VHPD oil pressures

[Golf Juliet Tango]

OK: installation is VHPD in EU3 format with apollo tank (in the 21).

The oil pressures get alarmingly low unless pressing on, despite the fact that oil level is OK.

On start up, when the oil is cold 4 bar.

When cruising at somewhere close to the NSL, pressure can easily get down to what I assume to be 1 bar (the top of the red mark.

OK so it builds to 2 bar with a bit of extra pressure on the loud pedal but...

 

I can not / prefer not to drive like a maniac all the time, the 21 is ideal for long distance/M-way stuff so I would like to have confidence that everything under the bonnet is OK.

I also know that the sender is no more use than an aeroscreen in a hailstorm.

 

Suggestions/observations/thoughts please

a) relax but check the level frequently

b) waterproof a new sender with tube of mastic/sealant (any pictures of this modification? In and out of situ)

c) mechanical o/p sender

 

Never had a problem with the Crossflow o/p - good aren't they?

 

_{Democratic dissent is not disloyalty, it is a positive civic duty.}

[I.Mupferit]

Personally I would be inclined to suspect the o/p sender as the culprit and change to a mechanical gauge. My experience of the original fit o/p and water temp senders was that they are about as useful as Anne Franks drum kit.

 

Brent

(aka Arfur Nayo)

[Golf Juliet Tango]

Hi Brent

Thanks - rather what I thought (although I was hoping that a) might be OK). I do think that b) is just a waste of money.

 

And I have had problems with at least one of the temp senders too! 10^oC too low ☹️.

 

Can I ask you about fans next? You are, after all the only professional mover of air on Blatchat 😬. (I know that there is a lot of hot air on Blatchat but at least you shift the stuff around deliberately)

 

_{Democratic dissent is not disloyalty, it is a positive civic duty.}

 

Edited by - Golf Juliet Tango on 29 Sep 2008 12:44:02

[Golf Juliet Tango]

I better print out this page on 7faq then.

 

_{Democratic dissent is not disloyalty, it is a positive civic duty.}

[I.Mupferit]

From memory, the complete kit from Think Automotive was around £50 but with the up side that it is a one off purchase you never need make again - unlike the Caerbont oil pressure senders!

 

A quick phone call to Think will give you all the prices and they will make up a kit to post out to you.

 

Now what do you need to know about fans?

 

Brent

(aka Arfur Nayo)

[Golf Juliet Tango]

Hi Brent

Thanks, I think you are optimistic on price but I will see.

 

On fans:- still on the 21, in the warm weather (of which we had so much this year) the disadvantage of the K in particular and the horizontal rad in the 21 become very obvious unless you can keep moving.

Rather than a bigger rad, wouldn't a better fan be of more use (as well as cheaper and much easier to install). However none of the radiator fans I have seen advertised tell you what their cubic feet per minute capacity is. All they tell you is the diameter, which is not the vital statistic.

Q1:- Do you know what the "standard" (if anything on a 21 is standard) rad pulls through and which fans are significantly better?

Q2:- If I put in a fan which is slightly larger than the smallest (height) dimension of the rad (but will still have a larger swept area) will this help?

Q3:- Could I get better coverage and more airflow by using several smaller fans?

 

_{Democratic dissent is not disloyalty, it is a positive civic duty.}

[I.Mupferit]

As for the price, I didn't include the pressure switch in mine, which brings it down a bit, and there may have been vodka and tonic on top of that but then again maybe I just plain forgot! 😬

 

As for fans, I don't know what they fitted to the 21 but if it is the same pathetic 9" job as fitted to the 7 then that may explain your woes. If the engine doesn't overheat when moving at reasonable speeds or when driving in a spirited manner, then I would suggest the radiator is doing its job and doesn't need to be bigger. If you look in the Demon Tweeks catalogue at Pacet fans, they show a table with air volumes where you can very easily pick the right fan for the job. You can easily see that a 11" fan moves an awful lot more air than does a 9" jobbie.

 

On my first 7, I threw the 9" job away and fitted an 11" Pacet Pro Series fan which, at a stroke, cured all my over heating woes when stopped in traffic in high ambient temperatures. On my last 7 with the big 2.3 Duratec, I managed to get a 12" fan fitting to the rad and it very quickly brought the temperature down when it kicked in, again even in high ambient temperatures.

 

Try to get the fan ring as close to the radiator matrix as possible without it actually chafing the fins. I had to fettle the ring slightly to allow this on the big fans but it does prevent the air from short circuiting round the side of the fan ring, rather than through the fins as it should.

 

On the 7, fan depth can be an issue as it may foul the A/R bar but with the horizontal fitting on yours, I guess this isn't a worry but, again, you will find this info in the D/T catalogue.

 

I would go for the largest Pacet Pro Series fan you can get within the size of your radiator matrix, bearing in mind you may need to wire it up via a relay as well. No engine ever suffered from over cooling while stationary, but they sure as hell don't like over heating.

 

Brent

(aka Arfur Nayo)

 

Edited by - Brent Chiswick on 29 Sep 2008 15:02:24

[CageyH]

Instead of getting the large warning light from Think, consider getting a smaller ultra bright LED, I fitted a 10mm red one to my car, just above the oil pressure gauge, and you can't miss it.

 

On my VHPD, with a mechanical gauge, I get 25 psi on tick over with hot oil, and up to about 65 PSI when making progress.

 

Only dead fish go with the flow....!

[Golf Juliet Tango]

Thanks Brent - I am pretty sure that the 21 has the standard fan and as you realise I understand that radiator size is no substitute for air-flow. I'll take a tape-measure to the rad next time I use the car and measure up.

