Thread: detonated
View Single Post
  #73  
Old 02-08-2018, 11:58 AM
wbnapier wbnapier is offline
Chief Ponti-yacker
 
Join Date: Sep 2017
Location: Encinitas, CA
Posts: 592
Default

Quote:
Originally Posted by dataway View Post
Not saying that is definitely your problem ... it was obvious in my case that the carb was too small .... installed a larger carb and was done.

The sound is actually a bit more like you would imagine a .22 caliber machine gun might sound.

Lean enough to cause a lean miss would have surely been spotted on the dyno so I doubt it's your problem.
Thank you for the reply. I've been struggling with compression / octane issues. The previous owner doesn't remember / have the engine build details, and I am new to the automotive hobby. The only thing I know for sure is that on 91 octane the engine diesels substantially, which doesn't happen on 100 octane. The sound of engine pulling is better with 100 octane as well. I don't know what really pinging sounds like, and I am unsure what the crackling sound at WOT is.

On the dyno, I was 1 point lean at WOT. We up-jetted the end carbs, and it didn't move the number. We also advanced the timing from 12/32 and the hp / torque didn't change. All this is contrary to accepted doctrine.

One day, I may pull the engine, re-gasket, aluminum heads, etc... It's just so expensive, so I just pay $9 / gallon in race gas until then.

__________________
1965 Pontiac GTO
455/469 w/ #48 Heads, '65 Tri-Power
9.25:1 CR
Stump Puller Cam
Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00
3.55 Rear Differential
Front: 225/60R15 Height: 25.6"
Rear: 275/60R15 Height: 28"