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Discussion Starter #1
Ok, so this other guy went and sold the car on me so now im looking at a TT manf. in 1/90. i know it says avoid turboed cars BEFORE 1/90 because of the defective valves, but i wonder if 1/90 would be alright. i have a picture of the engine at idle, the oil pressure and turbo psi are good and only 77258 miles.. i wouldn't normally ask a question like this without researching it first but i just... really dont know.
 

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yeah im the only case ive ever heard of with anyone actually having experienced the soft valve issue from one batch of heads used in the 90 models. Your chances of it happening are very slim. If you're that concerned just do a compression check. that should tell you everything you need to know about the internal's health.
 

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hahaha i've heard some interesting comments about my name. All good. :p yeah.. i guess it could have been fixed by now.. ill go for it.
 

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No issues with the 90 models that should detour you from considering it. The soft valve issue has long since been fixed. Most cars that had issues with the "soft valve" problem noticed them within the first 25K miles. In reality it was had valves that eat up soft seats.
 

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oh really? yeah you cant trust anyone. a man thats been building engines for 25 years said that 300zx's are ricers and junk. ...seriously? haha you know?
 

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"...a man that's been building [american engines every 10,000 miles] for 25 years..."
 

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Sorry to thread jack, but JT mentioned that 90 valves ate up soft seals. My JDM I installed was a early model, as it had the ribbed PTU on it. I wonder if it was one of those soft seal engines and that is the cause of my oil burning problem. Some on this site are predicting that my smoking issue is caused by leaking valve seals. This would make sense...the smoking is getting worse...
 

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how do you know hes a v8 guy? i dont know man, he said that it never won the 24 hours of daytona 3 times in a row or LeMans. which i know it did.. right?
 

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Ya, those crappy VG30DE/TT engines that just seem to go for 200,000+ miles between rebuilds. Yep, those High nickel iron blocks, Forged/Nitrited crank, Forged rods, Integrated main cap girdle pieces of crap. The dam things don't even have push rods. What were those stupid Japanese thinking.:/]
 

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kjaillett: All JDM engines came with the same ribbed PTU. You can't use that as an indicator of engine year. The PTU recall was only for North American engines.
 

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...and would have won more if restrictions weren't placed upon Nissan. I think "unfair advantage" was in one of the articles I read... :)
 

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Kjaillett, it wasnt the valve seat, those are a replaceable item. from what i understand (and what ash powers told me when he took my victim engine apart) is that there was a patch of heads (somewhere in the area of 500-750 INDIVIDUAL) heads had valves that were not properly heat treated which resulted in them erroding/pitting very early and easily in their life. Some cars had a pair of heads containing said valves, some only had one head effected (which was my case). Ash told me when he pulled the heads apart on my first engine, that the suspect side of my engine (having compression of like 100-90-120 with only 90k on the clock) had valves that looked like they were concave and pitted horribly and the metal looked like the dimpled surface of the intake plenum. Hope that gives you a rough idea of what is going on.

Your smoking issue is more then likely caused by the engine having sat a logn time and the valve stem seals are leaky. valve SEATS tend to produce puffs of smoke only on startup after the car sits for any period of time. stem seals produce oil smoke under heavy vaccume situations like deceleration or cruize. high milage ring wear produces a puff of smoke that "puffs" when you tap the throttle or take of from a start but stays very light but constant under all throttle position.
 
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