Radiant-Designer Posted September 30, 2011 Report Share Posted September 30, 2011 So i may change the head gasket on my L20b soon (77 620) to see if it was the cause of the smoking from exhaust (posted some info under magicly disappearing coolant). so i may take 2 days off next week and change the thermostat housing, water outlet and figure while I am at it why not, change the head gasket too. Should i do anything else while I am in it? I am used to timing belts so I dont know if the Timing chains should be replaced nearly as often. I was going to check all the valve adjustments and so on and replace the valve gasket too. Is there a good write up for how to replace the head gasket? I have searched a bit and saw that you have to wedge the timing chain but cant seem to find too much info or maybe a pic heavy post to help out. 1 Quote Link to comment
Laecaon Posted September 30, 2011 Report Share Posted September 30, 2011 Get some fuel pump gaskets. Helps to take the fuel pump off to get the cam gear off. Basically, unbolt intake/exhaust (you will need a new gasket for that). Take valve cover off. Remove fuel pump. Set motor to TDC. Loosen cam gear. Wedge chain, Very important! make sure it is wedged good enough, also make sure you can remove it later. Remove cam gear with chain. Untorque head evenly. Remove head. (note there are 4 bolts in the chain area that bolt to the front cover. Make sure to remove those!!!) Change head gasket. Reassemble. Make sure to clean surfaces for new gaskets. Quote Link to comment
Eagle_Adam Posted September 30, 2011 Report Share Posted September 30, 2011 go to tube and watch all of these - datsun L Series head replacement part 1- 6 Banzai did them and they helped me when i change my head gasket. 2 Quote Link to comment
bananahamuck Posted September 30, 2011 Report Share Posted September 30, 2011 go to tube and watch all of these - datsun L Series head replacement part 1- 6 Banzai did them and they helped me when i change my head gasket. Adam the Eagle is exactly right .... I thought i seen that original video has been re-posted in whole form again..but Utube one would lend itself to going back just far enough to where you are " at the moment " I sure wish i had this type of reference.. 25 years ago Maybe it wouldn`t have taken me forever to figure out oil pump / distributor shenanigans. Quote Link to comment
Laecaon Posted September 30, 2011 Report Share Posted September 30, 2011 I thought i seen that original video has been re-posted in whole form again.. you did... Quote Link to comment
610racecar Posted September 30, 2011 Report Share Posted September 30, 2011 you did... A must watch before doing ANYTHING on a head gasket replacement job. Saves a ton of headaches. Marc in Indy Quote Link to comment
izzo Posted September 30, 2011 Report Share Posted September 30, 2011 I uploaded that to youtube, the whole thing. It told me to piss off lol, video to large. So i broke it up, and sent it in chunks. then they email me saying i can upload it if i want to. Dicks. Quote Link to comment
banzai510(hainz) Posted October 1, 2011 Report Share Posted October 1, 2011 I had bought 10 timming chain wedges from CSK auto @ 5$ apc(gave them all away). cant find the link anymore but was thru now O Rielys. its somewhat soft and you need to Jam hard down into the tensioner. HARD at TDC and then dont move crank. try to find it makes it EZER some what. Can be frustrating. take your time getting the chain back up. u might have to rotate the cam in the direction you need the slack i think amazon might have it also Remember it looks EZ on the vid but remember I have ez access to the bolts as its a early style exhause manifold and intake set up. L20s started getting pack with emission gear later on. One might need U joint type socket extensions to get the lower intake bolts. ps ck if you have a water headed manifold the intake gasket might be worn or bad and its sucking up water from there. or loose intake manifold bolts. Quote Link to comment
flatcat19 Posted October 1, 2011 Report Share Posted October 1, 2011 Someone said unbolt exhaust and intake... If you just unbolt exhaust from down pipe, you can take the head and manifolds out in one shot. Heavy-but less work. Have you thought about replacing the valve seals? While the head is out, makes a somewhat tedious job easier. When doing it, if you do, don't have head flat on bench. Elevate it somehow. Don't want to bend a valve. Quote Link to comment
