Small Block & Big Block Chevy Specific Mouse & Rat Motor Discussion & Conversions

Timing problems

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Old 08-28-2007, 09:17 PM
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Default Timing problems

I am having problems getting my motor timed, at first I was using a timing light and trying everything, that as you know takes a few minutes each time I wanted to make an adjustment. Now I have the distributor tightened enough to where it wont move freely but I can turn it by hand so I can just step out and reach in through the cowl (I don't have the plastic cowl cover on right now just for this reason) and make changes pretty much on the fly. I have tried everything and it still pings, the best I can get it is so that it will start up easy and run up to about 3000 RPM's great but above that it starts to ping like crazy and I immediately get out of it. What gives? Its a GM Goodrench motor (the 290 HP one that you can get from Jegs)
Old 08-28-2007, 09:25 PM
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it sounds like the mechanical advance is advancing too much.
isi the vacuum advance hooked up?
Old 08-28-2007, 09:36 PM
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Yes its hooked up, if you say its to much that would mean I need stronger springs? Were do I get springs?
Old 08-28-2007, 09:43 PM
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How much timing are you putting in it? Are you setting the base timing, or full advance? Are you setting it with the vacuum advance hooked up? Does the engine have an egr system?
Old 08-28-2007, 09:44 PM
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the springs would just cause it to come in at different times...if it is a stock motor a stock distributor should work fine... is the vacuum advance hooked up where it goes? it must be on ported vacuum(only pulls vacuum when the throttle is opened partialy) not on manifold vacuum!

also i think the base timing should be at 10* at idle with vacuum advance disconnected.
Old 08-28-2007, 11:36 PM
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I'll bring my light home tomorrow, the vac advance is hooked to the timed port.
Old 08-29-2007, 01:53 AM
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Well, what octane are you running? Mine did the same with 87, but 93 fixed it. You are in the dark till you put a light on it.
Old 08-29-2007, 01:11 PM
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Do the following and post the results please:
Disconnect and cap off the vacuum advance.
Start real conservative with 10* BTDC.
Rev the engine until all the mechanical advance is in. Tell us what RPM and what advance you are at (with the 10*).
Hook up a vacuum pump to the vacuum can on the distributor.
When you pull all the vacuum advance in (at idle), how many degrees of advance did you hit? (With the 10*).
Place a vacuum tee in the ported vacuum line to the distributor and hook it up to a vacuum gauge. With your 10* base timing, what are the vacuum and timing readings at idle, 2K, 2.5K, 3K?

Did you reuse the existing intake, distributor, carb/TBI etc? Is the engine being used as a service replacement? Is it in the 94 listed in your signature? Shouldn't it be an LT1??? More info on the setup, and a good advance map will let us help you better...
Also, is there knock while you are testing?
Old 08-29-2007, 02:38 PM
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I'll do all the tests you asked for tonight when I get home, I will get some 93 octane on the way home as well, I just thought about that today. No, I dont have EGR. Yes it is in the 94 in my sig, it started out as a V6 car, thats why its not an LT1. It has a new Weiand intake and new edelbrock carb on it but its a used HEI distributor I had laying artound (new cap, rotor plugs and wires) Thanks for your help so far.

Edit #2: Well I went to my friends to use his light and vac pump and the first thing I did was take off the cap to inspect it, I ended up deciding I needed a new cap, rotor and button cause they were melted (my car did get hot when I was trying to use an LT1 radiator) that seamed to help out alot, set it to 10* and went to pull vacume and the vac can wouldnt hold any vacume, it was getting dark by that time though so I decided the best thing I could do was to set it to 12* and give up for the night. Thanks for your help again, when I get around to replacing the can this week/ weekend and if that still dosent help I'll be back asking for more help.

Last edited by Drumer919; 08-29-2007 at 08:14 PM.



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