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-   -   oil in intake system (https://www.rx8club.com/rx-8-discussion-3/oil-intake-system-19724/)

essentialspeed 01-30-2004 06:56 AM

oil in intake system
 
hello, has anyone found oil in their intake system yet?
Mazda is asking for it back.When we pulled it apart to build our twin intake system, we where suprised to find almost 100mm of oil in the intake tube.My stock filter was soaked in oil with a puddle in the stock box.
I have made it known to our RX8 CUSTOMERS TO CHECK THEIR INTAKE SYSTEM.
has anyone come across this?

rotarygod 01-30-2004 03:06 PM

That is very interesting. I wonder what the effects of that oil on the maf are?

Rotary Nut 01-30-2004 03:20 PM

It could be the PVC system is pulling excess oil into the intake Check to see if the engine oil has been overfilled!

essentialspeed 01-30-2004 04:10 PM

Actual i picked it up fro the dealer...drove 1500kms.
pulled the intake off to do our prototype and found this..the oil was actually down 1.5L!!
i know the new rotary is higher compression..maybe too much blow by..after all the rxb has 3 crankcase vent tube running into the intake piping
the car also boggs leaving the stop sign at low rpms...

oi812 01-30-2004 05:34 PM

Check out my thread with photos. Mine wasn't as bad as yours, just a bit on the filter, but a bunch in the intake tube.

https://www.rx8club.com/series-i-tech-garage-22/oil-air-box-19733/

Rotary Nut 01-31-2004 03:02 PM

I just checked my car during the oil change and my system is dry as a bone. I think your car may have been over filled causing some oil to be sucked into the PVC system.

my10ae 01-31-2004 04:04 PM

Please follow this thread and add comments here: https://www.rx8club.com/showthread.p...=oil+in+intake

Omnicron and myself both had the bad oil cooler hose issue where it leaked and blew oil on the air filter and intake track. I noticed the same thing when I replaced my stock air box with a K&N Typhoon intake.

Get it looked at the dealer asap, seems like a classic faulty oil cooler hose/fitting.

XCENTRIC 01-31-2004 08:11 PM


It could be the PVC system...
It's PCV (Positive Crankcase Ventilation). NOT PVC (which is mostly used for drainage systems in buildings).. :D

sferrett 01-31-2004 08:16 PM

Also I'm sure the PCV stuff vents to the engine side of the throttle plates where there's generally always vacuum. I can't imagine how oil would get into the intake near the filter and up the intake tube other than if it was being sprayed in the intake somehow, as has been suggested via the leaky oil cooler line.

On the FD rx-7 it's a bit different because the blowoff valves vent into the airbox (in a stock configuration) and can generate oil there. Also on the engine side of the turbos you can get some oil also. In the rx8 there's really nothing that connects to the intake prior to the throttlebody that would generate oil, at least that I've been able to see. So if there's oil in the early part of the intake tract it's definately worth investigating the source.

Rotary Nut 01-31-2004 09:47 PM


Originally posted by XCENTRIC
It's PCV (Positive Crankcase Ventilation). NOT PVC (which is mostly used for drainage systems in buildings).. :D
Damn dyleksia!

PCV!

Rick 02-01-2004 12:27 PM

I checked the intake tube on my 8 today and found oil in it. :( The air filter is clean.

Rick 02-06-2004 10:18 PM

I had Mazda look at the oil in the intake tube today. Unfortunately, by time I called them this evening the mechanic had gone home. However , the service desk guy told me that the mechanic said it was normal to have oil in "that" area. The service guy could not tell me how oil gets into the intake so I will talk to the mechanic on Monday to get an answer.

Rick 02-09-2004 07:07 PM

The mechanic said a SMALL amount of oil in the intake is normal and that it comes from the oil injectors. He then said something about the overlap design of the side port reverses part of the intake charge and that is how the oil gets in there. Does that make sense?
He sounded credible until he told me that it also happens to the FDs. I thought oil in the FD intake was fron worn out turbos:confused:

essentialspeed 02-09-2004 07:30 PM

My baby gt is going in tommorrow to get looked at.
Mazda Canada sent a techy down to look at it.
The comment of it "being normal"..doesn't jive with me.Yes the second and third gen. in fact all rotaries burn some oil...thats fine and espected.
But throwing oil into the intake track...so much that my air box,filter and intake tube is soaked with oil.
Lossing so much that in the 1200km i have driven since pick up gone through over 2L of oil.FOR the record it was never over filled.Since i found the issue i have added over 750ml of oil to my motor.
if they can't solve it i have fabricated a catch can to intervine with the crankcase vent tubes.

ON a side note...anybody found their 8 to be sluggish from idle to 1500 rpm, as in when you pull away from a stop sign..and have to feather the gas pedal so the rpms don't crash???.
Mazda has done a great job with the low end torque but i found the car in the upper gears doesn't have the pull it should have, hopefully our intake and exhaust upgrades will fix that issue.

zoom44 02-09-2004 07:32 PM


Originally posted by essentialspeed

ON a side note...anybody found their 8 to be sluggish from idle to 1500 rpm, as in when you pull away from a stop sign..and have to feather the gas pedal so the rpms don't crash???.
Mazda has done a great job with the low end torque but i found the car in the upper gears doesn't have the pull it should have, hopefully our intake and exhaust upgrades will fix that issue.

no and hunh? what upper gears don't have the pull they "should" have? at what rpm?

essentialspeed 02-09-2004 09:14 PM

coming out of highway cruise 6spd.. @ 3000rpm.
drop down to 4th...around 4000 and punch it..it pulls but not impressive.
I know i'm used to 31 psi of boost in my second gen...but the 8 feels that its very restrictive in the mid to high rpm range.
I'm wondering if in Mazda's redesign they sacraficied top end for low end pull??
If you have looked at other dyno for the rx8 with performance mods..they post gains from mid upward.
As in most N/A rx's they need alot of help to let the rotary breath...cold air intake and exhaust always gave the best gain for your buck.
Hoping our mods will bring the "scream " back into the rx8

zoom44 02-09-2004 10:28 PM

well check some posts here that talk about the ecu, intake and exhaust. you'll find that the intake and exhaust are very well engineered on this car and that the restriciton is mostly in the ecu. not much gain from intakes and exhaust on this car. the problem is the "cat-longevity" state of tune which is causing it to run "pig-rich"(thanks to paul yaw;)) in th eupper rpm ranges. and yes it doesn't have much punch at 3k rpm in 6th but then that is purely an overdrive gear, so it is as it is supposed to be. shifting to 4th is definetly the way to go in that situation if you want to pass.

B-Nez 02-09-2004 11:52 PM


Originally posted by Rick
He then said something about the overlap design of the side port reverses part of the intake charge and that is how the oil gets in there. Does that make sense?
Correct me if I'm completely wrong, but I could swear that due to the side ports there is NO overlap between exhaust and intake. In fact, let me track down the port-timing chart and we'll see for sure...

rotarygod 02-13-2004 11:39 AM

The Renesis has 6 degrees of dwell. No overlap.

Rick 02-14-2004 11:35 AM

I think I better have another talk with the Mazda Tech.:mad:
Anyone else find oil in the 8s intake?


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