Problem Diagnosis: May be bad

[NC Rover]

I used some previous advice from an old thread and decided to run the rover, and unplug a plug wire one at a time to see if there was any change in the motor. Starting from the front of the rover going back, I unplugged each plug wire, causing the motor to bog down. Well I got to the last plug and nothing changed. Regardless of whether I plug it in or unplug it...no change in the motor speed/sound. So with that said, I'm trying to determine if this is the sign of a motor rebuild or could it be something smaller..say the distributor.

And I'm bummed b/c I just installed a brand new 32/34 DMTL carb.

I"m taking it on monday to have a compression test / leakdown test done but figured I'd ask what I should expect to hear as far as results. Could the problem lay in the head with the valves or is this a sign of the cylinder...

Engine was rebuilt in '95 and it has seen quite a few miles...

What it has so far:

-New Weber Carb
-New plugs / 8.5 mm plug wires
-Petronix Igniter
-Jacobs Coil Ignition
-Cleaned fuel pump
-New Fuel lines/filter
-New Cap/Rotor

**How do you tell if your vaccum advance is working or not?

[BGGB]

i've had this problem before, i wouldn't jump right into a motor rebuild though i'm sure you still have some life in it yet. when mine was acting up i replace all ignigtion system with new... however this was in the plans for restoration so i justifided that way. i'd check the gap on the spark plug and lead going to it. i'f your careful you can hold the plug and wire agaist the block while turning it over (insulated screwdriver on starter...in nuetral) to see if there power is even reaching the plug. or it could be in the distibutor...rotor cap condensor. just take your time tracing it back and you should be able to find the problem. if your rover has been sitting new gas makes a world of differece too. good luck

[Oscar]

Yup, make sure there's a spark. You can get a compression tester at Sears for less than one hours worth of labor and get an earlier answer.....

http://www.sears.com/shc/s/p_10153_12605_00999071000P

Check all four. If #4 is out of whack and you have spark it's time to check the valve timing.

[yorker]

you did ensure you were getting spark from the # 4 plug wire- right? grounded it against the head withthe plug on it or something? When did you adjust your valves last?

[sven]

Hopefully its just a burned valve...much cheaper than a full rebore.

[greenmeanie]

Cheap test that will tell you something. Swap the #4 plug lead to another cylinder and see if that acts up. If so then you know it's the lead or cap. Do the same with the plug and it will allow you to eliminate that as an issue. Check inside the dizzy cap for tracking. Swap ther old one back on if you still have it.

[Jeff Aronson]

Greenmeanie's advice is ideal to remove the plug wire and/or plug as the problem.

When you pulled the plug, what did the tip look like? Black coated? Gas/wet coated? If the plug is not getting a spark, then the plug would be wet with gas or oil. You do want to determine whether it's something simple like the plug wire.

If you have another spark plug wire, then install it in place of the current #4 and see what happens.

I hope you luck out with something simple. When it happened to me, I found out I had a burned valve. A compression test showed that I had very low compression on that one cylinder.

Jeff

[1961 109 WAGON]

vaccum advance check..
pull the top off the distributor.
pull the line coming off the carb that goes to the dis.
now look at the plate on the dis. and blow or suck on the hose, it will MOVE IF IT WORKS.

[NC Rover]

Greenmeanie's advice is ideal to remove the plug wire and/or plug as the problem.

When you pulled the plug, what did the tip look like? Black coated? Gas/wet coated? If the plug is not getting a spark, then the plug would be wet with gas or oil. You do want to determine whether it's something simple like the plug wire.

If you have another spark plug wire, then install it in place of the current #4 and see what happens.

I hope you luck out with something simple. When it happened to me, I found out I had a burned valve. A compression test showed that I had very low compression on that one cylinder.

Jeff

I pulled the plug and it was dry. It was a little more darker in color than than the others...but no major oil residue and no wet fuel.

I haven't had a chance to see if spark is coming through the plug.

I'm going to check that as well as the vaccum advance when I get back. I have to leave out of town for work and don't get back till friday. I was going to have the compression test done on monday but wont' have time.


It may be a valve issue. Not sure. I just adjusted the valves twice and each one is adjusted properly.

The distributer has the petronix igniter setup/jacobs coil.

I'm really bummed out about it. I hope its something simple but I'm afraid it might be worse.

Question: If I discover that there IS spark getting to the plug, are there any other issues that could be causing this other than a burnt valve or cylinder problem?

[msggunny]

I had the same problem with mine. It was a bad spark plug.

Hopefully that is all that it is.

[NC Rover]

Since I'm somewhat new to distributers, I took it upon myself to read how to dismantle/refurbish. I will say Teriann's site had a great writeup describing how it works/etc in easy terminology for a dummy like myself.

http://www.expeditionlandrover.info/Distributer.htm

When I get back, I'm going to check the points/timing of the distributer. Possibly replace the points. The cap and rotor are new. Hopefully I can follow these directions and time the dizzy properly.


1.) From looking at the picture below, can anyone confirm that these plug wires are connected to the proper plug in the correct firing order? Right side of the picture if the front of the rover:





2.) Also this will be a really stupid question to most..but after I take off the cap and remove the rotor, how do I get to the points? I know my dizzy had a petronix igniter setup. Do I need to remove the metal plate and the points are beneath it? Just want to make sure I'm familiar with it before I take stuff apart. (see pic below)







thanks!

[greenmeanie]

IIRC the firing order is 1432 so your leads are in the right order. You'd need to check the timing to see how they are orientated relative to the rotor.

If you have a pertronix you do not have points. This is a big plus. The parts that replace the points are the magnet rotor which is the black cylindrical object right under the rotor and the sensor which is the block like object hiding behind the rotor in your pictures. There is no gap and nothing to wear so there is not much to check on that front. The magnetic trigger just tells the little box the rpm and the timing of the spark so if it fires on one cylinder it should spark for all four.

If you remove the plate and rotor you'll look down on the vacuum advance cam and the mechanical advance weights. There's not a lot to it.

[NC Rover]

IIRC the firing order is 1432 so your leads are in the right order. You'd need to check the timing to see how they are orientated relative to the rotor.

If you have a pertronix you do not have points. This is a big plus. The parts that replace the points are the magnet rotor which is the black cylindrical object right under the rotor and the sensor which is the block like object hiding behind the rotor in your pictures. There is no gap and nothing to wear so there is not much to check on that front. The magnetic trigger just tells the little box the rpm and the timing of the spark so if it fires on one cylinder it should spark for all four.

If you remove the plate and rotor you'll look down on the vacuum advance cam and the mechanical advance weights. There's not a lot to it.

I do appreciate the description. So I'm guessing with no points to deal with, my problem with cylinder 4 might be worse than I suspected. I just need to figure out if spark is getting to it...I'm guessing it is since there is no sign of oil or wet fuel on the plug. Hopefully the compression test will give me an idea.

[Jim-ME]

IIRC the firing order is on the intake manifold or at least it is on my 2.25. I could have sworn that it was 1342. I would be very suspect of the Jacobs wires before I got too concerned about an internal engine problem. I put in a complete Jacobs system in a Ford P/U years ago and wasn't overly impressed with it especially considering what I paid for it.
Jim

[I Leak Oil]

Your leads are on in the correct firing order, 1342. Can't tell if they are in the correct location but they are in the right order. To make sure they're in the right location put the engine on TDC on the compression stroke for cylinder #1 and make note of which plug wire the rotor is pointing at. This is the easy way but assumes your timing is close.
You have no points on the distributor in your picture.

Jason T.