VQ35 Valve Covers

[Hawairish]

One thing that has me concerned is it looks like the #1 spark plug looks to have a higher offset on the aluminum set, whereas it's the same height (flush) as the others on the plastic. If that's the case they're not going to be interchangeable without some modification.

Valid concern. I see different p/ns for the 2001 model compared to 2002+ models for all the coils. That said, the covers may physically fit, but you may be opening a can of worms.

Thanks for the info Toyojay. Agreed, it's a growing trend for parts to be less and less serviceable. I was just explaining to a buddy, who succumbed to failed alternator yesterday, that not too long ago it was easy to buy inexpensive rebuild kits for alternators and starters, as well as getting brake rotors and drums surfaced/honed for much less than the costs of replacements. Now, you just buy the replacement unit because voltage regulators and starter solenoids cost as much if not more than a complete, refurbished unit (which also has a warranty).

Some items have actually gotten better, though...on my other vehicle, I think a wheel bearing may be wearing down, and the thought of changing a wheel bearing wasn't sitting well with me. Well, the replacement is a rather inexpensive, complete wheel hub assembly that's held on by some studs and nuts. Now that's a bearing replacement I can deal with! (Compared to the front wheel bearing replacement I'll be doing on my buddy's R50 next weekend...or the floor-press-requiring rear axle bearing I've been meaning to do for the disc brake conversion.)

Test driving my Tacoma, I threw the salesman into the dash going for the ghost clutch and clipping the brake! HA.

LOL

[Toyojay]

^ True, there are lots of assemblies on newer cars, making down time for the car much shorter. Sometimes they are actually affordable haha. Those bearing/hub assemblies are much much easier to change at home. Very quick process comparatively speaking.

I remember reading a sticky a few days ago here, about problems with 2001 and 2001.5 model pathfinders. That could have something to do with different valve covers, because they changed the part totally after the 2001.5 model.

[atraudes]

I looked into this a bit more, and I've found that if I do end up using the valve covers I bought (or re-using the ones installed), I'm going to want to pop off the baffle and clean behind it. The used pair I bought were media blasted to clean them up which is going to mean there's plenty of sand and grit behind the baffles that I do NOT want to leave behind. The general consensus is that no amount of flushing will get it all out. The other reason to do this is the drain plugs in the baffles get clogged over time which is why we get oil sucked into the intake. Pulling the baffles off allows you to get everything cleaned up and unclog those drains.

The drain issue brings up an interesting question for me though: should I make the drain holes bigger while I'm in there? I think the existing holes are only a millimeter big, so it seems like a good idea to expand them to 3mm or more. Thoughts on this?

I'm also completely convinced now that the plastic and aluminum covers aren't perfectly interchangeable. I found a couple of other threads where people found the same thing with the VQ35DE in other vehicles. One would probably need a new #1 ignition coil at minimum, or be prepared to monkey with the fitment a bit. If I'm feeling particularly adventurous when I pull the trigger on this project I may look into it more.

My final thought is maybe buying new covers from the dealer (even if you have aluminum already) would be a good idea because it's possible the new set would employ revised baffling. This was the case with Lexus RX300s which had a similar problem. The trouble is I don't know who would know if what I'm buying is revised or the same as what I already have. I doubt a dealership would be much help, but perhaps I should give that a go first.

[Toyojay]

I looked into this a bit more, and I've found that if I do end up using the valve covers I bought (or re-using the ones installed), I'm going to want to pop off the baffle and clean behind it. The used pair I bought were media blasted to clean them up which is going to mean there's plenty of sand and grit behind the baffles that I do NOT want to leave behind. The general consensus is that no amount of flushing will get it all out. The other reason to do this is the drain plugs in the baffles get clogged over time which is why we get oil sucked into the intake. Pulling the baffles off allows you to get everything cleaned up and unclog those drains.

The drain issue brings up an interesting question for me though: should I make the drain holes bigger while I'm in there? I think the existing holes are only a millimeter big, so it seems like a good idea to expand them to 3mm or more. Thoughts on this?

