Knocking after cams installation ??? (powerFC)

[radiobar]

hi !

i just got my car back.
with new installed 272 cams/11.0 lift and uprated springs.

car was ok for 1 minute or so and then started to knock.
i did not drive over 1600 rpm for around 5 miles(to get home)
hope there is no damage now....

i got allways around 40 and it was up 108.

i use powerfc standard map at the moment.

any ideas ?

do i need to change ignition maps when using uprated cams ?

thanks
bye.

 

[campbellju]

What was your Knock level before?

My understanding is you can use a more aggressive map with cams so if you've not chnaged the map then they're shouldn't be a problem. If it is genuine knock then I can only think either your base timing is out or your cams have been installed incorrectly.

 

[radiobar]

hi !

before i had no knock. or it was around 10,maybe 20 max.

2 of ex valve have clearance of 0.10 (but it should be 0.15)
can this be the problem ? all other are ok.

ok,maybe they moved the distributor - will check timing tomorrow.


can i cause any damage to my engine when knock is around 60-100 ?
(no boost of course)

i might need to drive back to the garage....

bye.

 

[campbellju]

If its that bad then its not good but at light load won't do an real damage in the short term. I just can't understand that if its real why you can't hear the engine pinking all the time?

I guess if its like my engine then all you can hear is the top end rattling and injectors tapping?

 

[radiobar]

hi !

well...engine sounds normal.

i will try to retard ignition in few minutes....

even when car is standing - i need to rev little and got knock around 40/50.


bye.

 

[radiobar]

hi !

ok. changing ignition via laptop has no effect.
i retarded it by 5 and then by 10 degrees.
but its still the same.

it still knocks up to 108 - even when car is standing.
i dont rev over 2000 rpm.

maybe i should reset my powerFC ?

any other ideas ? can it be the distributor ?
powerFC shows 20 degrees timing at idle so it seems fine

bye.

 

[Fusion Ed]

Just shows how poor knock sensors are really. If the engine is off load it will most certainly not be knocking. You could try an ecu reset, but those knock measurements should be taken with a pinch of salt. They do more harm than good. Lock the base timing and set the distributor back to 20deg and check with a timing light.

 

[campbellju]

As Ed suggests.

IMO the PFC is a red herring.

 

[stumo]

I thought the PFC was an ECU?

 

[Fusion Ed]

It is, but it has knock sense which is been inaccurate in this case. Too much weight is put on these crude and basic methods of knock detection! Ion sensing is a much better method!

 

[campbellju]

I thought the PFC was an ECU?

NO your wrong!! its actually a sophisticated pink coloured fish in a metal box. Think of it like a sardine :doh: :lol: :lol: :lol:

 

[radiobar]

hi !

well...it was working for over a year now....

so something must be wrong...

or the sensor is giving up ?

bye.

 

[radiobar]

hi !

when i started my car today everything was fine for few minutes.

so when engine is cold its ok.

any ideas ?

i will check base timing later..

bye.

 

[pulsarboby]

you are assuming its a power fc or mapping problem!

what about a mechanical problem/ surely thats the most likely cause, i would have thought!
have you rechecked clearances on all valves yet (HOT), since you heard knocking?
something may be displaced on head installation.
take the rocker cover off first and double check everything, before you start tampering with everything else.

also noticed in one of your earlier posts, that youve overshimmed one or more of your valves, this is not good! better to go a shade smaller than over because when your engine gets hot, that clearance will be magnified even more, and you will end up with burnt out valves in no time.
i would seriously take a good look at what you have already done, before you go any further!

 

[Fusion Ed]

I've not assumed its a power fc problem! Chances are they are rattling around like crazy which is upsetting the knock sensor.

 

[pulsarboby]

yeah my appologies ed
have edited the post:-D

 

[radiobar]

hi !

ok,base timing is ok. (20 degrees)

its interesting that over 2500rpm its not knocking anymore.
its more than before cams install,but its not over 60.

i will remove rocker cover later and check everything again.

its not a mapping problem. because i actually use standard map
with 800 injectors and z32maf.


they also installed rocker arm stoppers. maybe one of rocker arms is tapping on it...

bye.

 

[campbellju]

Whilst6 we're on the subject, is there a better place to mount the knock sensor? I've got my inlet manifold off at the mo so now might be a good time to move things around a bit

 

[radiobar]

hi !

well...i have checked everything.
cams,rocker arms are ok. base timing is ok.
and i run standard map.

so i think its the sensor or my powerFC.


bye.

 

[campbellju]

Snesor of those two. On the PFC, what is your ignition timing when the knock is 100 compared to when its 60?