help with quench?
03-25-2004, 12:10 PM
#1
help with quench? I'm trying to decide how close to bring the quench (piston to head clearance) on my new motor. It is a:
Darton Sleeved 388 (4.130" bore X 3.622" stroke)
- the rods are 6.300" Eagle H-beam rods
- the pistons are Diamond LS1 427 forged pistons (4.130" bore X 4" stroke)
Everything I read says to shoot for 0.035"-0.040" BUT they say this is for tight bearings and pistons (won't rock).
I THINK I should be able to run about a 0.040" quench as my pistons are coated (thermal top/teflon sides = closer bore size) and the forged rods should not stretch (red line of about 7000-7500 RPM). How close should the bearing clearance be to make this all work?
The gasket I'm using is a Cometic 4.165" bore X 0.045" crushed thickness. If I just install everything as is, the piston will be 0.001" out of the bore thus giving me a 0.044" quench. Is that going to work or should I deck the block of 0.004" and get down to 0.040"?
Darton Sleeved 388 (4.130" bore X 3.622" stroke)
- the rods are 6.300" Eagle H-beam rods
- the pistons are Diamond LS1 427 forged pistons (4.130" bore X 4" stroke)
Everything I read says to shoot for 0.035"-0.040" BUT they say this is for tight bearings and pistons (won't rock).
I THINK I should be able to run about a 0.040" quench as my pistons are coated (thermal top/teflon sides = closer bore size) and the forged rods should not stretch (red line of about 7000-7500 RPM). How close should the bearing clearance be to make this all work?
The gasket I'm using is a Cometic 4.165" bore X 0.045" crushed thickness. If I just install everything as is, the piston will be 0.001" out of the bore thus giving me a 0.044" quench. Is that going to work or should I deck the block of 0.004" and get down to 0.040"?
03-25-2004, 12:59 PM
#2
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You should be fine. That is a pretty tight quench for a street motor, but should do well. If you're going for 7000-7500rpm, you need to be as spot-on as possible with your bearings and the rest of your blueprinting.
As long as the block is flat, I would not touch it to get that extra .004". Are you sure you're going to only be .001" out of the hole? I'd measure it. I've seen a lot of stock motors that had up to .005"-.007" of piston protrusion. Mine are .022" out of the hole with a .032" quench area, but that is after trying 18 sets of bearings to find the right combination.
As long as the block is flat, I would not touch it to get that extra .004". Are you sure you're going to only be .001" out of the hole? I'd measure it. I've seen a lot of stock motors that had up to .005"-.007" of piston protrusion. Mine are .022" out of the hole with a .032" quench area, but that is after trying 18 sets of bearings to find the right combination.
