Engine/Transmission (1994 - 1998) More valve lash questions...?

[SRath]

I picked up a barring tool from the local Cummins dealer today along with a front crank seal kit and a timing cover gasket (forgot to get a new belt). Gonna take care of some long overdue KDP business, oil leaks, and valve adjustment...



I have downloaded the valve adjust pages from Geno's, and it all seems very straightforward and simple, especially when compared to doing it with shims on our 4-stroke dirtbikes.



However, I am left wondering why the instructions for every version and technique they list, only talk about turning the engine over backwards to do the job, if they mention which way to turn the motor at all? Is there some reason you can't or shouldn't turn the motor the right way to adjust the valves? Or am I misreading because they jump straight from talking about using a barring tool directly to telling you how to do it with the alternator nut?



Also, and this is probably an even dumber question, will disconnecting my fuel shutoff solenoid relay ensure that the motor doesn't try to start while I'm turning it? Could that even happen? It starts mighty doggone easy and it doesn't need any spark... only a lack of fuel kills it.



Incidently, since really washing the motor clean yesterday and looking things over very carefully, I notice the timing cover has grey silicone sealer on it. It makes me wonder if the previous owner, who had the truck less than two years back in '96 and '97, might have already had the KDP done. . ? He was not mechanically inclined, and didn't mention anything about it, but he spent lots of bucks at his Cummins and/or dodge dealer to have any and every little thing fixed... Guess I'll find out soon enough.

 

[Bob4x4]

Key off,there will be no fuel pressure to ignite. Don't bother with the barring tool,it is too slow.

Many years did not use a gskt on the cover,only sealer



Bob

 

[Don Tanklage]

maybe it only talks about turning the motor over backwards cuz when you do it with a big wrench on the fan pully it will slip when trying to go the dir of rotation and grab only when going opposite of rotation?



dunno, never looked at the book



kinda glad as i hear it tells you to adj 6 valves with the crank in one position...



spinning it backwards int opens adj ex; ex closes adj int - for ea cyl



don

 

[CumminsPower98]

The gray silicone is from the factory. They used it on both sides of the gasket. As stated, it doesn't matter which way you turn the engine. The only time I use my barring tool is for timing adjustments or to hold the engine while removing/installing the balancer and clutch.



There is no danger of you starting that thing even if the fuel solenoid was engaged. If you did I would have to meet you!

 

[Vaughn MacKenzie]

It says to turn the motor backwards because it's the easiest way to quickly turn the motor to the position you want it by using a socket on the alternator. You cannot turn the engine forward this way because it slips on the belt.

The barring tool is for holding the engine and making very small engine position adjustments. It would be monumentally slow for turning the engine any distance. Exact engine position is not that critical for valve adjustments, but it is for timing the engine.

Vaughn

 

[Don Tanklage]

Exact engine position is not that critical for valve adjustments...



Vaughn

it is if you want them all to have the same clearance



vlv clr affects duration

 

[JFaughn]

it is if you want them all to have the same clearance

vlv clr affects duration

I think he is making the point that there is almost a 180* before the cam lobe reaches a lifter , so lots of room for adjustment .

 

[Don Tanklage]

I think he is making the point that there is almost a 180* before the cam lobe reaches a lifter , so lots of room for adjustment

if you want every tappet on the heel of the cam (ooposite the lobe) you have to use more than 2 positions



cam lift can inc slightly as the lifter approaches the lobe

 

[Joe G.]

That's true. However I expect that the clearance ramp is not that long on these engines because they are a low RPM design. I'm sure that the manual instructions are ok as far as the clearance ramp is concerned.

 

[Vaughn MacKenzie]

Yep . . . you can have the crank a few degrees off from TDC and be OK for the cylinders you are adjusting at that time.

 

[Don Tanklage]

hell, you can probably be 90° off and be OK



however, when working on an engine i try to do things with as much precision as possible



if OK is good enough for you than keep on man...



good luck with your trucks and make it a great day!

 

[Joe G.]

I really don't think where it is on the cam as long as it is not on the lobe or clearance ramp is more precise than any other. I use a dial indicator and adjust the valve clearance right on the mark. As far as I can tell that is as precise as you can get with ordinary hand tools.

 

[biggy238]

And here I was just happy to have the pushrods spinning and the rockers move freely.



IT's a freaking tractor motor. Most of them never ever have the valves adjusted and run a long- long time.





I use the barring tool... I paid for it..... might as well use it.

 

[Vaughn MacKenzie]

Now I do get fairly precise matching clearance between valves, getting them within . 001" of each other. The Cummins spec range is so huge it's almost absurd. I adjust . 008" intake and . 018 exhaust.

 

[Joe G.]

The manual says . 010" and . 020" so that's exactly where mine are set with a dial indicator. A feeler gage may not get them just right if the wear is not flat. I have a dial indicator with a small head so it fits under the cowling for cylindes 5 & 6.

 

[Bill Lins]

I need to set mine & replace the leaking rocker cover gaskets. Which gaskets are the better ones- grey or black? Anybody have the part #'s?