Carbon Deposits

[ehdrian]

Hello bros, when my mech dismantle my ck 4g93t's head 2 days ago, i found out that there're obvious difference amount of carbon deposits on the pistons..pistons on the far left and right got very less amount of carbon deposits compare to the middle two..the differences is very obvious as the carbon deposits on the middle two is atleast 2 times thicker compare to the left and right..wat could be the prob?..anyone who faces this prob b4 kindly share your solutions..thanks in advance..

 

[^pomen_GTR^]

have u did a compression test before removing the head???

if not then it might because of valve seal or worn piston ring....





if yes and the result was good/acceptable tolerance,then it might be valve seal only...

 

[ehdrian]

have u did a compression test before removing the head???

if not then it might because of valve seal or worn piston ring....





if yes and the result was good/acceptable tolerance,then it might be valve seal only...

bro, i din know until i open the head few days ago..if wanna do compression test then have to pasang balik the engine then only can go for comp test, right?..if the piston ring is worn then have to buka balik the engine to replace those rings?..two times work and of cos two times the labour charge.. >_<

 

[^pomen_GTR^]

yeah..if pasang balik sure doing repeatetive work...

then i guess u need to replace your valvseals and as well do some visual inspection on the cylinder block...(and if the mechanic got proper tools then measure the piston ring gap along the proccess)

 

[ehdrian]

mech ade pasang balik the head after changing the head gasket and studs before i can even tell him..lol..thx for the suggestions bro..

 

[jeffayn]

uneven carbon deposit is usually cause by different combustion efficiency
simply mean it can be worn out of the two out of four piston
or it can mean the fuel injection is uneven....
or even one of the plug is not working as it should have....

you can troubleshoot from easiest way firsts rather than the all the harder channel...

 

[ehdrian]

thx for the advice bro..easiest way is to go for compression test first?..

 

[Izso]

I think he meant to do the easy stuff first.

1. Change all your spark plugs and plug cables (or swap with kawan temporarily)
2. Switch the locations of your fuel injectors

Then see if it's still the same. Last option would be do a compression test