commando1
Old Man with a Hat
Interesting. Never saw anything like this.
Correct, .025 down. With gasket .039 and 73.5cc heads, I should be running around 9.3 to 1.You're measuring how much the piston sits in the hole?
youve never seen a ball hone Stan?Interesting. Never saw anything like this.
Got the pistons in and took some measurements. Order cam kit. Little by little I am getting there.
Nope. Then again, I don't hone. I drop the block off at the machine shop. lolyouve never seen a ball hone Stan?
Correct, .025 down. With gasket .039 and 73.5cc heads, I should be running around 9.3 to 1.
https://www.uempistons.com/installation_instructions/kb_installation.pdfThat's ring clearance in the lands. The rings are usually .0035-.004 per inch of bore and.the second ring is usually more loose like .004-.005 per inch. Larger gap on the second ring let's any trapped pressure out between so top ring can stay against the cyl wall and not flutter or be pushed off wall by trapped pressure, losing the seal. Always error looser than tighter, above numbers would be a minimum .028 is out at the far end okay if engine has 100,000 miles on it but to start that loose and when initial break in wear settles, I would think it would end up too big.
I found the comp cam k21-221-4 to my liking. I know a lot of people don't like them or the kb pistons, but every web page I turn, everybody hates every brand. So I decided to go with the best overall deal and cam that I believe will fit my needs. Picking out a cam is harder then choosing a women to marry!Cam kit. . . What kinda cam are you gonna run ? I remember Clay Smith had a solid lifter cam for a two four-barrel 383 that was developed with Chrysler engineering. It was a mighty fine cam.
I thought valve relief adds ccs?If your deck clearance is .025" you should be at 9.4:1.
If your deck was a true 9.98" I show .0265" below deck you would still have 9.37:1
Most posted piston compression specs in the past were way off and I still don't trust them, so I always do the math and always check my combustion chamber volume.
For a reference to others here's how to calculate your deck clearance before you buy pistons....
383 B engine specs
Bore 4.25"
Stroke 3.375"
1/2 Stroke 1.6875"
Deck height 9.98"
Rod length 6.358"
Keith Black piston specs
Comp height 1.908" (from wrist pin center)
Valve reliefs -5cc
9.98 Deck
- 6.358 Rod length
- 1.6875 1/2 Stroke
- 1.908__ Comp height
.0265 Deck clearance
I thought valve relief adds ccs?
Nope. Then again, I don't hone. I drop the block off at the machine shop. lol
You say dingle balls to me and all I can think of is an East L.A. upholstery job...