catch can filled quick!!?

[cjmirabal1]

Today i notice my catch can (exhaust side) was filled. Its never collected
More then a few droplets before, this is after a nite of drifting and ripping on her also.
Car runs perfectly fine, no power loss at all. Is this due to the high oil temps and reving during the drift session? Im running 10w30 if that helps

[TheMAN]

probably just lots of blowby when you were driving crazy.... sounds normal
how is the catch can hooked up? got pics?

try switching to 5W40, it helps reduce blowby

[cjmirabal1]

probably just lots of blowby when you were driving crazy.... sounds normal
how is the catch can hooked up? got pics?

try switching to 5W40, it helps reduce blowby

Im running dual catch cans. One from intake side vent inline with pcv. The other inline with exhaust vent on valve cover to intake pipe.

Yea thats what i was thinking of doing....a thicker oil.

Also idk if this is related but it happened at the same time. My bov sound is crazy muzzled compared to before.... Idk if oil happened to get on the diaphram some how?
Will be taking it off for inspection asap

[bentvalves]

what I did when my CA filled catch cans smashing rev limiter was to simply allow the head to breathe from as many places as possible. I removed the PCV valve and capped that hole with a 3/4NPT plug. Then I sent both valve covers to a catch can with a huge 1.5" filter ontop of the catch(picture a filter you could stick on your radiator inlet/outlet). If you have a look at my pic here, I also added the oil/air seperator from a pulsar or s*** and sent that to the same "vented to atmosphere" catch can. No more puking oil, ever. 25psi rev limiter burnouts don't even push oil into the catch anymore.

[float_6969]

It's probably not much to worry about. You're definitely running too thin of an oil. I don't run anything less than a 10w-40, and go to 20w-50 in the summers.

[TheMAN]

why do you even want to run 20W50? that's wayyy too high of startup pressure, even in the middle of summer... you'll have longer dry starts too
you'll be better off getting a 5W50 oil... less startup wear, faster oil flowing on cold starts, and lifters will probably be happier since the oil gets pumping into the HLAs sooner

it's always best to run as thin as you can for cold starts and thick as you need to for protection for the operating temps
0W40 also works great and is an alternative to 5W40... but I definitely think it's foolish to run 20W50... it's old school oil tech and 5W50 works far better as it's made based on today's technologies

[float_6969]

I would want to run 20w50 because the FSM states it as a recommended oil for the temperature range that I see in my area. (The FSM states that 20w-50 is recommended for the temperature range of 14°F-104°F+) Have you run that weight oil in the CA18DET before? How do you know the start up pressure is too high? Let's not forget that we're dealing with early 1980's engine technology here and this motor doesn't exactly have tight bearing clearances. I know that in my motor, in the middle of the summer in Kansas, 20w50 DOESN'T yield too high of a start up pressure, generally in the 50psi range at high idle. It quickly (with in a few minutes) drops down to around 25-30psi.

You DON'T nessicarly want a big difference between your cold and warm weights. The molecules that are used that create this property of oil, are prone to breakdown from heat and pressure. As these molecules break down, you loose viscosity. Lost viscosity means lost protection, and engine wear ensues.

If you're running a high quality synthetic, and changing regularly, then running a 0w40, or a 5w50 will probably be fine. But to make a blanket statement that 20w50 is "old school oil tech" is a bit close minded.

And FYI, my rod bearing clearances are on the loosest end of the OK range as per the FSM. If I try to run a 10w40 in the summer, I get some light rod knock on startup. This isn't an issue in the winter, and when I run my "old school oil tech" 20w50 Amsoil in the summer, I get no rod knock, my lifters don't make a peep, my oil pressure doesn't exceed 50psi during start up, and settles down to 20psi once warmed up.

[TheMAN]

the recommendations written in the FSM are from 25 years ago... don't you think a lot has changed in oil technologies since then? back then, what did we have... API SF? Now we're at API SN, with the ILSAC GF5 oils which have strict requirements against volatility, high temperature/high shear, etc... requirements that didn't exist, even just 10 years ago, let alone various multi-weight oils not available then!

your talk about "molecules" is hogwash... it used to be true, but not anymore... the way oils are made now, the quality ones are very stable against heat, shearing, and viscosity changes... good quality oil such as Mobil1 0W40 do not shear easily from mechanical stresses or heat... it takes a lot to drop it down to a 30 weight!

