RB questions

[JPsNissans]

Questions yo

[Coolwhip]

Do a leak down test on the motor to verify there are no valves stuck open as well as valve steam seals shot.

Shine a light down on the piston domes and see what kind of condition they are in, if they have major build up or not.

Checking the pcv valve and other components related to crank case ventilation is also a good place to look, making sure nothing was clogged and such.

Good luck man.

[Darius]

A lot of them end up looking cooked like that especially at the rear. The one on the right looks especially baked!

How many miles were on the engine? I'm just wondering if it has seen a lot of hard miles. Follow Coolwhip's advice and keep us posted on what you find. It would be interesting to know what is causing it in your case.

[StricNyne]

i was somewhat expecting to see a sock wrapped around the cam but uhmm yeah, isnt cyc 6 considered to be the leanest cyc

[Kansei240sx]

That looks more like that engine wasnt treated very well and serviced at its proper intervals. The color on that valve cover and the black sludge/carbon build up is characteristic of not changing the oil for long periods of time. Or a bad PCV since that is that side that part is on. Running an engine lean in that cylinder wont have anything to do with that. Those flakes are just the sludge drying up and deteriorating not explosions. I could probably bet just by looking at that picture, that the black build up goes alot further under that baffle than what we see.
Modified by Kansei240sx at 1:29 PM 5/26/2008

[JPsNissans]

A lot of them end up looking cooked like that especially at the rear. The one on the right looks especially baked!

How many miles were on the engine? I'm just wondering if it has seen a lot of hard miles. Follow Coolwhip's advice and keep us posted on what you find. It would be interesting to know what is causing it in your case.

100,000+ kms. It had it's 100,000km service done by Nissan right after it hit 100,000kms, had a sticker on the upper timing belt cover in Japanese.

[Kansei240sx]

100,000+ kms. It had it's 100,000km service done by Nissan right after it hit 100,000kms, had a sticker on the upper timing belt cover in Japanese.

Just because it has the sticker doesnt mean it was done by them, there is still a chance someone could have gone and got the timing belt and done it themselves.

Also even if the sticker is there for the timing belt, that doesnt have anything to do with how frequently the oil was changed or what else might have been skipped.

[fast_s14]

I would say that they did not change their oil every 3000 miles and the oil started to break down. Maybe they used a low grade oil. When i used to work in the service department for my local chysler dealer i always would notice the people that always came in at 2500 miles for service and the people that would come in at lets say 7 to 9k miles. What i am trying to say when i would open up the oil fill i could definately tell a difference on how clean it looked inside and the oil never had a chance to break down. While when the people went 7 to 9k miles the oil would be really black and would start to cake up in the fill cap area. (not always the case tho). When ever i got my rb25 i pulled the valve covers and there wasn't even a yellowish tint it was soo clean looking. *Crosses fingers* previous owner took care of the engine. Hopefully everything goes alright with your engine and there is no damage done. Maybe change the oil a couple times to try to get some of the crud out.. Thats all i can say just my 2 cents

[Kansei240sx]

Well, just remember oil doesnt break down... The additives in oil break down. The reason the sludge occurs is because the detergents and friction additives become overloaded and accumulate too much dirt and debris into the oil. The circulation of oil in the engine creates those deposits in the head and galleries in the head/block. When the oil isnt changed enough all that crap just accumulates and sticks to all and any surface it can. I work for Toyota as a technician and we actually have a campain for most 1MZ-FE and 5S-FE engines that have an actual problem with those.

Pennzoil actually has a ****load of detergents in it but if it isnt changed every 2500-3000 miles it turns into basically cake inside the engine because the additives in it deplete much faster than most oils. I could go on for hours about this crap but its time for a food run.

::edit::

Just clean out those valve covers and you should be ok. Your valve covers dont look that bad compared to some of the Toyotas and other Nissans i've seen from neglect. Most of the time we short block the engines and clean up the heads, and replace the valve covers because the valve covers and heads get so bad we replace THOSE as well sometimes.

[JPsNissans]

Just because it has the sticker doesnt mean it was done by them, there is still a chance someone could have gone and got the timing belt and done it themselves.

Also even if the sticker is there for the timing belt, that doesnt have anything to do with how frequently the oil was changed or what else might have been skipped.

I was just responding to his question of how many miles the motor had on it, not trying to prove anything.

[Coolwhip]

Might want to clean the baffling as well.

[Kansei240sx]

I was just responding to his question of how many miles the motor had on it, not trying to prove anything.

Its cool, i wasnt saying you were wrong, im was just stating that there are other that might be possible.