bad blow by

[hi comp]

ok im new to the forum and i am having a few problems wit my motor its a b18c2 it has 75000klms...

here is the list of mods..

>autronic ecu
>msd fireball ignition
>mugen headers
>a'pexi exhaust
>toda spec b cams
>toda cam gears
>spoon throttle body
>adjustible fuel reg
>injectors
>fuel pump

i think thats it..

any way the motor has bad blow by and only makes 120.5kwatw:(
not good. on the dyno sheet its pretty flat power curve.

i have had some runs wit modded vx ss and some done up gtst etc and havent been beaten and thats wit a slipping clutch. im worried my motor isnt healty anyone got ideas??

what power should i make? what causes blow by? piston rings? would that cause a lack of power?

sorry if im abit vaugue but im a lil confused. new to hondas have come over from a wrx sti.

[Perry]

can u post up the graph?

[hi comp]

will give it a go! the guy that tuned it wasnt very experianced with hondas. he does more skylines etc etc. i will scan it to the computer then try put it in here!

[hi comp]

yeah i figured that ;) saving up for rebuild hopefully by toda trying to get a price but they havnt replied

[hi comp]

here it is http://img409.imageshack.us/img409/7921/lastscanzc3.jpg

hmmmm could have been bigger! how do i resize it?

[Slow96GSR]

http://www.strathlan.com/CMS/images/dynographozhonda.jpg

[BlitZ]

how bad it bad? how much oil u loosing?
just make sure u run a catch can too.....

[Hipowerracing]

hi bro..

looking at your graph..
flat spot 6500~7250...
at 5000~5750 flat spot.
am i right???

no offence your cars tune is pretty average.. still Rich 12.8 at most time..

power drops off after 7250... "you can get more power at top end".
which computer are you using?

also use a compression meter to tell you which piston has dropped compression. usually cracked ring glens/ piston rings will definately have a drop in compression...

however flat spots are not from your mechanical set up but tunes do a big part of it..

sorry not trying to be a car "guru" just giving my opinion (helping a guy out).

Warmest regards

[hi comp]

i appreciate your coments so there is no offence taken mate.

im using an autronic computer the guy that tuned it hads no idea about hondas. i used him cause the car had some bad problems and he was the closest guy i could get to do it.

yeah the car is pretty flat to drive and has this massive kick when vtec hits. . not smooth at all.

what air/fuel ratio is safe? how lean can u go?

also where is a good tuner in sydney? i just want tot get the most from my car

[hi comp]

how bad it bad? how much oil u loosing?
just make sure u run a catch can too.....


its pretty bad! i took the oil cap off and f**k me i was shocked!

the car goes from the full mark on the dipstick to the refill mark or close to in 6000klms.

i have an oilcatch can but no oil ever gets in there i supose thats one good thing:p

[BlitZ]

its pretty bad! i took the oil cap off and f**k me i was shocked!

the car goes from the full mark on the dipstick to the refill mark or close to in 6000klms.

i have an oilcatch can but no oil ever gets in there i supose thats one good thing:p

if its hooked to your PCV is should pull out all the crank case pressure/blow by

[grumpy rooster]

Are you sure you don't have some of the oil breather hoses connected the wrong way around therefore pressurising the sump and pumping oil out of the engine? Is there oil all over the engine bay?

It just sounds weird to me that you have a catch can yet there is nothing in it.

[JasonGilholme]

A catch can won't pick up oil that is part of the blow by.

The catch can picks up oil that the oil seperator hasn't been able to get. Blow by is a result of poor piston ring to wall clearance.

have a compression test done to see what cylinders are down on pressure, and have it rebuilt accordingly if needed.

Once you've stopped blowing oil into the chamber and all over your plugs and valves you'll be able to get a better tune cause there won't be any oil in hibiting the combustion process.

Jase

[ginganggooly]

I'm wondering how a b-series with 75k km could suffer from blow by. How long have you had the car for??

