What could have cause this on cylinder no.4

P

prkwan

New Member
The engine has just been rebuilt and when we took the manifold to change the turbo we found out this on cylinder no.4:




what went wrong with it cos i am no mechanic so dont have a clue, thx! :(
 
zia

zia

Active Member
oh look one's black and other one's whitish........??????????? what are we talking about ? is it oil? soot? maybe it me being thick(does happen) :lol:

zia
 
zia

zia

Active Member
ahhhh i see, well need to know if it has been rebuilt with correct tolerance? any unsual noise from valve train? was it running rough? how long has it been running? (how many miles have you done on it) what spec is it? when asking for info, you need to give a detail description as possible!

zia
 
O

Odin

Guest
could it be the head gasket's done on that port somewhere :? :?:


rob
 
P

prkwan

New Member
spec for the engine:
87mm JE pistons
eagle rods
2.0mm metal head gasket
standard crank
tomei 262 cams 10.8 lift
uprated springs
standard injectors
fmic
standard afm
avcr+safc2

done about 1200miles with mineral oils+ using a standard turbo
was taking it gently so shouldnt be too much dmg to it?
 
G

geetee

Active Member
lighter deposits like that are either the cylinder running too lean / too hot or it could be oil deposits... hard to tell from a pic.

CHeers
GeeTee 8)
 
E

Edd

Guest
a number of things could have caused it to go wrong :cry:

is the safc wired up correctly?
could be a dodgy injector on number 4 not fuelling enough?
dodgy batch of fuel
dodgy ecu?
wrong timing possibly :?

it may even be nothing, it's hard to tell from the picture how bad it is really.
 
J

jiw

Guest
get an egt gauge fitted and run the car, if it aint smiking its bound to be an injector or a dodgy wire, jeff
 
G

GINGA

Active Member
The fact that it looks like only half the port is white and the other side is black might suggest that you've got a valve problem :?: do a compression test to see if theres any differences
 
zia

zia

Active Member
the egt is going to tell you f**k :roll: all other than the ext temp on total engine output!! unless drilled to exact cylindar :wink: it ,s quit possible it is lean on that particular cyl or the valve is not opening fully but without checking the piston face for correct analysis of the burn area you,ll be guessing,

zia
 
Fast Guy

Fast Guy

Moderators
Staff member
Is it running lean tho? I assume that port is the outler for both valves in cylinder 4? In which case I can't see half a cylinder running lean and the other half rich, So I'd be tempted to look at the valves, maybe one's sticky or something. Broken rocker arm? Or maybe the head gasket is causing a leak into that port?
 
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