hondafrk

Can valve guides cause engine smoking? I have read a hundred posts about people who's engines smoke past 5 or 6 grand and all anyone has to say is "your rings are bad". I have a 92 dx w/d15b7 and it smokes past about 5 grand all the way to redline. I regularly check my spark plugs to see whether or not they are oil fouled and they look clean as a whistle. My car has been smoking for about the past year and I still have the same plugs in and they are never fouled.
I had my head off a couple of weeks ago for an unrelated problem and I noticed that the pistons and the combustion chambers were very clean looking, only a thin coating of carbon on the tops of the pistons and in the combustion chamber, just like it is supposed to be.

One thing that I did notice is that a few of the valves were open and I checked their side to side movement and they were sloppy as hell. My valve guides are very worn.

My engine smokes when revving hard past 5 grand to redline, and smokes even worse if I hold it around 5,500 or 6 grand for a while when driving. I have a tendency to believe that my valve guides are causing my smoking problem, not my rings. When you rev and engine up to a high RPM the valves have a tendency to start floating, a condition commonly know as valve overlap. It is when the intake and exhaust valves are open at the same time due to high rpm and cam lift and duration. This is when I believe the the oil is entering the engine through the valve guides and burning.

Do you guys think that I'm on the right track?
If not please let me know what you think, any help appreciated.
thanks

Mista Bone

you hit the nail on the head!

With the worn guides your valve seals cannot keep oil from seeping past the valve stems because they "wobble"...........

Usually the exhaust seals/guides go first.

hondafrk

thats what I was thinking but I just thought that id get some other opinions too.

t0p_sh0tta

what do you have to do to replace the valve guides???

JD_B18CDX

Do not confuse valve guide with Valve seal.
True that valve guides can get worn and cause the valve to "wiggle" but the valve seal is the one that prevents oil from getting sucked into the chamber.

dogpile5

you have to pull the head off the block. typically this is considered to be part of a head refresh & restore job at most machine shops. pull the head off and drop it off with them. usually they will use a valve spring compressor, pull all the valves out, check the head and make sure it is not warped, and put new valve seals in. will prob cost you around 200 assuming your head is not warped and you do the rest of the work yourself. of course you should replace the timing belt, head gasket, water pump blah blah blah blah.....


[Modified by dogpile5, 11:21 AM 8/2/2002]


[Modified by dogpile5, 11:22 AM 8/2/2002]