Hi. This is my car.
1994 civic hatchback
B18c sir-g
98+ spec integra transmission 4.7 final drive
Fully gutted 2040 lbs
1320 rmf megaphone header
2.5" yonaka exhaust
Stage 3 clutch/6 puck disc/9 lb flywheel
Front suspension bushings polyurethane
New clutch master cyl.
Aem cai cut short because of hole in piping
Spectre air filter
Stock gsr intake manifold

So under full throttle at high rpms I am able to notice smoke from the exhaust in my rear view. I ran the car for a mechanic and he suspects over-fueling and bad piston rings and valve stem seals/guides. He thinks the rings are still compressing but vertically they are moving up and down within the slot. He gave suggestions and advice and this looks to be quite expensive: basically pull the engine and rebuild it. Also he suggested I try rislone and put it in with the oil. I've never ran it on a dyno and the 1/4 mile time is unknown to me also. So i cant really set a power goal. So I guess I'm asking how to approach this. I plan on keeping this civic for several more years. I already have a skunk2 intake manifold and hondata s300 just not installed. My budget is decent I guess. I can spend around $1000 right now.

 

How much smoke and what color smoke?

I'm riding a 93 eg hatch with a poor mans type r with gsr head and mine smokes a little at full throttle too but it's not a big concern to me unless it's like a big cloud of smoke where I I can't see behind me.

I believe it's just excess fuel not burning all the way if it's black. Blue tint smoke then u could have valve seal, valve guide, valve seat or Pistons rings letting oil go to the combustion chamber. It actually depends if your burning a lot of oil during normal driving then you need a rebuild or address the little issue if its small. A compression test will tell you where the problem is, But at full throttle every car will burn some oil and have excess fuel. The excess fuel is better than no fuel as long it's not a lot where it's washing out your rings.

 

And also if your mechanic says it's bad Piston rings then you would be smoking throughout driving normally.

How would he know if he hasn't done a compression test.

 

Leak down test would tell you the whole story.

 

The smoke is black/light black? lol At idle if you listen closely you can hear a burble/pop every now and then. While driving the smoke is only noticeable in the rear view under full-throttle above 5000. Vtec varies between 4100-4500...depends on which gear im in sometimes. I wouldnt call it a huge cloud or anything. My opinion thinks its just overfueling. Would having the s300 installed and tuned fix this and help with the health of the engine too? Like I said, my power is unknown, however my goal is to reach the maximum power potential for this engine on 91 octane.

 

Installing would MAYBE stop ur smoking if you are running too rich, BUT if you lean it out too much at wot then you could cause a lot more problems, but I wouldn't advise to do that without a wideband installed. You need it to make sure ur not running too lean at wot or ur motor is toast. Running a lil rich won't hurt ur motor just throw a lil light black smoke. And the wideband,it'll help you see how ur fueling is too, so it's a good idea to purchase one if u tend to do it urself.

I'm running the s300v3 too and I keep my a/f ratio at 12.6-12.9 at wot, idles the 13.7-14.0/ light throttle at 14.0-14.5, mid throttle/ uphill throttle at 13.0-13.7. A little on the richer side on wot so just in case I don't run lean for some odd reason.

 

Blueish=burning oil; Blackish-dark=unburnt fuel; Whiteish=coolant

 

Do a compression test both a leak down and regular before you throw it on a dyno and red line it for tuning. What's up with such a savage clutch in a mostly stock car though????

 

Lol My friends said the same thing about my clutch. I don't know. I just wanted something strong. And the clutch pedal feels amazing. I've had it compression tested twice. Once by the previous owner before I bought it and the 2nd and most recent was about a year ago. Both compression results were impressive. I can't remember the numbers, but it impressed the shop mechanics and each cylinder was very consistent with each other. However, since ive already started this thread I think I should note that the redline varies and annoys the crap out of me. The highest I see it reach is 8250. When it does it pulls strong and feels great. Thats not the problem. However, sometimes it will limit short anywhere around 7000. I think one time ive seen it cut short as low as 6500. This has been an ongoing inconsistent issue ive had with the car for about a year. I don't know when its going to limit early and I don't know what triggers it. When it decides to cut short i dont know how to describe it any other way than, weird. It just feels wierd. I think a proper ecu tune would cure all of my engine gremlins. Its a p72. Any information someone can share?

 

Does it sound like vtec just kicks out? Or like a rev limit ( something like a two step )?

 

Definitely sounds like something weird I'd going on with the ecu/tune on it if it's chipped. I would suggest pulling the ecu/chip and getting that sorted out asap weather that means getting the s300 and a wide band in or getting a new base map chip to see what's what. Easy way to tell if you're valve stem seals are bad..which usual is the exhaust side that goes first is to pull off the header and visually inspect if there's oil and do a finger swipe with a white glove or light colored shop towel ecu...to see if it's wet from oil. Valve stem seals are a generally cheap fairly easy fix with someone experienced. Also worth a check is the spark plugs for oil...that would tell if there's some kind of blow by on the rings or the intake valve stem seals are going/gone bad. Those 2 checks can be done in less then 30 minutes with a leak down taking all of 15 more on top of that .