I'm with the other guys here, go get a leakdown and compression test done...

I have thrashed the living sh!t out of my car for the last 200k km (now has about 260k km on the clock), and having replaced a clogged pcv valve, the oil consumption is pretty decent, about 1L/5000km.

[tinkerbell]

you say you have "blow-by"

but all i can see why you think this is due to your oil level going down...

you need to expalin more of why you think you have a blow-by issue on a 75'000km old engine...

[silver_screen]

that curve looks alrite to me
very flat torque curve.. 12.8 isnt rich.. sounds about right but he could get a bit more power uptop.. somethings not completely right

[JasonGilholme]

I'm wondering how a b-series with 75k km could suffer from blow by. How long have you had the car for??

I'm with the other guys here, go get a leakdown and compression test done...

I have thrashed the living sh!t out of my car for the last 200k km (now has about 260k km on the clock), and having replaced a clogged pcv valve, the oil consumption is pretty decent, about 1L/5000km.

My b16 has 140k on it and it doesn't blow smoke at all. No oil consumption either. i put in 4 litres and take out 4 litres each time i change the oil.

[BlitZ]

Please explain... then what does it pick up?...

my understanding
Oil separator is used to separate the oil in the blow by... honda has OEM separate called PCV..

PCV is ok.. but when there is alot of oil the oil still gets back to the head... so thats is the readson we run cathc cans




A catch can won't pick up oil that is part of the blow by.

The catch can picks up oil that the oil seperator hasn't been able to get. Blow by is a result of poor piston ring to wall clearance.

have a compression test done to see what cylinders are down on pressure, and have it rebuilt accordingly if needed.

Once you've stopped blowing oil into the chamber and all over your plugs and valves you'll be able to get a better tune cause there won't be any oil in hibiting the combustion process.

Jase

[tinkerbell]

I agree with BlitZ

it is the role of the PCV system (which involves the oil separator) to remove "blow by" gases and other substances like water and unburned fuel from the crank case.

a additional catch can augments this system and when set-up correctly , can completely prevent the ingestion of non-vaporised substances into the combustion process...

[JasonGilholme]

It doesn't seperate oil IN the blow by. But it does seperate the oil from the air in the crank case before it goes back into the combustion chamber.

The crank case is vented from the back of the engine and goes through the PCV then up into the intake manifold.

Blow by is where your piston rings aren't making a sufficient seal up against the cyllinder walls and oil is getting past. If the PCV valve worked on "blow by" it would mean that all cars would have poor piston ring to cylinder wall clearance from factory.

i hope this helps.

J

PS: I think ben has a good diagram which explains where the PCV system runs.

[tinkerbell]

how does that help?

you said:
A catch can won't pick up oil that is part of the blow by.

we said, yes - it will, that is what a catch can does...

[tinkerbell]

here are some links for you:

http://en.wikipedia.org/wiki/PCV_valve

http://www.honda-tech.com/zerothread?id=1199935

[DLO01]

Hi Comp, you say its Blow By, but I am not convinced the actual problem is Blow By.

[tinkerbell]

It doesn't seperate oil IN the blow by. But it does seperate the oil from the air in the crank case before it goes back into the combustion chamber.

The crank case is vented from the back of the engine and goes through the PCV then up into the intake manifold.

Blow by is where your piston rings aren't making a sufficient seal up against the cyllinder walls and oil is getting past. If the PCV valve worked on "blow by" it would mean that all cars would have poor piston ring to cylinder wall clearance from factory.



after trying to work out what you are saying - i need to ask:

do you realise that "blow by" is where the cylinder pressure rushes past the piston rings INTO the crank case? not the other way around?

[ginganggooly]

after trying to work out what you are saying - i need to ask:

do you realise that "blow by" is where the cylinder pressure rushes past the piston rings INTO the crank case? not the other way around?

I always had it in my mind that it was both ways... i.e. when the crank is pressurised, say from a clogged pcv valve or cactus rings, and the pressure pushes oil up past the rings into the combustion chamber- or, as per your above statement...

