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[Webby the Bear]

oh ok. Thanks for that. May be worth me looking over that again. Re the earth/ground i got to be honest i dont understand electricity. Ill investigate some more :-)

[Marks DTM Calib]

The simple thing to remember is that an earth is exactly what it sounds like, a strong electrical connection to 'earth'.

Have a read of the cav dpa pump service book here as the explanation of operation is quite good (with pictures!)

http://www.bluemoment.com/manuals/Lucas%20CAV%20DPA%20injection%20pump%20instruction%20book.pdf

[Webby the Bear]

thats great, thanks for that mate 

[Andy B]

.....

One point to make, there is no such thing as an earth on a car, its a ground or 0V connection (sometimes referred to as chassis or chassis return), for it to be an 'earth' it would need to be connected to a 2m metal spike inserted into the 'earth' !

but 'earth' is a generally accepted term for the side of the battery that connects to the chassis ie positive earth or negative earth 

[Marks DTM Calib]

.....

One point to make, there is no such thing as an earth on a car, its a ground or 0V connection (sometimes referred to as chassis or chassis return), for it to be an 'earth' it would need to be connected to a 2m metal spike inserted into the 'earth' !

but 'earth' is a generally accepted term for the side of the battery that connects to the chassis ie positive earth or negative earth 

Only in the uneducated world of the mechanic.....not in any other electrical or electronic field.

[Entwood]

[Devils Advocate Head on]

If you allow the use of "ground" ... (americanism) why are you against the english word "earth" 

[Devils Advocate Head off]

[Andy B]

.....

One point to make, there is no such thing as an earth on a car, its a ground or 0V connection (sometimes referred to as chassis or chassis return), for it to be an 'earth' it would need to be connected to a 2m metal spike inserted into the 'earth' !

but 'earth' is a generally accepted term for the side of the battery that connects to the chassis ie positive earth or negative earth 

Only in the uneducated world of the mechanic.....not in any other electrical or electronic field.

But most 'mechanics' aren't sparks!  Otherwise they'd be making a living without getting their hands dirty. 

[Marks DTM Calib]

The key point here is that this is a learning thread and in a learning thread it is important to ensure that Webby understands that the 0V is not actualy an earth and that the phrase 'earth' for vehicles is incorrect in the electrical world (and we are talking electrics).

An earth is a safety return path for fault currents.

On the 'ground' discussion, this is a different concenpt as its recognised that a ground is a return and not a safety related path for fault currents. Given the setup on a vehicle the chassis is the return path and hence may be considered a 'ground return'.

The truely correct phrase would be a 0V chassis return/connection.

 

[aaronjb]

Shamelessly stolen from the MR2 workshop manual (electrical section):

GROUND
The point at which wiring attaches to the Body, thereby providing a return path for an electrical circuit; without a ground, current cannot flow.

(Obviously it's referring specifically to the fact that the little 'ground' picture on wiring diagrams signifies the actual physical location of a connection to the chassis)

[Webby the Bear]

Evening guys, hope you're all well.

It's been a little while in coming but since I have fixed my phone I can now e-mail photos to myself and in turn share photos from today's practical

Well first of all yesterday and today was spent on lubrication system again. Yesterday was oil pressure testing; very simple.... get car up to temperature, remove oil pressure switch, screw in the pressure gauge adapter, pop on the gauge itself and take a reading at the specified revs in the Haynes. For example, the car we were on needed to read 2.8 bar @ 2000 revs. give it 2000 revs and take the reading. this will give you what oil pressure you're getting
it's worth noting that high pressure could indicate blocked oil galleries, clogged up filter or wrong type of oil being used. if the pressure is too low it could indicate a worn out pump.
me and my mate have took such a lead in the amount of jobs we've done that we got to actually remove an oil pump out of a clit engine, inspect it, measure it (specs in the Haynes), advise whether it should be replaced or is useable and refit on to the car.

so here's some pics of us measuring our prize....

using feeler blades and a straight edge to measure the end float...


using feeler blades to measure gap between inner and outer rotor...


using feeler blades to measure gap between outer rotor and the body...


the specs.....(pump clearances)



the only ones i've seen have basically been part of the oil filter assembly. are there different versions? 

[Webby the Bear]

...looking at the pics i cant remember if those are of a ford fiesta pump that was already off the car that we practised measuring or whether that is the clit pump we pulled out. maybe some knowledgeable person could tell? 

[Webby the Bear]

[Andy B]

.....
so here's some pics of us measuring our prize....

using feeler blades and a straight edge to measure the end float...

 ......

Turn your steel rule 90 degs so you're using the edge of it. Using it flat as you are, if your rule was bent, it'd give you an iffy reading with your feeler gauges. 

[Kevin Wood]

...looking at the pics i cant remember if those are of a ford fiesta pump that was already off the car that we practised measuring or whether that is the clit pump we pulled out. maybe some knowledgeable person could tell? 

Looks like it's off a Ford pushrod engine to me, but I'm not familiar with the clit.

There are several types. Most common these days are on the front of the block driven directly by the crankshaft as modern engines don't have a camshaft down in the block to drive it. This is the case on the GM V6. It's what you're looking at when you take the crank pulley off.

[Entwood]

.....
so here's some pics of us measuring our prize....

using feeler blades and a straight edge to measure the end float...

 ......

Turn your steel rule 90 degs so you're using the edge of it. Using it flat as you are, if your rule was bent, it'd give you an iffy reading with your feeler gauges. 

 

Pressing down with the "top" finger can also distort the readings .. as the rule will flex slightly .... on its side and it stays rigid ...