dat521gatherer Posted May 19, 2011 Report Share Posted May 19, 2011 I finally got around to adjusting my valves on my 71 521 l16 a87 head lazorite crate engine with original pollution control and now it's noisier. Way noisier. There was a tick I wanted to get rid of and check the specs. It does drive better now at lower speeds. Intakes 1 2 3 were touching. what gives? 1 2 3 4 intake .000 .000 .000 .0045 before adjusting intake .008 .008 .008 .008 after adjusting exhaust .013 .012 .013 .012 before adjusting exhaust .010 .010 .010 .010 after adjusting Quote Link to comment
68Datsun510 Posted May 19, 2011 Report Share Posted May 19, 2011 Your valve seats are receding. My L20B was junked because of that. If it happens again on your next valve adj, you need a valve job. Crate engine you say? From where? Ebay? Quote Link to comment
68Datsun510 Posted May 19, 2011 Report Share Posted May 19, 2011 And did you adjust cold or hot? Cold = sitting overnight. Quote Link to comment
dat521gatherer Posted May 19, 2011 Author Report Share Posted May 19, 2011 I did them cold. I have loads of room for adjustment so they can sink all they want for decades to come. I just dont see why the intakes need to be so tight to not tick. The engine was replaced in 1985 and I'm going to do some figures to see how many miles are on it. I dont think its that many. It doesn't even smoke on start up. I have 2 sunk valves on my other 521 l6 w53 head with no room for adjustment left. way under specs touching on one. it doesnt tick at all. smokes on start up though. Quote Link to comment
yello620 Posted May 19, 2011 Report Share Posted May 19, 2011 I finally got around to adjusting my valves on my 71 521 l16 a87 head lazorite crate engine with original pollution control and now it's noisier. Way noisier. There was a tick I wanted to get rid of and check the specs. It does drive better now at lower speeds. Intakes 1 2 3 were touching. what gives? 1 2 3 4 intake .00 .00 .00 .045 before adjusting intake .08 .08 .08 .08 after adjusting exhaust .13 .12 .13 .12 before adjusting exhaust .10 .10 .10 .10 after adjusting You might start with the correct specs, unless you just typed it wrong. There is a huge difference between the numbers you posted and the correct specs. Sounds like you have does Datsun valves before though, so i bet you typed it wrong. Intake, Hot 0.010in. (0.25mm) Exhaust, Hot 0.012in. (0.30mm) Intake, Cold 0.008in. (0.20mm) Exhaust, Cold 0.010in. (0.25mm) Quote Link to comment
68Datsun510 Posted May 19, 2011 Report Share Posted May 19, 2011 They run tight because they dont expand with heat as much as exhaust valves do. Hence the bigger clearances for them. WHat 'feel' did you use for adjusting them? Did the gauge slide in and out with no friction? slight catch? have to force it in? LOL this souns awful, but i cant think of a better way to describe it. Quote Link to comment
dat521gatherer Posted May 19, 2011 Author Report Share Posted May 19, 2011 Yeah I missed some zeros in there. There is a slight drag on the feeler gauge. I guess I should tighten the intakes back up some. Quote Link to comment
ggzilla Posted May 19, 2011 Report Share Posted May 19, 2011 yes, that's fairly common. Just do them again, this time making sure there is a little drag on the feeler. You should just be able to slip it in. Then again if they are worn they'll be noisy anyways even when properly adjusted. Quote Link to comment
wayno Posted May 19, 2011 Report Share Posted May 19, 2011 You do know that if you drive the truck with your foot into the pedal a lot, the valves are going to sink right into the head fairly quickly, unless you have put hardened seats in the head, the brass seats(original) just don't work with unleaded gas, I drove to florida from washington and back on a fresh head, by the time I got back(about 8000 mi.), I was out of adjustment on some of the valves, that head was a W53, with big valves and it was ported to match the SU intake. Quote Link to comment
banzai510(hainz) Posted May 19, 2011 Report Share Posted May 19, 2011 68datsun 510, My L20B was junked ??? the whole motor????????just have head redone. I set my valve lash to .006 .008 cold. Maybe try 40wt from the Korean store down the street from you? earlier head the seats might sink sooner cause they are a different material . then when unleaded cam the newer heads have better seats. I just dont like swapping out valve seats unless I kow the machinist is good. YOu could pay alot of money then wham a seat seapareates cause the guys didnt dod it right. One reason I dont do 44mm intakes valves. I just dont want to risk it for a 14% bigger valve. Quote Link to comment
dat521gatherer Posted June 5, 2011 Author Report Share Posted June 5, 2011 ok I re-adjusted the valves to .006 intake and .008 exhaust and when I got to the last valve which was #3 exhaust it was loosened all the way somehow. maybe I didnt tighten it last time but the the ball stud had turned several rotations all the way down giving me something like .045 clearence on the lash. :blink: no more ticking :D Quote Link to comment
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