The Stovebolt Site Forums The Shop Area Engine Shop "correct" valve adjustment procedure?

Evening All,
I have been going through valve adjustment posts and tech tips recently and I still have a few questions if someone could please help me out. Oly has a post on the TechTips about how to adjust about half of them and then you rotate the engine once and adjust the other half. What puzzles me is one f the last lines that say after you do all this you still have to do the "final adjustment." What does that mean?

My engine is running but I want to check the valves because I suspect that it would run much better.

There have been a few posts about this method, while acceptable, is not the best method of adjusting a valve and then rotating the engine a little and adjusting the next valve. What does that mean and how do you do that?

I have to say I am not a bid fan of adjusting them while the engine is running. I Know it can be done, but I would rather have the "correct" method and not the "close enough" method.

Any Help? Thanks.

The final adjustment that is being referred-to is the same adjustment procedure, but on a warmed-up (operating temperature) engine.

Here is another description of the same technique.

Both ways work, but I like to rotate the engine till #1 cylinder valves are closed and adjust only the two . I then rotate the engine till #2 cylinder valves are closed and adjust, then continue all the way down the engine one cylinder at a time. I don't like to think about which valves to adjust, so by doing only two valves at a time insures I have them all set correctly.

Joe

See if you can do a forum search and find my "companion cylinder" adjustment method. I get tired of writing it repeatedly, especially since nobody seems to be using it anyway. It's the most accurate method of being sure the cam lobes are exactly positioned for a good valve adjustment, even with a radical-grind racing cam.
Jerry

I set them cold first by adding .002 to the intake hot lash measurement and .003 to the hot exhaust lash measurement. Then I get the engine HOT (not warm) and do the final adjustment using the two position method that you describe using the hot lash specs. I find that if I use this method to set them cold first, it is much easier to do the final adjustment...when you get lucky, none of the valves need any fine tuning! Saves the amount of time that you spend leaning over a very hot engine.

Matt

Jerry, don’t get discouraged when the guys choose another way. I personally have always used the one at a time method. I have read your companion cylinder process over and over and each time I come away impressed but still haven’t tried it. I think many of our readers are stand out in the driveway, with a set of Chinese wrenches, mechanics and may be a bit intimidated by the process. No offense to the shade tree guys I’m pretty much right there with you. Hang in there Jerry.🛠

No shade tree aspect to lining up the bb (TDC) and adjusting half of the valves (which are closed).

This is for a 216/235/261 straight-6 engine (my only engine-interest here).

Which of those cam lobes shown in the adjustment procedure are in an incorrect position for adjustment?

I like Jerry's companion cylinder adjustment, shown to me by several old friends/mechanics.
It works on most any engine with an even number of cylinders, and with slight variation on any Detroit diesel, even the 3 cylinder.

With this method you're sure to be adjusting the valves while the lifters are on the opposite side of the cam lobes, no chance it is close to the lift part of the lobe.
The alternative adjustment method done with engine only in two different positions should also have all lifters on the base circle of the lobe for adjustment, but some will be close to the lift part of the lobe.. chance for mistakes if engine is not positioned just so, or as Jerry said, with a radical grind cam.

I also like that is is really easy to remember, for about any engine.

First understand that two pistons will come up to TDC together, one is finishing exhaust stroke and starting intake, and other cylinder is end of compression and starting power stroke.
The one starting power stroke is ready to adjust because the valves are as far from being open as possible.
The companion cylinder is easy to spot because as rotating the engine by hand it's exhaust valve is just closing and immediately after the intake valve starts to open. Stop here and adjust the other cylinder.

You can write down the firing order and pare up the two cylinders, or remember what they do if you ever watched the pistons with head off.
The Stovebolt 6 front and rear pistons move together, and the two center ones, and also #2 and #5.

So adjust #1 when #6 valves just move one then other.
Rotate engine more watching for an exhaust valve to close and its intake to start to open.
Adjust the valves on companion cylinder.
Continue, and take notes of which you already did.

This always works.

If you want to look real smart find or recall the firing order, write it down in two columns, first half in one column, second half beside it. Each row are companion cylinders, and you also know which cylinder to watch and which to adjust next. (This is almost required on V type engines, otherwise hard to visualize)
Firing order 1-5-3-6-2-4

1-6
5-2
3-4

I too have posted this several times and teach it at Stovebolt gatherings.
In practice it may take 10 minutes altogether.

Some people obsess over various ways to turn the engine..
Easy enough to grab the fan and if needed push on slack part of belt to add tension with other hand.

Not applicable here, but to not leave anyone hanging. For Detroit diesel 2 cycle the injector is operated by rocker arm, so it is the indication that that cylinder is on TDC. And when exhaust valves just close then injector can be timed, all on same cylinder.

Grigg

https://www.stovebolt.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/1231076/Searchpage/1/Main/180210/Words/%2BCompanion+%2Bcylinder/Search/true/re-finding-nemo-i-mean-tdc-on-a-235-truck-engine.html#Post1231076

I tried Jerry's companion cylinder method the last time I set the valves on my 261. I was a little confused till I actually did it . Very easy and quick. engine runs fine .

Now that I have actually been through it, I agree that it is not difficult and the theory is sound. I just recalled a few posts where some one eluded to the "proper" way to do things and I was just trying to find out what that was.

Thanks to all who replied.