Hey guys pretty sure I know the answer to this question but has anyone had problems with their lower intake manifold leaking? I've had mine off 3 times now and it will not seal up. I had it off to do cams and replace the knock sensor when I pulled the motor out. I also did some light porting on it with a flapper wheel. I cleaned the sealing surfaces with light scotch bright and they were clean and smooth. I started off with factory gaskets and had a huge vacuum leak. So I bought the sikky thermalnator gaskets and retorqued all the bolts to 25 ft lbs. And it's still leaking. I am pretty frustrated with this as I have Dyno time scheduled and need to get the mechanical stuff working correctly. I'm sure at this point that the manifold is somehow warped and will need to be replaced. I have a few hrs in Port work so I'd rather not replace it if I don't have to anyone have suggestions?

 

do you know where it's leaking from?

Assuming that the car is running, can you spray brake cleaner to identify the leaking area?

Do you have a second manifold you can borrow to verify that it's the manifold?

 

I don't have a second manifold I'm sure one wouldn't be hard to find though. Could be injectors I suppose but I forgot my brake clean can at work tonight so I'll have to verify where exactly it's coming from tomorrow night. The car is also smoking like a ****. Like killing the neighborhoods mosquitos bad... I need to put some miles on it to see if that clears up but I suspect turbos or turbo. I finally got to drive it today though. Vacuum leak or not it had to make it to the gas station. I'm pretty frustrated with the build right now. Absolutely nothing has gone right and now I'm pretty sure I'll be yanking the engine again to get the turbos off. I'm going to pull the y pipe off and see if it's one turbo or both turbos smoking. Or if by some mistake on my part I f'ed up valve seals. But I did those as I always have and have never had a problem. I would think that if it was valve seals that it would smoke instantly on start up but it gets worse as the car warms up and doesn't smoke on initial start up. I only have about an HR of run time on it and mabey 3 miles to the gas station and back.

 

I have an extra lower manifold I could part with and I could get it out tomorrow or thursday...but I doubt you warped it by your polishing - sounds like something isnt alighned or seated right.

Are you thinking your injectors arent seated right? Do you smell fuel?

what type of smoke? is it your tune? are you running super rich? And I'm assuming its smoke out of the exhaust? Did you overly coat your exhaust hardware with antiseize that might be burning off?

you didnt expect this to go per plan did you?

any check engine lights?

 

lol I fully expected issues but this is ridiculous haha. It's smoking pretty bad out of the exhaust and I didn't use any antiseize on the exhaust hardware. I overhauled the turbos myself and had some binding issues when they were assembled so I shipped them to gpop shop for Jerry to look at them. He said I had ever so slightly bent one of the Piston rings when installed them so he put new rings in them and shipped them back. I oiled them when I put them on the motor and cranked for oil psi before starting. I also cleaned the feed and return lines very thoroughly before assembly. Now for the intake manifold leak... I have tried 2 different gaskets and torqued everything to spec going with the high side of spec. Could be injectors still im not sure yet I got frustrated and had to walk away before I drove it or should I say pushed it off a cliff. I went to start it last night and again it would start after it had been running fine on Monday. Getting a P0373 code for a timing reference error. I replaced the bank 1 cam sensor and connector as I broke it pulling it off the first time. Everything was working great Monday besides the smoke vacuum leak and obvious tune issues. I will have to recheck all of my connections and wiring for can and crank sensors today. I will also be pulling off the exhaust and watching to see which bank the smoke is coming from.

 

https://youtu.be/oivMXaBbxgg. Here's the video of it smoking. I just pulled the exhaust off at the down pipes and started it to see where the smoke was coming from and its definitely from the right bank.

 

would you say that the smoke is white-ish?

 

It's definitely blueish. And it doesn't smoke until it's warmed up. Then it rids the neighborhood of mosquitos. There's no way it's coolant. Hg we're fine before I did cams n rebuilt turbos.

 

explain how are you draining oil from your turbos?

furthermore, where is the oil being returned with respect to the bottom of the oil pan?

 

Im using the factory setup from Greddy. The only thing I did was replace the hoses from the turbo drain lines to the oil pan. I replaced them with high temp silicone hose. No kinks or restrictions and they are the same lengths as the hoses that came with the kit. This was about the only pic I could find of the drains the line isn't hooked up in this pic but u get the idea.

 

Here's a little better pic of everything hooked up.


​​​​​the car only smoked before the overhaul when I was in boost or shortly after it was really bad when I would brake boost but It never smoked at idle before I did cams springs n valve seals and rebuilt turbos.

 

I see...

I believe your oil pan is the culprit...I think your turbos are heating up and burning oil that are creeping through the seals on the CHRAs. The problem is youre not efficiently draining oil from your blowers back to the pan.

You are fighting the static oil level in the pan...you gotta give the oil return line as little resistance as possible to get oil from the turbos back to the pan ... does this make sense? I can post a sketch if it'll help?

The fix will be to tap your upper oil pan for your return lines.

I had similar issues. I initially though I was over-oiling and needed a oil regulator but it's built into the turbo...but I believe my return oil was fighting the oil in the oil pan.
https://my350z.com/forum/forced-indu...l-pan-tap.html

the issues cleared up as soon as I installed my return lines.

