4G93 DOHC Problems

^pomen_GTR^

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drummydrew

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Dec 7, 2015
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good evening all, i started asking for advice under Car Talk section but i believe it's more appropriate to discuss real car problems in this section. to cut story short, my car started spitting and rumbling few days ago and sent it in, these are the identified problems as of now:

1. broken valve spring
2. broken inlet valve
3. broken inlet valve guide
4. chipped water vents on the cylinder head (requires welding and sanding according to mechanic)
5. dents on piston heads, caused by what seems like the valves due to the round-edged dents

for further details of discussion please refer to pix attached and link below:

http://www.zerotohundred.com/newforums/showthread.php?t=461048&page=2

my main concern now:
1. should i replace the valve spring/inlet valves/valve guides by the sets of 8 or it is ok to replace just the broken ones?
2. can't find ori parts, will the japanese made oem parts work just as well?
3. i'm totally clueless on the marks on the piston heads

:banghead::banghead::banghead:
(UPDATE) after leaving my car in the workshop for weeks, finally have it back! still got struck with some disappointment though.. basically here's what i did altogether:

1. engine top overhaul
2. replaced engine-radiator hoses
3. service radiator and gasket
4. replaced broken valve spring, broken inlet and exhaust valves, 16 valve guides

i bought most of the spare parts (~RM1k) and left the work to the mechanic and the bill still totaled to about RM2k. means i'm coughing out 3k in total to get these things done :confused:

guess what, the work is not done. picked up my car and found it spitting white smoke! to make it worse, there's a rattling sound coming from the fuel tank :frown: mechanic and i took it out for a drive and he told me that - the white smoke is caused by my worn piston rings but this problem didn't exist before i sent the car in. as for the rattling sound, he said faulty fuel pump :smokin:

this is my car restoration story. attached is a part of the service receipt, tell me what you think!
 

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6UE5t

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(UPDATE) after leaving my car in the workshop for weeks, finally have it back! still got struck with some disappointment though.. basically here's what i did altogether:

1. engine top overhaul
2. replaced engine-radiator hoses
3. service radiator and gasket
4. replaced broken valve spring, broken inlet and exhaust valves, 16 valve guides

i bought most of the spare parts (~RM1k) and left the work to the mechanic and the bill still totaled to about RM2k. means i'm coughing out 3k in total to get these things done :confused:

guess what, the work is not done. picked up my car and found it spitting white smoke! to make it worse, there's a rattling sound coming from the fuel tank :frown: mechanic and i took it out for a drive and he told me that - the white smoke is caused by my worn piston rings but this problem didn't exist before i sent the car in. as for the rattling sound, he said faulty fuel pump :smokin:

this is my car restoration story. attached is a part of the service receipt, tell me what you think!
Aiyo, then need to do OH again to replace the piston rings leh! Should have done it all in 1 go.
Yah if there's vibration sound from the fuel tank or the fuel line, then it can be the fuel pump assembly is already leaking air bubbles due to o-rings in the assembly not sealing properly anymore. So if this is the case, it's not about the fuel pump motor but the whole assembly/casing is the problem.
 

drummydrew

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Dec 7, 2015
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Aiyo, then need to do OH again to replace the piston rings leh! Should have done it all in 1 go.
Yah if there's vibration sound from the fuel tank or the fuel line, then it can be the fuel pump assembly is already leaking air bubbles due to o-rings in the assembly not sealing properly anymore. So if this is the case, it's not about the fuel pump motor but the whole assembly/casing is the problem.
exactly! i was too focused on the top and now this, im totally dazed with the idea of another overhaul :banghead: my mechanic however told me to get the fuel pump issue fixed first, will have to remove the fuel tank to check for that right? sighhhhh
 

vr2turbo

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What! RM1k just on the valves and seat? Why he need to skim the valve, valve end, machine valve guide etc???
 

drummydrew

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What! RM1k just on the valves and seat? Why he need to skim the valve, valve end, machine valve guide etc???
the 1k i spent on parts include hoses, spark plugs, engine oil, 16xvalve guides, top gasket set, 2xvalves, 2xtappets and thermostat.

i also asked him were those valves skimming necessary cos i was only replacing 2 broken valves, he told me that its all done together i was like WTF.. i think that the valve skim, valve end skim along with some other items are indeed a scheme. but i dono any better :stupid:
 

6UE5t

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exactly! i was too focused on the top and now this, im totally dazed with the idea of another overhaul :banghead: my mechanic however told me to get the fuel pump issue fixed first, will have to remove the fuel tank to check for that right? sighhhhh
No need to remove fuel tank, just the fuel pump assembly only.
 

6UE5t

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my mechanic said the fuel tank needs to be lower to replace the fuel pump, perhaps he doesn't know what he's talking bout..
Sorry did not mean to misled you, I don't know about your car if need to do that or not. I was talking about mine where it's located under the rear seat.
 

ixeo

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Problem isn't the car. It's the mechanic.
 

lsm1991

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Jap cars mostly have a fuel pump access via the back seats.. Little square access hatch
 

vr2turbo

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Yah! was about to ask about the mechanic, you know him well? Your usual mechanic? If not happy should try another.
Got one member here also, father usual mechanic. Car need engine change and was quoted RM5k and in the end it was only an engine kosong and not half cut, so he really got cut......:banghead: