Running on two?

[Littlewozza]

Hi been a little stuck since going to the car today, it will idle rough, but exhaust manifold was only getting hot on 2-3 cylinders so I pulled the plugs compression tested it and I'm getting 8.5 on every bore. Now I'm getting a good spark when checking outside the engine, I've tried swapping plugs etc, it's as if I'm not getting a spark to number 1-4 under compression and I can't understand why? Or maybe the carb isn't fueling one and four? No idea I'm stuck. Ive recently removed the air injectors etc and I'm wondering if this could be a vacuum leak somewhere would this cause it?, coil is getting pretty warm to so maybe that's to fault, wanted some other opinions from people who have messed with these engines though and though.

[Doctor510]

Sounds like the firing order is wrong.  i-3-4-2 COUNTER CLOCKWISE

[banzai510(hainz)]

olddatsuns.com read the tech section

 

valve lash maybe be tight thats why not feel like its fireing. your getting spark but no compression. Ck valave lash. or lash pad fell out

 

Highly unlikely 2 cylinders bad at same time so it may be fire order but I alwasy assume it was working right then stopped unless you did soemthing.

 

Coil HOT??????? you buy wrong coil or no ballast reisitor. Depends if a point distributor or a Electronic ignition distributor.

[Littlewozza]

Just got around to looking at this, you were spot on doctor510, someone has screwed up all the leads (probably me! They were 180Degrees out) that mixed with two split vaccum pipes made it miss badly. Thanks for the reply!

[distributorguy]

The truck won't run at all if the leads are 180-out.  It'll only let out a big backfire.  

 

The biggest reason 2 adjacent cylinders would get the manifold red hot is a vacuum leak - a bad seal allowing fresh oxygen into the exhaust manifold.  A rusted out air rail can also do this.  

 

The coil will get hot due to plug wire issues - high resistance or a failed wire.  Or two wires crossed.  

[datzenmike]

Two wires will always be correct when 180 out

 

The air rail blows fresh air in under pressure to burn off hydrocarbons. If rusted out even less air gets into exhaust.

 

Coils get hot from too much current flow in the primary. Ignition left on with non running points engine or EI distributor running a points coil without the ballast. The secondary flows very little current but much higher voltage. High resistance or failed would flow zero current in that wire. Unconvinced this would over heat the coil

[distributorguy]

I rebuild 1500-2000 distributors a year.  I know what I'm talking about.  Many are for cars that cost millions $$$$$$$$$$$.  Coils overheat from virtually any HT lead issue.  

 

Mike, you're comment is assuming the air pump works and is in service.  Rare to say the least.  

 

How are 2 wires correct when the distributor is still wired 1-3-4-2 but the wires are half-way around the cap?  ALL wires are 180-out.  If only 2 are wrong, then we're not talking about 180-out. unless the rotational direction of the distributor gets reversed, which it does not.  

1-3-4-2

4-2-3-1

Which two stayed the same?

 

Now if we assume its wired CW instead of CCW, then we have this:

1-2-4-3

1-3-4-2  and we have cylinders 1 & 4 firing.  Reversed, not 180-out.  

[banzai510(hainz)]

Onwer induced proplem

Now it fixed!!!!!!!!!!

[datzenmike]

$$$ cars? They should get Datsun coils.

 

Was thinking an owner would know the firing order and get it right just the direction wrong. As in CW 1342 vs. CCW 1342. one and four are still in one and four.

[Littlewozza]

I actually didn't have it 180 degrees out I had 2-3 in the correct place but 4-1 crossed me being tired and not thinking it though properly made me automatically think the worst and not the fact I could have been a idiot and just miss placed the leads!, the coil was getting hot I had short now sorted and is just warm to the touch when running, air pump doesn't work at all, all been ripped of now, is it safe to say now I've removed all the pumps leads etc, if I just weld the manifold up it will be okay? Nothing else to remove? Just got to rebuild the old walbro fuel pump and clean the tank, rebuild the carb, replace all vacuum lines, give it a good service and see how it runs.

[distributorguy]

Plug and eliminate smog vacuum lines including the one that went to the air pump/gulp valve.  With the Weber, the only vac line left will be ported vacuum to the distributor (no vacuum at idle).  I', not sure if you can weld the manifold.  May be better off putting in a short screw/bolt.  Or weld what's left of the fittings if you can't get them out.