The V8 Owners Forum -

sowen wrote:I'm getting confused here, you're planning on using a GEMS manifold because the heater outlet does not run underneath, but it does not have provision for the two water temp sensors? You are not using a hotwire manifold because it has a steel pipe that runs underneath but has all of the required water temp sensors already in place?

Almost. The hotwire manifold I have here doesn't have provision for the pipe which runs underneath. No tapping for it - the casting is blank. And I don't know how the hotwire derives that feed. I have seen a hotwire installation on an SD1 and wasn't impressed by the plumbing - it looked a mess. And I would like to get rid of that pipe, as anyone who has one leak will understand. BL did, as they only ever used it on the SD1, IIRC.

stevieturbo wrote:

DaveEFI wrote:

stevieturbo wrote:Just drill and tap for the sensor appropriate for the gauge.

But where? It needs (presumably) a flat surface to seal the sensor and access to the water jacket.

Lots of old temp senders are tapered, so they simple seal as you tighten. Or slap some sealant/PTFE on the threads

Mine isn't tapered. Square shoulder at the end of the thread with washer.

If I could fine a smaller one - say 10mm or so thread - would be great. But there is more than one for the SD1 which fits but is different electrically. And there's not much point in fitting one which doesn't work with my gauge.

If anyone knows of a table for all sensors - same as you can find for injectors - I'd be very happy.

Coops wrote:which manifold you using?
any pics?

I believe it's a Gems. Pic earlier in this thread. Definitely not a Thor which is not compatible with the early plenum.

DaveEFI wrote:

stevieturbo wrote:

DaveEFI wrote: But where? It needs (presumably) a flat surface to seal the sensor and access to the water jacket.

Lots of old temp senders are tapered, so they simple seal as you tighten. Or slap some sealant/PTFE on the threads

Mine isn't tapered. Square shoulder at the end of the thread with washer.

If I could fine a smaller one - say 10mm or so thread - would be great. But there is more than one for the SD1 which fits but is different electrically. And there's not much point in fitting one which doesn't work with my gauge.

If anyone knows of a table for all sensors - same as you can find for injectors - I'd be very happy.

Easier said than done !

Hence it's easier to fit the correct sensor anywhere possible.

The sensor for the gauge for my dash is just a regular NTC sensor..no big deal, pity the damn thing needs the engine ecu to drive the temp gauge on the dash !

So I've a Hayabusa engine ecu in my car, purely to drive the temp gauge on the dash lol
it streams that info over RS232 as opposed to it being a normal bloody gauge.

DaveEFI wrote:

sowen wrote:I'm getting confused here, you're planning on using a GEMS manifold because the heater outlet does not run underneath, but it does not have provision for the two water temp sensors? You are not using a hotwire manifold because it has a steel pipe that runs underneath but has all of the required water temp sensors already in place?

Almost. The hotwire manifold I have here doesn't have provision for the pipe which runs underneath. No tapping for it - the casting is blank. And I don't know how the hotwire derives that feed. I have seen a hotwire installation on an SD1 and wasn't impressed by the plumbing - it looked a mess. And I would like to get rid of that pipe, as anyone who has one leak will understand. BL did, as they only ever used it on the SD1, IIRC.

Just had a look at my hotwire manifold, identical to the GEMS one in your photo at the start of this thread obviously apart from having the thermostat mounted in the front.



There is a seperate steel pipe that is bolted to the underside of the manifold for the second heater feed pipe. The dashboard coolant sender is the standard hotwire one and as you know makes the gauge over-read, I'm thinking of experimenting with a variable resistor to see if I can get the gauge to sit on 90 instead of 105-110 all the time

If you really really want to retain the original SD1 coolant temp sender, why not have an alloy boss welded onto the manifold to take it saving all the hassle of trying to find another sender with an identical output range?

That's big help - thanks.

I'm calling it a Gems manifold, but may be wrong. The hotwire I have here has the same casting as the flapper - just some different sized holes for sensors and injectors, etc.
The major difference on the Gems is the heater outlet - front left in your pic.
On my SD1.the heater return runs alongside the rocker cover on the off side. It has a cut off valve for the AC. My intention was to run the feed alongside that using copper tube - there's plenty room. I'd really not rather have any pipe etc running under the manifold unless it could be replaced without removing the manifold. Had a very unfortunate experience with mine which cost a deal of money when away from home...

I take it your gauge sensor is the unit with the red connector beside the CTS? On mine, there is just a bolt there. The casting looks too small to tap out to take the SD1 sensor - the walls would only be about 2mm thick.

FWIW, plenty seem to have trouble finding the correct sensor for a standard SD1 - wrong reading gauges are common.

stevieturbo wrote:

DaveEFI wrote:

stevieturbo wrote: Lots of old temp senders are tapered, so they simple seal as you tighten. Or slap some sealant/PTFE on the threads

Mine isn't tapered. Square shoulder at the end of the thread with washer.

If I could fine a smaller one - say 10mm or so thread - would be great. But there is more than one for the SD1 which fits but is different electrically. And there's not much point in fitting one which doesn't work with my gauge.

If anyone knows of a table for all sensors - same as you can find for injectors - I'd be very happy.

Easier said than done !

Hence it's easier to fit the correct sensor anywhere possible.

The sensor for the gauge for my dash is just a regular NTC sensor..no big deal, pity the damn thing needs the engine ecu to drive the temp gauge on the dash !

So I've a Hayabusa engine ecu in my car, purely to drive the temp gauge on the dash lol
it streams that info over RS232 as opposed to it being a normal bloody gauge.

I'm told I can use a spare port on the MS3 to drive the gauge. A PMW output, and can be programmed temperature wise.

But I want to do all this in stages.

First stage is to fit the later injectors and get a decent tune on the MS2 (without going mad) before changing to MS3 and sequential.

But I'd not like to be without a temp gauge in the interim.

I'd be surprised if a PWM output could keep an old gauge happy that is expecting a variable resistance

stevieturbo wrote:I'd be surprised if a PWM output could keep an old gauge happy that is expecting a variable resistance

It's what's known as a hotwire meter - slow reacting. But PWM simply puts the energy into it in a different way. Just a posh name for a dimmer.