So the last few days has been spent working on getting the 3.8 MK2 back to a running state, this car was a shed find that was unused for 20 years, ever so slowly, the brakes have been redone, carbs rebuilt, engine checked over, cooling system overhauled.

However lately now that i'm starting/stopping it occasionally to do a few things to it, its apparent the starter is on its last legs, symptoms include very large amp draw, weak cranking speed, and even disengages when the motor almost starts.

Tried a larger battery and jump pack, and it makes no difference.

So my next step is to remove the starter and inspect it.

Having not done this yet on my 3.8 Auto, is there any surprises i'm in for, is it easy to get out?

What about rebuilding the starter, is it a feasible option, or should I look more towards a modern replacement like a gear reduction starter one of these below, once I work out which one I require.

Jaguar 3.8 High Torque Gear Reduction Starter

Jaguar

Jaguar E Type Mkii XJ6 Edge High Torque Starter Motor | eBay

NEW Starter Motor Austin Healey Jaguar Mark Series Landrover 2000 1954 1968 | eBay

Applications - WOSPerformance

I'll most likely remove the current one, strip it and inspect it, and get new brushes for it, but if it's still weak, look at something from the above list or any other options available I can find.

 

So today I removed the starter motor from the car, after removing the carb setup and dizzy (I also replaced the front welsh plug)

Stripped it down to reveal that it's fresh as and appears to have been rebuilt not too long ago, the brushes look nearly new, so all I did was sand the contact areas clean and just a general tidy up.

Tested it on the ground and it spins up fine and doesn't stick.

So my next guess is either the solenoid setup isn't supplying full power to the starter or the leads have a high internal resistance.

Will check all that once I find my multimeter.

 

One thing to also check is that the engine ground (earth) strap is in good condition and installed correctly. I have had an issue with this which caused exactly the same symptoms.

 

I have heard that the gear reduction starters can't cope with the heavy Jaguar engines for long, they wear out quickly and fail.

 

I guess it depends on how much you use the car, this will never be a daily driver, so the worry of the item wearing out over say 10,000kms, might take 10 years once it is back on the road.

The next task I had planned was to replace all the power cables to and from the battery, while the resistance is zero, the wiring is old and stiff and could quite possibly heat up easily and then lose resistance.

I will also get a decent battery with higher CCA's to help too.

If all that doesn't greatly help, then I will swap to a modern starter motor setup.

 

The cable that runs from the fire-wall to the battery is a pain to replace, on my 340 I had to take that section of dash apart to get at the nut on the other side of the fire-wall.
If you try and remove the bolt, it just starts spinning around and it's pretty much impossible to get at the nut with out removing the glove box and associated padding.
Jaguar in their typical British assembly methods did not use a caged nut _ at least not on my 340.

 

At some stage this cable has already been replaced with a modern generic earth lead when it was changed to 12V negative earth. So I dont have to worry about that issue.

It was more so the wiring from the solenoid to the starter motor that is original.

 

Check the bendix as well. A lot of "failed" starters are just fine and it's the bendix that's gone out with is an easy fix.

 

I had the starter on the bench, stripped and cleaned it, the bendix operates smoothly on the bench, I lubed it as well and removed any grit etc that might have been in it, the brushes are nearly new and the armature wasn't worn at all, yet I sanded it smooth and cleaned it again.

Cleaned the mating surfaces on the bellhousing to make sure the starter earths to the motor cleanly.

I have a really strong battery (900CCA) I will try out and see if that makes a noticeable difference compared to the current one in it, which is 450cca I think.

 

Once the starter is back in the car, jump it directly with cables and a fresh battery, this will by pass the solenoid/starter button circuit.
If it turns over freely, then the problem is with the solenoid/starter switch on the dash and/or a bad connection on one of the heavy cables.
Make sure it's out of gear of course.

 

Can the solenoid create a big enough voltage/amperage loss?

I would have thought if it did that, there would be evident heat at the solenoid

 

Yes it can, there is only 12 volts in the system, if the contacts inside the solenoid become dirty and corroded, there can be allot of resistance there.
Once it starts to arc, it snow *****. The action of the solenoid can be hindered by dirt inside itself or just wear and tear, this will cause bad contact on the big copper plates inside.
The only way to track down a problem like this is to eliminate the variables _ one at a time. Start by mounting the starter and turning the car over directly with your jumper cables _ you will need some meaty cables, not some cheap things from Wal-Mart.

If it turns over well, and the starter is OK and you need to look else where.

 

I'll pull it down and clean it, cant hurt anyway.

Hopefully if I get some free time, I'll have some new cables made up as well.

Next big task is the auto gearbox issues, I'd kill for a hoist.

 

Was this issue resolved? Long time ago, I know.

I have a similar issue. I swapped the stater for another on an old engine of unknown condition and have the same symptoms.

I’ll do some ground tests on the one I removed.

i did get symptoms over the last month in very hot conditions (+40 deg C), where I got the click, but then was able to ‘tap and go’ with a big hammer!

 

For a automatic I would not go for a high torq/reduction starter.
They will fail after a while, mine had a broken front bearing holder, that part is far to weak.
Try to revise the original starter, I did and it works fine.

Regards,
Peter Jan

 

I have used gear reduction on most of my cars from my Datsun Z cars to my LS V8 in the Jaguar and highly recommend getting a quality one. I have never had a good quality made gear reduction starter wear out and all of my cars are daily drivers. I have used this brand which specializes in British cars on one of my Datsun 240Z's and have had no issues, they use 5 roller bearings versus antiquated bushings which might be the reason some have no issues with other starters not built that well? I used this Classic Car Performance starter on my mild high performance 240Z engine and it starts immediately with no issues compared to the often repeated attempts with adjusting the choke, etc. and requires less amps that the stock starter , https://www.classiccarperformance.com/products/jaguar-mk2-saloon

On my LS V8 I used a high torque starter and have over 130,000 miles no issues. If you buy quality gear reduction starters they typically have better quality motors, bearings, better insulation for heat etc. if you buy a quality unit.