Cagey - the variation on yours is a little less than is showing on the on mine as it is less than 3:1 whereas I am getting nearly 4:1. Thanks for the note about warning light size - there is not much dash space on the 21!

 

_{Democratic dissent is not disloyalty, it is a positive civic duty.}

 

Edited by - Golf Juliet Tango on 29 Sep 2008 18:33:13

[Golf Juliet Tango]

Brent

Looking at this page I see what you mean about the volume of air shifted!

 

_{Democratic dissent is not disloyalty, it is a positive civic duty.}

[CageyH]

GJT,

 

I got similar readings with the electrcal sender. After changing it too many times, I went mechanical and have not had a problem since.

 

Having read this thread, I am now tempted to get a bigger fan! The 9" looks impressive, and I think it will still fit. May as well wire it up the ECU as well....

Another job for the winter!

 

Only dead fish go with the flow....!

[CageyH]

As for mounting of the fan, is the through core option the best, or would I be better off with a differentsolution?

 

In the high ambient temperatures down here,I get a bit worried when stuck in traffic,as the temp does not seem to come down!

 

Only dead fish go with the flow....!

[jackb_ms]

My oil sender has the same symptoms as yours, it was quite scary at the time but know I often check the oil level.

I don't want to go for the mechanical gauge because I want to keep the same dials.

 

I think the company based in Wallingford does an oil sender which might be better than the OEM one which I might try later this year.

 

Regarding the fan, the one I have sitting in the garage can nearly lift it self of the bench! I think it this one Spal fan VA09-54A

 

hope this helps

 

Jack

 

 

 

 

 

Emily, The Very Yellow 21

[I.Mupferit]

You can mount it using the through the core systems but I have heard of people having problems where these have chafed a hole in the core. This may well be because it wasn't quite tight enough and allowed movement to cause the wear though.

 

Personally, I preferred to mount from the radiator side fixings supplied to mount the standard fan and modify them as necessary to get the fan to fit. I think DT do universal type side mounting brackets which allow you to mount different types of fan to a standard radiator bracket. Dave Kimberley of DT can advise you on this.

 

As you can see from the link, the 11" fan will shift something like 35% more air than the 9" version. On your car CH, you may even be able to get a 12" fan in there as I did given that like me, you have the Freestyle inboard suspension without the A/R bar to get in the way of a deeper fan motor. The 12" fan shifts a whopping 83% more than the 9" although it is true to say that not all the open face of the fan will have a free opening through the radiator core so you won't necessarily realise the full additional volume of air available. My car had a bespoke Raceline rad which I think was slightly bigger than the standard Caterham job so gave me rather better performance anyway.

 

To be honest, the performance figures of the fans shown can only be a guide as you really need to know the comparative performances against a known static pressure (resistance if you will) in order to compare directly. Nevertheless, a bigger fan that effectively covers a greater area of the radiator will still give you better cooling performance whilst in traffic. As I said earlier, my 12" fan on the Duratec gave an heroic cooling performance in high ambient temperatures and very quickly brought the engine back to normal. In fact, I swear the car would move forward if I didn't have my foot on the brake, it was that powerful!

 

Living where you do CH, and especially with the K series known dislike of overly high temperatures, I would definitely fit a bigger fan and without the depth restriction of the standard a/r bar, you may even be able to go the full Monty and fit the Big Bertha 12" job. If you can't get a big fan close up to the fins, consider making up a cowl between the fan ring and the fins to take up the gap. I'm sure, working where you do, you must be able to get the necessary materials to fabricate something.

 

Edited by - Brent Chiswick on 29 Sep 2008 23:06:13

[CageyH]

Thanks Brent.

Having had a look at the various performance figures for the SPAL and Pacet pro fans, I have opted for the girly 9" jobby. I had a chat with SVC who did not seem to think the 10" would fit in the available space, as the 10" is larger than the OD stated on the website.

 

The SPAL is marginal in traffic, and the 9" Pacet pro shifts in the region of 80% more air, so it should cope. If not, then I'll flog it on ebay or similar, and then go for an 11" or 12" fan. It is relatively eay getting things made, but not so easy getting them past security! 😳

 

I saw that Myles made a spcer for the fan to get a 10" to fit his rad, but I think the 9" pro will pull more air anyway.

 

A bead os silicon round the edge of the cowl should help avoid the chaffing/wear of the rad core. Also, using the same size rad, should mean I can modify the fittings fairly easily, so it should almost be a bolt on upgrade.

 

I was actually going to see if I could get two fans fitted side by side, so I have built in redundancy.

 

Only dead fish go with the flow....!

 

Edited due to rude word filter, as I missed out an "f" in the relevant place

 

Edited by - CageyH on 30 Sep 2008 16:33:56

[I.Mupferit]

An 11" fan can be made to fit the standard Caterham radiator fairly easily but the 12" is a bit of a challenge, although nothing you won't be capable of I feel certain, and made all the more possible by having plenty of room behind the rad.

 

Good luck with it anyhow, hopefully the Pacet Pro 9" will be sufficient for your car.

 

Brent

(aka Arfur Nayo)

[CageyH]

I'll see how the 9" works out.

It has to be an improvement on the SPAL - an extra 400 CFM is quite an increase.

As long as it manages to bring the temp down, instead of the continuos running of the SPAL I will be happy.

 

If it does not work, I think an 11" or 12" with an aluminium shroud to ensure air is pulled through the rad will be on the cards.

 

The car survived ok this summer, but the fan did run for quite some time in slow moving traffic, and the temperature just seemed to increase slowly. I hope the extra 4-- cfm makes a difference!

 

Only dead fish go with the flow....!