Hey all,

I am replacing my valve springs and just did a check by feel of guide tolerances. I am not sure what is considered "normal". I move the valve stem back and forth parallel to the rocker arm and there is very slight play of maybe a few thousands. I move the stem perpendicular to the rocker arm and less than a thousands movement occurs.

What is normal?

Thanks,
Ben

 

The clearance spec may differ for different year engines, but my FSM shows .001"-.0027" as the guide clearance.

To measure what clearance you have, you need to install a dial indicator on the valve stem with the valve open a certain amount ((I'd have to look up how much to be accurate on that - Found it: about 1/16").

Jake

 

That's probably a bit loose but it's hard to tell by feel. A good machine shop will have the ability to measue the guides. Special tools are needed. A really experienced enigne builder could tell something by feel, but it should be measured properly. The method suggested by "JAKEJR" is not useful, IMO.

How many miles on the motor, and was it using oil (the primary symptom of excessive guide wear, though it has many other causes)?

Rich

 

Not only is it USEFUL, it's the recommended way. GEEZZ, I don't make up this stuff.

Jake

 

I guess they do it differently in Texas.

Rich

 

Sometimes what you read in a book isn't the right answer.

 

One tool for the job:
http://ep.yimg.com/ca/I/yhst-5808251..._2089_22055436

Another:
http://ep.yimg.com/ca/I/yhst-5808251..._2089_18336329

Rich

 

Be careful guys, seems you're both becoming counter-punchers and are so determined to disagree you're damaging your creditability in the process.

The holes you dig for yourselves may become so deep you won't be able to climb out. Always leave yourselves some wiggle-room like so many others do.

The dial indicator method is even shown in the General Motors Factory Service Manual as the recommended procedure. They're even photos showing how to do it.

Those FMSs were written to cover more than just Texas, weren't they? LOL

Jake

 

lol, your dial indicator method is useless as pointed out. It would only tell you haw much the tip of the valve was rocking back and forth, not the actual clearance. That's why they make ball gauges. To get an accurate valve guide clearance you need to insert the appropriate size ball gauge in the guide and open it up. You then measure this ball with a micrometer. Then measure the valve that your going to stick in that guide. subtract that from the ball size and you have your guide clearance. To the OP, If it's not burning oil I would put new seals on them and keep running them.

 

Jesus Christ... is this what I get to look forward to when they combine the LS1/LT1 Tech Forums?

 

Is this really gonna happen?

 

It's not MY dial indicator method, it's GM's recommended method. You guys are trying to kill the messenger. So direct your hostility at GM, not me, I didn't create the procedure. I'm only reporting what GM says.

Did I.Q.'s suddenly drop while I was away? (Taken from "Aliens")

If GM's method is, in fact "useless" GM would not have recommended it. It's the wrong word, anyway. Vocabulary enhancement time.

Here's the direct quote taken from the GM Factory Service Manual; Page 6A1-11:

"Excessive valve stem to bore clearance will cause excessive oil consumption and may cause valve breakage. Insufficient clearance will result in noisy and sticky functioning of the valve and disturb engine smoothness.

Figure 6A1-19 Measuring Valve Stem Clearance

3. Measure valve stem clearance (Figure 6A1-19) as follows:

a. Clamp a dial indicator on one side of the cylinder head rocker arm cover gasket rail.

b. Locate the indicator so that the movement of the valve stem from side to side (crosswise to the head) will cause a direct movement of the dial indicator stem. The indicator stem must contact the side of the valve stem just above the valve guide.

c. Drop the valve head about 1/16" off the valve seat.

d. Move the stem of the valve from side to side using light pressure to obtain a clearance reading. If clearance exceeds specifications it will be necessary to ream valve guides for oversize valves".

Now if you prefer not to use GM's recommended method, fine. Don't use it. Ask me if I care. Yet to say GM's method is "useless" is yet another example of imprecise use of words; using it grossly over-states a position to the point that it becomes inaccurate.

I made an New Year's Resolution to combat the inaccuracies I find on Forums like this one. Someone has to do it. My mission is to cause many of you to become more precise in what you do and write. Don't just throw around words without first considering their definition and meaning. Failing to do that is irresponsible.

As with many things having to do with these engines, there's more than one way to accomplish the same task. Just think about the different procedures for phasing a camshaft, adjusting lifter preload, determining correct push rod length, on and on. Yet to characterize one method as "useless" just because it's not the author's preferred way is flat out wrong.

Jake

 

/\
Sounds reasonable to me.

 

Oh, yea and MORE. As one member posted a while back, it's why older people, those with a lot of knowledge and experience, steer clear of this Forum. Some even refer to this Forum mockingly and cite the immaturity of so many of the members.

That's not a pleasant thing to read but it's the opinion of others and what they're writing me in PMs.

Jake

 

Here we go again............................................. .........