20W50 *is* built off old tech... it's been made pretty much the same way for years, while better multi-viscosity oils that have a wide viscosity difference are made off higher quality base stocks and use better additive packages

oil technologies evolve year to year, in a rapid pace because of the quest for longer drain intervals, lower friction, lower viscosity to reduce pumping losses... all in an effort to reduce carbon footprint both in oil waste, and improved fuel efficiency
I really suggest you read some of the threads on BITOG... whatever you learned before, you can throw out the window... that's what I did eventually, once I saw all sorts of evidence that the new school stuff allows 5000 mile dino oil changes and twice that with synthetic, EASILY on any street motor without worries or any added harm to the engine... I hate to say it, but old habits and old ideas die hard... why do you think California launched a public education campaign against 3000 mile oil changes? Even Jiffy Lube stopped the 3000 mile nonsense recently and they started putting 5000 mile stickers on customers cars as reported by some people on other forums.... my point is, things have changed a LOT over the years and it takes an open mind to accept those new ways

[float_6969]

OK, after re-reading my post, I wasn't clear in my opinion. I'm not against modern oils or think they don't work better than they used to. In fact, I'm such a huge fan of them, that I run synthetics in all my vechilels, and run 7500 mile oil change intervals on everything but the 240sx (I beat the heck out of it, and the oil needs changed more often) The only issue I had was your statement;

but I definitely think it's foolish to run 20W50... it's old school oil tech and 5W50 works far better as it's made based on today's technologies

and I was sharing my experience as to why I don't have any of the issues you said running 20w50 would give you. And maybe I've missed something, but the shop I work at is an Amsoil dealer, and I'm pretty confident Amsoil doesn't use "old oil technology" on the 20w50 vs. the 0w40. To make a blanket statement that 20w50 has no place in any engine is what I have an issue with, and what I was addressing.

I have a very open mind. Open enough to accept that even though my engine sounded better and ran smoother in the SUMMER on 20w50, that I would try the recommendations of people like you and my father in law (he owns the shop I work at), who insisted that I couldn't possibly need to run a 20w50.

And to be clear, I think 20w50 has it's time and place. There are VERY few motors that would require it's use in the winter. As I said before, I run a 10w40 in the winter. I've run 0w-40 before, but the lifters seemed to make a lot of noise with it.

It's almost as if your mind is closed to accepting the idea that a 20w50 could have any use....

[TheMAN]

you're right... amsoil and other boutique oil makers don't necessarily make 20W50 with old tech, but they make and sell them because there's people like you who would buy them However, I was actually referring to the generally available oils you find at the stores... there has been no incentive or effort to make the mainstream 20W50 oils much different than they did years ago
but have you actually tried 5W50? The facts remain that 20W50 doesn't flow as well in ambient temperatures as the 5W50. The less startup wear we get in engines, the better for long life and maintaining tight clearances.

as for your need to change the oil sooner in your 240, that's debatable... have you ever done a UOA? I've seen people who autocrossed their cars and did other "hard" driving and not have any problems even with the extended oil change intervals... UOAs proved that

[boost_boy]

X2 for the 20W-50 and that's all I run in my cars. Doesn't get cold enough to run lighter oils down here, so who cares; as long as my engines are happy and they are. I say run what you feel works for you. And though the topic is debatable and though your opinions are appreciated, we all still run whatver oils we want . It has worked for me in the past and still works for me to this day and I truly do try to beat the oil right-off the journals, but no spun bearings to discuss here .

[bentvalves]

you guys are going to turn a "my catch can filled quick" thread into a huge debate on oil weight? to the original poster the weight of the oil you were running had nothing to do with your catch can filling quick. IT IS A BIG DEAL if you drive the car hard enough often enough for long periods of time. CA's do puke oil blowby. SR remedied the issue with the self draining blowby collector that everyone thinks is a catch can behind the exhaust manifold. Just give the head more places to breathe from and it wont puke oil.

[float_6969]

Yes we are. The OP hasn't been back and how often do we get any sort of entertaining reading in the CA forum? 70% of the posts in here are about ppls busted cars not running and how they can fix it cheap. If the OP has an issue, he's more than welcome to ask, and I'll clean this thread up.

To TheMAN, I tried Mobile1's 5w-50. It seemed to work alright, but during cold start the engine seemed...more rattly. Can't really put more to it than that. I've had this engine for nearly 10 years now, and I know it well. As I've said before I built this engine loose, especially on the rod bearings and the piston to cylinder clearances (when cold, they're a high expansion rate forged piston). These extra clearances dictate the necessity for the thicker oil, but a 20w50 is still within Nissan's recommended oil viscosity. As for the shorter change interval on the 240sx, I meant in relation to what we normally recommend. All of our Amsoil customers at work are on 7500 mile oil change intervals and 1 oil filter change and fluid top-off halfway through. I'll usually go 5-6K miles depending on how badly I've treated it and 1 oil filter change half way through. I probably could go longer, but with out an oil test, I fee that this is a safe range that will leave me some headroom.

