RB25 S14 Puff of Smoke

[Touge Whore]

Hey guys!

I've recently noticed that when I am driving through town, the car will throw a puff of "white-ish" smoke if I drop it to neutral and cruise to a stop light. It doesn't seem to do it if I down shift between the gears and then come to a stop. Also, it doesn't smoke under normal/hard acceleration or idle. I am running a cat-less exhaust system if this helps at all...thanks in advance guys!

[MADE]

Sounds like the valve guide seals, are you losing oil is the smoke really white ish or blue ish?

[nismoman]

check the turbo too, sometimes causes similar symptoms when the seals go.

[Touge Whore]

Thanks guys...I'll check both of those things today along with a compression test on the motor. I'll have somebody drive behind me to confirm the actual color of the smoke, because it is a little harder to see while you're driving. Should I also check the intercooler piping to ensure no oil residue is present?

[Touge Whore]

UPDATE

I went to my buddy's shop today to perform the compression test and inspect the turbo. We drove the car around for a bit and it would produce black smoke (fuel) under acceleration, and produce blue-ish smoke when let off (oil). We then took it back to the shop to perform the test and look for oil fouling on the spark plugs. The gauge wasn't fully acurate(about 20-30psi off), so we just looked for consistency between the ratios on all cylinders. Results follow with Piston 1 being closest to radiator:

Piston 1 - No Oil Fouling on Plug - 100psi
Piston 2 - Slight Oil Fouling on Plug - 110psi
Piston 3 - Oil Fouling on Plug - 110psi
Piston 4 - Oil Fouling on Plug - 110psi
Piston 5 - Oil Fouling on Plug - 110psi
Piston 6 - Oil Fouling on Plug - 110psi

I am assuming this is the rings going bad because of the lack of oil on piston 1. Am I correct to assume this? Do you guys still feel it would be valve seals? Turbo seals? Thanks!

[MADE]

Im not a mech so I don't know the technicial term for it, but the place the let me know my seals were bad did a leak down test, basically put air into the cyclinder and watched for a leak and confirmed my NO1 cylinder valve guide seals were bad.

[Touge Whore]

*UPDATE*

Well, as of now, it seem the the turbo was the issue with the engine. I was able to replace the shaft-play infested, oil spitting original turbo with a brand new NEO turbo. Although it was a pain trying to not snap rusted bolts, it seems to have fixed the problem with the puffs of smoke at stop lights and stop signs. I'll continue to check and watch for this and the turbo begins to break in more and more. Thanks guys for all your input and help.

[Touge Whore]

Guess not...the plumes of smoke are back while driving. I've noticed they occur most often, and largest, when down shifting or blipping the throttle to rev match coming to a quicker stop. Generally, they don't happen, or are very small if it is a normal, gradual stop. I did slightly overfill the oil because I was trying to compensate for removing oil from the entire system. I am assuming it is NOT this though, and it is most likely the valve seals. Am I correct to assume this? Thanks guys...

[Touge Whore]

Also, just for reference, I am going to purchase the Nissan RB25 OEM Rebuild Kit. I figure replacing all the gaskets and seals should eliminate this problem. Here is a link to the kit I am referring to. Let me know what you guys think...thanks.

The Nismo Shop : West Covina Nissan : RB25DET Engine Rebuild Gasket Kit (http://www.thenismoshop.com/catalog/Skyline-Gaskets/RB25DET_Engine_Rebuild_Gasket_Kit.html)

[Touge Whore]

Where are all my engine guru's? haha...I know somebody has some input, even if it isn't the solution, talking it out generally leads to it...