Ok so a little backstory here I bought a dc4 with a b18c1 swap, when I got it it was the most hacked together swap I have ever seen in my life, wiring was an absolute clusterfuck. Just to give you an idea, whoever did the swap attempted to wire vtec by twisting the pressure switch signal and the vtec solenoid wires together, and wiring it straight to the negative terminal on the battery. haha. idk if he was trying to make vtec on all the time or what, but it was ******* ridiculous. anyways got everything wired up correctly vtec is engaging but its been blowing CLOUDS of smoke after like 6.5k rpm. did a compression test at my buddys the other day and got:

180 182 180 180


the numbers look a little low from what i'm seeing for a gsr but I forgot to do it with the throttle open so that could be why i'm seeing low numbers. also i'm in denver so i'm a mile high in altitude.

anyways compression is even across the board so is this indicative of a valve problem? discuss.


tl;dr version compression is even across the board, car is smoking ALOT in the high rpm range. valve seats?

 

compression doesn't show a valve guide or oil control ring issue, which is the 2 main reasons for burning oil on Hondas.

smoking under acceleration is most likely due to bad valve guides. people will say valve seals but the underlying cause for seals to leak is guides being out of spec, especially with these engines being so old.

does it burn oil on decel?

 

No burning on decel, but it does let out a plume of smoke when I let off the gas in between shifts. How can I distinguish if its an oil control ring issue? Is there any way to tell if the problem is in the block or the head without ripping the thing apart?

 

^Leakdown test

 

it's a worn out engine. very good chance the rings and valve guides are worn.

honestly, drive it till it blows. you're going to either crack a ringland or an exhaust valve when it goes

you're either looking at a jdm engine or a full rebuild

it's beyond unusual to have compression that even with the symptoms you describe and have it be JUST the rings or JUST the guides

 

no.

 

if its In gear at a high rpm and u let it coast, does it smoke? that would indicate valve seals


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nope. it doesn't smoke on decel. just up at the high rpm ranges, especially in between shifts.

i'm inclined to agree with racebum. it's probably just worn throughout the whole motor. it doesn't baby it as long as i don't take it to redline, so i'll just baby it for now until I rebuild it. planning on purchasing the kraftwerks b series rotrex supercharger kit when it comes out. :D

 

limp sucked up rings,

word guides/valve seals.


One of the two.

 

Mileage? I had a c1 with 240k on it that smoked like a freight train at high rpm, when I pulled the thing apart, the control rings were good and the valve guides themselves were good, but the valve stem seals were so far gone, that the springs for the seal had come through in some spots. Plz don't "drive it till it blows up." Take the time to have the head refreshed and then try it. If it still smokes then all your really out is some gaskets. If you plan on rebuilding it at some point, your gonna have to refresh the head, why not do it now and maybe get a few more years out of it before a rebuild.

 

why? it's the same money either way. you can't physically see if rings are good and guides you can test for run out. with a large amount of oil burning you can more or less guarentee the exhaust valves are stressed and will fracture eventually. pulling the head and doing 8 new exhaust valves and a valve job on all 16, check guides for run out and new seals along with decking the surface and a new MLS gasket is a crapload of time and gasket money. if the rings are down on tension and they most likely are he'll still have an oil burner with a new head and a bunch of wasted time. typically valve seals only fail if they are REALLY old or the guide has too much run out and the stem is wobbling around. the 3rd way is sustained valve float that beats the seal to ****. unsure if a vtec head can even die this way. very common way to kill small block valve seals though. all would depend on if the retainer can contact the seal

tearing the engine apart is so much work i'd hate to do it more than once

even though i have swapped and screwed with countless vtec engines. it's just not enjoyable to always be working on crap. the number of hours this stuff takes out of your life is hard to measure with dollars

drive it till it goes and rebuild. the worst case is you'll melt a piston and you're probably going to overbore on a rebuild anyway

oil burners always blow up one of two ways. either an exhaust valve frags and you sound like a subaru or a ringland lights up and you will look like spy hunter trying to drive it with plumes of smoke

 

why would you wait till the motor was dead to fix the problem? even if the rings were bad you could pull them at the same time and replace them for the cost of a set of rings. maybe rehoning the block if needed. waiting till valves kill themselves or ringlands exploding just buys you into replacing the pistons and having to have the block bored. if a valve eats it and the left overs dont leave the combustion chamber you run the risk of seriously damaging the head. might as well save all the trouble and buy a master gasket kit and a set of rings and set aside a weekend to replace it all. waiting for parts to fail just sets you up for more problems. and ill disagree and say that most b series hondas valve stems go around 100k

 

time. i mean if you feel like pulling it now and doing it it's going to need to be done anyway. just depends on when you want to start it. generally you overbore and use new pistons on a rebuild anyway. i'm just saying the likelyhood of any real damage to the head or block from oil burning is very minimal. any way you stack it you're going to be spending 1800 on a jdm sir-g engine or 3000 on a rebuild. more if you do any high end parts

for a driver i'm a big fan of just dumping in jdm motors, rebuilds get expensive when done right and eat up a bunch of time

have never found any real evidence on valve seal life on hondas. i have seen 250k engines that do not burn any oil at all. the only thing i have noticed is that engines that are driven hard die much earlier. there's one pampered gsr i know of going on 300k. most blow up around 150k. how they are operated is the big variable

 

i agree with the abuse to longetivity aspect. my wifes da is 260 and just now started to burn oil, but 90 percent of the b series that ive messed with have ended up with bad valve stem seals at around 100k. hell, 2 of them i replaced with honda oem valve stem seals and they went bad again at 200k. the work is going to have to be done. obviously, the motor is burning oil. my point is why wait until it buys you into other work, if you can fix the problems now. ill also agree that a b series buring oil can last another 100k. i know it will. seems like we are on the same field. just opposite sides.

 

Wear found within the guides is what promoted the early deterioration of your valve seals.
Valve seals can and will have a much longer lifespan then 100k givin they are installed on a head that specs out.

Should of at least had them measured and knurled if needed before replacing the seals

 

well thank you guys for the massive amount of information. like I said, this thing runs completely healthy as long as i don't rev it past 6k. so i don't think it's going to do any harm to daily this thing around for a while and then rebuild it all at once. I agree about the not "driving it until it blows up" argument, but I also see eye to eye with only pulling apart the motor once. not to mention i'm planning on building the motor for boost when I finally do pull it anyways, so no big deal. as long as I don't rev it past 6k i doubt it'll blow.

 

whatever you do just be smart about it. i drove mine burning oil like that for quite a while and when it did go, i didnt realize it at first and i was doin 120 by the time i got it off and got it home, the exhaust valve had bit it, and the parts that were left chewed up #3 cyl so bad i had to have it sleeved. Its a good excuse for the upgrade, but if it hadnt, i wouldnt have had to spend the 1400 bucks for the sleeve job, and the money for the new pistons.