Hi guys, how much valve to block clearance is safe, this is a drag engine with a lot of spring pressure (180 on the seat), currently the valves hit the block and I am going have to grind a notch, I just  don't know how deep, I am shooting for .100 piston to valve, however when checking the valves hit the block first (intake and exhaust)

Sorry I have no answer to your question but I have pic what tells how to find too small gap between valve and block.




Hyvinkää, FI

Nice, do you know what your clearance was? also how much deck height do you run?

Deck height is -0.0something with dished pistons. ~8.0:1 comp ratio and 1.7" exhaust valve size.
Seppo might remember better.

I think nobody knows the valve/block clearance but is good up to 9178 rpm. :0

The big hit was caused by loosened springs during winter.


Hyvinkää, FI

See if these past threads on the subject help.
http://forums.y-blocksforever.com/FindPost65970.aspx
http://forums.y-blocksforever.com/FindPost66749.aspx
http://forums.y-blocksforever.com/FindPost67127.aspx
 
It’s important to measure the distance from the top of the piston to the top ring land and insure that any notching performed to the block does not get into the top ring area.

Lorena, Texas (South of Waco)

180 on the seat may be a little hard on cam, lifters, rockers and shafts but as long as longevity aint in the equation I would love to hear it run with Zoomies!

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?