I'm also completely convinced now that the plastic and aluminum covers aren't perfectly interchangeable. I found a couple of other threads where people found the same thing with the VQ35DE in other vehicles. One would probably need a new #1 ignition coil at minimum, or be prepared to monkey with the fitment a bit. If I'm feeling particularly adventurous when I pull the trigger on this project I may look into it more.

My final thought is maybe buying new covers from the dealer (even if you have aluminum already) would be a good idea because it's possible the new set would employ revised baffling. This was the case with Lexus RX300s which had a similar problem. The trouble is I don't know who would know if what I'm buying is revised or the same as what I already have. I doubt a dealership would be much help, but perhaps I should give that a go first.

I completely agree, they must be cleaned after blasting of any kind before they go on the motor, that's just asking for trouble. Looking back at that photo posted before, Its kind of difficult to see how those baffles are attached. Are they rivets? Or spot welds? You also must think about how to reattach them after your done, they need to be there for the PCV system to ventilate properly. Unless you've got a TIG setup at home they won't be spot welded back in, and if the bosses above those spots aren't thick enough you won't be able to drill holes for a rivet. Perhaps drill a hole there to tap for a screw (a screw with blue locktite!) to make them permanently removable/serviceable.

I personally think buying new covers just for this seal issue is a complete waste. That's a s*** load of money, others may feel different. I do agree, the coil bosses from the aluminum ones and the plastic ones are definitely different. Most likely you'll need just the ONE coil for that cylinder, for whatever vehicle your "new" aluminum VC came with. That will probably require you to get the pigtail for the coil and cut and splice that in too, as I'm sure it's different.

Do you know what the differences are in the new baffles? They are pretty simple parts, and if the "old" style baffle can successfully be taken apart and cleaned then it is just as good IMO. I see absolutely no issues with making the drain holes a few MM larger, but if you do that then you'll HAVE to take it apart as metal shavings will get up there during that process.

I'm work for Toyota and am a Toyota guy...the RX300 would've had a 1MZ-FE 3.0 V6. The valve cover on that engine supercedes a few times, but isn't revised. Those engines did have some slight oil sludge issues, and PCV's getting clogged but every motor I opened and found that, the customer had a poor oil change routine. Really wouldn't believe people leave the same oil in a car for 20k+ miles.... but some do.

[atraudes]

IIRC, they're spot welded in. I was planning on just drilling the welds out and using JB weld to put it back together. The idea of tapping to use screws is pretty tempting though...I guess it depends on how thick the standoffs are, like you said. Worst comes to worst I could bring it somewhere and have them weld it back on. I also remember that the outer edge of the baffle had a sealant attaching it to the cover as well. I'm guessing something like black RTV sealant would do the trick.

Yeah, $400 for new covers is a tough pill to swallow without some reassurance that it's going to be worth the cost. Here's the link to the RX300 discussion if you're curious. It doesn't necessarily have a ton of bearing on what to do here, but it was interesting food for thought.

I don't know what the difference in baffles is. I'd like to find someone's spent plastic covers for next to nothing, pop them open and see for myself. You know, for science I don't think anybody's done it yet!

[Toyojay]

I gather most people just have the dealer do it, and don't get the old ones back. Those that do probably don't think to sell them. I have a few friends with VQ Z cars and a few buddies at Nissan, I'll ask around for a pair. Hmm... I can't think of why there would be any sealant up there. Are you sure it was supposed to be there and not remnants of a nasty poorly cared for engine? Even if it is factory, I bet it wouldn't do any harm not to put it back. I'd be super worried about any kind of silicon or non hardening adhesive up around the valve train.

Some one might have to (possibly) sacrifice a pair of the aluminum ones (which I did get around to looking, my 2001 VQ35 DOES in fact have the aluminum ones as well.) to know for certain if this mod is possible.

[atraudes]

I'm going to be moving in a month, but curiosity got the better of me so I pulled the spare passenger side cover out of its box to snap some photos. After looking at it a second time, there's no way I'd install these without pulling the baffles off and doing some serious wire brushing. I'll take some more pictures when I do.

