Earth Strap

[greyhulk]

Hi guys,
looking to replace this earth strap from the negative terminal to lower swirl pot for good measure, few strands are broken..

Its around 12" & i think its a 6mm hole (will double check) pretty sure theres a m6 bolt running through it, before i order a replacement does anyone know what amp it should be rated at?
Theres 240amp, 170amp & 110amp options on evilbay (hexagonally crimped copper tube terminal, heat shrink wrapped) not sure what to go with one of these or if anyone can recommend one?




Cheers
Steve

[phillpot]

Thicker (higher amperage) the better!

looks from that little picture like the 240amp is 35mm cable, that's the one you want






can you link to the ad or give us the item number?

ETA, just realised I can click on the pictures and make them bigger!

Looks like yours is bolted down to one of the swirl pot bolts?

Mine has an 8mm stud welded to the chassis about where the yellow circle is.

If you don't have that (can't see it) I'd suggest drilling a hole somewhere into good solid metal and using a bolt solely to secure the earth, maybe one of the lugs going out to the shock absorber. Clean paint off so cable eyelet makes good contact and touch up after bolted on.

Edited by phillpot on Tuesday 3rd May 19:20

[greyhulk]

phillpot said:

Thicker (higher amperage) the better!

looks from that little picture like the 240amp is 35mm cable, that's the one you want
If it goes where mine used to it's an 8mm stud welded to the chassis.
can you link to the ad or give us the item number?

Cheers Mike, the ad is http://www.ebay.co.uk/itm/UP-TO-305-MM-12-240-AMP-...QIAAOSwyZ5UpwNu

and yes it goes to the upright bolt running through the swirl pot/battery tray fastened in place with a nut (stainless of course )

[GreenV8S]

You may already have it, but while you're looking at earths I recommend you fit three earths: battery to chassis; battery to engine; engine to chassis. This way you have two redundant earth paths between all the things that need to be connected together so you don't have a single point of failure.

[greyhulk]

GreenV8S said:

You may already have it, but while you're looking at earths I recommend you fit three earths: battery to chassis; battery to engine; engine to chassis. This way you have two redundant earth paths between all the things that need to be connected together so you don't have a single point of failure.

Cheers, sorry im not so great with the auto electric side of things but on my engine bay below if possible, do you know where these should be so i can check?
Im pretty sure im missing at least one..

[greyhulk]

phillpot said:

ETA, just realised I can click on the pictures and make them bigger!

Looks like yours is bolted down to one of the swirl pot bolts?

Mine has an 8mm stud welded to the chassis about where the yellow circle is.

If you don't have that (can't see it) I'd suggest drilling a hole somewhere into good solid metal and using a bolt solely to secure the earth, maybe one of the lugs going out to the shock absorber. Clean paint off so cable eyelet makes good contact and touch up after bolted on.

Mike I do recall a very tatty looking earth strap (didnt know what it was at the time) just hanging loose from the same bit of the swirl pot again but it was going to the near shock absorber wasn't fastened in anywhere at all & was swinging about which was strange so i ended up just removing it awhile ago

Edited by greyhulk on Tuesday 3rd May 19:34

[phillpot]

GreenV8S said:

I recommend you fit three earths: battery to chassis; battery to engine; engine to chassis.

Battery to chassis is the one you're looking at replacing.

Battery to engine would be a non standard but sensible addition. In practice getting two cables onto a round negative terminal is not so easy so I'd look at a compromise by running a cable from where the battery to chassis cable bolts down to the engine. Somewhere on the alternator bracket may be a good point to secure it?

Engine to chassis is probably actually gearbox to chassis and will be tucked away underneath by the gearbox support cross member.

greyhulk said:

Mike I do recall a very tatty looking earth strap just hanging loose from the same bit of the swirl pot again but it was going to the near shock absorber wasn't fastened in anywhere at all

Possibly something someone had improvised to go to the engine? (or how TVR did it before fitting the earth strap by the gearbox)

Edited by phillpot on Tuesday 3rd May 19:47

[greyhulk]

phillpot said:

Battery to chassis is the one you're looking at replacing.

Battery to engine would be a non standard but sensible addition. In practice getting two cables onto a round negative terminal is not so easy so I'd look at a compromise by running a cable from where the battery to chassis cable bolts down to the engine. Somewhere on the alternator bracket may be a good point to secure it?

Engine to chassis is probably actually gearbox to chassis and will be tucked away underneath by the gearbox support cross member.

Yep battery to chassis is the one i can spot a mile off with its broken strands so ill get to replacing that one asap, i know i got a M6 bolt running up through the swirl pot hole & hoop with a nut securing it so 8mm hoop should be fine?

As for the other two ill have a nose around the engine bay & see what i got, they may be there already but im guessing at least one of them isn't.

P.S will have to give it a spin out up to yours one of the weekends, pondering about a magnolia wheel cover now too

[phillpot]

greyhulk said:

P.S will have to give it a spin out up to yours one of the weekends

Will it make it this far?

[greyhulk]

phillpot said:

Will it make it this far?

