Deck height

What would be a problem if any with rebuilding a lycoming case with a
deck height out of spec.
As a matter of fact How does one measure a deck ?
I am assuming that the deck is where the cyl barrel is bolted down to.
If so then I would assume that haveing a slightly smaller height would
in turn allow the piston to go a smidge further in the cylinder. If the
valve train was fixed then the valve would not seat fully. However these
things have hydraulic tappets that will take up some play yes ?


I have looked in my 0-360 overhaul manual but have not found anything on
it.

Thanks in advance
Sean Trost
Mj-5 in restoration

Depends on how much out of spec.. A 32nd would probably be OK.
Deck height is measured by first cleaning and honing flat the split side of the
engine case. Also clean and hone flat the surfaces the cylinders bolt to.
Lay the split side on a layout/inspection plate and measure from the cylinder
flange surfaces down to the layout plate using a depth micrometer with the
proper length blade. A good machine shop can do this for you in 5 minutes.
Yes, the hyd. lifters have a good bit of range, however, you should still check
the dry dimensions of the lifters when assembling the engine. Do this by
collapsing the lifters and measuring the gap between the valve stem end and
the rocker arm when the vavles are closed. Should tell you how in the manual.
IIRC, Lycomings have a little tighter tolerance, 1/32 to 3/32. Continentals
tolerance is greater. 1/16 to 3/16. But check your manual.
Good luck,


Warren