 

I'm not going to say that you are wrong about the return lines and what u say does make sense and I've heard of others doing the same thing on the oil pan. But if that indeed is the case than every single 350z Greddy turbo kit out there would have the exact same issue and every car would smoke like a ****. I think that would **** a few people off and there would have been a redesign or recall of the kit for modifications to the oiling system. None of which I have heard of on the Greddy kits. Doesn't mean it hasn't been done I just haven't heard of it. I also have the crank case ventilated to atmosphere from my catch can so blow by or crankcase pressure is not an issue.

 

many factors into why or why this isnt happening to everyone. I dont know that greddy would recall their products - they are not under the same restrictions as a car manufacturer. Venting (or not venting) the crank case isnt a solution or a cause to this.

If you're pretty confident that you arent blowing oiling through the engine/cylinder walls than I'd keep your spacer (use it to add additional oil) and tap into your oil pan. good luck! keep chasing it and you'll figure it out.

 

Ya I'll figure it out eventually just pretty frustrated with it. I think I'm going to pull the engine back out and go over a few things. I'm going to replace all of the timing components chains, tensioners, guides, and sprockets to try and fix the P0373 code which I can't find very much info on. On another forum I read about a guy that had intake cam sprocket failures and it spit that code. I'm gonna guess it is super rare and I probably have another issue like a missing oring, bad cam seal, or something stupid simple that fell out on assembly. Have to cover my basis on getting the car running as decent as possible to get some miles on before Dyno time. While I have the engine out I will look into drilling the pan and welding a AN bung in for oil return above static oil level. After thinking about it it definitely makes sense. It's also possible that with the lack of vacuum on the crankcase from the intake manifold (cause I'm venting crankcase to atmosphere from my catch can) isn't allowing the turbo oil to drain like it was originally designed to do. Not sure if that has a single thing to do with it or not but it's one of the things I have changed since I bought the car working perfectly and not smoking at all.

What do u want for your spare lower intake manifold? I might be interested in that if I can't find this dam vacuum leak. The first time I noticed the vacuum leak I had the factory spacers installed with the cjm fuel rails. I didn't realize the CJM kit came with new spacers that are stainless machined and don't fit quite right in the stock spacer locations. CJM's lack of instructions with their stage 2 kit is quite frustrating in my opinion. Their kit has a lot of small parts that yes most only have 1 possible location but there should still be detailed instructions with a $1000 dollar return fuel system. Anyway I fixed that and the injectors should be seated properly now. After the spacer replacement I still had a massive vacuum leak that I confirmed was at the lower intake manifold to head area with brake clean. I bought a set of the Sikky thermalnator gaskets and installed those. Torqued everything in sequence and went a little above spec this time and still leaking pretty bad.

For now I trailered the car to storage out of frustration. I need a few days maybe​ weeks to relax and contemplate about what my next steps will be to get the car right. I've been coming home from work and working on it almost every night for the past 2 months. I have some pretty serious goals with it. I'd like to see it make 800+ on C16 and spray. And 650ish on pump 93. So I absolutely need to make sure every aspect of this car is perfect and taking my time possibly even canceling dyno time until it's perfect is probably my best option. I don't want to rush anything and have the mistakes I made scatter the motor on the Dyno.

 

one thing at a time...baby steps...

you want me to send out a extra intake cam sprocket? I think I have a few in a box. Maybe $40/shipped on the manifold?

when you do the oil pan, did you install a spacer on the oil pump pickup tube?

you got that sexy-*** upper plenum, right? Did you plug the 4 holes in the OEM lower plenum that arent being used?

Take those spacers and epoxy/JB weld them in place...they will fall into an open intake runner at some point in time...

member Phunk is Charles from CJM (I believe) - he's a great guy, he's helped me quite a bit in the past ... is it running the lines or the fuel basket mod youre having issues with?

baby steps man...get it road worthy first...then let the dyno destroy your dreams!

 

Lol dyno destroy my dreams... made me laugh. Cause im sure that will be the case. I know what 4 holes you are talking about on the lower plenum. Do they need to be plugged? where the factory 6 bolts would have came through from the upper plenum the crawford only uses 2 of those bolt holes? Lol thats probably my problem HAHAHAHAHA damnit!

 

I bought the Crawford plenum used from another forum member. No instructions didn't think anything of it. So I think what I'll do is pull that lower plenum off and drill the holes and tap them for 1/8" pipe plugs which I have many of at home and work. Easy fix. Thanks for clearing that up man lol I was pulling my hair out with that one. I did find it odd what to do about the missing 4 bolts. The thought had crossed my mind and I completely bypassed it cause I didn't think those bolt holes would seal externally in the manifold.

 

is your lower plenum OEM or aftermarket?

If it was me I'd put an OEM bolt in (from the bottom) with a little locktite and call it good. No need to drill it out, only to tap it, only to put a plug in it - I'm not completely clear on what your lower plenum looks like but clarify for us...

 

It is an oem plenum that I did some minor Port work on the holes on the left I believe are the open holes where the bolts would go in to secure the upper plenum. 4 of which are no longer used with the Crawford plenum. So instead of just putting a bolt in it and loctiting it which would probably be fine I will drill the holes out and tap them for 1/8 pipe so they will properly seal.
The four bolt holes in the left and right will be taped and plugged.