Welcome, Guest. Please login or register.
December 02, 2008, 02:38:57 AM

Login with username, password and session length

Visit ReillyMotorSports
* Home Help Search Memberlist gallery Login Register
+  The BigBlockDart Message Board
|-+  Technical
| |-+  Engine, Drivetrain
| | |-+  opinions on cylinder wall thickness
Pages: [1] Go Down Print
Author Topic: opinions on cylinder wall thickness  (Read 129 times)
moparteacher
Sr. Member
****
Offline Offline

Posts: 744

BigBlockDart.Com


opinions on cylinder wall thickness
« on: June 29, 2008, 08:44:02 PM »

I have sent my 383 block to the shop for a thickness check. The plan is to take the block overbored the maximum allowed per the NHRA class rules for Stock Eliminator, which is .075". The final bore would be 4.325". Stroke 3.39 Displacement 398ci.

The block will be at least 1/2 to 3/4 hard blocked. Vintage 69' block.
It's a short stroke with a long rod so piston to cylinder wall side force should be less than a shorter rod/stroke ratio engine.
Maximum rpm of 7800.
Naturally aspirated.
Compression ratio of 11.1:1
Small AVS
112 Gasoline
4-speed car
1/4 mile only

So give me your best educated opinion of what would be considered safe for major and minor cylinder wall thickness.
.2"?
.18"?
.15"?
.12"?
.1"?
More?
Less?

Thanks

Logged

Moparteacher
68 HEMI GTS
Full Member
***
Offline Offline

Posts: 364



Email
Re: opinions on cylinder wall thickness
« Reply #1 on: June 29, 2008, 10:25:46 PM »

as a rule of thumb, .090 is about as thin as you want to run. hopefully the thrust side of the cylinder will be a little thicker than that. when i was doing that sort of work i use to fill out a sheet for the customer that would have 12, 1:30, 3, 4:30, 6, 7:30, 9, & 10:30 positions measured at the top, middle, and bottom of the cylinders. they will not measure the same thickness all the way down so it is important for the person doing the sonic check to take his time and find the thinest spots. good luck with your build!
Logged

moparteacher
Sr. Member
****
Offline Offline

Posts: 744

BigBlockDart.Com


Re: opinions on cylinder wall thickness
« Reply #2 on: June 30, 2008, 11:12:14 PM »

I recieved the results today. It's been OK'd for .075" over. It'll be back to the shop on Wednesday, for the bore and hone, after the hardblock is dry.

Thanks for the opinion.
Logged

Moparteacher
Pages: [1] Go Up Print 
Jump to:  

Powered by MySQL Powered by PHP The BigBlockDart Message Board | Powered by SMF 1.0.5.
© 2001-2005, Lewis Media. All Rights Reserved.
Valid XHTML 1.0! Valid CSS!