Timing question
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Re: Timing question (Ron 75 L48)
Ron I have heard a car backfire/pop on acceleration when timing retarted too much - intentionaly to pass smog. They say a car will get detonation with too much advance but I can't really comfirm this. I used to have a high compression GTO and on a hot day I thought I could hear what sounded like lifter noise - but faint. They say preignition/detonation will put holes in your pistons fast. I bought a MSD knock detector but have not installed it yet. Only about $100 if your really worried. :smash:
Okay to answer the question: retard timing should reduce predetonation.
Okay to answer the question: retard timing should reduce predetonation.
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Re: Timing question (Older Than Dirt)
Could be your vacuum advance is too much. Total timing with VA hooked up should be around 52, I think? If it's too high, buy an adjustable unit.
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Re: Timing question (Ron 75 L48)
Is this a new problem? If so, think about what you've last changed such as the timing you mentioned or if you've adjusted your valves, etc. If you've not changed anything in a while, you might have a little carbon starting to build up which is increasing your compression ratio. :smash:
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Re: Timing question (Ron 75 L48)
I swapped out the carb. I went from a Holly (kept boiling the fuel after shutdown) to an edlebrock.
Ron
Ron
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Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,115
Likes: 0
From: VA
Re: Timing question (cardo0)
I swapped out the carb. I went from a Holly (kept boiling the fuel after shutdown) to an edlebrock.
Ron
Hey Ron this is really good info on carbs. Now this will help diagnose a lean condition. Just hope this makes into the archives. :thumbs:
Ron
Hey Ron this is really good info on carbs. Now this will help diagnose a lean condition. Just hope this makes into the archives. :thumbs:
Thanks,
Ron
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
Re: Timing question (Ron 75 L48)
Like others said, check the timing. Set the base at about 8-9 degrees to start. Get or borrow a dial back to zero timing light. Diconnect and plug the vacuum advance. Check timing for base, and what total is for mechanical and at what RPM. You shold have no more than 34-35 degrees total. When you add vacuum advance you can go up to the numbers you have. Check it out.
The Edelbrock carb should be ok, but if your timing it good, then it may be too lean on WOT or high speeds. Look in the instruction book and see what rods and/or jets to change to go richer at cruise and WOT.
The other thing is wha temps are you running. Too hot can cause detoniation.
The Edelbrock carb should be ok, but if your timing it good, then it may be too lean on WOT or high speeds. Look in the instruction book and see what rods and/or jets to change to go richer at cruise and WOT.
The other thing is wha temps are you running. Too hot can cause detoniation.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Re: Timing question (Ron 75 L48)
Well if yu can't find the time to install an Air/Fuel ratio gauge and O2 sensor, I think yu owe yurself an hour of dyno time. At least to nail that carb (after correcting timing). :yesnod:
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,115
Likes: 0
From: VA
Re: Timing question (cardo0)
Well if yu can't find the time to install an Air/Fuel ratio gauge and O2 sensor, I think yu owe yurself an hour of dyno time. At least to nail that carb (after correcting timing). :yesnod:
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
Re: Timing question (1SGRET)
Just the timing at normal idle speed of say 600-700. If you think there is something off like it just does not idle fairly decent at 8-10 degrees or is way off, (make sure the dial back to zero tiing light is at zero) maybe you need to check to make sure the timing of TDC and zero are correct.
Take the dist. cap off. Mark where the #1 wire is on the cap and make a mark.
Pull the #1 spark plug, put your finger tip in the hole and crank the engine over slowly until you feel air pushing your finger away.
Look at the balancer and see if the TDC mark on the balancer is lining up.
Bump the engine until the rotor on the dist. gets to where the #1 wire mark is. With the #1 piston on TDC, the timing marks should line up with zero on the pointer and the dist. rotro should be on the #1 plug position. This is just to check tos see if the balancer has slipped and/or someone put the dist. in the engine 1 tooth off. This will really screw up the timing.
Good luck.
Take the dist. cap off. Mark where the #1 wire is on the cap and make a mark.
Pull the #1 spark plug, put your finger tip in the hole and crank the engine over slowly until you feel air pushing your finger away.
Look at the balancer and see if the TDC mark on the balancer is lining up.
Bump the engine until the rotor on the dist. gets to where the #1 wire mark is. With the #1 piston on TDC, the timing marks should line up with zero on the pointer and the dist. rotro should be on the #1 plug position. This is just to check tos see if the balancer has slipped and/or someone put the dist. in the engine 1 tooth off. This will really screw up the timing.
Good luck.