Oil Temperature

[AlastairA]

Hi All,

I'm currently building a 420R and of course there is a water temperature sender and gauge built in. I'm just wondering whether it's worthwhile connecting the oil temperature sender and putting in the modification to be able to switch the dash gauge from water to oil. Is having the oil temperature as well as water temperature helpful / useful?

Sorry for the basic question but thanks in advance for your education!

 

[Temple Cloud]

IMO oil temperature is of paramount importance and in fact I'm just having Milwoods install a dual oil temp/pressure guage on my Crossflow. High revving of the engine at low oil temperature can do a great deal of damage and I've always been surprised that Caterham don't have them fitted as a default.

[AlastairA]

That makes sense - thanks for the reply 

[ScottR400D]

It's a cheap and easy mod to make to flick between water/oil and is a good guide to when the oil's warmed up. 

Bear in mind that the temperature you see is just before the oil goes into the engine and after it's been cooled. Measuring peak temperature is better but not so simple to achieve and this way does let you establish a norm.

 

 

 

[KnifeySpoony]

On my recently built 420R, I put in a Spa designs dual digital gauge that displays both water and oil temps. Very convenient. The factory location for oil temp sender is in the tank, which is the coldest place in the circuit. Be ready to see some scary-low oil temps. Many advocate tapping the sump but I haven't gotten around to it.

[Gridgway]

I can't imagine not knowing the oil temp on a 7, even if it's in the DS tank.  It's perfectly valid knowing the bulk oil temp there to tell you what's going on 

[AlastairA]

Thanks all - sounds like oil temp is more relevant than water temp but I'll investigate the mod. I've wired the sender into loom but will need to find where it emerges behind the dash.

Thanks again!

[ChrisC]

I looked into doing this with my 420R.  The loom is separated into a number of sub looms on modern cars for a modular approach around the different engine, and dash combination (well when it was changed back in 2016ish).    The chassis loom and engine looms both have a oil temp gauge wire.  One is tied up in the unused wires near the starter, and the other is near the headlight/fan connections near the DS tank near the sensor blank.

Unfortunately this is where the good news ends because the connection wasn't extended into the dash loom or switch loom.  These are connected via a small module (or a large module if you have the 620 dash), so the connections doesn't reach the gauge.   It is possible to make it work, but it will be more effort that it could have been, and there won't be any plug and play solutions.  So (and assuming you want to keep your warranty) it had to wait for me as a future mod. 

[ScottR400D]

I'm surprised that anyone would try to run the cabling actually through the loom for this, it's such a.simple exercise to run the wire from the submarine to a switch, and one from the switch back to the loom near the submarine; a new wire from the oil tank sender to the switch and it's done. 

The only work is putting a grommeted hole in the scuttle and a hole in the dash for the switch and other than that it's the work of minutes to reverse the mod. 

 

[7Up]

What would be considered too high an oil temp for a 420?

[Gridgway]

#10, now you are asking!  Probably a huge can of worms opened here.  Knowing that the oil in the engine will be hotter than that in the tank, if the tank temp was over 120, I'd be wanting it not to get hotter.  If it got to 130, I'd be stopping to cool down, before it got to 130!

[StevehS3]

I think I know (or at least have an indication!) when my oil is up to normal temperature by the oil pressure dropping slightly on the gauge after a cold start. A proper gauge would be useful though. The heat exchanger on the Sigma which uses the coolant to warm the oil initially and then the coolant to cool the oil when hot is clever.

[John Vine]

#5: Many advocate tapping the sump but I haven't gotten around to it.

Easy with a wet sump, of course, using the big blue plug:

More tricky with a dry sump, I imagine.

JV

[ScottR400D]

For the dry sump, I understand some have fitted modified finger filter covers, drilled and tapped for the sensor to screw into. 

If I could get a spare cover I'd try it. 

[John Vine]

#14:  I replaced the standard untapped blue plug with a ready-tapped one intended for a Stack temp sender. 

It also retains the finger filter.  Does the dry sump use the standard plug for this, or a special plug/cover?

JV

[aerobod - near CYYC]

I have found the oil and water cooling on a 420R / R400D is very efficient when moving at speed, idling at high ambient temps being the only time the temp can get particularly high due to only airflow from the fan.

On track at 30 to 35C ambients I have never been able to get the DS tank bulk oil temp above 90C (I have an 82C thermostat and 90C fan "on", 85C "off" setting on my R400D), when thrashing at full throttle with the revs kept between 5500 and 7800. In these high ambient conditions most road cars (such as BMW M3s, Corvettes, Caymans, etc) can only manage 5 hard laps before needing to cool down, whereas my R400 has a bulk oil temp of about 85C and is limited by the driver overheating.

[ScottR400D]

#15 The dry sump has a plug fitted with an O ring that pushes into the finger filter hole and is then secured by an M5 screw. So not threaded itself. 
 

The black plug bottom left of this image. 
 

[ScottR400D]

#16 That's my experience too James. 

On the road it takes about 4-5 miles for the oil temperature to show on the gauge, and it then climbs and settles between 60 and 70c depending on ambient and how I'm driving. 

On track it will typically run at about 80c, 85c occasionally. 

I run it with a cover over the oil cooler on the road. 

[John Vine]

#17  Thanks for that. 

#14: If I could get a spare cover I'd try it. 

I assume you've tried Raceline?

JV

[ScottR400D]

#19

Actually I haven't yet. I looked on their site and they don't list any spares or a sump with that bit as far as I could see. 

I might contact them and ask though now that it's come up again.  

 

[AlastairA]

Again - apologies for my ignorance but what is the finger filter for? I've noticed the cover on the side of the sump but haven't investigated.

[7Up]

Interesting. I watch the gauge a lot on the road and from cold, it takes a good while to register any temperature. Once warm and settled it's 85-90 deg and hardly moves. On track I find it difficult to monitor for obvious reasons! I do remember a club instructor suggesting we cooled off, the gauge was over 110 but can't remember exactly. I also think it was during those really hot days we had last year.

[John Vine]

#20:  Raceline list the Duratec dry sump kit here.  (A site search function would help a lot.)  No doubt they'll expect you to order the "finger filter and cap" set!

#21: ...what is the finger filter for?

In the wet sump, the finger filter sits in the oil pick-up line and stops crud from the sump reaching the oil pump.  I imagine it does a similar job in the dry sump.

JV

 

[Jonathan Kay]

"#20:  Raceline list the Duratec dry sump kit here(link is external).  (A site search function would help a lot.) "

How about the same trick that works on this site?

https://duckduckgo.com/?q=site:www.raceline.co.uk+dry+sump+duratec

; - )

Jonathan

[Geoff Brown]

alastaira #21 - The 'finger filter' is a fine mesh sintered filter which is what I would refer to as a scavenge filter. Apart from the main filter it is the last line of defence against contamination.

On my first R400 oil change I found a small blob of black sealant captured in the filter. Obviously a result of post engine build. So without that small filter where would have the blob of sealant migrated to?