[Buddyworm]

probably just lots of blowby when you were driving crazy.... sounds normal
how is the catch can hooked up? got pics?

try switching to 5W40, it helps reduce blowby

Im running dual catch cans. One from intake side vent inline with pcv. The other inline with exhaust vent on valve cover to intake pipe.

Yea thats what i was thinking of doing....a thicker oil.

Also idk if this is related but it happened at the same time. My bov sound is crazy muzzled compared to before.... Idk if oil happened to get on the diaphram some how?
Will be taking it off for inspection asap

1) How much boost you making?

2) What about Nissan's ridiculous "L-pipe" that runs from the top of the oil filter flange back to the the rearward valvecover hosebarb? It runs back from the oil filter to the back of the engine and then up between the butterfly control stuff and the #4 cylinder intake runner. IIRC that pipe is one of two ways that gasses can vent out of the crankcase; the other is the oil drain on the exhaust side of the head.

I've met a lot of people who say the CA over oils the head at high revs so if the L-pipe gets clogged or restricted enough you'll have blowby gasses with nowhere to go but up the same hole all the oil is trying to go down. Dunno if that'd be enough to cause you to pick up a ton of oil but, meh.

When I put my 17c on with a fresh hone on the motor I was getting gnarly spray out my breather hose JOINTS because I didn't have my exhaust side breather hooked up to the intake pipe. Not enough suction I guess but bottom line is that I now have a crankcase vented in the factory method with a catchcan between the head and intake and I'm not spraying oil no mo.

[float_6969]

I used to have this issue as well. I think the CA's main problem with blowby is the "L pipe", as Buddyworm called it. In my most recent built, I removed all of that completely, plugged off the hole in the intake side valve cover, turned the pipe on the oil filter mount, ran a big silicone hose the size of the pipe on the oil filter mount, up to an oil separator from an SR20, reduced it down right at the separator, and then have the outlet vented to atmosphere right now. I was going to connect all of the valve cover openings back up to the intake and the turbo intlet, but since doing this I've had ZERO blowby issues. I'm still going to connect it up, but I think that the CA's main problem is that the stock setup didn't allow enough of the crankase gasses to get to the head in the stock configuration. So the gasses would instead come UP the oil drains, causing oil to pool in the head, and EXTREME oil saturation of the PCV gasses in the head.

I think anybody with blowby issues should first look at that pipe under the intake manifold and make sure it's clean and clear. It also wouldn't hurt to increase it's size CONSIDERABLY. I think (I don't have any experience with this) that if someone were to design a new pipe that was a larger diameter, that more gasses would make it to the valve cover, and you would get better drain back, and less oil saturation of the PCV gasses.

[Buddyworm]

I used to have this issue as well. I think the CA's main problem with blowby is the "L pipe", as Buddyworm called it. In my most recent built, I removed all of that completely, plugged off the hole in the intake side valve cover, turned the pipe on the oil filter mount, ran a big silicone hose the size of the pipe on the oil filter mount, up to an oil separator from an SR20, reduced it down right at the separator, and then have the outlet vented to atmosphere right now. I was going to connect all of the valve cover openings back up to the intake and the turbo intlet, but since doing this I've had ZERO blowby issues. I'm still going to connect it up, but I think that the CA's main problem is that the stock setup didn't allow enough of the crankase gasses to get to the head in the stock configuration. So the gasses would instead come UP the oil drains, causing oil to pool in the head, and EXTREME oil saturation of the PCV gasses in the head.

I think anybody with blowby issues should first look at that pipe under the intake manifold and make sure it's clean and clear. It also wouldn't hurt to increase it's size CONSIDERABLY. I think (I don't have any experience with this) that if someone were to design a new pipe that was a larger diameter, that more gasses would make it to the valve cover, and you would get better drain back, and less oil saturation of the PCV gasses.

FTW. I'm 90% sure it was one of your posts that originally brought my attention to that grotesque piece of multidiameter ugliness.

What causes oil saturation of the PCV gasses? Are the gasses hot enough that they'd vaporize some of the oil as it was runs down the drain?

[bentvalves]

crankcase windage-the tornado of oil that circulates around your crankshaft. Then blowby (boost that makes its way past the piston rings down into the crankcase) goes back up into the cylinder head carrying this windage with it through a variety of different places (path of least resistance) and viola you have a cylinder head puking oil.

[float_6969]

^ This

[cjmirabal1]

sorry for the late update on the op. thanks everyone for the info.

i rerouted the catch can set up and using 15-50 oil...lowered the plug gap to .8

she now runs amazing!!!!! no more blowby at high rpms! fell in love with the ca all over again.



no i didnt have an issue with the oil debate...enjoyed it