To bleed or not to bleed

[Bio]

That is the question 🤔

Just fitted a mechanical oil preassure gauge from Think Automotive and noticed the movement of the needle going up the scale is a little jumpy.

Do you need to bleed the supply pipe to purge it of air to get correct gauge operation 🤔

Great service from Think Auto and 15% off for being a club member

 

John

[ccconn]

I have just done the same and mine jumps a little on the way up so maybe just the way it is...?

[Roadsport06]

No need to purge the oil.

 

BRG and Yellow nose now with added brooklands

[Bio]

Just thinking that if there is a pocket of air in the pipe going to the gauge it may be able to be compressed untill overcomming the internal resistance within the gauege mechanism.

But then if the engine is not run for some days would the oil drain out of the supply pipe untill next time 🤔

A question for these dark cold evenings

 

John

[Dyrill]

John

I have just fitted a Stack mechanical OPG and have noticed that once the engine has cooled down the oil creeps back down the hose. So I don't think bleeding will have a significant effect. That said the gauge is smooth so perhaps the circumstance you describe is normal on the Think gauge

 

Cheers Darren

 

 

C7 SUP now with DVA K06 Upgrade

[dannylt]

I've fitted the Stack mech OPG too and thought about bleeding it. Seems to work fine and smoothly though, but definitely lags the Stack electronic one. I imagine the air is damping the pressure changes, so will try bleeding as much as possible.

[Mick Day]

It doesn't matter whether there is oil, water, air, or even hydrogen in the oil line. The gauge is set to measure pressure so will measue the pressure of whatever squashes up against the pressure diagphram inside.

 

So to recap it doesn't matter whether it's gas or liquid in there; bleeding will at best be messy & worst will squirt oil everywhere.

[Ozzy]

You don't hang about, do you John!

 

I reckon you've got too much time on your hands, so I'd better bring my car round for a service 😬

 

Nigel.

 

C7 FST....Powered by DVA

 

A Wolf in Clams Clothing!

[Bio]

Hi Nigel

Thanks for coming over last weekend. now sorted

Have tried bleeding the line and the gauge is more "Instant" in operation but after a couple of days has reverted back so the oil must drain back ☹️ however this does not cause a problem

One more job done

 

John

[Phil G]

Hi John,

 

Slight hijack……..I have been meaning to buy all the bits from Think Auto myself. There appears to be a number of parts combinations which all give the same end result. What list of components did you choose?

 

 

-----

Phil

“If you want a place in the sun, you have to expect a few blisters”

 

[djg]

Ring Matthew at Think and he will provide all the bits, he just put in the part no's when I asked for a MOPG for a K.

 

I can vouch for the kit as have just fitted one as have many others.

 

Doug.

[Phil G]

Thanks Doug - I appreciate that there is a standard fitting kit which is the basic requirements; however, I’m interested in how different people tackle the job.

 

I have looked at the kit listed on BC forum and IMHO it is overly complicated and the number of joints required can be reduced. There is also the option of securing the main manifold block or just tie wrapping it somewhere convenient. Some people use braided lines throughout and others use the plastic capillary tube supplied with the gauge.

 

-----

Phil

“If you want a place in the sun, you have to expect a few blisters”

 

[Bio]

Hi Phil

Just looking at the bill now...although the T piece will be a differant thread on a K as mine is a VX

 

TFE3 Hose braided 2.0 meters long

OPG 100 Oil pressure gauge black face 100 PSI

TP7 T piecw 14x1.5 (This will be differant for a K)

E321-3 Fitting that screws into TP7 to take hose TFE3

E332-3 90 Degree fitting to make hose TF3 90 degrees at one end

BPS2-55 Blanking plug for T piece (i did not fit an oil pressure switch)

BSSC-14 Sealing washer for blanking plug

 

You get 15% off for being a club member

 

Hope this helps

 

John

[dannylt]

It doesn't matter whether there is oil, water, air, or even hydrogen in the oil line. The gauge is set to measure pressure so will measue the pressure of whatever squashes up against the pressure diagphram inside.

What? The equilibrium pressure sure, but air is very compressible, so it will damp a sudden change in pressure. Oil is virtually incompressible, so bleeding it should reduce the delay.