Detonation?

NEED SOME HELP HERE ON CAUSES,SIGNS,WHERE TO LOOK,AND WHAT TO DO..MAYBE SOME READING MATERIAL SOMEWHERE,PAST POSTS?THANKS HARRYTRANS.:

 

this may help http://www.dragstuff.com/techarticles/reading-alcohol-spark-plugs.html

 

Causes of detonation and preignition; too lean, too much timing advance, sharp edges in combustion chamber including piston dome, hot intake temps

Symptoms; rod bearings not lasting very long, spark plug porcelain breaking out, ring lands pinching closed, cylinder head eroding (kind of looks like a bad casting), copper head gaskets moving/stretching, piston ring edges chipping

 

hey Mike Iam going to start and print all your post put them in book form and have a number 1 seller...I myself am very glad you post here..thanks Dave lowe

 

I WANT TO THANK,MIKE,SoDAK AND CRAIG FOR THE GREAT INFO ON DETONATION.I SOLD A BLOCK THAT HAD WHAT I WAS TOLD "FRETTING" OR SHINNING BETWEEN THE CAP AND BLOCK.(CAST IRON) THE BUYER THINKS IT IS FROM DETONATION.IT IS A BBC THAT SEES 30 TO 35 LBS BOOST.I HAVE BEEN RUNNING THESE TYPE OF BLOCKS FOR 10 YEARS OR SO AND THEY HAVE ALL "FRETTED" THIS WAY.I HAVE NEVER HAD ANY BEARING OR FAILURES OF ANY KIND RELATED TO THIS SYMPTON.EVERY TIME WE FRESHEN THE MOTOR WE SEE IT.DOESN'T MATTER IF YOU USE BOLTS OR STUDS,IT'S STILL THERE.THANKS FOR THE SPACE WILL,....harrytrans

 

Harry, I've grown up with BBC caps fretting. I should be able to minimize it for you.
What heads, ignition type and timing, block, fuel, etc. do you run?

 

fretting

SoDak,used dart 360,chevy w ports,and at the end profilers.990 pump 10.0 to 12.0 compression.509 & 540 cu.in. bird catchers,760 to 860 lift cams@114&116.bryant cranks&callies.1471@28 to 35%over.all powerglides.110 to 80 jets depending on weather.ran best 3.99 in 8th best quarter was 6.18 2200lb dradster.timing again dependent on conditions 34 max usually stayed in 28to30 range.very little shake ever.960 to.980 sixties leaving 5500rpm.tried all bearing types full grove v's m's,kings.oil presure120lbs with 50wt.SoDak maybe you can teach and old dog new tricks,thanks harry

 

On this subject, is pinning the caps effective at keeping them from dancing on the BBC, and if so where do you like to drill them and how large a dowel do you use?

Thanks in advance for any replies,

Richard G

 

Harry, no response from SoDak yet? Just curious to find out myself.

 

What block and cap style?
Are the caps tight in the registers?
The fretting makes for high spots on the mating surface, this needs to be fixed. A cap to block surface that has been tranfering material won't hold like a clean smooth flat surface. While the machine shop is doing that, have them check the line bore for straightness along with your crank.
I'm assuming methanol?
Whats your piston to head clearance? How fast you turn the motors?
Do you sand roll dome and chamber edges?
Any idea how much of your total fuel % you run through the blower?
What mag?
Has the fuel system ever been flowed?

 

SoDak fretting

sorry for the delay answering your response been out of town.steel caps,cast iron block,msd 10,piston to head .090,55% through the hat,new block,decked,squared,line hone.no transfer of material,just shinny.