My 27 coupe appears to be running on two cylinders.

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Unprr
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My 27 coupe appears to be running on two cylinders.

Post by Unprr » Wed May 08, 2019 10:37 pm

My question is this.
My T started to run very poorly last year, so I decided to put in a set of new aluminum pistons. I honed out the cylinders and the walls measured stock. With that said, I replaced the original valves with the new type. ( Non-adjustable)
Now that have it back together, it’s very hard to start and when it does start, it runs better with the timer all the way down. It appears to be running on the front two cylinders, since the two back ones still look clean and have the magic marker order number on them.
I have tried timing it by the book, the spark from each plug looks hot.
I need some expert help, on what to try next.

George Schmidt
Elkhorn, Nebraska

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Ruxstel24
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Re: My 27 coupe appears to be running on two cylinders.

Post by Ruxstel24 » Wed May 08, 2019 10:50 pm

I would probably check compression next.
Did you check the valve clearance ?? All good ??

Could you possibly have 3 & 4 wires crossed ?

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HalSched
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Re: My 27 coupe appears to be running on two cylinders.

Post by HalSched » Wed May 08, 2019 11:28 pm

What about timing?? Did U install the timing gear to the correct match?

Basic timing:
Spark lever up, #1 cylendar just past top dead center on the compression stroke (remove #1 plug and with a wire feel the piston go just past TDC ) The #1 coil should start to buzz. (Fireing order:1,2,4,3)

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HalSched
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Re: My 27 coupe appears to be running on two cylinders.

Post by HalSched » Wed May 08, 2019 11:31 pm

Did you adjust the valves?

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Steve Jelf
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Re: My 27 coupe appears to be running on two cylinders.

Post by Steve Jelf » Wed May 08, 2019 11:55 pm

I agree, check compression and timing.
This details the latter: http://dauntlessgeezer.com/DG97.html
The inevitable often happens.
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1923 Touring


Altair
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Re: My 27 coupe appears to be running on two cylinders.

Post by Altair » Thu May 09, 2019 6:23 pm

Remove the two plugs in question lay them on the block and see if they fire(in the right order) If they fire then check the wiring on the timer and on the coil box. It is easy to get wires mixed up. The small wires tell the big wires what to do. There are wiring diagrams available.


Norman Kling
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Re: My 27 coupe appears to be running on two cylinders.

Post by Norman Kling » Thu May 09, 2019 9:19 pm

Since you say you replaced the pistons and valves, I would start there to find the problem. First thing is to do a compression check. Another potential problem with two adjacent cylinders not firing, would be a blown head gasket between the two cylinders. That would also cause low compression on those cylinders. All cylinder compression should be approximately the same. If the two rear cylinders show low compression, check the valve clearance. With the lifter resting on the heel of the cam, it should be about 12 thousands. If not, you have either sticking valves or too tight clearance. If your compression tests OK and it runs on two cylinders. next I would suspect the ignition system. As posted above, might be two wires crossed. You could have two bad coils, two bad spark plugs or problem with the timer. Did you remove any wires from the timer? If so, you could have two of them mixed up. One other possible problem would be something either blocking the intake manifold or a vacuum leak on the rear port of the intake manifold.

Have Fun finding the cause, and when you find it, please let us know what you found.
Norm

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