Worst fears confirmed.. VQ35 (TT G35 sedan)... 4600 miels

[GurgenPB]

hey Guys This is on 5w40 truck & SUV oil..not 10w40 like the analysis report says. I guess I do have a sleeve leaking issue. It only got worse from THIS past oil analysis on the same setup (not sure why the reords got separated). There was a thread that was started about this latter report.. and we we all thinking/hoping that the K/Na content at 50ppm were remnants from the previous head gasket repair... ala that was not be. Quick Stats: The tune on the car was very good...making about 460lb-ft torquw (same hp). This engine was sleeved by AEBS. The #6 cylinder at the time was obviously drawing coolant into the chamber.. and this time that ver yspark plug looks "lighter" than all the other. I am asking for you help guys...From the design of the block it looks like it impossible for them to sink. SO is it possible that the block isn't true (straight) and doesn't mate well with the heads? I used the ARP studs which technically should be retorqued, but because it is 10-15 hours of labor to do so, no one including myself does it. Could this be it (one backing out)? I'll try to post the pictures of the spark plugs (hi-res) later..prolly tomorrow. So please check back from that... i need all the help i can get. This will be engine number 5!!! blows!!!

 

[Shannow]

Can't offer much. 'cept an old article I read years ago that suggested that neither heads, nor block had to be dead flat. It suggested a mock build up using pressure sensitive paper to see if there was even distribution of pressure...two bananas could still make a seal.

 

[The Critic]

Gurgen, Did you add that 1 bottle of Auto-RX you bought for the last 1500 miles of this drain? E-mail Terry to let him know that you used 5w-40 T&SUV, but he probably sees it on this forum. I'd have to say that the Ca is being depleted by the Antifreeze but this oil sure held up well. Michael

 

[The Critic]

BTW, reports were separated since the "total miles on engine" did not match the previous reports. MW

 

[Al]

Wow..sucks to be you..wish I could add insight

 

[Drew99GT]

Throw a GTI-R SR20DE-T in it and thrash it! Hope you get it worked out. Isn't there a few Nissan tuners that build these motors? Or is that what you got? Perhaps you should look around for a more reliable builder.

 

[nicrfe1370]

quote:

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Originally posted by Shannow: Can't offer much. 'cept an old article I read years ago that suggested that neither heads, nor block had to be dead flat. It suggested a mock build up using pressure sensitive paper to see if there was even distribution of pressure...two bananas could still make a seal.

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I think the failing of this argument in this situation is that this guy is making double the power that this motor was designed to make, and so any area between the head and block that doesn't seal well is dramatically more likely to leak than in the stock motor. This report I think is substantial proof that elevated wear is relevant and is a problem. If this amount of coolant in the oil creates wear numbers that are high, but less than fifty, then we know some of the old arguments that wear number of 50 or 100 being okay are flawed. What I want to know is, how is this motor running? If not for the oil analysis would you know there was a problem? I wonder how many people making this kind of power, who don't do oil analysis, think the motor can handle it because everything "seems" fine. Even with coolant and wear like this, this motor probably would live a long time, but there is obviously a problem.

 

[The Critic]

UPDATE: I talk to Gurgen yesterday and the car runs fine. He is currently running 2 quarts M1 EP 15w-50 and 3.5 quarts Mobil 1 Truck & SUV 5w-40 with 1 full bottle of Auto-RX. If I'm not mistaken, he took the sample in Los Angeles prior to leaving for San Francisco, and he didn't get the results until he came to SF, so the car was driven from Los Angeles to San Francisco, so the oil currently has 550 miles. He plans to drive the car a bit for the next two weeks before driving it back down to Los Angeles. Oil will have 1000-1200 miles before it gets dumped and the engine teardown. It'll be interesting to see how Auto-RX will work in terms of engine clean-up with coolant pouring into the engine simulataneously. MW

 

[ebaker]

Does this car have a functional knock sensor? What boost is it running? You may have to pull a little boost and timing. Maybe the head's only lifting under detonation.

 

[GurgenPB]

Hey Guys Sorry for not being around...and thanks very much for Michael to post on my behalf. Some answers: I would NEVER know that soe thing is worng with the engine just from the way it drives... it drives VERY nicely. About 510-530 rwtrq/rwhp, insane ride, not hat i am boosting at all. I am driving the car without goingf into boost at all. The other huge symptom is that it is going through coolant very quickly (a pint for every 500 miles or so if not more), and yes it has gotten worse over the last couple of thousand miles. I don't want to deal with motor swaps...these are CAN-driven engine management systems...an engine swap would simply not work in a nice daily driven luxury supercar unless i was ready to give up on the instrument panel, security system, not to mention the automatic transmission. I love this motor. Just thinking about this motor vs. all the other N/A motors that get turboes...there are relatively very few problems with it, to a point of course. I mean when you push 600 whp you do need to do change rods... but not the block, heads, cams, etc, ignition system. The cooling system is what does in fact require a radiator upgrade for this much power. I will be tearing the motor out in the next 3-3.5 weeks. I will be driving back to L.A. tomorrow, and the first thing i do is drain some oil for analysis. It seems that I will be putting hte pre-oiler system in, if I can afford it. Looks good, and cudos to a fellow G35 SEDAN owner.

 

[Steve S]

This is what happens sometimes when an engine is hotrodded. It seems there is to much to learn sometimes.

 

[AV8R]

Before you get too excited, re-torque the heads to ARP (not factory) specs. Even if nobody does it.