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turbo max trouble


mtcookson
11-11-2003, 12:20 AM
This post is about some troubles I'm having with my engine (VG30ET) but since its exactly like the VG30E in the 3rd gen some of you guys might have some ideas for me.

Some info before I go on: This engine is the JDM VG30ET out of the 87-91 Cedric (from what I can tell). It has the intake manifold design that was on the 89-94 Maxima with the VG30E. I swapped it into my 1990 Maxima. The engine is supposed to have the euro cams which add around 10 horsepower due to a change in the duration, lift is the same as the USDM engines. The only thing that is not stock on the engine is the Maxima oil pan and pickup (the little thing that sits in the oil pan with the metal net on it) and the turbo was replaced with an 85-86 300ZX turbocharger. I relocated the turbo to the crossover pipe by having one custom made and had the stock turbo flange on the driver's side manifold welded over with a steel plate to seal it off. I did this due to fitment problems in the Maxima's engine since its front wheel drive.

I think I'm getting closer to getting my dang engine running. I believe the problem goes all of the way back to when I was having trouble with air coming out of the intake during the compression stroke. I had the heads cleaned, milled, and had a full valve job done on it. I thought it had fixed the problem until I went to do a compression test and heard air coming out.

At some point during the compression stroke the valve is open and air is coming out of the whole front bank (cylinders 2, 4, and 6). The timing is perfectly lined up how it is supposed to be i.e. all marks are lined up correctly and I have the cam gears on the correct cams. The cam gear with R3 on it goes on the back and the cam gear with L3 on it goes on the front. The real kicker, that seems to stump everyone, is that I still have perfect compression, being around 175-180 psi, on all 6 cylinders.

When trying to run the engine it ran like crap. It wouldn't idle, it would just die if I tried letting it idle. It also wouldn't rev very fast like my VG30E normally would. This engine revs to about 4500-5000 rpm somewhat well, not as fast as it could/should, then it would just pretty much stop revving from there. Vacuum was only at 10 inHg at an idle rpm which I believe is directly due to half of the engine creating vacuum and the other half blowing air out

At first I thought the valves weren't sealing properly so I took the rockers off and cranked the engine and there was no leaking at all. So... there has to be something wrong with the rockers, lifters, cam, or cam gear. I was thinking that possibly the valves are sticking... but what are the chances of that since I just had them cleaned a few months ago?

Any of you guys ever experience or heard of anything like this? I think this is my final step into getting my car running.

Any and all help would be much appreciated. Thanks in advance!!

Pick
11-12-2003, 04:04 PM
try www.maxima.org and got to the forums.... We have tech info here, but there are tech geniuses over there.

mtcookson
11-12-2003, 04:20 PM
i actually post over there all of the time. no one has been able to figure out what the problem is.

but now... I don't have to. i figured out the problem just now. I think this will get it running for sure. I can't wait!!!!

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