valve adjustment on 720 SD22

docdillio · #1

just recently put in a new head gasket, etc. Truck starting and running well, but valves (or lifters?) seem to be making more noise than i think they should. I'm fairly new with diesels, so maybe this is normal. I did adjust the valves as per the manual, but in idle, they seem to "rattle" more than seems normal. and when i'm driving and initially step on the gas, it rattles. or when i'm going uphill, it rattles. i know it's a diesel, but now i'm wondering if i didn't actually have piston 1 and 4 at tdc when i made the adjustments. or maybe my lifters are shot? or have i missed some timing adjustment I'm not familiar with? any thoughts or advice?

#2

They do ( diesels) rattle and cackle etc more than a gasser and these older ones are more noisy than a lot of the newer ones. A procedure to set valves that was shown to me YEARS ago was to take the firing order of any engine. In this case yours is 1-3-4-2. On a piece of paper ( more needed for V8's to keep the numbers straight) write the first half of the firing order on one line ( In this case 1 and 3 ) and under that write the second half of the firing order ( 4 and 2). As you bar the engine over, in proper rotation, watch the rocker arms. When the exhaust valve closes on, lets say #1, and the intake valve is just starting to open, at the point when they change, or "Rock", then the valve clearance of the cylinder "opposite" to it in the firing order can be set. The lifters for that cylinder are on the bottoms of the cam ramps and that cylinder is at TDC. In this case you would set the valves for #4. So, "Rock" #1 set #4, "Rock # 3 set #2, "Rock #4 set #1 and "Rock" #2 set #3. I know that there is a procedure for setting valves in the FSM that will allow you to do all 8 valves with only rolling the engine once, but this system is pretty much fool proof, it just takes a bit more rolling the engine, although just a little at a time. You also do not have to keep referring to the manual to see what valves you can set. It's one cylinder at a time and not intake on some and exhaust on others. . I still revert back to this after 40+ years. Old dog, new tricks and all that I guess

The lifters on your engine are "Solid Lifers" or "Followers" or whatever you want to call them. They are not like a "hydraulic" lifer that is present in most gas engines and, by themselves, are inherently noisier to begin with.

HTH

Paul

docdillio · #3

Thanks Pauly! I'll give that a try. Can I do this adjustment cold? Or should I get the engine up to normal operating temperature first?

#4

You can do this adjustment cold, but usually only to get the engine running after it has been taken apart.

This method is just another way to figure out which valves to adjust for a given engine position. The clearance is always the same no matter the method used to determine which gets adjusted. The factory specs say warm engine.

Paul is right on the solid lifter noise issue. I have always liked the noise when they are all in spec. The lifters have a very even, steady, sewing machine-like noise when they are all at the correct spec. on many engines. Ditto on the diesel combustion clack.

#5

Byron is correct, and seeing as how the engine runs already, take it for a drive and then bring it home and do the adjustment hot. Another trick we used ( back in the day ) was to get two feeler gauges. In your case you need the .014 for the correct clearance. Also get a .016 feeler as well. Set the valve with the 014 and tighten the lock nut. Then re check it again and if the .014 goes and the .016 does not you are done ! Nissan in fact, back in the 70's, used to send in the tool kits for their engines a "Go NoGo" guage that was just that.

They did that for the consumer that wanted to do their own service etc. Edit! I was referring to the industrial and marine versions of Nissan.

#6

You guys are right on about those adjustments. I too like rolling each cylinder to TDC for adjustment. Nothing old dog/new tricks about that! It simply is fool proof.... And an engine that is set perfectly even on clearances seems to sun smoother and sounds great.

N_R

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