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ea71 timing


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Before I got the timing light I just fudged around with the distributor till it was running good, now months later when I hit it with the timing light it said it was at 22 degrees so I retarded it down to 8 degrees and now it is running like crap.

 

What is the factory timing for the ea71

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The popcorn symbol basically means 'watching this thread with interest', or something to that effect.

 

The factory specs for a EA71 are 8 degrees BTDC but you can ususally advance the timing a little, say 10 or 12.

 

22 degrees seems a bit excessive... Sorry not sure what would be causing that.

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ok i seriously just slammed my palm into my forehead as i just read the sticker on the hood of my car

 

8 degrees plus or minus 2, disconnect the vacuum hoses going into the distributor before timing it

 

with this timing now i am getting even less top end power and it's backfiring when i step on it in third. fml.

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  • 4 months later...

'78 BRAT EA71: 8 degrees with all vacuum lines connected, +- 2. Smog tech doesn't disconnect anything to check the timing, just puts a light on the flywheel at correct idle and wants to see those numbers. I think that is not advanced quite enough either due to exhaust backfire when its cold and based on general engine performance. But I get detonation if I advance it any further (under high manifold pressure). I may have weak flyweight springs and am beginning to look for an alternative to the distributor:-\

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I stand corrected; I wonder if it makes any difference at idle speed. At the smog check they didn't plug any hoses, just shot it with the timing light at idle.

Will this engine run better with an ea81 distributor? I read a comment somewhere that says the 2wd version has a better spark curve. Don't most of those also just have an advance vacuum?

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  • 2 weeks later...

You may want to check if your mechanical advance is working correctly. Sounds like it could be jammed

 

Turn the rotor to see if it rotates about 10 degrees and then snaps back smoothly. If not then this could be the problem. (worn or broken springs or springs fallen off or rotor sticking)

 

For sure, disconnect and plug VAC advance when testing. Don't worry about the VAC too much. All it really does is give you better millage when cruizing. Most cars of this age have broken VACs and people don't even notice.

 

Also you may want to verify the timing marks on the flywheel. I changed the flywheel on my EA71 and figured out the hard way that the timing marks are not the same as the original one. If you take out the NO 1 spark plug you can just about see the piston at TDC. Not a very accurate method but it will give you a ball park to work on.

 

Keep us posted on the out come.

 

Lastly, a super rich fuel mix could also be the problem but I would want to check the above before looking at this.

 

Dirk

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  • 2 weeks later...

found my (new) rotor was loose on the shaft, and also the distributor advance plate was worn and sloppy which varied the air gap and probably timing a bit, too (shaft bushings were fine). Installed a good tight electronic distributor from my '79 parts truck and another new cap and rotor with some improvement. Vacuum diaphragm tests good both directions. Initial advance vacuum signal seems weak from the block but does work until the mechanical takes over, and the vacuum retard works quickly upon throttle closing. On engine deceleration I get popping out the exhaust when it's cold, but goes away after it warms up. The choke is set lean as is the idle mixture; maybe that is causing the backfire when cold. Timing is about 10 degrees at idle. Overall it is very driveable, just nothing like electronic fuel injection...Does anyone know how much vacuum should show for the ported advance when initially opening the throttle?

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Regarding the backfire when cold. I had put up with this for years. I stopped it by blocking the input to the pulsed air injection system, which stops the introduction of air into the exhaust system. You will need to put things back to normal before going in for a smog inspection.

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