Guest tony78_280z Posted May 25, 2004 Share Posted May 25, 2004 Well, I'm new to this page 'cause I just got my 350 motor into my Z but of course I got problems. The motor installation is not my problem. It is installed and it does run although not very well at all. The problem I'm having is definatly with the timing of the motor itself. It sounds best at around 30-35o, and I know that's not right. Runs like crap, horrible fuel consumption and runs way rich. If I time it by ear it sounds best when it is off the meter. Ya know, the little meter tab on the harmonic. It reads “ 12-8-6-4-0-4-6-8 †well it sounds best when it is WAY over the 12 mark. Of course it sounds best there, but it still don’t run right. It throttles OK, then sputters and backfires on the down throttle. I can tell it’s running rich and not getting the performance it should at that setting though. I don’t think this motor should run timed off it’s own tab. I replaced the distributor and I could have put it in wrong, but it didn't run right before I did that anyway. It seems I'm looking at the timing chain perhaps. Any ideas on how to test to be sure it is the timing chain before I go replacing it? How does one replace the timing chain? Any other advice? The 350 motor automatic tranny is from an 86 Chevy Vandura Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 25, 2004 Share Posted May 25, 2004 Welcome! 1. Have you checked the distributor clearance to the intake....sometimes you need to put shim washers between the intake and distributor....take the cap off and check to see if you have some (just a little) up and down play on the rotor. 2. Get the #1 Cylinder to top dead center on compression (pull the #1 spark plug). Check to see if the rotor is pointing to the #1 plug wire. Double check the firing order on the rest of the wires. 3. Make sure that the mark on the crank pulley (damper) is pointing to zero on the timing marker. 4. MAke sure that the fuel system is working correctly and is not over fueling. 5. Put the spark plug on the plug wire and rest it on the engine (so it's earthed), put the dizzy cap back on (after confirming that the rotor is pointing to #1 lead), and turn on the ignition (not start). Turn the dizzy back and forward, watching for spark at the plug. When it sparks, your timing is at zero degrees. Put the plug back into the head and start the engine. Check with timing light, it should show zero degrees timing. Make sure the vacuum advance is disconnected and the connection at the manifold plugged. Set initial timing at 10 degrees and see how that works. Tim Quote Link to comment Share on other sites More sharing options...
labrat Posted May 26, 2004 Share Posted May 26, 2004 Definitely check with a timing light. If you just time it by ear at idle and no load, it will be WAY too advanced and detonate in the higher RPMs. I've seen motors that like as much as 30* initial to idle nice and smooth, but at 4000 RPM with vacuum and mechanical added in you will be around 50* or even 60* advance. That would be bad. Bill Quote Link to comment Share on other sites More sharing options...
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