oil pressure new isspro sender fitted

oil pressure new isspro sender fitted

Author
Discussion

ClassicChimaera

12,424 posts

148 months

Thursday 22nd December 2016
quotequote all
bobfather said:
I believe the gauge is expecting a range of 10-180 Ohms for 0-100psi. Not all senders use this range and I can't find any info regarding the resistive range of the Isspro senders. Could it be that the sender is simply incomparable with the gauge
If the sender I've been sent works to 240 Ohms that's surely the problem.
Let's hope they do the same one with 10-180 ?

By eventually doing this I've at least discovered what I consider to have been my problem all along, break in my wiring causing resistance about two inches from the sender connection.

I'll need to re connect a spade connector but when I'm bored of seeing these inflated readings I'll re connect my original sender and hopefully it will be even more accurate smile
I still want to try and fit the (long ) filter but need more ramp time to get it right thumbup

caduceus

6,069 posts

265 months

Saturday 24th December 2016
quotequote all
I'm a little concerned about hearing the results of these alternative senders. There was a topic some time ago, and whilst I was knee deep in engine build I thought I'd plump for a shiny new sender too. http://www.ebay.co.uk/itm/171741104403?_trksid=p20...

Engine has not had its first fire yet, nor filled with oil. So I am in a position to change it out for an OE one. Is this the consensus now with these alternative senders? Are they not worth using at all? I realise I haven't even used it yet, but I get the feeling the one I bought off eBay will give the same inaccurate reading frown So I'm in a batter position to change it now with now oil in the block yet.

ClassicChimaera

12,424 posts

148 months

Saturday 24th December 2016
quotequote all
As you are going to be starting it and looking for oil pressure straight away put the original back in.
As discussed before whatever sender you use it seems to be an indicator rather than a statement of fact.
As I've mentioned earlier and having had 3 senders in my car now, the two originals are far more accurate at lowish revs.

It's often said the originals start to leak prematurely, pfffft, mines nearly 3 years old and oil tight.

All I can say is if you put a mechanical gauge on my RV8 which incidentally does have new oil pump gears it's oil pressure changes directly related to revs, and quickly too, my Original sender now I've done that test is clearly the most accurate at lower revs and that's where you need it!

If like me you have put this sender in your car and it displays 25/30 psi at idle it's not accurate at all.

If I was rebuilding an engine I'd have it hooked upto a mechanical gauge to start with.

If others have used a mechanical gauge and can confirm their pressure readings at low revs then it would be useful as I don't know if it's just my engine that exhibits these low 15psi readings or it's normal. Watching the mechanical gauge makes me think it's totally normal

I had a good few hours driving the other night, the Isspro sender is miles out even considering I'd re calibrated where zero pressure now was (15 psi). It's still dosile and holds 35-40 psi on tickover etc and builds and falls way to slow.
Looks the business with high pressure readings, basically 60 psi when revving it and stays there for hours!
Dave, thoughts please!
All I want to do is work out why this hadn't worked, is it my late gauges need different ohms or is it simply that this sender is ill matched.
Odd as Dave seemed to pin it down to this one.
I'd like to see how his gauge acts with this sender, if it's anything like mine it's a joke of a reading.
Dave does your gauge move and settle on 15 psi before you even start the car?
Anyway it's just one of those things, I can't risk leaving it in mind, looks great but I now have no belief in the readings at all.

caduceus

6,069 posts

265 months

Saturday 24th December 2016
quotequote all
Hmm, I think I'll put the old OE one back in Alun biggrin

Shame, I was under the car the other night routing and fitting an earth for the eBay one. Very nice job I did of it too heherolleyes

As I type this I've just remembered, I threw the old one out frown

Are OE ones available on eBay or is a call to Racetech on the cards?

bobfather

11,171 posts

254 months

Saturday 24th December 2016
quotequote all
Additional mechanical gauge is the way to go, you'd need to remote mount it so that you can isolate it from engine vibration as that will knock it out of calibration over time. If doing this you need to prime the pipe so that you minimise compressible air in the gauge feed pipe.

After that you could acquire a 0 - 150psi sender and add a 100 ohm variable pot in the signal line which could then be used to calibrate the dash reading so that it reads in line with the mechanical gauge in its normal operating window. Calibrating the gauge in this way will mean it isn't accurate at the low and high end of the scale but IMO that's better than the totally inaccurate dash gauge reading we're suffering from the current options

Bassfiendnoideawhathp

5,530 posts

249 months

Saturday 24th December 2016
quotequote all
ClassicChimaera said:
Essentially yes, I'm now re calibrating my brain to read the gauge with these new levels but it's not good.

