View Full Version : Engine to chassis ground
Where is the best location on the engine, for the engine to chassis ground strap? This is for a negative earth 2.25 series motor.
thank you.
clearcut
07-31-2015, 10:41 PM
what rover series are we talking about?
lumpydog
07-31-2015, 11:01 PM
On mine, it's from the starter motor mount/bolt to the frame.
I think I've seen some go from negative battery terminal directly to one of the oil fill tube securing bolts. Or maybe it was from where the negative ground from the battery is secured to the frame - then from there, to one of the oil fill tube bolts.
Others will chime in. Important part is cleaning the wire contacts and also the frame mating surface so they are free of oil and paint. Bare metal is key - 600 or 800 grit sand paper works nicely. Once cleaned you have two bare metal mating surfaces - some dielectric grease will help stop corrosion around the contact points.
ignotus
08-01-2015, 05:58 PM
On the starter side of the block just around the drain petcock there should be a hole with a bolt in it, or maybe a stud. From there over to the chassis steering box support bracket bolt.
antichrist
08-02-2015, 08:05 AM
Absolute best, IMO, is from a starter mounting bolt to the bolt where the battery chassis earth attaches. It costs a bit more but when I make cables that's how I make them to fit.
I went with the oil fill tube bolt to the chassis where the battery is grounded. Still not getting any spark at the plugs.
SafeAirOne
08-02-2015, 09:04 PM
What is it that pointed to a poor ground path from the engine as the cause of your no-spark issue? It is possible, I'm just wondering what troubleshooting steps have been taken so far.
antichrist
08-03-2015, 08:00 AM
If the engine was cranking before, then the engine ground was certainly good enough for the ignition.
What is it that pointed to a poor ground path from the engine as the cause of your no-spark issue? It is possible, I'm just wondering what troubleshooting steps have been taken so far.
Just wanted to start with making sir I had a good ground. The I tested the voltage at the ignition switch which was good, the. Tested the voltage coming into the coil, and that was good except that there was a slight voltage drop at the coil. Switch was 12.4, and the coil was 11.8. No spark at the plugs or the lead going into the top of the distributor.
I also noticed that when I had the distributor cap off, and I was cranking the engine, the points were closed and didn't open. I'm a novice at automotive electronics.
SafeAirOne
08-03-2015, 09:14 AM
If the points don't open, you'll never get a spark at the spark plug.
-When the points open, the electricity flowing through the primary winding inside the coil stops.
-When the electricity in the primary circuit in the coil stops, the magnetic field produced by electricity flow through the primary coil winding collapses past the secondary windings in the coil.
-When this magnetic field collapses past the secondary windings, it creates a large amount of voltage in the SECONDARY windings. It is this large voltage that goes out of the fat wire in the middle of the coil to the distributor cap for distribution to the spark plugs.
So, no points opening, no field collapse, no high voltage to the spark plugs.
Your engine ground is just fine.
SafeAirOne
08-03-2015, 09:28 AM
https://farm1.staticflickr.com/397/20258955585_02a55f8dee_o.jpg
If the points don't open, you'll never get a spark at the spark plug.
-When the points open, the electricity flowing through the primary winding inside the coil stops.
-When the electricity in the primary circuit in the coil stops, the magnetic field produced by electricity flow through the primary coil winding collapses past the secondary windings in the coil.
-When this magnetic field collapses past the secondary windings, it creates a large amount of voltage in the SECONDARY windings. It is this large voltage that goes out of the fat wire in the middle of the coil to the distributor cap for distribution to the spark plugs.
So, no points opening, no field collapse, no high voltage to the spark plugs.
Your engine ground is just fine.
Now what? Where do I go from here. The coil is new.
mearstrae
08-03-2015, 10:20 AM
Set the points to .015" and then when it starts check the timing.
'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S
lumpydog
08-03-2015, 11:52 AM
I always find John Twist's videos to be helpful. The MGBs that he works on are basically the same in function to a land rover.
Distributor Video: https://www.youtube.com/watch?v=7fUbvKgmmQQ
[Edit] By the way - depending on your distributor type, the process for removing and replacing the points and the condenser will be similar but different in terms of the use of clips, screws, etc to secure the points and the condenser (which may vary in location).
SafeAirOne
08-03-2015, 02:24 PM
Now what? Where do I go from here. The coil is new.
