The Stovebolt Site Forums The Shop Area Engine Shop Setting lash with running engine.

I have just under 200 miles on the rebuild and I think it's about time to do the 'final' lash set. I bought a Zim wrench and am thinking of setting the lash while the engine is running. I've always done a static set in the past so setting a running engine is new to me. Is it done by ear or do you use a feeler gauge? If it's done with a feeler gauge where do you grow the necessary third hand??? The tech tips only address a static set.

I've always done this bit of fine-tuning by ear. I like the interaction with the engine!

Here's what I do..
Get engine hot. Hot.. Up to engine temp.
Box wrench on the nut screwdriver in hand, loosen the nut leaving it on the nut as I put the screwdriver into the slot.
Pick up your feeler gauge, check lash, hold screwdriver in place and tighten the nut.
takes some practice I reckon. And it kicks a bit of oil about.
Robert's your mother's brother...
Piece of cake...

Jeremy

When I've adjusted lash on a running engine I use a stepped feeler gauge. I'm not looking for perfection on a daily driver, so a stepped gauge works just fine. The step on my KD feeler gauges is .002. IF the gauge slips through the valve, and rocker, but won't go pass the step, your close enough. IMO

Larry

Tiny, By using the Zim wrench you can hold the feeler gauge in one hand and use the other to hold and turn the wrench. You use your thumb to turn the adjusting screw while the rest of your hand hold the wrench. I've got a Snap On wrench that is similar to yours that I use. It does take a bit of practice, you need to have a limp wrist to make it work. With the idle turned down low it will still want to bounce your tool and hand of the rocker arm. Once you get the feel it will be easy. At first you will think its crazy.
Good Luck
Don

The nice thing about doing it with the engine running is if you have a loud one, you'll know it as soon as you get the feeler gauge in there. All of a sudden the noise will go away.

Tiny, do you have hydraulic or solid lifters?

I always thought adjusting this way while running with solid lifters was a no-no.

Jeff

Doing any sort of running adjustment is less than effective, but trying it on hydraulics can be particularly frustrating. Getting slapped by the cam lobe several times a second means that the lifter never gets the chance to top itself out fully, so the adjustment is always a SWAG. Engine stopped is the way to go, solid or hydraulic!
Jerry

With the engine running was the only way we did it way back. I've got mashed out feeler gauges to show for it. The only good way is with the engine off.

I believe the manual for my 218 flathead recommends adjusting the valves with the engine running. But a machinist did tell me that it wasn't a good way to do it. Hm.

Tiny,
What is the Zim wrench for? I've never seen anything like it.

...click...

...click...

I would like to see a video of someone setting the lash with the engine running.

I would too. I've heard of a lot of people who've done it but I never have. I thought it might be fun to try. Back in the day when I was just a puppy I remember the mechanics mentioning that setting lash on a running engine was the best way. Many said they did it by ear rather than use a feeler gauge as well. In a worst case scenario if I can't master the wrist timing I'll just shut it off and do it the way I always have.

When we were just high school kids we wore out the feeler gauge setting the lash. I would be afraid to try to set it by ear. If the valves are anything like the old VW Beatles, too tight meant burning the valves. At least that's what I've always heard.

I was taught by a few good old boys (back in 1969) to set the valves with engine running. What a pain and what a mess.

Now, I only do the static adjustment technique. This could not be much simpler: after finding #1 at TDC and setting half of the valves, you just rotate the crankshaft 360 degrees and then set the other half of the valves.

I bought an old Zim valve adjuster a few years ago and the job is now a little easier.

The Zim tool shows up regularly on eBay.

I have an old setup called a Valve Gapper. It sets on top the valve & has a dial indicator that gives the amount of clearance. I have not used it for 50 years. When I started working on Cummins Diesels I found out how much better it is to do it statically.