datsunpolisher Posted October 2, 2011 Report Share Posted October 2, 2011 So i may change the head gasket on my L20b soon (77 620) to see if it was the cause of the smoking from exhaust (posted some info under magicly disappearing coolant). so i may take 2 days off next week and change the thermostat housing, water outlet and figure while I am at it why not, change the head gasket too. Should i do anything else while I am in it? I am used to timing belts so I dont know if the Timing chains should be replaced nearly as often. I was going to check all the valve adjustments and so on and replace the valve gasket too. Is there a good write up for how to replace the head gasket? I have searched a bit and saw that you have to wedge the timing chain but cant seem to find too much info or maybe a pic heavy post to help out. Quote Link to comment
datsunpolisher Posted October 2, 2011 Report Share Posted October 2, 2011 I'm having the same prob with loosing coolant. If you can do a compression test and leakdown test and a coolant pressure test first before you take apart your engine cause this will tell you if you have a bad head gasket. I found out my heater core was leaking and draining out thru the drain hole in the heater system fixed heater core now I don't have coolant problems anymore. Quote Link to comment
zed Posted October 3, 2011 Report Share Posted October 3, 2011 I would consider putting in new valves, depending on condition of the old ones. Definitely new valve stem seals. Valve cover gaskets seem to last a long time - I never needed to replace one Quote Link to comment
datzenmike Posted October 3, 2011 Report Share Posted October 3, 2011 I'd remove head with manifolds and carb on it. Don't tilt it upside down to keep any sediment in the bowl. Be sure to find and keep the two locating dowels in the block. You can still use an angle grinder or a drill with a wire wheel to clean the head surface. Do the block too but place rags in the middle two cylinders to catch the crap. The head is soft aluminum so go easy. BTW you can't over do the cleaning, get as shiny as possible. Use an old head bolt with a vertical groove ground down two sides to twist into the block bolt holes to clean them. Rub a little grease in the grooves to catch and hold the crap. You could do the valve seals now but I think it's easier to do on the motor. Use a straight edge to check for pockts or warping, a good idea on any head that has blown a gasket. Head bolts are totally re-usible, just check for damage. Do NOT use any kind of gasket dressing. Assemble dry. Quote Link to comment
izzo Posted October 3, 2011 Report Share Posted October 3, 2011 I have not had any luck with that damn 5 dollar timing chain wedge. Every single time the fucking chain tensioner comes out. I took a wooden handle and hammered that wedge down in place. Still popped out. http://www.amazon.com/Alltrade-648831-Nissan-Timing-Holding/dp/B0002Q8TV4 Quote Link to comment
banzai510(hainz) Posted October 3, 2011 Report Share Posted October 3, 2011 http://www.amazon.com/Alltrade-648831-Nissan-Timing-Holding/dp/B0002Q8TV4 yes thats the one I used it twice already key is JAM it down hard so you can see it drop down past the tensioer Quote Link to comment
oldschool90 Posted October 3, 2011 Report Share Posted October 3, 2011 "Before removing the camshaft sprocket, cut a piece of wood 10 inches long, 3/4 inch thick,1-1/2 inches wide at the top and approximately 1-inch wide at the bottom. "Now remove the camshaft sprocket bolt and fuel pump drive cam, if equipped. A rod can be positioned through the camshaft to keep it from turning while the bolt is loosened. "Insert the piece of wood into the timing case (small end down) until it's wedged between the two runs of chain. Be sure it's wedged securely in place. The timing chain must not be allowed to separate from the crankshaft sprocket, as it would be necessitate removal of the front cover in order to reinstall the timing chain. "Carefully remove the camshaft sprocket from the camshaft and work the chain off it until the sprocket can be removed. The chain can be left resting on the piece of wood." Taken from Haynes repair manual Quote Link to comment
pondking Posted November 11, 2013 Report Share Posted November 11, 2013 how can I get an original file of these videos? I dont have internet at home but I would like these as references while in the garage banzai wont receive messages Quote Link to comment
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