Stormcrow agreed to help me get rid of this knocking sound I was having in my engine. [that's his sweet-looking red Z in the first couple of pics].

He ended up adding this catch can to the hose running from the pcv system to the plenum to catch oil that was getting sucked into the plenum and diminishing my octane rating. (the lower octane rating was throwing off the timing, causing me to have the pinging noise and taking away engine power).

the first image shows the catch can (genius idea) after the install and the next image shows the catch can after my 15 minute drive home from getting the catch can installed. As you can see, I already had oil in the catch can after only a 15 minute ride.

We also added racing fuel to the car and the pinging was completely gone by the time I got back to my apartment.

A big thanks to Jeremy, and I hope this helps anyone else who may be having this same problem.

 

i also would like to say thanks to sharif for allowing jeremy to pull my car in to Forged Performance to have it looked at!

 

We would have to run huge oil/air separators like that in Ford Lightnings all the time, they work like a charm. Just don't forget to empty it.

 

yeah. i'll have to keep an eye on it. i was shocked at how much oil had collected in it after only one 15 minute drive!!

 

Jeremy is a very nice guy. Glad to see him help your little problem.

Also, hit up the South East Region section and veiw the thread on the moutain run next weekend on Sunday. I'm sure you would have fun.

 

yeah. jeremy is a cool guy. i will def look into the mountain run next weekend. jeremy was telling me that there was a meet this weekend as well on sunday. i'm going to try to go to that one as well.

 

So why are you getting that much oil going through your pcv tube into your engine? Also, you're saying that this oil entering your engine was lowering the octane rating of the gasoline?

 

the factory hose goes straight into the plenum from the pcv system. most cars have a tube that comes from the pcv system below and comes up into the plenum. with a system such as this (with the tube coming from below), gravity keeps the oil from entering the plenum.

because the pcv hose on the Z's is horizontal, the oil can go straight in from the engine. the hose simply creates a vacuum and sucks air into the plenum and oil droplets from the engine get sucked in as well. the catch can is just a reservoir to collect that oil before it enters the plenum.

that oil in the plenum gets into the air and fuel mixture and, basically, dilutes the fuel, lowering your octane rating from 93 to something like 87, which retards the timing, causing the knocking sound.

***disclaimer...all that information i gave is what i have gathered from talking to some people so i may have some things wrong. I'd say the general principle is correct, though.

 

I'm having knocking too... so the solution was to install an oil catch can?

 

more info please, can someone do a DIY on this.

 

fairladyz47597, Glad everything worked out, it was also good to meet you and Jeremy at Forged.

 

Jeremy is FTW!! BTW.. how did he make that catch can????

 

There is a write up on the forums about the CC...nice job Jeremy, car is clean as always.

 

jeremy installed the catch can for me on saturday. i've done a fair amount of driving this weekend and the knocking is gone.

i was worried that the knocking would come back after the racing fuel burned off (we added 3 gallons of racing fuel to an empty tank to clean out the plenum). sunday morning, after all the racing fuel was gone, i filled up with 93 octane at qt and drove it a lot of the day sunday--still no knocking. i now have about an eighth of an inch of oil in the catch can.

i'm confident the knocking will not come back because before the install, i had the knocking sound all the time. there was never a time when it didn't knock if i just listened closely.

i'll take a couple more detailed images of the catch can with the hose so you can see how it was constructed. jeremy bought the parts at home depot.

the green stuff at the bottom of the plastic catch can is epoxy, which he added to seal off a valve that came with the catch can. the install was super-super easy and quick. i'd say the hardest part would be finding those parts at home depot and putting the little contraption together.

 

i would pm stormcrow. he can give you a much more detailed and educated response regarding this fix.

 

Hey there! It was great to meet you as well. Your car was looking nice with the new suspension. Hope you were able to get it aligned. I'll look for you at the next meet or mountain run. I'm going to meet up with some guys on the 26th for a drive in the north ga mountains. should be a good time.

 

yeah. ftw fo sho.

he bought some hose and some other parts from home depot. you would have to ask him exactly because he bought all the stuff and assembled it, himself, at his place. we just installed it in the engine on saturday. i doubt that it is too hard to put together. i would check with him if you are going to do it though, so you can make sure you do everything right.

 

https://my350z.com/forum/engine-drivetrain-and-forced-induction-diy/237059-homemade-catch-can.html

The only thing different than above is the 90 degree elbows.

 

Thanks guys

 

Hmmm might have to try this out... I'm getting horrible knocking...

Do you mind taking more detailed pics of how it was installed? Like where the 2 hoses go? I read the other DIY but it was kind of vague.