4g93 Engine Knocking after 3k RPM

[N E O]

Hi guys, this problem has been bugging me for quite some time.
Couldn't find any solution to settle the problem. Hope you guys can provide some advise..
Engine was just rebuilt about half a year ago, rarely driven.

Engine is 4g93 with 1.6 oversized pistons (82mm), mild cams and all others stock.
E-manage tuned. Having about 150hp and about 180nm tuned on RON97

Engine has slight knocking after 3k RPM during the afternoon even on RON100. At night barely heard.
If on RON97, knocking is slightly louder. After retarding the ignition timing a few times myself, knock still present. I'm afraid of retarding any lower.

My questions are:
1. Any tuners to recommend to iron out the knocking across the whole rpm range? Preferably OTR tune rather than on dyno (cus on dyno can't really detect knocking?)
2. Would retarding my ignition timing too much cause engine failure?

 

[6UE5t]

Engine newly rebuilt but got knocking? What's your compression ratio now, was it increased further by the rebuilt? Coz std 4g93 already has 10.5:1 compression ratio which is quite high already.

Then how many degrees is your ignition timing now after you retard it? As far as I can remember, when I was using my 4g93 in Indonesia, that engine can run smoothly even with just ron92 but the std ignition timing for Indonesia market was only around 5-7 degrees. Sometimes we even use ron88 only but then retard the timing even further to just about 3 degrees. But of course these were all full stock without aftermarket cams and piggybacks.

You can also try to run stock cams and ECU without piggy back and see how. How aggressive is your cam?

 

[N E O]

Engine newly rebuilt but got knocking? What's your compression ratio now, was it increased further by the rebuilt? Coz std 4g93 already has 10.5:1 compression ratio which is quite high already.

Then how many degrees is your ignition timing now after you retard it? As far as I can remember, when I was using my 4g93 in Indonesia, that engine can run smoothly even with just ron92 but the std ignition timing for Indonesia market was only around 5-7 degrees. Sometimes we even use ron88 only but then retard the timing even further to just about 3 degrees. But of course these were all full stock without aftermarket cams and piggybacks.

You can also try to run stock cams and ECU without piggy back and see how. How aggressive is your cam?

Forgot to note down the compression ratio tested after the rebuilt. As far as I know, 1.6 oversize pistons, stock block and stock head untouched.
No idea of degree also as each time i retard i would just slightly push it a little.
Im guessing my cams are 26x. No idea also cause it came with the car when i bought it.

No plans to run back stock, idea is to iron out the issue and run this setting now.

 

[Shinjite]

Engine newly rebuilt but got knocking? What's your compression ratio now, was it increased further by the rebuilt? Coz std 4g93 already has 10.5:1 compression ratio which is quite high already.

Then how many degrees is your ignition timing now after you retard it? As far as I can remember, when I was using my 4g93 in Indonesia, that engine can run smoothly even with just ron92 but the std ignition timing for Indonesia market was only around 5-7 degrees. Sometimes we even use ron88 only but then retard the timing even further to just about 3 degrees. But of course these were all full stock without aftermarket cams and piggybacks.

You can also try to run stock cams and ECU without piggy back and see how. How aggressive is your cam?

guess his static compression is very high
We have a member also suffered the same thing, 93 DOHC with 92P pistons......crazy high compression

 

[yeehau86]

Afternoon knocking could be due to our scotching hot weather nowadays, so it is normal as the difference in temperature with during the tuning day and nowadays could have gone up a bit.
But is the knocking due to Wide Open Throttle (WOT) or cruising towards 3k rpm and above it happens?

 

[N E O]

Afternoon knocking could be due to our scotching hot weather nowadays, so it is normal as the difference in temperature with during the tuning day and nowadays could have gone up a bit.
But is the knocking due to Wide Open Throttle (WOT) or cruising towards 3k rpm and above it happens?

Only noticeable when cruising above 3k RPM.
I've always wondered are there any dyno tunings with knock-listening? Or have to do OTR tuning based on our ears?

 

[6UE5t]

Forgot to note down the compression ratio tested after the rebuilt. As far as I know, 1.6 oversize pistons, stock block and stock head untouched.
No idea of degree also as each time i retard i would just slightly push it a little.
Im guessing my cams are 26x. No idea also cause it came with the car when i bought it.

