Engine Run On/detonation - PART II

SUPPORT OUR SPONSOR

		Club Cobra > Club Cobra Tech Areas > Shop Talk
Engine Run On/detonation - PART II

Welcome to Club Cobra! The World's largest non biased Shelby Cobra related site!

» Representation from nearly all Cobra/Daytona/GT40 manufacturers
» Help from all over the world for your questions
» Build logs for you and all members
» Blogs
» Image Gallery
» Many thousands of members and nearly 1 million posts!

YES! I want to register an account for free right now! p.s.: For registered members this ad will NOT show

Main Menu

Forums

Nevada Classics

Advertise at CC

November 2025

S	M	T	W	T	F	S
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23	24	25	26	27	28	29
30

CC Advertisers

· Kirkham Motorsports
Superformance
· Finish Line
· Hurricane Motorsports
· Serpent Express
·
· Planet Cobra

· Shell Valley Classic Wheels
· Eight Stack Injection

LinkBack

Thread Tools

Display Modes

#1 (permalink)

10-17-2001, 03:23 PM

cdog

CC Member

Join Date: Apr 2001

Location: West Suburbs, IL

Cobra Make, Engine: Titanium SPF, 521 CID Gessford.

Posts: 338

Not Ranked

Engine Run On/detonation - PART II

I should have been more specific on this from the get go...

The 514 BB car is running on 93 octane. It has 10.25 : 1 compression.

It does have pretty severe run on / detonation when I shut it off for 5-15 seconds..

What causes this? How is it harmful to the motor?

Also, under full load in 5th gear it has some detonation like at 2,500 rpms or so...what causes this?

One other issue, under full throttle for 3-4 sec it emits a large, large cloud of brownish smoke/dust... what causes this?

The motor is newly rebuilt. But the last motor had the same setup same problems and ending up self destructing by chewing up the cam, clogging the oil pump... Could this have been caused by detonation issues?

As to carb size, Demon and other makers agree that 975 cfm is about right for a built 514. Some guys even run 1200 cfm+ dominators with no ill effects. My 975 RS Demon should be right on the money.

I'm going to the dyno/carb guy on friday to work on the problem.
Any thoughts on how to approach it?

« Previous Thread | Next Thread »

Posting Rules
You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is On Trackbacks are On Pingbacks are On Refbacks are On Forum Rules

All times are GMT -7. The time now is 04:22 PM.

CC Polices Contact Us - Club Cobra Home - Archive - Top

The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: CC Policy