[Guest]

I am driving a nissan model that uses the pre 94 GA16 engine. Recently, I went for a full rebuild and the mech did a high compression using dome pistons from another car. Ever since the rebuild, I would experience a rattling sound when the engine is warm and especially when I rev from 2500 to 4000rpm. In addition, it would sometimes start to emit bluish smoke when the rpm is in this region. When this happens, there is also a strange odour in the cabin. I have tried adding a aftermarket piggy back ECU and changing the timings and fuel supply but the problem still persists. Really confused and helpless. Please help!!!!

 

[javierb14]

if u gave us some specific info about the parts your using and or pics we might be able to help

 

[Teknokid]

Is that weird smell fuel??? I suggest using a thicker viscosity oil and maybe the bluish smoke will go away.

 

[By Nature]

because you increased your compression, the rattling sound is probably pinging/detonation.. what oil and gasoline are you using? I would find out more info from your mech and give a call to JWT, maybe they could reprogram your ECU and you can get some extra power from your engine rebuild

 

[LIUSPEED]

i got that rattling. i changed my gas to the 89 octane or 1 step up from regular and it seems 2 have gone away. hope maybe this helps. and on the blue smoke how many quarts of oil did you use? if you did 1 or 2 more than 4 than of course your going 2 get the blue smoke. if not try a higher grade oil.

 

[Guest]

Thanks for all your replies. First of all, I understand from the mech that he bored the head and used pistons from a Mazda BP engine to increase the compression. I am residing in Singapore and am using 98 Octane petrol but the same thing still happens. Is there a EGR valve in the GA16 engine? The cabin smell seems to be like unburnt fuel exhaust smell. To counter the problems, I installed the Greddy E-manage system to adjust the fuel n ignition but still no can do. Very sad!!!

 

[Teknokid]

Yes there is an EGR valve. ON the U.S. spec sentras, it is behind the intake manifold, just below it.

 

[dookie]

the FSM says it might be an EVAP system problem. i'll have to check my haynes manual.

 

[Guest]

I hope my car has the EGR valve like the US spec. Anyway, what is the EVAP system???Thanks!!! My car model is the Nissan presea and it is only available in some countries but shares much similarities to the B13. Really hope that I could solve this bproblem soon. Cheers

 

[Guest]

Hmm....

To me it sounds like there might be excessive piston to cylinder wall clearance. Would those pistons be forged? If they were they might have been fitted with larger clearances. Forged pistons require greater tollerances. We used to listen for the rattling noise to determine how serious the mods were in the old muscle cars before racing them

A set of low tension rings, free up a few hp as well, but can lead to oil burning like that. Also, if oil is entering the combustion chamber, it can cause detonation becasue it is basically a low octane hydrocarbon.

Just my thoughts...


Jeff

 

[Guest]

Dr Dodge,

I think you may be right. He may have bored the chambers too wide. What can I do to reduce the clearance? Coating? Not sure whether they have it in Singapore? If it happens only in the range of 2500 to 4000 rpm, does it indicate which particular piston is affected. Thanking all of you again for your help. Cheers!