Oil Near Spark Plugs And Coil Packs? (rb25det Neo)

[V28VX37]

Hi all,

I recently got an R34 GTT (RB25DET Neo) and have had some trouble with shudder/miss on idle once the engine warmed up.

The car had an injector and fuel system clean in 2008 and new NGK plugs put in. I decided to pull it apart on the weekend and replace the plugs anyway to see if that would make any difference. Some findings:

• Getting the valley cover off is a b___h. I had to loosen heaps of clamps and pull the whole intake pipe off to get clear access.
  
• I found a fair bit of oily gunk around the spark plugs, under the coil packs. This was on all cylinders except no. 6 (very little on 1, too) and especially noticeable on 4 & 5. The oil did not seem especially fresh, and I don't think this was cleaned back in 2008.
  
• The was some oil in the intake pipe as well.
  
• The 2008 spark plugs were NGK PFR6A-11.
  
• The car still has all original leads and coil packs. The coil packs seemed in good condition with no visible cracks.
  

I pulled out all the coil packs and cleaned up as well as I could around the plugs. I then pulled out the plugs too and cleaned up some more.

I have now put in some fresh NGK BCPR6E-11's with stock gaps (1.1mm), torqued 1/2 turn by hand as per NGK's guidelines. I also cleaned and taped up all the coil packs as per these instructions.

After putting it all back together I started the engine, it fired straight up with no hesitation at all. There was some white smoke coming off the exhaust in the beginning, I suspect this was some of the oil from around the original plugs burning off? After warming up it runs fine, no smoke.

Based on the first half an hour test drive it's all splendid, no shudder on idle anymore when warm. However I did notice very slight shudder (once or twice) when stationery on another drive today, so it's clearly better but still not quite 100%. Mind you it seems all fine at higher RPMs and pulls alright.

Some questions:

1. With the oil in the valley I'm suspecting a slight rocker cover leak, is this plausible? What's involved in fixing that, is it just a gasket replacement job?
   
2. I left the valley cover off to keep an eye on things. Is there any harm in driving around without it on?
   
3. Where can I buy a new ignition wire set for an RB25DET Neo in Melbourne? I might also look at replacing the O2 sensor if I can find one.
   

My plan of attack is cleaning the AFM, replacing the fuel filter and replacing the oil filter next just to see if any of these would help. And yeah, the car is completely stock.

Cheers

Before:

After:

[BOOZTJUNKEY]

no harm in not having a valley cover on it is better for your coil packs because it let the heat out although you can get defected for it ...

the oil in the valley cover is possibly from an leaking rocker cover or splilt oil from a change .

first off make sure your car has got the right amount oil in it if its got to much it will shoot them out your engine breathers into your intake.

if the oil amount is at the right level then fit a catch can and stop it going into your intake it seems like alot of oil in your piping you could plug your pipes with

a tennis ball and spray degreaser or tip acetone or thinners down wipe it out with a rag take the pipes off also lol

[V28VX37]

the oil in the valley cover is possibly from an leaking rocker cover or splilt oil from a change .

first off make sure your car has got the right amount oil in it if its got to much it will shoot them out your engine breathers into your intake.

Cool thanks man. Oil is way above max mark on the dipstick when cold so I reckon it's been filled pretty generously at last oil change. I'll leave the valley cover off for now just to keep an eye on things...

[mad082]

if the oil is only a few mm above the full line when cold then that's ok, because once the car is running and the oil is circulating the oil will be at the full level. if you run the car then turn it off and then check the oil it will be at the full mark. once the car has been sitting for a while and the oil has had a chance to drain back down out of the head then it will be above full.

as someone said above, the oil could've been spilt when filling it up after doing an oil change, or it could be from the rocker covers. generally though if the rocker covers are leaking then there will be oil down the exhaust side of the block, however not always. changing the rocker cover gaskets isn't that hard to do.

personally i think that leaving the valley cover off is a good idea as it keeps the coilpacks a little bit cooler.

may i ask why you want to replace the ignition wires? and what exactly do you mean by the ignition wires? as for replacing the o2 sensor, you can test the current one with a multimeter to see if it needs replacing or not.

[V28VX37]

if the oil is only a few mm above the full line when cold then that's ok, because once the car is running and the oil is circulating the oil will be at the full level. if you run the car then turn it off and then check the oil it will be at the full mark. once the car has been sitting for a while and the oil has had a chance to drain back down out of the head then it will be above full.

Thanks I will check the oil level when warm, too.

may i ask why you want to replace the ignition wires? and what exactly do you mean by the ignition wires? as for replacing the o2 sensor, you can test the current one with a multimeter to see if it needs replacing or not.

This is what I meant by ignition wire (lead) set:

It's still the original set and some of the plastic bits are getting a bit brittle, if a replacement set is not too dear might just throw one in.

Thanks for letting me know about the O2 sensor, I'll test it first before getting a replacement.

[chuckie]

G`Day Don`t thing COILPACK HARNESS is available any more,

On COILPACK`S clean them with Scotchbright & Presol,& Spary with URETHANE SEAL COAT,& then spary colour you want them,

Hope you get Problem fixed soon,

Cheer`s Chuckie.

[mad082]

just jap do the coilpack narness. it's over $200 though.

[V28VX37]

just jap do the coilpack narness. it's over $200 though.

Cheers, good to know. I'll try the other options (test O2, clean AFM, change air/fuel/oil filter) to see if any of them will help get it to 100% first.

[Jay11]

Cheers, good to know. I'll try the other options (test O2, clean AFM, change air/fuel/oil filter) to see if any of them will help get it to 100% first.

I know this is pretty old now, but I have the same thing with oil on my coilpacks mainly in the middle ones.

Some advice given to me is just tighten up the bolts on the rocker cover coz over time they may have come a bit loose?

Anyway I'm prob a bit late haha.

[Moodles2]

Might need new rocker cover gasket

[tiberis]

Just give the bolts a bit of a turn (just so they feel firm, no need to over-tighten)

and clean up the area where they are leaking. over the next few days or week, have a look back, if its still leaking then you will need a new rocker cover gasket as the old one has gone hard and is not sealing anymore.

i just changed my gasket, cost around $100 for both sides from Nissan, had it changed in one afternoon.

changing the rocker cover gaskets isn't that hard, would only take 1-2 hours for someone with little mechanical/ car experience. just don't forget to have a look at the half-moons at the rear of the head if they need replacing as well. though they normally seem fine and a bit of gasket goo and they will seal up perfectly again.