.. My issue now is it starting it back up when the engine is warm? Tested it sunday (hoping to go S club heaven on the mon) drove like a dream then i pulled up had a chat with a chap who has E-type jag for half hour or so & it wouldn't start back up! Eventually it did with just the turn of a key so god knows :/

[Bobhon]

On the not starting when hot thing. Did the starter motor spin it up and it just wouldn't fire, or did the starter motor not turn over at all?

On my S2 the starter motor wouldn't turn when hot. It came down to too much resistance in hot wiring to pull the starter solenoid in. Easily fixed with a relay wired in to take the load.

I know that Mike has also fitted a relay. Easy fix, takes a couple of hours. I'm as local to you as Mike is if you need a hand.

Bob

[greyhulk]

Bobhon said:

On the not starting when hot thing. Did the starter motor spin it up and it just wouldn't fire, or did the starter motor not turn over at all?

On my S2 the starter motor wouldn't turn when hot. It came down to too much resistance in hot wiring to pull the starter solenoid in. Easily fixed with a relay wired in to take the load.

I know that Mike has also fitted a relay. Easy fix, takes a couple of hours. I'm as local to you as Mike is if you need a hand.

Bob

Hi Bob, hmm it felt like there was no power? It would try & start up (could hear it trying to turn over) but nothing happening.
In general every time I start it I have to apply throttle which seems odd, but no revs were present when I tried it after the engine was warm.

I tested it again earlier & it started straight back up after a 15min drive so I'm puzzled..

That would be a great help if you could help out, appreciate it

Steve

Edited by greyhulk on Tuesday 3rd May 21:24

[GreenV8S]

greyhulk said:

Hi Bob, hmm it felt like there was no power? It would try & start up (could hear it trying to turn over) but nothing happening.

I'm not sure how to interpret that - are you saying you heard/felt the starter power up but the engine didn't crank over? The normal 'hot start' syndrome is that the starter solenoid doesn't engage so there is no reaction at all when you try to crank the engine over, but this doesn't seem like what you're describing.

[greyhulk]

GreenV8S said:

I'm not sure how to interpret that - are you saying you heard/felt the starter power up but the engine didn't crank over?

Yeah so basically put key in the ignition everything comes on as normal, gauges, handbrake light etc then turn it to start the car up an it was just struggling to fire up (it wasn't completely dead that nothing was happening)
Whats strange was the chap with the E-type had a go quickly turned key an It fired up without having to apply a bit of throttle

Edited by greyhulk on Wednesday 4th May 07:16

[Bobhon]

I got your PM and have replied.

E Type owners know how to restart a hot car as they can be prone to flooding if you give them any throttle. Could it be that NOT giving yours any throttle when hot is the way to go??? Even if it needs throttle when cold...

Sounds as if your starter motor is turning over when hot so the additional relay/solenoid wouldn't help you out.

I would suggest 'hot' comes in 2 different types, i.e.
1. Hot as in just had a run turned the engine off and fairly soon turned it back on again.
2. Hot as in just had a run turned the engine off and left if for 10 minutes or so and tried to restart it.

Option 2 would be a heat soak where the residual heat in the engine and exhaust radiate into the engine bay increasing the underbonnet temperatures. This would be the worst case for the starter motor not turning over and would be most likely to induce a vapour lock in the fuel lines. It would also put a strain on any weak ignition components such as the coil, ballast resistor, dizzy cap, etc.

Does the 2.8 have an ignition control module bolted onto the body of the dizzy? This needs heat conducting paste on the joint face to stop it overheating (option 2 above).

If you are missing the engine to chassis or battery earth then that could cause strange running, potentially worse when heat soaked (option 2 above).

A mate of mine had an S1 years ago and he got someone in Banbury (?) to set up the ignition and fuelling system. Reckoned that the bloke was akin to a 2.8 guru. I will ask him if he remembers the contact details and post them up on here.

HTH

Bob

[GreenV8S]

greyhulk said:

Yeah so basically put key in the ignition everything comes on as normal, gauges, handbrake light etc then turn it to start the car up an it was just struggling to fire up (it wasn't completely dead that nothing was happening)

Sounds as if the engine was cranking over as normal but not firing, then. This is not the most well known hot start problem where the starter motor fails.

The engine fuel requirements will be different during a hot start and if it is not easy to start it's possible that the technique you've learned for cold starts isn't right for hot starts. If everything was perfect you wouldn't need any special technique in either case - just crank the engine over and it should start.

There are various electrical components that can break down with heat and it's possible you're seeing a temperature related electrical/electronic fault. Sometimes it's possible to diagnose these by cooling components and sensor down with a bag of frozen peas etc and see whether the behaviour changes.

There's also a problem where the fuel rail gets so hot after the engine is switched off that the fuel in it boils. There have only been a couple of times when I've suspected it happened to me and each time it seemed to clear after running the fuel pump for thirty seconds or so by switching the ignition on and off to flush the hot fuel out of the rail. Insulating the fuel rail stopped those problems for me.