1985xjlaredo
NAXJA Forum User
- Location
- Kansas City
I fixed my blow by problem on my old 88 about 3 years ago now. I cant find the write up I did with pics and all that good stuff so here is the short of it.
I was getting at least a quart of blow by every Hundred Miles. If you have ever removed the stock valve cover on a renix then you can easily see why there is such an issue.
The dummy who designed this cover put an aluminum tube that goes down to the oil valley in the top of the head. So you have these tubes which are very very close to the top of the head... If you have any kinda gunk built up in the oil returns (and YOU DO) then these tubes are down in the pooling oil. Now with these tubes having vacuum lines on top of the valve cover to suck out any built up pressure, they instead suck up the pooling oil. So here is how you fix the blow by problem for good!
1.Run Seafoam in oil for an hour at idle.
2.Pull valve cover
3.Pull oil drain plug
4.Get some good parts cleaner and a few different brushes a can of carb cleaner helps a lot too
5.Clean the top of the head and the oil returns
6.Pour another can of Seafoam on top of the head
7.At least take the aluminum tubes off of the old valve cover and clean it very good! I put the Crown valve cover on and started with a nice new red one. It has Baffles in it over the ports for the vacuum tubes. Make sure you don't use the screws that come with it. Tap out the holes with a 10-32 machine screw tap and install new screws. It comes with small wood screws holing the baffles on.
8.Reinstall the valve cover and use a valve cover breather instead of the small orifice and hard tube on the back and on the front. The old grommets will not fit the new crown cover. Use Mr. Gasket # 2057 breathers, only ones i could find that fit. You will also need to get new grommets in the HELP section of a parts store. New Head doesn't come with them.
9.Cap the vacuum lines
10.Put fresh oil and filter in it, let it idle for about an hour again
11.Change oil again to get any of the crap from the head out of the engine
12.Enjoy not having any oil in your air box, or running out of breathers. I GUARANTEE that you will not have the Vacuum Sucking Oil into the Air Box , i.e. Blow By problem any more.
I was getting at least a quart of blow by every Hundred Miles. If you have ever removed the stock valve cover on a renix then you can easily see why there is such an issue.
The dummy who designed this cover put an aluminum tube that goes down to the oil valley in the top of the head. So you have these tubes which are very very close to the top of the head... If you have any kinda gunk built up in the oil returns (and YOU DO) then these tubes are down in the pooling oil. Now with these tubes having vacuum lines on top of the valve cover to suck out any built up pressure, they instead suck up the pooling oil. So here is how you fix the blow by problem for good!
1.Run Seafoam in oil for an hour at idle.
2.Pull valve cover
3.Pull oil drain plug
4.Get some good parts cleaner and a few different brushes a can of carb cleaner helps a lot too
5.Clean the top of the head and the oil returns
6.Pour another can of Seafoam on top of the head
7.At least take the aluminum tubes off of the old valve cover and clean it very good! I put the Crown valve cover on and started with a nice new red one. It has Baffles in it over the ports for the vacuum tubes. Make sure you don't use the screws that come with it. Tap out the holes with a 10-32 machine screw tap and install new screws. It comes with small wood screws holing the baffles on.
8.Reinstall the valve cover and use a valve cover breather instead of the small orifice and hard tube on the back and on the front. The old grommets will not fit the new crown cover. Use Mr. Gasket # 2057 breathers, only ones i could find that fit. You will also need to get new grommets in the HELP section of a parts store. New Head doesn't come with them.
9.Cap the vacuum lines
10.Put fresh oil and filter in it, let it idle for about an hour again
11.Change oil again to get any of the crap from the head out of the engine
12.Enjoy not having any oil in your air box, or running out of breathers. I GUARANTEE that you will not have the Vacuum Sucking Oil into the Air Box , i.e. Blow By problem any more.