[DLO01]

Also I think the orignal topic starter is suggesting that the oil itself is getting past the Rings in to the combustion and again I question that.

People are on different wave lengths.

Some are thinking the affects of blow by from combustion to crankcase other people are thinking effects of blow by from crankcase to combustion.

[JasonGilholme]

after trying to work out what you are saying - i need to ask:

do you realise that "blow by" is where the cylinder pressure rushes past the piston rings INTO the crank case? not the other way around?

I always thought it was oil getting direcly into the chamber via going past the piston rings.

Never thought about it happenning the other way round. :(

[tinkerbell]

I always had it in my mind that it was both ways... i.e. when the crank is pressurised, say from a clogged pcv valve or cactus rings, and the pressure pushes oil up past the rings into the combustion chamber- or, as per your above statement...

sounds far-fetched to me... each piston upstroke has higher combustion chamber pressure than crankcase pressure (ie compression of A/F or pushing hot exhaust out) so as to have little to no chance of getting past the rings...


http://www.bobistheoilguy.com/blowby.html

[ginganggooly]

I know with my car, it suddenly developed a huge oil consumption problem and started belching out copious amount of blue smoke.

Changed PCV valve and problem was solved. DynoDave and I put it down to the crank case pressurising and pushing oil up past the rings... It seems more or less logical to me- bearing in mind that the rings are over 260k km old....

[BlitZ]

Blow by is where your piston rings aren't making a sufficient seal up against the cyllinder walls and oil is getting past. If the PCV valve worked on "blow by" it would mean that all cars would have poor piston ring to cylinder wall clearance from factory.

i hope this helps.

J

PS: I think ben has a good diagram which explains where the PCV system runs.
hmzszs... i think im on the same page as tink
i think you could be wrong there.. correct me here but this is what makes sense to me
Its compressed air esacping into the crank case on the ignition stroke and not oil sepping into the combustion chamber.... Air is much much smaller than oil in particle size..

That is why you do a compression test.. u test how much pressure it hold.. if it looses pressure means the pressure is going into crankcase...... the pressure theyere will be the unburnt stuff call blow by....

And the word also implies:
Air Blow By Piston ring

[tinkerbell]

I know with my car, it suddenly developed a huge oil consumption problem and started belching out copious amount of blue smoke.

Changed PCV valves and problem was solved. DynoDave and I put it down to the crank case pressurising and pushing oil up past the rings... It seems more or less logical to me- bearing in mind that the rings are over 260k km old....

yes, if the crank case is sealed, this maybe one outcome...

[hi comp]

shit now im confussed!! ok i havnt been on here for a few days so my appoligies.

when u take the oil cap off there is a massive amount of air rushing out?? worse than i have seen on any other car. it has no oil leaks but has rather high oil consuption?? but doesnt blow excessive smoke if at all.

its has 75000klms but has been track by the previous owner and there for not had an ezy life.

do u guys recommend i get a compression test to see whats up?

i cant get this fixed till i get my box and clutch done anyway but i am trying to work out what it is:confused:

[BlitZ]

I always thought it was oil getting direcly into the chamber via going past the piston rings.

Never thought about it happenning the other way round. :(

that what we are trying to tell you for the last 20 posts..

Air is small than liquid... you will be loosing Compression air long before the oil seeping through

[JasonGilholme]

Yeah but noone ever directly said that the compression air was pushing oil vapour from the crank case though the PCV system into the IM and then into the chamber did they.

it makes sense to me know lol. sorry. :)

[TODA AU]

shit now im confussed!! ok i havnt been on here for a few days so my appoligies.

when u take the oil cap off there is a massive amount of air rushing out?? worse than i have seen on any other car. it has no oil leaks but has rather high oil consuption?? but doesnt blow excessive smoke if at all.

its has 75000klms but has been track by the previous owner and there for not had an ezy life.

do u guys recommend i get a compression test to see whats up?

i cant get this fixed till i get my box and clutch done anyway but i am trying to work out what it is:confused:

Lots of air rushing out of the oil cap is a symptom of blow-by
This will cause excesive oil consumption via the PCV valve...
It could also be valve guides or both...
If really depends on how hard a life the thing had before you purchased it.