It's not as accurate as my original at the lower revs when hot so unless we can get one that does work I'll go back to the original.
Good if you want to sell, not very good if you want to know your true pressure.

Sadly Dave it hasn't worked for a couple of us, no worries as I've learnt that these experiments are just that, if it had worked I'd be stoked. wink

Mechanical gauge is how I'd like to go with a TVR face on the front smile
Anyone got any ideas
Or a modern stepper motor gauge with a modern 0-5v sender...

I used these:

http://www.demon-tweeks.co.uk/motorsport/gauges-au...

Phil

caduceus

6,069 posts

265 months

Saturday 24th December 2016
quotequote all
Do you mean something like this Bob? https://www.machinemart.co.uk/p/clarke-cht712-oil-...

Where does it screw into?

ClassicChimaera

12,424 posts

148 months

Saturday 24th December 2016
quotequote all
caduceus said:
Hmm, I think I'll put the old OE one back in Alun biggrin

Shame, I was under the car the other night routing and fitting an earth for the eBay one. Very nice job I did of it too heherolleyes

As I type this I've just remembered, I threw the old one out frown

Are OE ones available on eBay or is a call to Racetech on the cards?
Personally Tvr Power sell the O/E and seem pretty good.

I admired my wiring effort even though we'd run out of heat shrink frown

I'd routed it nice and everything hehe

Hey, I'm sure I'll get an inappropriate Crimbo present so this is just mine to the old girl smile
It hardly broke the bank.

Looks very impressive under there but I'll polish my original up and she'll be reet. biggrin

ClassicChimaera

12,424 posts

148 months

Saturday 24th December 2016
quotequote all
caduceus said:
Do you mean something like this Bob? https://www.machinemart.co.uk/p/clarke-cht712-oil-...

Where does it screw into?
Yes that looks like the one

Screws into the opening the sender fits into.





Bassfiendnoideawhathp

5,530 posts

249 months

Saturday 24th December 2016
quotequote all
bobfather said:
Additional mechanical gauge is the way to go, you'd need to remote mount it so that you can isolate it from engine vibration as that will knock it out of calibration over time. If doing this you need to prime the pipe so that you minimise compressible air in the gauge feed pipe.

After that you could acquire a 0 - 150psi sender and add a 100 ohm variable pot in the signal line which could then be used to calibrate the dash reading so that it reads in line with the mechanical gauge in its normal operating window. Calibrating the gauge in this way will mean it isn't accurate at the low and high end of the scale but IMO that's better than the totally inaccurate dash gauge reading we're suffering from the current options
Why would you need to minimise the compressible air in the pipe? The air will be at the same pressure as the oil and so the gauge will still read "true".

I'm not sure that I agree that in-dash mechanical gauges are the way to go ... they are as liable to being inacurate as a sender and electric gauge. I think the issue that people are having here is much more likely to be - as has already been suggested - mismatched gauges and senders. It tends to be quite poorly understood that there are a number of different standards for gauges and senders and that you can't just bung in any sender with any gauge.

Phil

ClassicChimaera

12,424 posts

148 months

Saturday 24th December 2016
quotequote all
Bassfiendnoideawhathp said:
Or a modern stepper motor gauge with a modern 0-5v sender...

I used these:

http://www.demon-tweeks.co.uk/motorsport/gauges-au...

Phil
I can't wait to see it in operation smile

You haven't got a picture of those have you hehe
I digress smilesmile

Well it needs someone with a bit more suss than me to work mine out frown

I might start with some new wiring from sender to gauge. That'll be fun re routing but eliminates one area of concern.
Maybe that should have been my first check, a continuity test!


Edited by ClassicChimaera on Saturday 24th December 10:32

caduceus

6,069 posts

265 months

Saturday 24th December 2016
quotequote all
ClassicChimaera said:
Looks very impressive under there but I'll polish my original up and she'll be reet. biggrin
Exactly what I was excitedly thinking, until I realised I'd thrown it. Bugger hehe

Bassfiendnoideawhathp

5,530 posts

249 months

Saturday 24th December 2016
quotequote all
ClassicChimaera said:
You haven't got a picture of those have you hehe
I may have somewhere ... why, have I not put 'em up here before? Want to see them? hehe

Actually, the good thing with the Smiths ones is they'll do you custom calibrations and custom graphics quite happily so you could have a TVR oil pressure gauge calibrated to 15psi FSD which should be about right. wink