The coil is fine. My lengthy reply about how the system works was primarily to give you the opportunity to have one of those "AhaaaHa!" moments, when you realize that the points need to open and close to make the engine go.
Have a look at the procedure I copied out of the workshop manual and posted immediately before your latest query. Start at step #7.
The coil is fine. My lengthy reply about how the system works was primarily to give you the opportunity to have one of those "AhaaaHa!" moments, when you realize that the points need to open and close to make the engine go.
Have a look at the procedure I copied out of the workshop manual and posted immediately before your latest query. Start at step #7.
Great. Thank you for your help.
So I have a gap now between the two contacts, but still no start, and no spark that I can see.
antichrist
08-03-2015, 06:16 PM
Did it ever run? Did you replace the points?
If the points aren't installed correctly they will short to ground. There's an insulator that has to be fitted correctly.
Did it ever run? Did you replace the points?
If the points aren't installed correctly they will short to ground. There's an insulator that has to be fitted correctly.
It has never ran since I bought it 10 years ago. I'm in the middle of a frame off restoration, and am at the point of hooking things up to start it. It is not ready to drive yet though, but I just wanted to see if I could get it started. The distributor is the original, but new cap, rotor, points and condenser. Also new coil, leads and spark plugs. I would say that it hasn't run in 20 years.
yorker
08-10-2015, 01:38 PM
It has been at least 20 years so century Gary Foster drove that 109. Double check the points. I don't remember what distributor that had on it but I once assembled mine and put the insulator in the wrong spot as Tom mentioned and it was frustrating. Relatively easy to diagnose with a test light though. Also don't forget to turn your ignition off when done. You can melt the points otherwise. I did that once and got stranded in the cemetery over in Edmeston... had to make some from scratch to get home. Fun times.
Thanks Matt. It has the original 25D distributor in it, but the points, condensor, cap and rotor are new. I'm getting 12V at the point contact with the points open. It's probably something simple, I just don't have enough experience to see it.
yorker
08-11-2015, 10:36 AM
I'm confident it is something simple. Get a test light and go from there. Some tips here:http://www.minimania.com/Troubleshooting_Lucas_Points
SafeAirOne
08-11-2015, 01:40 PM
This is a fairly simple system. To maintain the system, you really should know how it works and what each component's role in the system is.
This is one of the best and most thorough explanations of the theory of operation of a points-type ignition system I could find on YouTube:
https://www.youtube.com/watch?v=OMLSNwQiiKg
Once you understand how the system operates, you'll be able to test your non-functioning system in a logical manner till you find the problem. You'll want to be able to test to see if there is an electrical path between certain things in the system and you'll need to be able to test for voltage at certain places in the system.
For example, you've got to realize that with the points OPEN, one contact (the one that is NOT connected to the capacitor/condenser) will still be grounded (there will be an electrical path to the metal engine) when the points are open, while the other contact (the one that's connected to the capacitor) MUST NOT go to ground (must NOT have an electrical path to the metal on the engine), otherwise the circuit will never be broken, even with the points wide open because the electricity will still have a path to ground, causing the system NOT to work.
At this point, I don't care if I come across as a moron with regards to this subject. I went on the link that Matt(Yorker) listed and followed the tests, and I can get a spark on a test spark plug through test 4. I have some seemingly stupid questions.
1. I'm getting 12v on the condenser side of the points with the points open and closed. Is this supposed to happen?
2. How does the rotor fit on? Mine seems to spin freely. How is it supposed to be at the ignition terminal in the cap when the points are open. Do you get the points to open and make sure that the rotor arm is in line with one of the contacts in the cap?
I'm really not stupid.
SafeAirOne
08-11-2015, 06:11 PM
1. I'm getting 12v on the condenser side of the points with the points open and closed. Is this supposed to happen?
Yes, the condenser side of the points should have 12v whenever the ignition switch is on. The other side of the points should only have 12v when the points are closed.
2. How does the rotor fit on? Mine seems to spin freely. How is it supposed to be at the ignition terminal in the cap when the points are open. Do you get the points to open and make sure that the rotor arm is in line with one of the contacts in the cap?
Generally, that takes care of itself. The rotor only fits on the distributor shaft one way, with the flat in the hole in the rotor matching up with the flat on the shaft. There may be a small bit of play/slop in the distributor shaft, but that shouldn't matter.