No plans to run back stock, idea is to iron out the issue and run this setting now.

guess his static compression is very high
We have a member also suffered the same thing, 93 DOHC with 92P pistons......crazy high compression

Ic. It's the 4g92 Mivec piston, is it?

I suppose need to fine tune the e-manage, maybe try visit RS Dynotune? Other ZTH members here should be able to suggest more tuners.

As for retarding the ignition, if you retard too much, it will just make it difficult to start or the start not smooth (coughing2 a bit), high fuel consumption, and less power.

Have you check your air fuel ratio/lambda, is it running too lean or rich?
Have you tried using colder spark plugs?

 

[N E O]

Ic. It's the 4g92 Mivec piston, is it?

I suppose need to fine tune the e-manage, maybe try visit RS Dynotune? Other ZTH members here should be able to suggest more tuners.

As for retarding the ignition, if you retard too much, it will just make it difficult to start or the start not smooth (coughing2 a bit), high fuel consumption, and less power.

Have you check your air fuel ratio/lambda, is it running too lean or rich?
Have you tried using colder spark plugs?

Not mivec pistons bro, its the 1.6. Smaller dome compared to mivec.
AFR seems to be in check from the dyno last time.

Colder spark plugs could make it less knocking?
The way is to get a proper OTR re-tune i suppose?

 

[vr2turbo]

Wow! Ron 100 also cannot solve. I think if you retard too much your initial pick up will suffer...

 

[Shinjite]

Ic. It's the 4g92 Mivec piston, is it?

I suppose need to fine tune the e-manage, maybe try visit RS Dynotune? Other ZTH members here should be able to suggest more tuners.

As for retarding the ignition, if you retard too much, it will just make it difficult to start or the start not smooth (coughing2 a bit), high fuel consumption, and less power.

Have you check your air fuel ratio/lambda, is it running too lean or rich?
Have you tried using colder spark plugs?

92 SOHC pistons, if its MIVEC, his static compression is will be off the charts haha

 

[^pomen_GTR^]

Hi guys, this problem has been bugging me for quite some time.
Couldn't find any solution to settle the problem. Hope you guys can provide some advise..
Engine was just rebuilt about half a year ago, rarely driven.

Engine is 4g93 with 1.6 oversized pistons (82mm), mild cams and all others stock.
E-manage tuned. Having about 150hp and about 180nm tuned on RON97

Engine has slight knocking after 3k RPM during the afternoon even on RON100. At night barely heard.
If on RON97, knocking is slightly louder. After retarding the ignition timing a few times myself, knock still present. I'm afraid of retarding any lower.

My questions are:
1. Any tuners to recommend to iron out the knocking across the whole rpm range? Preferably OTR tune rather than on dyno (cus on dyno can't really detect knocking?)
2. Would retarding my ignition timing too much cause engine failure?

use oversized piston.... and then using high compression 1.6 piston... is 100% knocking...u might need race fuel to eliminate that..

UNLESS:


1-lower back the compression ratio

or

2-install aftermarket camshaft to fully utilize the extra CC and compression

or

3-install adjustable cam pulley and play with camshaft advance-retard with stock camshaft to get better intake and exhaust timing and reduce the chance of knocking

 

[y2188]

i feel you bro...the struggle is real

 

[6UE5t]

use oversized piston.... and then using high compression 1.6 piston... is 100% knocking...u might need race fuel to eliminate that..

UNLESS:


1-lower back the compression ratio

or

2-install aftermarket camshaft to fully utilize the extra CC and compression

or

3-install adjustable cam pulley and play with camshaft advance-retard with stock camshaft to get better intake and exhaust timing and reduce the chance of knocking

He is already using some aftermarket mild cams. Probably good idea to try dial in those using the adjustable cam gears.

 

[dking91]

Gasket thickness?? B4 this my 4g93 sohc use 82mm 1.6 piston got no knocking.... Last thing to check is the valve..mybe valve bengkok..happen to me b4 after overhaul.. Also need to check all firing components..

Sent from my Redmi Note 2 using Tapatalk

 

[N E O]

He is already using some aftermarket mild cams. Probably good idea to try dial in those using the adjustable cam gears.

Cams are properly dialed in during rebuilt bro.