SR20 Forum - View Single Post

ashtonsnissannx · 04-17-2008, 11:01 PM

Here i will do you a favor, i might do a How to right up on the next one i do. which might be this weekend. But here it is in general

jack the car up....a given
start by draining the oil.
Then remove the crossmember by loosening the rear mount bolt, disconnecting the front dogbone mount and then removing the 4 mounting bolts two at the front and two at the rear, to make this the easiest use a jack under the tranny to help get the bolts out nice and easy, you can do it without but easier with. Then you will need to remove the exhaust from the cat to the secondary or the whole exhaust manifold. I dont think this is possible to do with it in there and its easiest to get it out of the way. I dont have an exhaust on my car or my friends car that i just worked on so the work went by alot faster. haha
Remove the lower oil pan bolts.

Carefully pry the lower oil pan off using a flat tip screwdriver and you want to try and do it in a line with the direction the flat sealing surface of the pan goes to keep from bending the lip too much. Another not is check and make sure your lower pan isnt dented up in the middle. I like to make the middle of my pan especially where the pickup tube is sit a little lower than the edges of the pan to ensure proper oil pickup. Doesnt take alot to block that pickup tube and might be the cause of the spun bearing if it is dented up.

Remove the baffle that is attatched to the upper pan that goes around the pickup tube area. 10mm bolts.

Remove all upper oil pan bolts. all 12mm exept the 2 small 10mm nuts behind the dust cover on the upper pan where it meets the tranny. behind that are two nuts that need to be removed that are attatched to the rear main seal housing. If you dont remove these and try to remove the pan you will most likely break the housing and your in for more work than what you started. Make sure and double check you have all the bolts out. there are about 6 total bolts that are behind that baffle you just removed on the inside of the motor. If the pan doesnt come off fairly easy you probably missed one. The pry point is at the front most corner near the tranny on the block, you will see the indentation where a flat tip can easily lodge under the upper pan.

Next take off the smaller baffle that sits between the main cap girdle. 5 10mm bolts.

Turn the crank over with a ratchet until the counter weight closest to the crank pulley is down meaning the number 1 piston is at TDC Look up in the space between that front corner of the motor and the main girdle to find the numbers for the rod bearing grade size. This is the set of numbers on the top if looking up into the motor. you will see two sets a set of 4 numbers on top and a set of 5 numbers on bottom. They read off in the piston order and are upside down so they read from right to left if looking up into the motor. They are on the counterweight itself you might have to turn the motor over slightly foward or back to see them, best spotted if using a good bright flashlight.

For example the numbers on the nx i did today were 0111. I was doing rod number 2 so the number needed was 1. Now you need the number off the rod which is more than likely a 0. This is located on the rod itself on the side of the rod that faces the front of the block. Its samped on the upper bearing portion of the rod. My rod was of course a 0 just like all the other ones ive seen. So the bearing grade i needed was a 1.

Next you can start on the bearings. This applies to all if your doing them all. Turn the crank over with a ratchet until the rod you want to do the work on is at the bottom and you can get to both 14mm rod cap nuts. Remove the cap nuts then take something with a softer tip that can reach up where the piston is and tap upwards on the piston to dislodge the bottom cap. Move the rod up so the rod bolts clear the journal, try carefully not to let the rod bolts hit the journal because it could scratch the surface.

Remove the old bearings which are most likely just laying on the rod journal and not even attatched into the rod or cap anymore due to being worn and spun.

Clean the surface of the bottom cap and top bearing seat on the rod really good to get any dirt or oil off them. Then clean the rod journal on the crank really good to get any dirt off. You dont want it scratching up your new bearings. The rod journal is very very smooth from the factory, depending on the sevarity of the knock there will probably be some slight marks/scratches into the journal. As long as these are not really deep and the journal is still pretty smooth you should be fine for a long while after the bearing replacement. When i took this bearing off today the bearing did not spin back into its normal place like it usually does. So the oil holes on the bearing were not lining up with the crank no longer causing basicly little to no oil in there. Even then the journal was only slightly marked. No big deal. Just make sure and get it nice and clean. Then you can lube it up with fresh gear oil like i used or assembly lube.

Then install the top bearing onto the rod. I found this easier to place the bearing on top of the journal and bring the rod down on top and then position it tightly onto the rod. Make sure the notch on the bearing is in the notch on the rod and that the edge of the bearings are flush with the cap mating surface. The notches go on the same side of the rod. If you somehow forgot the direction that you pulled the bottom cap off the easiest way to tell is the notches or the position number of the rod is marked on the bottom of the cap. The blank side faces toward the front of the block. The side with the position number faces the rear of the block.

Make sure to lube the bearings good with either assembly lube or what i used is some of my clean mobile 1 synthetic gear oil 75-90. its thick and works great for first startup.

Then install the bottom cap making sure again that its in the same position as taken off. notches on the same side or numbers in the right position. Then snug the nuts down hand tight. Then take your torque wrench and torque the nuts to 11ft lbs or so. Then tighten them to 31 ft/lbs +-2.

Next turn the motor over by hand at least one complete revolution to make sure the motor turns freely. If so then move onto the next or reasemble everything in reverse order removed when work you want done is completed.

A tip on the silicone. Make sure you clean all sealing surfaces good with brake cleaner works well. Then apply a good bead around and around the bolt holes. Let the silicone sit and tack up for about 10-15 minutes, then put the pans up and tighten the bolts hand tight with a ratchet.

A tip: dont forget to reinstall both baffles. Sometimes you can forget. It happens. After the pans are up there. Allow at least at a minimum 1 hour of cure time for the silocone. I used the Ultra black which is best oil resistant. It takes me a little over 1 tube most of the time. ive cut it to only 1 on occation when doing both the upper and lower pan but it pushes every last drop out of it if you do a perfect bead, but most of the time that never happens. Haha.

Take your time again and do it right. It might take you probably 5-6 hours to complete but well worth it.