TypeS

Guys, I know this is way to off topic because this question is not regarding to any S2000 but I need some help or advice.

I have a 1997 Honda Prelude with 110,000 miles in it. There are a lot of bluish dark smoke coming out from my muffler whenever I hit the gas at full throttle. I changed all valve seals and it's getting better but not good yet. Right now the smoke are a lot less but I still see the bluish smoke a little bit whenever I hit the gas pedal at full throttle. I can't think of the problem beside the piston rings are wearing out . The smokes only comes out when I hit the gas pedal at full throttle, when it's just idling there are no smokes coming out from my exhaust.

Right now I'm using a Mobil 1 15W-50 synthetic engine oil. I'm thinking about using a thicker synthetic engine oil like Castrol Syntec 20W-50 for my next oil change, would it help to reduce the smoke or the oil burning? I also saw at my local stores an STP oil additives that according to them, it'll help reducing the smoke coming out from the exhaust and the oil burning, is that true or it's just some gimmicks? Would it help also if I add the STP oil additives?

Sorry guys if I waste your time reading this questions because it has nothing to do with an S2000 and I know this is an S2000 forum. Any help or suggestion will be appreciated. Thanks a lot.

ccarnel

Why are you using 15w50 weight oil. That seems way to heavy to me. My friend has a toyota t100 in it that had 217,000 miles on it and someone (why i dont know) decided to put 50 weight oil and it felt quite sluggish. He just changed the oil to 10w30 (like the instruction manual reccomends) and the engine drives like it is brand new. While none of this is scientific I think what the engine manufacutrer recomends in the book is a pretty darn good thing to follow.
On a side note I had a Honda prelude before the s2000 and sold it at 135,000 miles more than half of which was on mobil one 5w30 just as reccomended in the instruction book. That car never burnt one drop of oil (at least measurable by the dipstick)

TypeS

So you think I should change the engine oil back to 5W-30? You think it'll help?

ccarnel

I can't promise you anything but I would at least try it. Of course I have no idea the condition your car is in (or the engine for that matter) so it may continue to smoke or smoke even worse. You may have something like severe ring wear.
Also I don't know if the 97 and newer preludes use 5w30, Mine was a 93 si with the 2.3 liter engine so yours might use a different weight. Just look it up in the ol manual

TypeS

Well, according to the manual, I have to use the Honda 5W-30 engine oil. I will give that a try and see what happen. I have the car ever since brand new. Usually I use Mobil 1 5W-30 synthetic engine oil until the car reach about 70,000 miles then I switch to a thicker oil. I don't think the piston ring wear is severe yet on my car because if it is then the car would have a lot of smoke even if it's just idling.

Thanks for the advice though, I really appreciate it.

ccarnel

No problem. Just a postulate though. I dont know how it works but a more viscous oil on startup will starve the engine for oil for a longer period of time than a less viscous oil.. Perhaps some more ring wear occured here. Anyways eager to hear your results. Post back how it turned out.

SECRET AP1

[QUOTE]Originally posted by TypeS
[B]Well, according to the manual, I have to use the Honda 5W-30 engine oil. I will give that a try and see what happen. I have the car ever since brand new. Usually I use Mobil 1 5W-30 synthetic engine oil until the car reach about 70,000 miles then I switch to a thicker oil. I don't think the piston ring wear is severe yet on my car because if it is then the car would have a lot of smoke even if it's just idling.

TypeS

So you think the ring wear was cause by switching to a thicker engine oil?

Well, when I try what you suggest and I'll let you know, thanks again.

TypeS

I just replaced the cap, rotors, air filter, spark plugs, and the spark plug wires about a month ago. Would 15W-50 hurt my engine though?

ccarnel

Type S,
Its no guarantee but just check if the change in oil changes anything. If not I suggest going to a dealer and getting a leakdown test and a compression test. The leakdown I believe can spot ring wear (dont hold me to this) Basically a guage is connected to the top of one of the cylinders and the piston is brought to the top of the compression stroke thereby pressurizing the cylinder. It is then determined the time it takes for the air to leak by. ( Once again I could be wrong about this but it seems that excessive ring wear could be detected by using this method).