Adjusted my valves today

[LSMITH]

I had a little time today and figured I might as well adjust the valves on my 99. It has almost 90K miles on it now and had never been done. What I found is not what I expected and I am a bit confused.

The intake valves were loose (as in a lot of lash), two cylinders over tolerance and 4 very near the high end. The exhuast valves were all in tolerance, but were at the high end too. The spec for the adjustment is really wide for both too, a lot bigger tolerance than I have seen in the past.

In the past I have seen the lash get smaller as the valves pound up into the seats wearing the valves and the seats, on neglected engines to the point that there is no lash at all. The only other times I have seen the lash too large is a bad adjustment or serious cam/lifter wear. I am confident that the cam and lifters in my engine are in good shape as the oil analysis has been good so far. The kind of wear that would have to take place to get the lash that I had would be major. The only reason I see for the state of my valves is that Cummins builds them with a ton of lash initially to compensate for the wear on the seats and valves over 150K miles before the first scheduled adjustment. Any opinions on this?



After action report is that the truck does run better. Low end torque definately improved, boost and EGT come up faster with EGT leveling off sooner, and overall throttle response is a lot better. Smoke at WOT is less as well. The engine is a tad quieter now, I heard the rockers ticking some time ago and that is why I did the adjustment to begin with. I am glad I made the adjustments. I expect fuel economy to come up slightly as well, but time will tell on that.



Time from start to finish was just under 40 minutes, piece of cake really.



EDIT: I adjusted to the low third of tolerance on all valves, a bit tight of middle.



Any opinions comments or questions?

 

[Fireman Dave]

992, Howard.

 

[fj40charles]

Is this a hard procedure? Should I be thinking about doing it with 65K miles on my truck? This sure would be a great time to install some bigger injectors. .



Charles

 

[LSMITH]

Charles, it is really easy. I am stealing a post put up by Chad Sheets a while back, it is to the point and accurate. Hope this helps.



If you do decide to adjust them here is how to do it THE RIGHT WAY to do it.



Back all the adjustment nuts off on all rockers, then run them down with

your fingers until they touch (you will only be able to run down the rockers

with no tension on them... the ones with tension will have to wait their turn

on the next round when you rotate the engine 360 degrees. Zero the gage out

and adjust for ever how many mm or whatever measurement you want to use.



1. Put cyl #1 on TDC by using the TDC mark behind the crank case breather

on the front of the engine. You will have to remove the breather... I

believe it unscrews. You will see "TDC" stamped at 12 o'clock inside the

case and a mark on the fuel pump timing gear. Put that mark on the 12

o'clock TDC position.



2. Remove the valve cover, and mark the following INTAKE valves with a

paint marker, 1,2,4.



3. Now mark EXHAUST valves 1,3,5. with the paint marker. You should have 6

rockers marked now.



4. Adjust the INTAKE valves somewhere between . 15mm and . 38mm. , I shoot for

the middle of the road . 25mm.



5. Adjust the EXHAUST valves now between . 38mm and . 76mm. , again I shoot

for middle of the road about . 57mm.



6. Give all the rockers a good wiggle before removing the gage to make sure

all the play is out of them.



NOW ROLL THE ENGINE OVER 360 DEGREES AND ADJUST THE 6 ROCKERS NOT PAINTED

WITH A DOT.





Like I said it took me a little over 35 minutes. Tools are minimal and you might as well knock them out while you are in there for the injectors. I don't think I would pull the cover just to do the valves at 65K unless I was bored. Hope this helps, Howard.

 

[barryg41]

Do I wish to opon... NO!!!



But I am glad to see that waiting till 150k is just to long for the first valve lash check.



LSMITH, I only have 43k right now, but if you would like to fly down to sunny Lousisana.



It's really not THAT humid down here... really!! I will give you a shot on my valves.



Thanks for the Info!

 

[fj40charles]

LSMITH,



Thanks for the info... I'll have to keep this for future reference...



Charles

 

[LSMITH]

Bringing this back to the top looking for some more input, what have you guys found when checking your valves?

 

[Tom W]

I checked mine recently at 89K miles. All were right on the money, no adj. necessary.

Tom

 

[JMichelson]

Valve Setting

I read LSMITH instructions and there much better written than my Chilton book. I have three additional question if anyone can help. One is the procedure the same for a 12valve? Two, how do you know for sure that you are on TDC for number one without pulling an injector? Three if you have to pull an injector any pointers? Thanks, Jeff

 

[HTRDHLR]

Do you know the measurement in . 000? I set my lash on the race car pretty often but I use . 000 I dont know the conversion for mm?

 

[Hostetter]

the feeler gauges that i use have both sae and metric printed on them. they are sold by snap-on but im sure there are others out there

 

[LSMITH]

The inch values are:



. 157mm=. 006"

. 38mm=. 015"

. 76mm. 030"



The conversion is . 1mm=. 003936" or mm/25. 4=" or "x25. 4=mm.

. 010" and . 022" are the middle of the tolerance values for our valves.

 

[roadranger]

Question

OK, I've got a dumb one...



Do you adjust valves with the engine stone cold,

or warmed up to operating temp. ,then shut down??

 

[rubberneck]

Engine should be cold, the service manual stated water temp should be below 140, i like to do them stone cold. 0. 010 and 0. 020 is what the manual says to set lash to (for those of us like me who dont convert well from metric to thou. ) i set mine at 0. 010 intake and 0. 023 exhaust

 

[THancock]

One other question. How do you fellas rotate your engines? I figured I'd do mine, but started thinking how would I rotate 18 to 1 compression. For my cars, I just stick a socket on the crank snout and roll her around, but don't think I can do it that way with a diesel.

 

[lschultz]

Another Dumb Question

In the quote LSMITH put up---Zero the gage out and adjust for ever how many mm or whatever measurement you want to use. What gage are you talking about?One of them fancy dial indicators. I don't have nothing but feeler gages. I've adjusted valves many time on motorcycle engines,etc. but I haven't tryed the Cummins yet. But I'm sure I can do it. My sons getting close to 100000 on his 99. So why pay somebody the money to do it?

 

[KatDiesel]

at 28,800 miles.....



#1 and #2 exhaust valves were out and the #2 intake was off slightly.

 

[Mad Max]

THancock -



You need a "barring Tool" this Socket U/V joint looking tool goes on the end of a long extension and plugs into a port on the passener's side of the front of your front bellhousing cover.



If you look between turbo and block, then look down, close the pan/block juncture you'll see a black port held in with two bolts on my ETH (ETC may not have bolts?) anywho, that's the spot, ya need the tool and I have no clue what kind of effort it takes?



On the note of what temp? I'm curious why you'd want to do them completely cold? I can understand the low 140' number as hey, you're opening her up and touch'n stuff, but if you did it cold and it had sat for an extended period of time couldn't the hydralic lifters bleed down somewhat? Granted turning the motor a few times would pump them right back up w/o having to add heat to what you're working on.



MaX

 

[THancock]

I don't think they are hyd. lifters. If they were we wouldn't be needn to adjust them with lash figures. Hyd. lifters run . 000 lash.