[DLO01]

when u take the oil cap off there is a massive amount of air rushing out?? worse than i have seen on any other car. it has no oil leaks but has rather high oil consuption?? but doesnt blow excessive smoke if at all.

Hi Comp, You need to:

1. Test your compression

2. Check to see if your PCV valve is working ok and not stuck. You can simply take it out, shake it up and down and you 'should' hear the little ball move up and down.

3. Make sure you PCV system is plumbed up correctly

Also a lot of people have their Oil Catch Can plumbed up incorrectly. I have got mine hooked up between the PCV valve and the Intake manifold. There it catches the oil vapours after the crankcase, but before it enters the Intake Manifold.

Photo for your reference courtesy of Ben:

http://i13.photobucket.com/albums/a265/DLO01/Temp/accord_pcv_657b.gif

[tinkerbell]

do u guys recommend i get a compression test to see whats up?




have a compression test done to see what cylinders are down on pressure, and have it rebuilt accordingly if needed.


at least you got one thing in post #14 :thumbsup:

[hi comp]

thank u very much DLO01 for your help! i will do all that asap.:)

cheers!

[hi comp]

at least you got one thing in post #14 :thumbsup:

nah i got two things out of this thread. . . i also learnt that you, 'tinkerbell' are a TOOL! :D

honestly mate if u havent got anything constructive to say then why say anything at all???

thanks to everyone else for there help ;)

[aaronng]

I know with my car, it suddenly developed a huge oil consumption problem and started belching out copious amount of blue smoke.

Changed PCV valve and problem was solved. DynoDave and I put it down to the crank case pressurising and pushing oil up past the rings... It seems more or less logical to me- bearing in mind that the rings are over 260k km old....

Even if the crankcase was pressurised, it would be from the combustion chamber pressure leaking past the rings. So the combustion chamber pressure will always be higher than the crank case pressure. The oil would have been blown through the PCV into the intake manifold and then into the combustion chamber. That's why replacing the PCV valve fixed the problem. The valve was sticking open. With the new valve, it stays closed even with the higher pressure and so you didn't have your oil vapour being pushed into the intake manifold.

[hi comp]

ok, update on motor!!! havnt got a compression test as yet but there is now drops of oil spiting out the motor when u take the oil cap off :(

this is bad so i asume i should get the head pulled off and check the condition of the bores and rings?

also i checked out my oil catch can and its not fitted right, its been fitted from where u usually put the oil breather not anywhere near the pcv valve.

cheers Jared

[tinkerbell]

oil drops spit out of my engine when i take the oil cap off too!!!!

taking the oil cap off is NOT a terribly useful diagnostic proceedure.

take it to a actual mechanic, as we have all suggested you do for the last 40 posts...

[sivic]

rofl.
of course oil is going to spit out.
see how the cam is sitting just bellow the oil filler hole. when the engine is running that is spinning very fast. there's a good chance its going to flick some oil up.
why do you assume this is bad? you do realise that there is supposed to be oil up in the head and it doesn't just get there via bad seals/rings?
at this point it really does look to be an issue with the PCV system. is the catch can picking up much oil?

[Rasputin]

Hey mate, I noticed you're on the central coast, same as me.
If you want to pm me, I can give you names of people worth seeing on the coast, and people to avoid. Plenty of the latter around here.

What you may want to do in future is, for major work (e.g. engine work) and issues which don't require you to be towed, take the car to Hanny's Performance in Smithfield (Sydney)

Was a bit of a drive for me, but well worth it. If you have a honda and can get there, I'd get there.

P.S. didn't realise i was raising the dead, shoulda pmed him. my bad.