well, in my friend and i's efforts of taking off the heads to replace a head gasket, last night really gave me really interesting feeling about my car. i knew that my car had some problems, and probably (okay, it was more of an "educated" guess) was cylinder 1. well, sure enough, i take off the intake manifold upper plenum and i see a ring of oil going around the gasket of cyl #1. then, off comes the lower plenum and a much thicker ring of oil is confirmed around the gasket (both sides) of cylinder #1. heck, when i just stuck my finger in and rubbed it across the somewhat damp surface of #1, i could smell oil reallllly well. we took the valve covers off last night but had to stop there due to time. it's pretty amazing to get a look at the vq's innards for once (even though we don't have the heads all the way off yet). anyways, we've decided that while we've got it all apart, we might as well do what i can/want to the engine. heads'll be ported and polished. i might dremel out the intake manifolds some (to what they can be at least). rc engineering told me that i can even get my injectors balanced and blueprinted for about 25/injector. my friend is trying to convince me to go with forged pistons. unless there's something dramatically wrong with my engine now, i don't think i'm gonna spend that much money. oh well, i just had to share my headaches so far. i'm just praying still it's only a head gasket wrong, which is what it's looking to be.....

 

The oil in your intake around cylinder #1 is normal. It's related to the PCV system. (Positive Crankcase Ventalation) Just happens thats where the oil film winds up. 3M makes an intake cleaning system that cleans the entire intake plenum(sp?) with a foam while it's on the car. That usually cleans up the oil film that gets into the intake system.

 

Part of it is from the PCV system but most of it is from the EGR system.

 

I wondered about that too because when Mr. Cranman did my MEVI, we noticed some oil gunk/build up there around #1.

 

so there's supposed to be oil there? even though it managed to get itself up around the upper plenum gasket? i believe you guys, that just seems really odd to me. anyone know what the reasoning is for it?

 

I'd say stop with the cylinder head. If you're not planning on doing some serious racing with this thing, tearing the engine down to replace the pistons is much much more work than its worth. Besides, if you replace the pistons, you might want to go ahead and replace the connecting rods with stronger and lighter ones as well as performing the maintenence on the bearings.

If I were you, unless you're going to boost the car a lot, keep the modding to the top end. If it ain't broke, don't fix it. When you start getting down to the real guts of the engine, experience is something you are going to wish you had. Especially for your Maxima.

 

well, like i said, unless there's piston damage discovered for some uncanny reason, or something of the sort, i highly doubt i'll end up doing it. but nonetheless, how many other chances will i have to do this kinda work. also, i will be running nitrous here soon. so i'd like to be rest assured that it won't blow with the juice at full blast. i figured pistons, ported/polished heads and the liking would help a lot for the engine, and help me to worry a little bit less about things going boom.

 

I don't know if you realize the time, effort, and experience it takes to make everything you listed above to work. This is no easy task and will require a handful of special tools to extract some parts. You could have easily checked the condition of you motor with a $30 vacuum gauge and $30 compression testing gauge. Both of these will tell you if there are ring and gasket problems.

Nitrous should be fine assuming three things:

1) Check the running condition of your engine and verify it's within spec. Check vacuum, compression, tranny, and make sure you have no CELs.

2) Run ALL the necessary nitrous safeguards. Ghetto-nitrous setups are a no-no.

3) Don't get greedy with the nitrous. Only use it every once and a while. A 70-shot should be very reliable. Remember that nitrous makes ton more torque than HP and torque is what breaks stuff. You might gain 65-70hp with a 70-shot, but you'll gain ~110 ft/lbs of torque.


Dave

 

OK - this is going to be someone OT - I apologize ahead of time.

Dave - You seem to have some knowledge.

What if you do a vacuum test and only read 17 at idle in P, and 13-14 at idle in D (Auto)?

But then you do a compression test, and get these readings:

Front Bank:
190
190
190

Rear bank:
210
210
210

(Essentially perfect)

Manifold and all gaskets have been replaced and resealed, Every hose in the vacuum system has been checked and some hoses that looked even slighty worn were replaced. BOV on the SC was resealed and tested, etc, etc, etc. - There's no leak.

So generally - There's no vacuum leak and vacuum reads really low - but compression looks good.

Any ideas?

IanS
Well Dave

 

these have actually been off for a bit, but i thought i'd share the pictures with you. i'm kinda shocked by the amount of buildup on an engine with only 120k on it. in any case, they're in a machine shop now being very well cared for i'll post pics of the finished product when they get back from the shop too, but here's the dirty side of the story. (i dunno if you'll have to copy and paste the links, cuz geocities likes to be picky sometimes)

http://www.geocities.com/horrorfreak...headbottom.jpg
http://www.geocities.com/horrorfreak...ontheadtop.jpg
http://www.geocities.com/horrorfreak...headdetail.jpg
http://www.geocities.com/horrorfreak...headbottom.jpg
http://www.geocities.com/horrorfreakopc/rearheadtop.jpg

 

Those heads look great for 120K.