The theoretical way it should work is that the points open up as the contact on the rotor passes one of the contacts on the underside of the distributor cap so that pulse of high voltage that occurs when the points open up will immediately have somewhere to go.
I'm really not stupid.
You'll be fine--It's just a matter of getting used to how the thing works. You'll be an ignition system expert by the time you get this engine running.
That flow chart that Yorker linked to is pretty good.
Are you getting spark at step 4, where you have a grounded spark plug connected to the center coil wire (the fat one) and you make/break the primary circuit manually with the ignition switch on, or just UP TO (but not including) step 4?
PS: Most painless way to ground the spark plug is to clamp one of the leads from a set of jumper cables to the spark plug threaded body and the other end of the same jumper cable to a ground or the - battery terminal. That'll save you from trying to hold it next to the engine to ground it (and you won't be zapping yourself).
I'm not getting 12v on the other side of the points when the points are closed. And I am getting spark at step 4.
SafeAirOne
08-11-2015, 07:25 PM
I'm not getting 12v on the other side of the points when the points are closed. And I am getting spark at step 4.
You were getting 12v on the condenser side of the points with the points open before. Now you're not getting 12v there when the points are closed?
1) Is the ignition on?
2) Are you probing with your meter on the 20v scale, with the red lead on the points contact and the black probe on a good bare metal ground on the engine?
SafeAirOne
08-11-2015, 07:47 PM
Just re-read your last post...
If you ARE getting spark in step 4 when you manually break the circuit and you're not getting 12v on the NON-condenser side of the points when the points are closed, then, presuming the ignition switch is on, electricity is, for whatever reason, not making it across the contact points when the contacts are touching each other (closed).
I would:
1) Make sure the ignition switch is on and re-test if it was off.
2) Make sure the little cam follower is completely off the little lobes on the distributor shaft and that the contact points are actually touching when the points are closed. Even a little open won't cut it in this position. (Ignition off when you're doing this!) Retest.
3) With the ignition off, take a tiny file or some sandpaper and clean off both contact points so that there is nothing inhibiting the flow of electricity from one contact to the other when they are fully closed (physically touching each other). [EDIT:] Oh, hey--This is step 5 of the flow chart test procedure!
I will do this tomorrow. Thank you so much for your help.
yorker
08-13-2015, 11:48 AM
Any luck?
Haven't had time to do anything yet. Possibly after work tonight. I'll report back after that.
So it's been a while since I have messed around with trying to fix the distributor. I've been spending most of my time painting body panels and parts while the weather is nice.
I replaced the points, condenser, rotor,and low tension lead. Still not getting 12v where they need to be. I discovered that with the ignition on, I can get 12v to the points if I lift up the base plate with a screw driver. Any significance to that? Thanks.
SafeAirOne
09-18-2015, 05:52 PM
So it's been a while since I have messed around with trying to fix the distributor. I've been spending most of my time painting body panels and parts while the weather is nice.
I replaced the points, condenser, rotor,and low tension lead. Still not getting 12v where they need to be. I discovered that with the ignition on, I can get 12v to the points if I lift up the base plate with a screw driver. Any significance to that? Thanks.
Yes. You are on the right track. Either a short, an open exists where it shouldn't in that area.
stomper
09-18-2015, 06:13 PM
I believe I've read somewhere about a fiber insulation washer that is supposed to go on the screw that holds the points into the distributor. If you mix up the placement of the washer, it can ground out the points.
Someone else can confirm this, but it may be your issue.
I believe I figured out what is wrong. I took everything apart again to see why when I pry up the moveable base plate, I get 12v at the points. When I took the two base plates off, I noticed that the plate that moves has a metal contact that is supposed to touch the fixed plate. Well, the contact on mine was not touching the fixed base plate. This explains why when I pried the moveable plate up I got power, I was making the metal tab hit the fixed baseplate. I simply just bent the tab so it would make contact. I have everything apart and cleaning it up. I will get everything back together in the next couple of days and update.
Ok, so I have nothing figured out at this point. Haven't messed with the distributor in a while because I was doing other things on the truck like pulling the transmission out.
Revisited the distributor today, and have some more information.
When the points are open, I have 12v at the points.
When the points are closed, I do not have 12v at the points or anywhere else.
When the points are closed and I lift up the moveable part of the base plate, I get 12v at the points.
I never get 12v on the fixed side of the points, just the moving side.
So is something shorting out at the base plate? I don't know where to even look. Help!!
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