well if u search under my name u will find iv had problems with smoking blue smoke. i just rebuilt my bottom end with aftermaket parts and baught a 2000 crv head from the junkyard that had 5000 miles on it

well the bottom end has about 7000 miles or so. and the head now has about 12000 total and my car blows blue smoke sometimes. not everytime it usually is mostly everyday but not allways everyday. it smokes sometimes on start up. sometimes at idle and sometimes when im driving - its really intermintent. like sometimes it would be very clear no smoke and other times it can fill my whole driveway with a big cloud of blue smoke for a few minutes. i did a compression check and it was 175,173,175,175 - well a few ppl and friends said its gotta be rings and i went along with them cause i allways heard that valve seals wont smoke when the engine warms up.

well i talked to 3 mechanics and a guy that builts motors and heres what they all said

they said it prolly 97% would be seals/or guides or maybe valves. they said it would most deff. prolly be somewhere in the head. and i asked them about valve seals smoking when car is hot and they said "oh they deffently can" they said because its DOHC and a honda that theres allways a good bit of oil in the head and it can deffently still smoke after getting at normal operating temp (they said something to that effect) i asked about a leakdown test but all of them said it wont show anything because the compression rings in the pistons are good. and even if the oil rings are bad it would still show good leakdown numbers. but then when i told them i got the head from a junkyard they said they would be 99% sure its somewhere in the head seals/guides etc. they said junkyard heads no matter the milage can go bad from sitting.

but inconlusion they said it would be seals or somewhere in the head. esp since its a junkyard head and i had good compression numbers. and the leakdown test wont show nething.

well what do you guys thinks?

i really hope they are correct as it saves me alot of money and they do know a good bit about cars. so just wanted some of your thoughts b4 i took head off.!!!

thanks

 

guides are prob. bad . ive replaced honda guides many times due to oil smoking .clearances from the factory are somewhat loose to begin with.are u sure the head had only 5000mi. on it ie. did u see the car odom.it came out of?

 

no im not sure
i baught the head offa the partstrader. the kid said he baught it from a junkyard for his b20 swap and just used the bottom end he sent me the head and it had "5,000 Mi 2000CRV" written on it just like all junkyard parts do?

so i guess

but i heard nething from a junkyard can go bad esp seals and such cause they can get hard from sittin and such

i never adjusted the valves when i put the motor in drove it about 3000 miles and changed the headgasket (block guard problems) well neway the mechanic adj the valves and said some of the valves were very tight?

also could a valve be burnt or something?

or do u still think its guides or seals?

i mean i dont think its rings. it runs strong not very fast and has some problems but seems to run good. revs up great goes to 6500 easily no problems and runs good...plus good compression numbers


thanks

 

Your compression number don't sound bad at all.

A burnt valve should give you low compression pressure on that cylinder.

Valve guides and/or valve stem seals leak oil, so it can burn. But they are above the place where the valve seals, so they don't have anything to do with a compression test or a leakdown test.

 

ok so
ur saying the rings seem ok
and u doubt its a burnt/bent valve cause that woudl cause low compression

and what the mechanics said about the stem sea;s guides not being able to tell by the leakdown test is true?

so u think it IS guides and stem seals

 

what did the mech say was tight about the valves not enough lash or tight in the guide?

 

he didnt say all i said was about how i never adjusted them
and he goes "yeah they were really bad. and all outta spec. and some were very tight" thast all he said unfortunallity

 

my car ticks. i did valve adj but still ticked so i figure inj. but i heard if valve guides are bad it might tick - could that be it

see and now im still hearing that valve seals wont let the car smoke on accel. some ppl still say i smoke at accel. could bad guides cause smokeing at accel?


like i said heres when it does smoke it used to just be like 2-3 times a week. but not its more often usually smokes every day sometimes a few times aday but not all the time

sometimes at start up. not everytime but a good bit of the time. this is when it is the worst. sometimes a huge cloud and will smoke for a min to a few minutes. the more gas i give at start up the more smoke. when i drive off it usually clears out and i cant see it in the rear view mirror after like 3rd gear

sometimes after i drive for like 30 min or even 15-20 and stop and let the car idle for like 5 minutes or so. then it will start to smoke. smokes a good bit but not usually as bad as when i start the car up. again smoke is dependent on how much gas i give at idle (see at first i didnt think seals would smoke after car is warmed up but the mechanics said seals can smoke at any temp)

