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JonOfScio

1st cylinder not firing, how do I tell if it's a crack or piston rings?

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Never had any problem with rings before, and I don't suppose they just 'go'

 

I put some oil in the cylinder to test it out, all it did was puff smoke out the back. Taking the spark wire off the plug results in no change of idling sound at all. Is there a crack in the intake and exhaust ports?

 

Is the only way to find out to take the head off?

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Youre sure its not a wire or plug gone bad?

 

Sorry just wishful thinking maybe I didn't read something completely.

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Do a compression test. Then do another after putting a little oil in. If the reading increases after putting oil in, it's rings. If not, it's either valves or head gasket.

 

As to rings "just going", that's apparently what happened to my engine. It was running in tip-top shape then all of a sudden it wasn't making any power. I tested compression and three of the cylinders were perfect, while the other had half their compression. The rings were the culprit. I have no idea what made them go, but I'll tear that engine apart after I get the rebuilt one in.

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yeah, tested out the wire on a couple other cylinders, and also used another good wire. They aren't bad.

 

Used a new spark plug as well. As well as an old but good one.

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My engine is all internally an '88 EA81, so it has hydraulic lifters, and the old heads used to have bigger valves, but the heads I have on now are two drivers' side '83 heads. Not quite sure about the year, but they have the same size valves for sure.

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if it fires on three other cylinders, is it possible there could be something wrong with the distributor when it comes to the first cylinder?

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I know it gets spark to the plug, I got zapped a couple times playing with wires.

 

:clap:

 

so maybe it's not grounded properly to the head? this sounds like an all too EASY and certainly interesting idea as a fix. This is probably it.

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hm, now that I think about it. I think the spark plug hole's grooves and very top of the head are dirty with fried oil. I lubricate the spark plugs as I put them in so they don't go in wrong and so they make a good fit... I wonder if it's so charred it's not making a ground for the spark plug!

 

Hm. Oh well, the car is at my girlfriend's house, so I have to wait to touch it until tomorrow.

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Possibility here of a slight carbon track inside the disty cap, either to ground or another terminal on the cap.

 

Could be enough of it to cause plug not to fire, as carbon will flow the electrical charge easier than the charge can jump the gap of the plug.

 

As for you getting a charge when playing with the wires. :eek: Still could be in the disty cap. As "you" will flow an electrical charge easier than the carbon track will.

 

As mentioned above, pull the plug, re-attach the plug wire, lay it on the block assuring a good grounding of the plug, then have an assistant crank engine while you watch for spark at plug.

 

No spark would lead me to think of bad wires, and/or disty cap.

 

If you get a spark at the plug, I would then pull a compression test on the engine.

Also, if you have the means to do it. I would use the tester fitting to apply an air source to the cylinder. Helps to have the piston at Top Dead Center when doing this test. (use pencil in plug hole to verify TDC).

Listen for air at the intake opening, exhaust pipe, oil fill tube, and look for bubbles in the radiator.

Results of this test are;

At intake--bad, or stuck intake valve/seat.

At exhaust pipe--bad, or stuck exhaust valve/seat.

At oil fill tube--bad piston rings.

Bubbles in radiator-- bad head gasket/cracked head.

 

Just my .02

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well, first off, I've cleaned the disty cap and cleaned the rotor, and played with new spark plugs and different wires, so I'm pretty sure it's getting spark.

 

I do have a compression tester on loan from Hondasucks. Just need someone else's help with it.

 

The rest of the info is surely good to know.

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its very possible that the head has dropped a valve seat. the only heads i have seen that were too bad to use had loose valve seats.

 

one head that was questionable that i used, took a dump later, i suspect a dropped valve seat also

 

a compression test will verify this.

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When this happened to me, the culprit was a LIFTER went south. It was the last thing I checked, because Subaru brags about how there lifters are indestructable. Well quess what, I had a bad lifter. I was just about ready to throw in the towel when I was pissing around with the rocker arm & noticed the one arm was really spongy. Got junk yard lifter out of old hatch, popped it in, then bled it down over-night. Next morning equal compression on 4 cylinders. Hope this helps!

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when i got ole Junky from the scrap yard she ran on 3 cylinders.. but at first glance i knew it was plugs because they were rusty..

 

3 plugs were burning normally.. the 4th on #1 was black and oil covered.. very fouled..

 

so i changed all the plugs, and she runs like new.. but you already got new plugs.. i'm still wondering why mine was gooey with oil.. am thinkin she might have a valve issue as well, but she doesn't smoke, miss, nothing.. i did have to add half a quart of oil since i got her (1500 miles ago) but shes got 199,500 somthing on her and looks original.. going to take a pic when she his 200k even..

 

let us know what ya find out.. would be interesting to know.. how'd your old plugs look when they came out?

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cylinders two and four were normal and 1 was completely black minus the electrode and metal parts that spark. two was a little dark grey.

 

one was probably black from the 'oil in the cylinder' idea.

 

will check valves later today.

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sounds about what mine looked like really... your cracked valve seat or somthing might have progressed a little farther than mine has.. i'd clean the threads in the head on that cylinder real good..

and give that a shot... maybe even try the new plug from #2 in #1.. might have a bad plug even though its new..

 

in any case, your problems might be what i'm looking at in the future if its the same thing.. which it sounds like it is..

 

i'm thinkin about doin an ea82T transplant into mine this summer tho :D have all the parts to do it really...

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