I want to check valve adjustment on my 3 cylinder Yanmar. I have no record of it ever being done. The manual says to remove the starter to see the timing marks. I would rather not remove the starter and I have read about alternate methods. Here for one: https://www.hoyetractor.com/valve-set.htm
That system will work , although more common is a timing method from the eng mfg that sez something like "measure cylinder 3 when the exhaust valve on number 1 is just lifting "
You can pay attention to the firing order on your particular engine and save some time, or on pretty much any engine you can watch the valves go through a cycle and ensure that the valve is fully closed on the base circle and not in the process of lifting or falling and go ahead and adjust. Often takes less time turning the engine over a few times than finding or documenting the procedure from somewhere else. You really just need the lash settings for exhaust/intake.
Using the timing marks will give you exact TDC which is nice but you can find just about exact TDC with a bright led flashlight and watching closely as you bar the engine. You should be able to set clearance well within tolerances.
NOTE: make sure fuel solenoid is off as you turn engine
Turn engine til an intake valve opens, then closes. Then turn another about 120deg. That will be close to TDC. Then set lash on both valves for that cylinder. Repeat for other cylinders.
My method is : EO-IC, when exhaust valve starts to open set the intake. When intake valve is almost closed, set the exhaust. You can do the cylinders in any order. I think it will work on any 4 stroke engine.
Impossible??
How so??
There would be specs for hot and cold adjustment. Using a feeler gauge while the engine is running is/was (w solid lifters) the most common method as I recall.
How could it be impossible?
Have you done it?
Thinking back one does need the right “feel” of the resistance of the feeler gauge. As you pull the feeler strip out it can’t be w/o any resistance at all. That’s too loose. And if it’s too tight the engine won’t run right.
And sometimes the rocker arm, nut and adjustment screw will be dificult to work with. But it’s fairly easy to tell when you’ve got it right w the feeler.
I don’t think I’ve ever done it cold.
Also to Ak-guy the method you linked looks bullet proof to me .. providing you have the propper cold clearance number.
So sorry I left out that detail.
My posts have been too lengthly for many in the past so I’m frequently looking to shortening them. Got caught this time.
Adjusted all my old V-8's running. Rockers were rocking but so was wrench.
There wasn't that much movement to make it impossible.
I believe Yanmar gives specs for cold adjustment so just make sure you are using correct clearance if engine is hot and/or running.
SoWhat,
Most V-8’s had hydraulic lifters. I think.
But I sure did a few 6’s and straight 8’s.
Idea ...
One could adjust an engine cold and then measure the clearence hot while running. Then down the road the results could be used as a benchmark. Checking hot takes very little time so seeing when the next adjustment should be done would be easy. May cost a valve cover gasket .. depending on engine design.
Back when solid lifters were the norm they made special wrench/screwdriver combos to adjust valves on a running engine. Loosen lock nut with wrench, screwdriver adjusts the gap to where the feeler gauge just moves, then tighten nut and move to next valve. Still see the old wrenches on Ebay