(now heres the stumper) and when im driving some ppl say at accel some at decl. i dunno cause i cant see the smoke when im driving through the mirror (dunno if its just a tiny bit or not) but some ppl that like drive behind me say they see it while im driving. i dunno how often because i never see it. when it is night time and i floor it i can see smoke from my car in the headlights of cars behind me soemtimes but not all the time and i cant tell what color because its dark.

see that bothers me cause like i said ppl said seals wont burn while giving gas. so like i said maybe the guides. do they burn while giving gas? that is why i thought it was rings at first but mechanics said no its not.

but thats about it for when it smokes

and compression numbers again were 175-175-173-175. and its teh junkyard head. the mechanics said with the junkyard heads they can go bad quickly. esp in the head. seals/guides/valves etc.

also somethings that help i havea gutted cat so that might be making it smoke alittle of accel what do u think? (im getting full thermal soon with a cat)
also i have forged pistons and i heard sometimes they smoke a tiny bit normally

what ya think about it all

 

Technically the only places that the oil could use to get in to the exhaust and smoke is either the piston rings, head gasket or valve seals/guides, there is no other way in. The valve seals are made to be a bit loose because they control the amount of oil that gets through to lube the valves inside the guides. The valves wouldn't slide very well if the stem and the guide were totally dry. that’s why you should lubricate the valve stem before its inserted into the guide. (lubrication very important yes!)Since the valve seal is alredy seeping oil through it doesn't take alot to make it seep to much. To me it looks like the steams/guides as well, maybe the head you got snapped a timing belt and bent some valves, valves were replaced but guides were not(that’s just hypothetical). The b16/18 heads have a date stamp on them, doesn't a b20 head have a date stamp on it too? maybe its not a 2000 head. Any ways you are getting good consistent compression through the whole motor so it can't be the H/G or the rings. Look in the exhaust ports maybe you will be able to se the trail of burned oil on the ports.

 

hey thanks alot
well yes i am getting good compression

yes and it is stamped from 1999
when i last had teh header off about 2k ago (b4 it was smoking bad. but was still smokin)
there was alot of carbon build up in exhaust ports as head (just as much as my head that had 160,000 miles iis that bad?

but i hvanet checked lately

 

I'm inclined to say stem seals also. I'd buy a new set, a head gasket and get ready to pull that head soon. Once it's off, you can inspect those things, in addition to the valve seats, and get a better idea of what's going on. If the valve seats look ok, replace the stem seals and reassemble.

 

sounds like guides to me . When u step on it the int velocity pulls oil out of the guides.

 

valve guides

 

allright thanks alot
cause a friend of mine today said everytime he was behind me said when i gave it gas it would smoke. (not much and not as bad as it does at idle) but it did it most of the time
so i was thining maybe rings again cause seals dont usually leak under accel

but i didnt know that guides did

so guides can leak under accel. so its guides u think

thanks alot!

mike

 

bump

 

ok: well u know how i said ppl see it smoking when i get on it. well like i said i have never seen smoke from my car while im driving

Untill now!

but it was under deceleration.

heres what happened i drovecar about 10 minutes pretty hard. (test and tune session well on a straight away floor first to redline. shift smoth into 2nd catches 2nd a bit take to redline. shift to 3rd. take thrid to about 5.5k and the straight away is about to end. so i let off the gas but i dont give any break i just coast from the high rpms. well the straightaway ends and i make like a decent turn like 50-55 degrees or so and the rpms at that time fell to about 3 - 3.5 as soon as i made the turn (still havent hit the break or downshifted just kept off gas) i see a little cloud of blue smoke right where the turn is.
i even repedtad the same situtation again and it did the exact same thing.

so what does that sound like
still guides or seals too you. it was under deceleration.
agaain my friends say its under acceleration which it might be but ive never seen it so i dunno
but this time was DEFFENTLY under deceleration.

 

Intake valve seals & guides usually leak more under deceleration. The high vacuum in the manifold sucks more oil down through the valve guide. On acceleration it can happen when you shift, for the moment you lift the gas pedal.

 

allright thanks alot.
any other opinions.

 

guides almost never have to be replaced.
Seals will cause smoke at high vacuum situations such as idle, cruising and deceleration.

 

so ur saying seals can smoke at crusing?

huum i ehad t aht to bout the guides
but the mechanic said since the head is from a junkyard it is possable for them to go bad.

 

bump

also i noticed i havent smoked much on start ups for a week or so but the last 2 days i did.

but neway it seems that it smokes a good bit when i put it in reverse to get out of a parkin spot or something (on cold start up) - but maybe its just that im going through the big cloud of smoke maybe thats why it seems so much.