Bad Detonation Problem Any Ideas?
Thread Starter
|
New User
Joined: Apr 2004
Posts: 2
Likes: 0
Bad Detonation Problem Any Ideas?
I have recently built a 460 engine and installed it into my 87 F-250. It runs well but detonates bad. It is an 86 460 block bored .030 with flat tops. The heads are DOVE-C heads with 1.6 rollers. Which i believe are 70 429 heads? The heads have been mildy ported. I am running a Holley Street avenger 770 carb, Edlebrock performer manifold with L&L headders. I have re-jetted the carb and that certainly helped , the primarys had 72s and the secondaries 75s originally. I changed them to 75s and 77s. I have been all over the place with timing starting with a base of 10. I have changed the weights and springs in the distributor back and forth ten times. I can get the detonation to go away with 8 degrees of base timing and stiff springs in the distributor, but then the things a slug. Im out of ideas any help guys? One more thing i did a cranking pressure test and have 195 psi. Is this just too much for 93 octane pump gas?
Posting Guru
Joined: Jun 1999
Posts: 2,404
Likes: 1
From: Everett, Wa
Ya you are in trouble. You are running almost 12-1 compression. This is way to much for pump gas. If you want to keep those heads you need to swap pistons or throw 90cc heads on. Also may I ask why you are only running 1.6 rollers. You should be running 1.73. You are losing a bit a breathing running the 1.6's.
I would also talk to your builder. He should of provided better advice on what you where building.
I would also talk to your builder. He should of provided better advice on what you where building.
