How much timing is your 402 on.
Thread Starter
Launching!
Joined: Aug 2004
Posts: 248
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From: Ashland, Ky
How much timing is your 402 on. Just like it says, i want to know how much timing is on your 402.
Mine is pulling 18 degrees. If its at 20 or more, it starts rattling the valves, can anyone point me to the right direction.
Thanx,
Bobby
Mine is pulling 18 degrees. If its at 20 or more, it starts rattling the valves, can anyone point me to the right direction.
Thanx,
Bobby
Originally Posted by Kounsy
Just like it says, i want to know how much timing is on your 402.
Mine is pulling 18 degrees. If its at 20 or more, it starts rattling the valves, can anyone point me to the right direction.
Thanx,
Bobby
Mine is pulling 18 degrees. If its at 20 or more, it starts rattling the valves, can anyone point me to the right direction.
Thanx,
Bobby
start with a safe amount of timing with a fatter A/F ratio...once you get past peak torque which is also where VE occurs at 100% then you can increase timing 2 degrees after peak torque to gain hp...When the car starts falling on HP after each 2 is added then back it up to where the last setting was at....Every head is different, every combo is different. A proper tune in a fuel injected motor will never have a flat line A/F curve. I like to increase timing after peak torque simply because you are no longer at pure VE (volumetric efficiency)...your VE generally fades to say 80%or less and you can get away with running more timing..to help burn the extra fuel that nots being used up...reading your plugs is a great way to see this. WB 02's dont tell the whole story of whats going on in a motor...they get close...
Thread Starter
Launching!
Joined: Aug 2004
Posts: 248
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From: Ashland, Ky
i appreciate the input. I am running a tr6 plug. I havent had it on a dyno yet, which it prob would help though. I have a prc stage 2 ls6 cnc ported heads with a 250/258 .580 .580 on a 108lsa. I understand each head is differ, but i never seen the timing so low on one. Do u think it needs more octane?
Thread Starter
Launching!
Joined: Aug 2004
Posts: 248
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From: Ashland, Ky
well when the timing is at like 25 or so, and you get on it. It will start pulling hard then drop off around 4-4500 to like 6000 then start pulling hard again, and with that the valves are rattling? i dont understand
Thread Starter
Launching!
Joined: Aug 2004
Posts: 248
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From: Ashland, Ky
Originally Posted by ONEBADWS6
What compression are you running? What fuel are you running? Is anything on the car rattling? I need more info.
93 octane. Scoggin Dicky's built the 402 with a -14cc dish piston. The heads were cut to a 61cc (which were suppose to be 59cc) the comp. is suppose to be 10.9.1. PRC stage 2 heads, fast 90, NW90, 42lb injectors, 1 7/8 hooker headers. 250/258 .580 .580 lift, and 108lsa. running a 3500 tci converter with a turbo 350 with stock 3.42 gear.
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Well first try running 100oct fuel to see if that makes the knock go away. If it does get that thing on a dyno and tune it as it should run fine on pump gas. You just have to go step by step and go through everything.
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Originally Posted by Kounsy
Just like it says, i want to know how much timing is on your 402.
Mine is pulling 18 degrees. If its at 20 or more, it starts rattling the valves, can anyone point me to the right direction.
Thanx,
Bobby
Mine is pulling 18 degrees. If its at 20 or more, it starts rattling the valves, can anyone point me to the right direction.
Thanx,
Bobby
Originally Posted by ONEBADWS6
You should not be using any oil. Your pcv is sucking it into the intake and lowering your octane and causing the knock.