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Discussion Starter #1
ok..on an intek ...the piston comes up on each cylinder 2 times... 1 time is the compression stroke....the next is the exhaust and intake stroke...right??..it looks to me that on exhaust / intake stroke......the piston pushes out the exhaust....and as the piston reaches the top of the cylinder the exhaust valve closes and the intake valve immediately opens to suck in the gas...(my valves are tighter on this stroke..no clearance at all.... is that normal?) ...the next stroke is the compression stroke...on this stroke the valves seem to be both closed for a long time..,so I put the piston at its highest point in the cylinder...and set the clearance to .005 on both intake and exhaust valves...did I use the proper procedure for setting the valves???..did I find TDC properly just by finding the highest point of the piston??...my problem is this...I Have a little backfiring at idle....very minor...and some smoke....at high throttle..can improperly adjusted valves cause smoke??
 

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You found TDC okay, it occurs when both valves are closed. Some engines (Briggs, for one) want you to continue turning the crank until the piston goes down ¼", other engines may differ. Then you adjust the valves for that cylinder. When the cam is opening or closing a given valve, there will be 0 clearance for that valve, since the cam is pushing against the valve stem.
If you are sure the clearance is .005" on both, and have set both valves properly, that's it.
I don't think improperly adjusted valves will cause an engine to smoke. Your popping at idle, and smoke at higher revs may indicate some carb cleaning/adjusting is in order.

What color smoke?

There are 2 TDC's, but only one where both valves are closed. You found the right one.
 

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Discussion Starter #3
thanks for the information!!...so I see the one mistake I made is maybe I didn't go 1/4 inch down ...before setting the clearance...would that would make a difference???...the smoke is light colored...sort of gray...maybe a slight bluish tint
 

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You're welcome!

You need to find the instructions for your particular engine. Some guys turn the crank until a valve is wide open, then turn the crank one complete revolution. This turns the cam ½ turn, so the lifter is on the base circle of the cam while the clearance is adjusted. Repeat for the other valve. Repeat for the other cylinder.

I'd try to find the correct instructions, though. I think you are close enough now, anyway. The ¼" is to make sure they're off the compression release in the cam. I don't know what Intek wants you to do.

That sounds to me like oil smoke. Is the breather clear and working properly? Pressure buildup in the crankcase will cause oil burning, and other bad things.
 

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Discussion Starter #5
Interesting about what you said about the crankcase pressure....I just noticed I have a major oil leak between the two engine halves...so I am wondering...if its pushing oil out between the two halves...maybe its also sucking some air between the halves...and not lowering the crankcase pressure as much as it should...and pushing some oil out the cylinders???...make any sense???...well..just guessing...
 

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There is always some blowby past the rings, even in a new engine, and that causes pressure buildup in the crankcase. The breather lets the pressure out, while keeping the oil and oil mist in. Your oil leak could be a bad gasket, or excessive crankcase pressure, or even something else. Check your breather, not difficult to do. Some engines have a one-way valve in the breather. If it's installed wrong, or stuck, or clogged, you get pressure buildup.

I doubt any air is getting sucked into the crankcase, more like pressure from blowby every engine has. Worn rings, of course, let more combustion pressure leak into the crankcase. The smoke coming out could be - not oil smoke per se - but combustion gasses, and the oil mist they push out the breather with them because they overwhelmed the breather's ability to separate oil mist and gasses.

Time for a breather/vent check.

I remember seeing old cars going down the road (before PCV systems) blowing a steady stream of smoke out of the road draft breather tubes. It sure sucked being behind them going up a hill! Roads would have an oil slick down the middle in heavy traffic areas, especially on the upgrades. That was really dangerous when it rained - a wet oil slick is reeaally slippery!. Things sure have changed!
 

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To get the proper advice, instructions, you need to post the model number of the engine. I probably have the correct instructions and a PDF of the Service Manual IF I knew what the model number was.

Walt Conner
wconner5 at frontier dot com
 
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