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ea71 top dead center woes


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15 replies to this topic

#1 Sickly

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Posted 06 April 2013 - 04:25 PM

In trying to get my 78 wagon through DEQ we have run into some timing issues.  We are trying to get TDC on the motor, then reinstall the distributor to be sure that the timing is where it should be.  Following the bentley manual it says that when you turn the crank, you should feel air pressure on #4 when you pass TDC, but we are getting pressure about 1/4 rotation after we see the marks. What could be causing this? Why does the manual tell you to use cylinder #4 instead of #1 like most cars? 



#2 Sub78

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Posted 06 April 2013 - 08:16 PM

According to my Sooby manual "How to Keep Your Subaru Alive" it states that it should be to Cylinder #1 not #4. PM me with your email address and I can send you over a PDF copy of it. It is for all Soobs 75-88 minus the Justy. It has been indispensable these last few months while working on my 78. Luckily my ride came with a well worn copy but the PDF is great for some late night reading in bed when you don't want to get engine oil on the bed sheets. Damn significant others. Ha. 



#3 Sickly

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Posted 06 April 2013 - 08:53 PM

We used the #1 cylinder and it's dead on now.  Is it normal to use the #4 for other engines?  The bentley manual we went by was for a very broad range of years.



#4 maestro

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Posted 06 April 2013 - 09:33 PM

Probably a misprint. Never heard of that before.



#5 Tsuru

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Posted 06 April 2013 - 10:53 PM

The International Harvesters V8s time on the #8 cylinder...it throws a lot of folks off. Book on those is right at top dead center (zero). me, however...I ran shaved heads with about 8 degrees advanced, made it extra oomphy!

 

backwardky,

timothy



#6 Sickly

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Posted 07 April 2013 - 04:58 PM

Got the timing figured out, drove it to the gas station and put some treatment in with a full tank of premium. Ran and drove very smooth and nice. Start it today and drive it around and the idle keeps going up. Pulled into the driveway to turn the idle down, and find that neither the idle mixture screw or the idle adjustment seem to keep it from revving. This is really strange. Was the built up junk in the carburator finally loosed from the fuel only to reveal a bigger problem?

#7 ferox

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Posted 07 April 2013 - 05:26 PM

Sounds more like a vaccum leak.



#8 Sub78

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Posted 07 April 2013 - 05:42 PM

Second the vacuum leak. Going through the same problem with mine. She starts well enough and purrs but after she warms up she wants to rev a bit and eventually gets too lean and will die. Let her cool down and had the fire extinguisher handy and did a quick carb fluid vacuum leak test.

Once started just squirt a bit of carby cleaner at each of the ends of all the lines and carb gasket points. If the idle jumps up then that is where a leak is. Found mine right at the base of the carb where it bolts to the top of the manifold. Easy enough to pull off and replace the carb gasket but if its off and out may as well do a rebuild. That manual I sent you lays it out really well. Whole rebuild kit cost 27$. Just be meticulous.

Do the cleaner test with the engine cold. Carb fluid + hot engine= flammable. Sorry if you knew a lot of this. Just ran in to the same issue literally this past week, figured I'd share seeing as it seems identical. Good luck.

#9 Sickly

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Posted 07 April 2013 - 05:55 PM

Wouldnt turning the mixture screw all the way in make it die?

#10 Sub78

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Posted 07 April 2013 - 07:15 PM

I don't think so, if it was all the way in if I have it figured right you would just be burning really rich (a lot of gas). But... it could be that the vacuum leak somewhere on the carb would allow enough air in for it to run. I mean, when you start your vehicle the choke is making the vehicle run rich to get her started. She can run on a lot of gas but what will happen is that you will run really hot to the point where you will actually burn up the exhaust system ie: glowing red catalytic converter. This is just my thought on the process. I am pretty new to these Soobs and in depth mechanics and such but I've been having a blast with this old wagon. This is almost identical to what I have gone through with mine in the last few weeks. I was able to turn my mixture screw in all the way with only slight change. Along with every now and then I would try to adjust the idle and it wouldn't change anything then all of a sudden she would high or low rev compensating with the idle speed screw. I've likened it to the gasket leak sealing and unsealing itself. We will see what happens. I've got the carb out right now and am just waiting on the rebuild kit to arrive but she looks fairly user friendly to tackle. I hope. 

 

If I'm wrong or mistaken on one of these points please someone feel free to correct me. 



#11 Sub78

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Posted 07 April 2013 - 07:22 PM

Scratch that... with no vacuum leak and the idle mixture screw in all the way it SHOULD die. The vacuum leak is what is keeping it alive. 



#12 Sickly

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Posted 08 April 2013 - 10:53 AM

Okay... that makes sense.  I also just this morning found a little piece of what looked to be a black, paperlike piece of gasketing inside of the second barrel of the carb, so maybe thats where I'm getting a leak.  Its acting like the throttle is opening more and more. It seriously revs up and sounds like it's trying to take off like a jet. 

My girlfriends dad came by while working on it and he suggested that it might be a racing motor. LOL!



#13 Sickly

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Posted 08 April 2013 - 10:54 AM

BTW Sub78 thank you very much for the PDF of that book.  When it comes time to rebuild my carb the walkthrough in there is exactly what I am going to need.  Thanks!



#14 Sub78

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Posted 08 April 2013 - 02:58 PM

No problem man. I'd have been lost without some of the help here on the board. Just returning the favor.

#15 ferox

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Posted 08 April 2013 - 07:19 PM

Wouldnt turning the mixture screw all the way in make it die?

Not necessarily.  If you have bypassed the idle circuit then the mixture screw won't do anything.  If you blew gasket in the secondary, then that's probably what's happening more or less.



#16 Sickly

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Posted 09 April 2013 - 02:11 AM

There was a substantial piece of gasket material in the secondary.  I am going to spray and pray when I have some free time.  In the meantime, she sits.






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