Pin holes in the head sealing surface..., Can I run as-is, or should they be welded up? Options

[jhadler]

Hey all,

The motor is going back together, and upon close inspection of the heads, there are some small pinholes along the sealing surface of the head. I'd like to drop the head gasket and lap the cylinder to the head, but will these holes be a problem?

Based on the measurements, the pinholes will be 0.016" outside of the ID of the jug, and as such, covered by the jug. But is that enough? Can I run this as-is? Lap the jugs to the heads, and run sans gasket? Should I run I gasket? Or should I have the holes welded up and re-flycut the heads?

There's all of about 40 minutes run time on these heads right now.

Thoughts? Experience?

Thanks!

-Josh2

[ME733]

Pin Holes....the most reliable, and cost effictive way to solve your problem is to "fly cut " the head sealing to ( cylinder) surface...until you get a flat pinholess sealing surface....then...you can install the "stock" cylinder to head sealing ring,after a light lapping of the cylinder to be used......AND.....to really do this right consider duplicating this work to the other cylinder head....so everything is matched up..........THEN.....you can use cylinder barrell shimms of equal thickness under ALL the cylinders. consider this also ...the stock head seals will "CRUSH'' ,compress, when the head is torqued down....measure the before ...and after....crush....torquing.(gotta torque and remove and remove, measure and reinstall and retorque the heads.).....now the measurement of the head sealing ring will show how much LOSS in deck clearance occurs.(due to being crushed)......(you already installed a quesstomated,(measured) number of Barrell shimms.....and with the clay....you stragetically....previously...placed on the combustion chamber and piston tops.....at the smallest area of "squish"...you can now accurately measure the P/H...piston to head clearance.(deck-height).....My technigues over 35 years has been to keep everything in balance. and use the best parts available. piston to head clearance....bore diamenter and deck height "estimates" are just a wild ass quess....UNLESS....your engine builder has experience with the EXACT piston(make, design and weight)...and the connicting rods to be used.....Gotta consider the strech of everything at temp.and rpms to be used...Therefore consider using at LEAST .050ths inch as a minimum p/head clearance..the pistom material does matter and you did not say anything about them..a very minor loss in compression,by using a SAFE piston to head clearance is far far more cost effective for a street car/autocross...than the results of a LACK of Piston to head clearance. (IMG:style_emoticons/default/bye1.gif)