My ole mav smokes pretty bad just at the first crankup, but when it gets to idling, or road driving no smoke and smooth running...Any tips/ideas?
clean out the oil returns and replace the valve seals ...when it sets the oil leaks past the seals and sets on the pistons just waiting for you to start it up
Totally agree, valve guide seals are the place to start looking. Pull your valve covers and take a look. There will be bits and pieces of the old seals everywhere. Don't be surprised to find many of them gone or almost gone. This is quite common.
I agree that it is your seals. They are not too hard to change if you have some tools. Pop off the valve springs, drop new seals in, put the springs back. Oversimplified, but you get the idea. Otherwise, if your engine checks good compression, you could pull the heads and have them worked. Generally speaking though, the problem you describe is not really hurting the big picture if you just want to overlook it until you do a more thurough rebuild. Good luck Dave
guides If you have a high mileage motor, there is a chance the valve guides are shot. This will allow a ceartain amount of oil to seep down even if the seals are good. However, replacing the seals is going to be your best bet for starters. Good luck, we dont need any chevy boys laughing at you.
Question: How do you remove valve springs with the heads on the car? Is there a special tool? What holds the valves up when you do it?
valves I believe there is a fitting to presurize the cylinders via the sparkplug hole. I've never used one, but you may want to look into it.
That is correct - there is an air fitting with spark plug threads that allows you to hook an air hose to the cylinder and apply GENTLE pressure that will hold up the valves and keep them from falling into the bore. It is also very useful in locating the cause of low compression. If you have a cylinder or two with bad compression, when you hook up an air line to it you can hear and see where the air is escaping the most. Remove the air cleaner, oil fill cap on the valve cover, radiator cap. Also, if you can easily drop the exhaust at the header collectors or mufflers. Set the cylinder you are checking half way up the compression stroke and lock the flywheel so the crank can't turn under the air pressure. Now hook up an air hose and listen where the air escaping is coming from the most. Out the carb or exhaust would indicate a valve. Out the valve cover would be past the rings. And bubbles and air out the radiator would indicate a head gasket. Really a nice and simple tool for a serious do-it yourselfer to have. We used to use these in the shop all the time "back in the old days". Eric
You can also remove the spark plug and feed rope into the cylinder, as much as possible. Then run the piston up. Works great for those that dont have a compressor.
Yeah, I have done cylinder leakdown tests before, but not many have a decent size air compressor at home. Some of the posts above make it sound painfully easy. I have used the rope trick too, with some success. Is the a valve spring compressor that works with the head still on? There isn't a lot of room to work with there.
I should have said that a real good air supply is required. I guess I just take for granted a lot of times that a shop air compressor is the norm As for the heads on spring tool, it is an extreamly simple little "lever" type pry bar. $8 at Northern Tool. Just hook it into the rocker stud, pry down the spring and remove the keepers. Here is the link: http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=4006970&storeId=6970&langId=-1&productId=200002095&cm_ven=TL&cm_pla=DF&cm_ite=auto Eric
Here is the air hose / spark plug attachment - $10 at Northern Tool http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=4006970&storeId=6970&productId=200002096&langId=-1&search=909399 and a screw type spring compressor - $13 at Northern Tool http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=4006970&storeId=6970&productId=200002094&langId=-1&search=909397
