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:

http://i32.photobucket.com/albums/d49/W8kbrder/Land%20Rover/5.jpg



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)

http://i32.photobucket.com/albums/d49/W8kbrder/Land%20Rover/2.jpg

http://i32.photobucket.com/albums/d49/W8kbrder/Land%20Rover/3.jpg

http://i32.photobucket.com/albums/d49/W8kbrder/Land%20Rover/1.jpg

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.

[Jeff Aronson]

While lots of owners have positive experiences with Petronix and similar electronic distributors, I've not shared those good results and I've helped other owners on the side of the road whose distributors failed them.

So, if you ask around, I'll bet someone has an old points distributor they could send to you. If you check and gap the points, and then time the car, and then run the car, you can either eliminate or confirm the distributor as the problem.

At the British Invasion a decade ago, one enthusiast joined a crew of friends doing an overnight valve job in the belief that his poorly running car suffered from a burned valve. When he fired up the car the next morning, it ran no better. A skeptic of the original plan, a man who really knows auto electrics, again offered up the spare distributor he carries with him. The car hummed like a turbine. The problem was inside the distributor all along.

Jeff

[Bostonian1976]

I had very positive experiences with Pertronix right up until this...I'm still getting another one (under warranty no less). It's definitely an easy solution but I learned that I should have a backup in the vehicle...

http://farm4.static.flickr.com/3272/2923965980_c9b4ab777f_b.jpg

[Bertha]

While lots of owners have positive experiences with Petronix and similar electronic distributors, I've not shared those good results and I've helped other owners on the side of the road whose distributors failed them.

So, if you ask around, I'll bet someone has an old points distributor they could send to you. If you check and gap the points, and then time the car, and then run the car, you can either eliminate or confirm the distributor as the problem.

At the British Invasion a decade ago, one enthusiast joined a crew of friends doing an overnight valve job in the belief that his poorly running car suffered from a burned valve. When he fired up the car the next morning, it ran no better. A skeptic of the original plan, a man who really knows auto electrics, again offered up the spare distributor he carries with him. The car hummed like a turbine. The problem was inside the distributor all along.

Jeff

I agree . I am a big fan of points-no guessing with them.

[I Leak Oil]

I've had a pertronix unit for 8 years now with nothing but flawless performance. Don't leave the ignition key on without running the engine as it can burn up a pertronix just as easily as a set of points.

Nothing against points but they never stay in tune for very long. Just a gradual, but constant degradation of performance. 2.25L don't have much to lose to begin with so every little bit helps!

If you like constant tuning then go with points, If you're not scared of little black boxes then consider a pertronix....That's my take....
Jason T.

[Bostonian1976]

Don't leave the ignition key on without running the engine as it can burn up a pertronix just as easily as a set of points.


yeah - that was my mistake.....I didn't think this would behave as a set of points would...

the cell phone charge that night was not worth the burned out Pertronix :)

[JimCT]

one advantage of an electronic, non-points set up is it pretty much ignores the wear on in the shaft bushing that might make the dwell inaccurate. Nothing rubbing against the lobes. Just a thought.

[NC Rover]

While lots of owners have positive experiences with Petronix and similar electronic distributors, I've not shared those good results and I've helped other owners on the side of the road whose distributors failed them.

So, if you ask around, I'll bet someone has an old points distributor they could send to you. If you check and gap the points, and then time the car, and then run the car, you can either eliminate or confirm the distributor as the problem.

At the British Invasion a decade ago, one enthusiast joined a crew of friends doing an overnight valve job in the belief that his poorly running car suffered from a burned valve. When he fired up the car the next morning, it ran no better. A skeptic of the original plan, a man who really knows auto electrics, again offered up the spare distributor he carries with him. The car hummed like a turbine. The problem was inside the distributor all along.

Jeff

Well considering the distributer / petronix is at least 12 - 13 years old, I'd say it might be time for a new distributor.

If anyone has a spare points distributer I could buy or borrow long enough to determine if it is the distributor, then that would be great. I'm hoping for the best, as there is no one in my area that deals with rebuilding rover engines.

[mechman]

Looking at your pictures, you seem to have a fair bit of carbon tracked onto the business end of the rotor. Have you checked the lugs in the dizzy for matching carbon? I know you said it was new, but so was the rotor, and... I've found that if there is a healthy buildup, the slightest wobble in the shaft can cause an intermittent arc on one or more cylinders, depending on where the wear is in the dizzy shaft bushing.

I'd start with the compression test, that'll tell you a lot. Compression testers are cheap and easy to use, and every shade tree mechanic should have (at least) one. If you test it dry and the compression is low, squirt a shot of oil in and take another reading. If it comes up, your rings are suspect (or a valve MIGHT not be seating correctly). If the number stays the same, you probably have either a burned valve (it'll look like a pie slice was whacked out of it) or scorched piston (the edge of your piston will have obvious damage - this is a more rare occurrence though).

I've never had a problem with Pertronix units, I love 'em, but I've heard tell of quality issues in the last few years, and 12 years is a pretty good run IMO. YMMV of course. If you're worried, carry a spare dizzy set up with points with you in your tool kit, wrapped well against moisture. I don't use points, personally, unless forced to (usually by a lack of cash flow). Technology has made them obsolete, IMO.

I HAVE had both Compufire and MSD units burn out though.

Mech

[Jeff Aronson]

Mechman is right, and you've received good advice from enthusiasts on this thread. You need to do a compression check; it's easy to accomplish and the gauge is well worth purchasing.

I am intrigued that your spark plug did not look wet or blackened on #4 cylinder. If you've actually been driving the car for any distance, then this is a pleasant surprise. A clean plug tip usually indicates proper firing and at least some compression. Again, your compression test will tell you a lot - just use the procedures outlined before this post.

However, if you're not using the vehicle very much, then your spark plug will not have much chance to load up, so the plug tip observation will not mean much.

When I had a burned valve and had to change the head for the first time, the job took me about 6 hours from start to finish, and I took my time.

I was nervous and petrified; I'd never tackled something that substantial on my Rover at the time. I borrowed a torque wrench, ordered the head gasket, the rebuilt head [my choice - I could have taken the head to a machine shop and had them install new valves instead], intake manifold gasket [might as well at the same time] from Rovers North, plenty of PB Blaster and a carbon cleaner. I opened the the Haynes Manual and followed it closely. I called Rovers North a couple of times with questions and tips on installing the new gasket correctly, and completed the job successfully.

My point to you is that if your tests indicate a valve problem, this is a job that can be tackled successfully by a mechanical novice - just as I was at the time.

Jeff

[NC Rover]

Geez so I discovered the problem. One plug wire was faulty. Sometimes it would work, sometimes it would not depending on which way it was bent. So the vibrations of the engine would cause it to connect/disconnect causing the misfiring.

Compression Check:
Cylinder 1 = 150
Cylinder 2 = 110
Cylinder 3 = 145
Cylinder 4 = 150

Going to double check the valves to see if something is slightly off causing that Cylinder 2 to be down at 110. Then maybe a leakdown test.