Brace yourself, it's about to get image heavy around here. First, some establishing photos of the outside and inside. The PCV port is on the bottom right in the top shots (bottom left in the bottom shots).









And I was (fortunately) wrong, it's held in with rivets



There's no doubt that the engine wasn't properly taken care of, but that stuff around the edges is definitely supposed to be there. I had previously removed most of what I saw since it was crumbling apart so I don't have any really good pictures of it, but I can see in the untouched areas it bulges/mushrooms the way sealant does when the top layer is applied and pressed down. It's sort of a yellow/brown color now, but I'm guessing it started out white. It's texture was hard but still slightly spongy. It's hard to get a good picture of it, but this should give you an idea.



Here's an inch or two that's still intact



Any ideas on a replacement sealant? I think putting a sealant in its place would be a good idea since it will seal up the areas around the vents.

The other thing that struck me was I didn't see any drain holes like I was expecting. There's the big empty spots in the baffle and that little nipple thing in the top center, but no holes in the baffle. Not sure what's getting plugged that's causing the PCV issues.

I've got it out now, so let me know if you want any more pictures.

[Toyojay]

I'd imagine sludge is building up there and plugging the PCV. I would THINK drilling some drain holes would be beneficial, but it may be detrimental to the PCV ventilation process. That may be why there are none.. hard to say lol. Fortunately they are rivets, and that aluminum ridge they are sunk into looks pretty thick. I'd sand the head of the rivet down with a narrow belt grinder, with like some 80 or 100 grit. Then use a steel bit to make the hole. It will take some time to remove that guy without damaging it.

I do think it's worth it, now seeing the VC without the seals in it they definitely look like they were supposed to come out of that cover, and this cover is what the Nissan part is for. With removable baffles, and replaceable seals I absolutely think this would be the VC all VQ owners would want. In theory, this should fit all VQ35 motors (with the proper coil/pigtail for that cylinder, of course).

That cover is pretty nasty, but it would clean up pretty easily. I bet once its apart if you soaked it in warm water and degreaser for a few hours, and then used one of those small soda blasters from harbor freight it would clean up real nice.

I can't think of a single sealant I'd feel safe putting in an engine, that would cure like that. Its soaked with oil, your right it probably was white. I guess I'd put Ultra-Blue up there, use like a Q-tip (or similar tool) with no cotton on it to cut an even bead of it in that groove. Ultra blue is sensor safe and oil resistant. I'd just let it completely cure for a day or two before it went on the motor.

Probably going to wait to move to tackle that, ehh? I know I hate starting a project with multiple pieces to have to stop and pick it up later, or move it...etc. Parts and pieces always disappear.

[Toyojay]

Not to mention, if you get it all stripped and blasted then its the perfect time to paint it a different color if you wanted to and toss it in the oven.

[atraudes]

Yeah, I'm going to wait. All of my tools are packed up and the new place will have a garage and an actual workbench. Right now I do all of my work outside on my lap and the weather and daylight haven't been so permitting lately Good call on the soda blaster; I'll have to look into that. I didn't know about those but it looks like it'd be perfect! Come to think of it, I should fix up my old covers when they come off and sell them.

I thought about painting them but couldn't settle on a color. A dark blue or light gray-blue might be kinda cool...

[atraudes]

Just found this $5 soda blaster

[Toyojay]

I hear that, I'll be moving from an apartment to a house (finally) in 4 or 5 months. I haven't quite packed up my tools but, it will be fun getting everything into a real garage! Lol. My pathy is sitting, for at least that long. I don't drive it every day as its got quite a few issues. Thinking of pulling the drivetrain for something else, I prefer most Toyota V6 motors, but damn this VQ35 pulls so great, it really makes driving fun with the 5spd. Maybe I'll drop it in a 240..haha.

