets when doing basic turbo conversions isnt it? To "cheaply" lower the compression...

That was my understanding anyway. Please correct me if I'm wrong!

22nd February 2011, 07:57

Get the car setup on the rollers . What timing works for one engine may not work for the next.

22nd February 2011, 11:05

Quote:

Originally Posted by JoshB

If you are reducing the volume inside the combustion chamber then arent you going to increase the compression ratio?
yes
Thats why people fit thicker headgaskets when doing basic turbo conversions isnt it? To "cheaply" lower the compression...
yes also

That was my understanding anyway. Please correct me if I'm wrong!

however hes increasing the volune in his cylinders by fiting low comp pistons thus lowering the compression....

so let get this straight....... do the pistons have a full cavity across the crown, or have they got larger valve cut outs fitted?

if its the first id be very carefull about advancing the cam timing, as the valve cut outs on low compression pistons should be no deeper then the standard items....

23rd February 2011, 21:17

well first of all these are the pistons:

About what i-ve done.. well i went to my friend and he advanced me the camshafts and than i tried to compare with the civic ep3 but he went away again...

well what my friend said its that these pistons, need a lot of km's to star to rule... because they were new also.. so.. until i make 5000 kms or so.. i wont get the best from the pistons and my advance in the camshafts..

23rd February 2011, 21:24

Na you dnt need that many miles to get the best, should of all bedded in after about 1000 km the lest time it take to bed in the better.

Like I said you need to go to a dyno/rolling road and move the cams around to as it all ways best to just advance the cams.

Every engine different, and the pistons change it again plus to get the best out of it, it needs the map doing to get the right ignition timing doing aswell.

Also the pistons will not give you much top end power, by should need the torque, but you compression figures are low for a n/a engine which will not help.

23rd February 2011, 21:34

as andy says, take it to a rolling road for cam timing and map changes. this is the only way to achieve the best overall all round performance. a wide spread of good power is better than a high bhp number right at the top rpm.

23rd February 2011, 22:41

nice posts guys! thanks!!

well and ive already made 2500 kms...

23rd February 2011, 22:51

How did you bed it in? What did you do, the compression should be higher for a n/a though, my compression with high comp pistons is 250 psi which is just over 17 bar.

What make pistons are they? Standard bore size?

But you need to get the map corrected and timing set up on there to get the best balance.

23rd February 2011, 22:55

i guess u didnt get but its NOT turbo!
just a regular 16v

with headwork, camshafts, manifolds etc..

i guess 17 bar to a atmosferic Saxo its HUGEEEEEEEE

the original compression its 8.1 bar.

23rd February 2011, 23:13

Dnt think you right about the 8.1 bar statement,

And I never said anything about turbo did I?

23rd February 2011, 23:46

hmm so whaat do u mean with n/a? :\

23rd February 2011, 23:52

Naturally Aspirated, I.e. Not turbo or super charged.

On turbo or s/c the compression should be lower than a Naturally Aspirated compression.

Your compression is low for a n/a engine, I would want to see figures closer too 180 ish on a standard ish engine.

If the cams have a bigger duration the compression could be alittle lower but not too much the bigger the duration the more it will effect the compression.

But if the psi is down around the 150 psi is abit low.

Also how dose the compression move on the gauge dose it come up in little bits or most the psi/bar come in one big lot?

24th February 2011, 09:26

the compression doesnt cove all in one piece on the gauge...
in the first cilinder it wnt only at 3 bar.. but than started to grow.

the others went like to 8 bar or something and than went sloly to 11,5 bar.

24th February 2011, 09:55

Sounds fucked.

24th February 2011, 11:20

Yer they are low figures, or the guage not great if the compression good most the compression will come in one big lot first then alittle more to get the final compression.

If the rings are good, the compression will jumP in one big lot.

But if they are high comp pistons which do look like but with very flat crowns, should be over 200 psi really, anything below with high comp pistons would worry me.

Maybe they are not bedding in well? What the oil like dose it burn oil?

24th February 2011, 12:32

well if the inlet and exhaust cams are open the compression and running engine vacuum will be very low at cranking and idle rpm. its directly effected by camshaft and cam timing.

- colin.

24th February 2011, 12:38

Also when doing the compression test is it with throttle open or closed?

24th February 2011, 13:58

asnswering the questions:

- the throttle what do you mean? my gas pressure its 3.5 bar.
- but i had the ignition coil off, and i just turned the key until the compession in the gauge didnt move more.

- about the oil.. i've got a 5W40, but i-m loosing a bit of oil threw one of the retainers of the camshafts. but i guess its the only spot thats is loosing oil

24th February 2011, 14:10

No way the butterfly open I.e. Throttle open? So did you press the throttle plate down when doing the compression test?

Show much oil are you losing? As a little leak if little wouldn't show too much on a dip stick for a bit, if the rings are letting oil passed, oil level will drop.

24th February 2011, 19:32

yes the admission butterfly its worked also, with more air entry.

In the compression test, ive taken out my ignition coil, and plug sparks, and put the gauge in each hole, and turn the keys on.

the oil i think its not related.. the level is dropping, but the differenc is more if i ride a lot of time... its weird.. cause the retainers are new.

24th February 2011, 20:11

what kind of pistons are those, same box as my omega's are in....although may not be related lol, the valve cut outs look huge, were they used or new? picture isnt very good.

24th February 2011, 20:31

they are new

called piston T4 in here..