Two cylinders not firing, And I thought I was doing so well Options

[Maine914]

I got this resto project over the winter. Drove it from Albany to Maine. It has Dellorto carbs on it. In number 4 cylinder, the secondary venturi was melted. It took me two months to find a replacement [from Italy, no less]. Rebuilt the carbs. New plugs, new wires, new rotor, new condensor, new distributor cap [its got an 09 Bosch], gapped the valves, timing is fine, dwell is fine.
I test drove it around a bit. And the car zips along. Had it over 70 on the highway.
But it was spitting oil out of the exhaust. Played with the mixing screw on the carbs. When I'd close the carbs for 2 and 4, no difference. Thought it was plugged jets or something. Took apart the carbs again. REALLY cleaned them up. Put them back on. Same problem.
So, I began to experiment. I disconnected the ignition wire to 4...no effect on the engine. I thought maybe it was the wires -- switched them around -- still no effect.
I don't know whether only two cylinders were working when I bought it -- but I drove it back from Albany at 70 mph. Can these things really go that fast on 2 cylinders?

It was late, so I did not want to do something REALLY stupid [as compared to the average stupid things I do with the car.]
What advice, expertise, sympathy, recommendations, help can you folks offer? If I'm missing something really basic here, don't hesitate to explain how stupid I am. If its really bad, don't hesitate to give me the news.
Thanks.

[Bleyseng]

Adjust the valves and then do a compression test to see if all the cylinders work.
Geoff

[Maine914]

I forgot to mention that according to the synchrometer, the barrels for the 2 and 4 cylinders are sucking air. So, I think they're working...but not firing.

[Bleyseng]

Check to make sure the spark plug wires are in the right location. The firing order is 1-4-3-2 so look at the number stamped on the engine tin to make sure the wire is the right one connected to it.
Simple thing to mix them up when doing a tune up.
Geoff

[Lawrence]

Spitting oil out the exhaust?

What do your plugs look like now? Are they so crudded up they can't fire?

-Rusty

[Maine914]

thanks. Wires are in the right location. I'll pull out the plugs...maybe tonight if I get home early enough. Would it be helpful [and safe] to plug the wires from the 1 and 3 locations on the distributor into the 2 and 4 plugs to see if its the distributor?

[Brad Roberts]

The plugs could be jacked up (oil or gas fouled)

The idle circuits for that side could be jacked up (physically something blocking them)

One you are over 1500 (or so) RPM the main circuit pick ups and is slightly fed by the idle circuit... so it could run at higher RPM once its "off" the idle circuit.

B

[Lawrence]

I wouldn't deliberately misroute wires.

How did you check your sparkplug wires? Are you using known good components - remember, just because it's new, it's not necessarily good.

This may open a can of worms, but I try to use Bosch stuff when I can. What are you using?

-Rusty

[seanery]

Be careful when replacing your sparkplugs-especially if you have 2.0 heads and 1.7 sheetmetal-DON'T crossthread them.

PLEASE DON'T ASK HOW I KNOW! (IMG:style_emoticons/default/huh.gif)

[need4speed]

my 72 Ghia with it's stock 1600 dp motor can do 65 on three cylinders. I wouldn't be suprised if a 914 could do 70 on three. 2? maybe? - I'd also guess that maybe the cylinders are intermittently firing at speed, but not at idle? (what Brad said).

[Maine914]

All the ignition stuff [wires, cap, points, condensor, rotor, plugs] are from PP. I checked the wires by taking them off the plugs that were firing, and putting them on the plugs that weren't [after changing the location at the distributor as well]. I guess the carbs somewhere could be blocked, I just don't know where -- and would that account for the gas in the exhaust? This is very frustrating. I'll have to go home early to deal with it.

[Brad Roberts]

If I had a melted carb component.. that carb would have been thrown away. It means that you coul have other issues "buried" inside that carb that NO amount of cleaning will help.

Can you pull the plugs and show us with pics... ??


B

[Maine914]

Good point by Brad but how would that account for the other carb?

[Maine914]

Back again. Today was engine day. Last week, as you may remember in the long running serial, I was getting nothing out of cylinders 2 and 4.

Good news: Today, I put in a second set of new ignition wires, and the number 2 valve worked.

Bad news: Still getting nothing from number 4. Get sparks out of the ignition wire, so must be something else.

Good news: Did a compression test. All of the cylinders were within 5 psi of each other.

Bad news: The average was 80, assuming my new, off the shelf, Sunpro compression tester is accurate. Do these things not work? Anything under 100 is supposed to be bad, right? So, they're all bad?

The spark plugs when they came out were as follows: #1 - black sooty, #2 - a little oily, #3 - oily, #4 [the bad cylinder] - clean as whistle.

So, Brad may be right. That was the cylinder that had the melted venturi.

So, I got a general engine problem -- low compression, assuming the tester is accurate.

And a particular one -- number 4 cylinder.

What do you think?

[mskala]

For compression test, engine has to be warm and you should
pull all the plugs so it spins fast. If you didn't do it that way,
the 80 is probably not the real number.

[Maine914]

I ran the engine so it was warm, let it cool off for about 10-15 minutes, and I pulled all the plugs. Should I try it again and not let it cool off at all?

[mightyohm]

That should not make a difference.

[crash914]

Don't forget to open the throttle. If the throttle is closed, you will drop to around 80 lbs.

[rhodyguy]

try removing the af needle screw and the idle jet and blow some compressed air through the circuit, those little cans you can buy work well. with the tops off the carbs you should see a fine spray when you operate the linkage, motor not running, in each throat. melted metal components in the carb? alumimum goes fluid @ about 1200 f. that's a real puzzler. have you checked continuity in all of the spark plug wires? if you pull each plug, one at a time, still attached to the wires, and crank the engine over, how many and which ones show a spark when you hold them just off of a ground? are all your new parts made in brazil or germany? when the idle jets are out hold them up to a bright light and ensure there is light coming down the center, do not shove anything through them to try to clean. i feel your pain (IMG:style_emoticons/default/wacko.gif)

kevin

[Maine914]

The ignition wires are sparking. No cloud is in the bad barrel when I open the throttle, and there is a cloud in the good one. Idle jets seem clear. I'll clear the cirucuits out again. I'm wondering weather the "meltdown" caused some of the circuits to melt as well? Its a mystery.