Ok I'll tackle it again in the morning, It's dark here and I have no lights in the garage.
Thanks
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| timing issue need help! https://slantsix.org/forum/viewtopic.php?t=52869 |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 3:45 pm ] |
| Post subject: | timing issue need help! |
I had my van running pretty good, but I pulled the dizzy to change the o ring due to a leak. I set the #1 p[ston at TDC, dropped the dizzy back in with the rotor pointing to #1 and now it doesn't run right. It starts and runs but acts like it's running on 4 cylinders, and when I give it some gas it backfires through the carb. I tried moving the dizzy1 tooth advanced and 1 tooth retarded and it just runs worse. I spent a couple hours researching the problem in books and on the board but I covered everything I found. The engine is a new rebuild (not by me or anyone I know) and it was just running fine. Gm HEI conversion- Carter BBd professionally rebuilt- What am I missing???? |
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| Author: | jhdeval [ Sat Jul 27, 2013 3:52 pm ] |
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I know you just pulled it to replace the o-ring but did you check the rotor and cap to see if there was any signs in there? Also verify you got the vacuum advance back on. |
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| Author: | Reed [ Sat Jul 27, 2013 3:56 pm ] |
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Are you sure you didn't put the distributor in 180 degrees out of time? The timing mark will show #1 at TDC when #1 is at TDC on BOTH the compression stroke AND the exhaust stroke. You want it at TDC on the compression stroke. I know for a fact that a slant will run with the distributor 180 degree out of time, it just won't run well. Go through the steps to verify that your base timing is set for #1 at TDC on the compression stroke. |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 3:58 pm ] |
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Yup I acutally put a new cap and rotor on and the vac hose was reconnected I thought I just put the dizzy in wrong but I dont think it is-very puzzling |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 4:02 pm ] |
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Reed, I used the hose from my compression tester and a long hunk of fuel hose to the #1 cylinder, found the compression stroke, then verified the piston was at TDC. Then I checked for the mark - it was close at that point- and just set it at 0 then How would I know If I was on the exhaust stroke? |
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| Author: | Reed [ Sat Jul 27, 2013 4:15 pm ] |
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What is your base timing set to? |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 4:22 pm ] |
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Well as a newbie I'm not sure how to set that up- I've done most of my own repairs my whole life but this van project is a first as far as how deeply into the technical field i've ever gone. I'm learning as I go |
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| Author: | Reed [ Sat Jul 27, 2013 4:43 pm ] |
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Do you have a timing light? |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 4:51 pm ] |
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Yes- bought a new one for this project- Earlier when I had it running I checked the timing and it was about 4deg BTDC that said, there are 3 timing marks on the balancer. I marked the one with yellow the other white and left the third alone. Only one mark lines up with TDC with the piston at yhe top of the stroke. before I pulled the old motor from the van I pulled the lean burn distributor from the new engine, confident I could set it straight, so its probably out of whack- doesnt explain why I had it running good the other day- |
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| Author: | Reed [ Sat Jul 27, 2013 5:21 pm ] |
| Post subject: | |
OK. Here is what you need to do. First, you need to get a piston stop tool and verify that the timing mark on the vibration damper is still accurately indicating TDC. Pull the #6 plug and install the piston stop tool (on a car, you normally pull the #1 plug. However, in a van I know getting at the #1 plug is a PITA. Fortunately the 31 and #6 pistons move up and down in tandem, but 180 degrees out of phase, i.e. when #1 is at TDC on compression #6 is at TDC on exhaust and vice versa). Rotate the engine by hand completely clockwise until the piston hits the stop tool and the engine won't turn over. Make a mark on the damper next o the TDC mark. Now rotate the engine by hand counterclockwise until the piston hits the tool and the motor won't turn over any more. Make another mark at TDC on the damper. The midpoint between the two marks you just made is true TDC. Hopefully there will be a notch in the damper at or near the midpoint between the two marks. If it isn't, make a new mark that is. Remove the piston stop tool and reinstall the spark plug. Second, you need to verify that you have the rotor pointing at the #1 tower on the comparison stroke. Pull your valve cover and turn the engine over by hand while watching the #1 intake valve. Keep turning the engine over as the intake opens and closes. Now keep turning until the FIRST timing mark lines up with TDC. The motor should now be at TDC on the compression stroke. Put your valve cover back on and verify that the rotor is pointed roughly at the #1 plug tower on the distributor cap. If it isn't, make it so it is. Now start the engine and set your base timing to about 6-8 BTDC using the timing mark you just verified is accurate with the piston stop tool. For good measure adjust your valves while you are in there if you have a solid lifter motor. .012 intake and .022 exhaust HOT. |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 5:41 pm ] |
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Thanks Reed I bought a piston stop tool the other day but I don't know how to use it yet So I just install the tool ramdomly without establishing any reference points first? How far does the all-thread need to be turned in? or does it matter? Other then that I understand how to do the other things you said. It's a 1980 engine and I set the valves hot last week while running ( a lot of fun that was ) to .010 and .020 but i'll relash them to your sugesstion. I'll post the results, thanks again |
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| Author: | Reed [ Sat Jul 27, 2013 5:45 pm ] |
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I run the center portion of the stop tool all the way in until it seats firmly to avoid any changes while you are using it. Then remove the #6 spark plug and install the tool. Unless the piston is already at TDC the tool can be installed at any point in the crankshaft rotation. If the piston is at TDC the tool won't thread into the spark plug threads in the head. The only requirement is that the piston not be at TDC when the stop tool is installed. If you set the valve lash recently, don't worry about it. Your issue is almost certainly a timing issue. |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 5:50 pm ] |
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Ok I'll tackle it again in the morning, It's dark here and I have no lights in the garage. Thanks |
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| Author: | Reed [ Sat Jul 27, 2013 5:59 pm ] |
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Bummer! That's what candles are for, man! Or, use the headlights and the interior dome light in the van! I've been there and done that.  Good luck and let us know how it goes. |
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| Author: | vanmansl6 [ Sat Jul 27, 2013 6:03 pm ] |
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If I needed it to get to work tomorrow candles would do! 
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