F-head oil soaked plugs and miss.

I have a 59 F head I'm working on for a friend, #2 cyl. is dead and intermittently #1 as well. Plugs & piston tops in both cyls. are oil soaked especially #2. Compression test was #1-4; 115, 120, 95, 105. Wet test increased all by about 5 lbs. I swapped #1 and #2 wires and the #2 is still consistently dead (no change in idle when spark plug boot is pulled off while running). I know my next step is a leak down test but I have a few days before I can get to it again. So I figured I would post up here for any suggestions.
If I recall it has a Omix-Ada solid state distributor, and I have had very poor luck with their quality. I have not known these distributors to missfire on only one cyl., they either work ok or not at all. Cap & wires are all new. Plugs are not carbon bridged. The compression results while not great would indicate rings are ok in #1,2 cyls. The spark plugs in cyls. 3,4 show no oil fouling just rich. It starts really good no matter the temperature, but has a miss at all rpm's.

 

Pull 1 and 2 plugs and put the wires back on and ground the plug threads to the block. Check for consistent spark. If you are getting good spark then it has to be fuel. Check for vacuum leak in 1 and 2 area. You said it runs so timing is not an issue at this point.

 

I have confirmed that #2 is consistently not firing, and #1 will fire intermittently. I confirmed the distributor is a Omix-Ada reproduction electronic pick up unit. I agree timing is good it starts readily and runs at all rpm's without issue other that the said miss. I started it and sprayed starting fluid at the base of the carb where the gasket is located and the throttle plate bushings are, there was no change in rpm so I feel confident there is no vacuum leak.
I am suspicious the distributor cap coil electrode may be bad. Can I get a new distributor cap for this solid state distributor at a auto parts store? If so what application is it?

 

My suspicion is that the pick-up coil is colliding with the reluctor inside the dist. Any time the reluctor tip touches the pick-up core it will kill that trigger. Don't know much about Omix stuff but electronic distributors are pretty critical on spacing between reluctor and pickup. Is the pickup-coil to reluctor distance adjustable?

 

That's unpleasant and I am very sorry for you.
Do not make the mistake I did, check one thing at a time, not 2.
Omix-Ada is making the parts, I bought some, but they are very cheap made.

I cannot help you, what I know with electricity is that all parts must be tested separately.

 

I agree Alan diagnosis is a methodical process. I discovered the coil electrode in the Omix cap is chipped and a piece of it is missing. This engine has less than a few gallons of gas through it since the distributor swap. It took 6 pick up modules to get one that works, I HATE their products. They are fine for a static display vehicle but not if you have any expectation of using it. I got a new cap from NAPA so hopefully it is better quality.

 

Well the old cap was definitely bad, new cap helped and made #1 cylinder fire consistently. The #2 cyl is still dead, I swapped wires from #3,#4 cyls. onto #2 plug and it is still dead. I did notice when the plug wire is 1/2 way on the sparkplug #2 will start firing, but when pushed all the way on it goes dead. This happens no matter which wire I use on #2 so I don't think it is a bad wire. Likely a bad plug is what I am thinking.

 

Swap #2 plug into hole #4 and see if it will burn the carbon out of it.

 

This sounds like the old "spark gap" trick. By creating an artificially large gap before the spark plug, it forces the HT charge to build a higher voltage before leaping the gap and then it successfully fires the plug. Maybe a sign of excess resistance in your plug, or it is gapped too wide.

 

I hate to say it, but just when I was getting a handle on this, it throws me a curve. I installed new plugs and now #3 cylinder is the dead cylinder and #2 is firing along consistently. Even if I swap #3 plug with another cylinder's plug #3 hole is not firing.

 

If it was me I'd put the old "points" distributor back in, if you have it.

 

PeteL your reply gave me an idea. I wonder if opening the gap on the plugs would help? I set the new plugs at about .022.

 

The old distributor is not servicable which is why the new one was installed.

 

Should be .030" Do you have a FSM? Well worth it.

 

Yes I have repo FSM's but I looked on line and it said depending on the distributor either .020 or .022. I'll open them up to .030 and try that. Here is the link I found for the gap info. http://cj3b.info/Hurricane.html

 

020" is the distributor point gap. not the plugs.

 

020" is the distributor point gap. Not the plugs.

As is correctly shown in that link, plugs are 030".

 

Stupid me!........

 

It is running very well now that I gapped the plugs properly. It's got a miss at higher RPM's, bad weather around here has kept me from taking it for a test drive out on the road. But driving it around my yard it is doing great.