Through my reading, found this thread. It appears this guy put VQ30 valve cover(s) (looks like from the late 90's VQ maxima) on the VQ35 in that 240 he built. He did say he had to modify them, didn't see exactly what had to be modified was mainly looking at the pictures LOL. Not sure if the VQ30 covers would fit under the OEM pathy intake, looks like he used the 350z intake. I think the pathy one sits over the VC more and those covers LOOK taller to me. The pics of it are somewhere in the first 10 or so pages. Good thread to read, lots of info.

vq35de-in-s13-in-progress-t207033.html

[Pathy415]

I just looked up part numbers from Nissanpartswarehouse and confirmed 2001 and before had one part number and 2002-2004 had another. So 2002 and up get the plastic, non-serviceable covers I guess. Damn, that means I gotta fork over $180 for each cover if I plan on doing these. In addition, the gaskets are different as well FYI.


http://www.nissanpartswarehouse.com/par ... am=3617600

http://www.nissanpartswarehouse.com/par ... am=3617600

[Toyojay]

I just looked up part numbers from Nissanpartswarehouse and confirmed 2001 and before had one part number and 2002-2004 had another. So 2002 and up get the plastic, non-serviceable covers I guess. Damn, that means I gotta fork over $180 for each cover if I plan on doing these. In addition, the gaskets are different as well FYI.


http://www.nissanpartswarehouse.com/par ... am=3617600

http://www.nissanpartswarehouse.com/par ... am=3617600

Look for a set of aluminum ones, from what I can tell should fit with the coil.

[atraudes]

I was finally able to drill the rivets out and pop the baffles off. I brought it to a shop down the street and they tanked it for a while and they cleaned up quite nicely. The passenger side had significantly more sludge than the driver's side but it's mostly gone now. I still need to remove the leftover bits with a steel brush, but you get the idea. It looks like the internal baffles are pretty primitive: a cheese-grater panel that the vapors go through and a solid one right behind it that they go around the edges of.

That brown spongy sealant stuff was definitely used to seal up the baffle's passages to force the vapors through the desired route. At this point I'm planning on using a good oil-resistant RTV when I reassemble unless I find something better. RTV seems to get a lot of flak online, but it sounds like as long as you use a moderate amount and minimize hanging bits it's fine. The cheese grater baffle has a black lip around the edge and had a line of sealant around its edge to ensure a good seal.

Some photos!
Drivers side:

Passenger side:

Passenger side on top, driver's on bottom:






And some crude diagrams of the airflow. The green is air entering or leaving the valve covers, and purple is the air entering or leaving the crossover tube between the covers. The red lines are where the baffles are located.
Driver:

Passenger:

[atraudes]

I wanted to follow up since I was able to get the new gaskets installed a little while back. I ended up getting and using OEM valve cover gaskets (on a hunch, I think, I can't recall why). When I got them I was very glad I did, though. The OEMs were much softer and had little nubs molded in a few spots which held the gasket in place. These nubs meant that I could flip the covers over without them falling out and without using any sealant or anything to hold it in place. This made me very happy The other nice thing was the Fel-Pros had bits of extra material hanging off where the injection mold pieces met while the OEMs didn't have this problem. I was really concerned that this overhang would have caused leaking issues. I couldn't get a good shot of what I mean but have a look. You can kind of see it on the sharp bend on the right-hand gasket.



Once I got the holes tapped and cleaned up, I ordered some 8-32 x 1/4" Button Head Socket Cap Screws and installed them with some threadlocker on them and RTV sealant on the baffle backs. A new coat of paint and I was ready for a long day of turning bolts. It took a while to get everything out of the way but I took the opportunity to drain the coolant and replace a number of coolant hoses that were in the way anyway which made the job much easier. Taking the air ducting and whatnot off also allowed me the opportunity to replace the upstream oxygen sensors without much fuss.

I used new grommets for the screws (also a good move; the old ones were pretty spent) and ended up hammering the spark plug tub seals as far as they'd go. I wasn't certain about how far at first but it looked similar to the ones I had just pulled off and they appeared to seal perfectly fine in that spot.



Funny story, when I first fired it up it was stumbling horribly and backfiring out of the intake. I just about had a stroke thinking one of the cams had contacted a screw and snapped or skipped a chain link or something. Turns out I had simply spaced putting the hose back from the PCV valve to the intake runners so I had ended up with a massive vacuum leak. That resolved, everything was smooth as butter again!