Phil


Edited by Bassfiendnoideawhathp on Saturday 24th December 11:06

Bassfiendnoideawhathp

5,530 posts

249 months

Saturday 24th December 2016
quotequote all
ClassicChimaera said:
I can't wait to see it in operation smile
Me neither ... hehe

Phil

ClassicChimaera

12,424 posts

148 months

Saturday 24th December 2016
quotequote all
Bassfiendnoideawhathp said:
I may have somewhere ... why, have I not put 'em up hhere before? Want to see them? hehe

Phil
Merry Christmas bloke with a very amusing handle, And yes corse we wanna see them hehe Working biggrin

Come on Phil your holding us up by keeping this on the mantelpiece, we need to see it up and running,
Phil's autos sounds good cos if it does work you'll be inundated hehe

bobfather

11,171 posts

254 months

Saturday 24th December 2016
quotequote all
Bassfiendnoideawhathp said:
Why would you need to minimise the compressible air in the pipe? The air will be at the same pressure as the oil and so the gauge will still read "true".



Phil
Correct however many years ago all dash oil pressure gauges were mechanical and it was known that air in the impulse pipe caused the gauge to react slowly. That's okay if you want a dampening effect but if you want an instant reading a primed impulse pipe it the way to go. Don't forget, any oil that finds its way into the pipe will remain cold and viscous. That's okay if the incompressible oil is present all the way to the bourdon tube and preferably within it too. If on the other hand, viscous oil needs to move along the pipe to compress and decompress air then response time will be compromised.

As an artificer in my youth it was well known that mixing compressible and non-compressible materials in an impulse pipe was a bad practice

Bassfiendnoideawhathp

5,530 posts

249 months

Saturday 24th December 2016
quotequote all
ClassicChimaera said:
Bassfiendnoideawhathp said:
I may have somewhere ... why, have I not put 'em up hhere before? Want to see them? hehe

Phil
Merry Christmas bloke with a very amusing handle, And yes corse we wanna see them hehe Working biggrin

Come on Phil your holding us up by keeping this on the mantelpiece, we need to see it up and running,
Phil's autos sounds good cos if it does work you'll be inundated hehe
I do too but lets just say that it's 'dragging' a little ... *sigh*

Phil

ClassicChimaera

12,424 posts

148 months

Saturday 24th December 2016
quotequote all
bobfather said:
Correct however many years ago all dash oil pressure gauges were mechanical and it was known that air in the impulse pipe caused the gauge to react slowly. That's okay if you want a dampening effect but if you want an instant reading a primed impulse pipe it the way to go. Don't forget, any oil that finds its way into the pipe will remain cold and viscous. That's okay if the incompressible oil is present all the way to the bourdon tube and preferably within it too. If on the other hand, viscous oil needs to move along the pipe to compress and decompress air then response time will be compromised.

As an artificer in my youth it was well known that mixing compressible and non-compressible materials in an impulse pipe was a bad practice
I am in the correct ball park when I say these old mechanical type pressure gauges in effect work in the same way as the Clarke's one I used to give me fairly accurate readings.
A feed pipe filled with oil(or some liquid) that directly pressures at the gauge.

Simon, my engine was a re fresh using original pistons and bore size, honed and new rings but essentially still standard so maybe that's why I get 45/50 psi from around 2500/3000 onwards.
It's got good compression but feels loose and revy smile

ClassicChimaera

12,424 posts

148 months

Saturday 24th December 2016
quotequote all
Bassfiendnoideawhathp said:
I do too but lets just say that it's 'dragging' a little ... *sigh*

Phil
It's not if, it's just when smile
The 20/20's it will be in vogue so you'll be quids in biglaugh
You've got to smile and whenever it's done it will bring one massive smile...... everytime you enter the car.

I like the classic oil gauge, with the needle hanging down,,, mega hehe

QBee

20,904 posts

143 months

Saturday 24th December 2016
quotequote all
ClassicChimaera said:
Bassfiendnoideawhathp said:
I do too but lets just say that it's 'dragging' a little ... *sigh*

Phil
It's not if, it's just when smile
The 20/20's it will be in vogue so you'll be quids in biglaugh
You've got to smile and whenever it's done it will bring one massive smile...... everytime you enter the car.

I like the classic oil gauge, with the needle hanging down,,, mega hehe
Happy Christmas to two of my favourite guys on PH. Hope you both have a good one.

We need to do another Castle Combe track day in 2017 (preferably without the Phazed-induced hangover this time), then you two will meet up and the rest of us can leave you chatting away in Peter's motor home. whistle
You never know, all three of us might even have Chimaeras on the road at the same time.
No, don't be silly, Anthony

xmas