K-Series Oil Pressure Sender location.

[Jamesh]

Good Morning,

I currently have my K-series engine and gearbox out of the car for an overhaul. Gearbox was dropped off at Road and Race Transmissions for Phil to work his magic on and a new clutch/flywheel has been supplied by RedLine Components.

As the old baffle foam was ten years old, I took the opportunity to remove the sump and replace. As I suspected, the old foam was in bits completely clogging up the oil uptake to the engine.

At the same time, I wanted to check the oil pressure sender assembly for blockages and also to remake the sender bracket. Fortunately the hose was all clear with no blockages.

However, it occurred to me why does the engine have a braided flex and various adapters? The sender could be mounted directly into the gallery hole behind the filter - i.e. directly to the engine block, hence removing the complexity and potential failure of the braid, adapters and mount?

It fits perfectly with no interference and the copper washer tightens snugly. I wondered if anyone can provide any thoughts as to why I shouldn't remove the braided hose and complexity?

My best guesses are:

- The sender must be oriented upright?

- The flex removes any vibration and gives a better reading?

- The oil cools along the braided hose which gives a more accurate reading?

Happy to provide some pics if its helpful.

Many thanks,

James.

[revilla]

The electrical oil pressure sender is very prone to failure. One of the things that seems to kill it is vibration. Also exposure to water from the road. They are often moved remotely to avoid these issues. I'd leave it where it is.

[John Vine]

Andrew is right.  The remote mounting was CC's way of prolonging sender life by reducing the effect of engine vibration.

As the old baffle foam was ten years old, I took the opportunity to remove the sump and replace. As I suspected, the old foam was in bits completely clogging up the oil uptake to the engine.

When you say "replace", do you mean the sump or the foam?  If the latter, I think a far better move would be to scrap the foam altogether.

JV

[Jamesh]

Hi John, Andrew,

Thanks for your comments, I figured it would likely be something like this and someone had already thought about it. Ill put it back together as it was.

It was the foam that was in a mess and had deteriorated, the sump and gasket were fortunately ok. I have read some posts in favor of the foam and some against. My understanding was that because the engine in the Caterham is mounted at 90deg to the "normal" application in the Rover the foam helps prevent oil surges and ensures a constant pickup - especially when frequently cornering on the track?

My application is for road use, so perhaps its less of an issue; but I would value any thoughts you might have.

James.

[paul richards]

Keep the sender remote. Scrap the foam. 

[revilla]

My car has the foam removed and has done since I bought it 8 years ago. I've done the modification to the sump gasket with a couple of extra strategic holes to help oil return around the pickup too (you should be able to find pictures on here, if no I'll post one up).

I'm road only, in addition I must say I run T1R tyres which do limit the amount of lateral G you an generate as they tend to slip progressively rather than hanging on to the bitter end as sticky rubber does.

My car is also a VVC, which is probably "worst case" for oil surge due to additional oil retention in the head.

I also have a mechanical oil pressure gauge which is very fast responding, so I would see even the slightest flicker in the oil pressure.

In all the time I've had it, I've never seen oil pressure fluctuations when cornering other than when I've allowed the oil level to get too low (I had a problem with the engine burning a lot of oil for a while so it was difficult to keep up with it!). With the oil level where it should be, the pressure has always been rock solid for me, even when hooning it quite hard.

On a track with sticky tyres it's definitely a different story; as an absolute minimum you would need an Apollo tank but even then you see oil pressure dropping off significantly and for serious work you need dry sump for sure. On the road with stickier tyres you could probably manage to provoke significant oil surge too.

[John Vine]

Dave Andrews (oilyhands on here) probably knows more about the K than anyone, and his advice has always been to ditch the foam, for the very reason you've demonstrated -- disintegration and subsequent blockage of the pick-up.  

I'm not sure anyone has offered a clear and logical reason for its use.  The longitudinal orientation of the engine might be one, but I don't think many are convinced.

JV

[John Vine]

Gasket mod.

JV

[Jamesh]

Perfect - thanks for the guidance and advice. One less thing to go wrong as far as I am concerned, happy to ditch it.

Ill see if I can find some pics of the extra holes in the sump gasket on the forum, I presume that they allow the oil to flow more directly down through back into the sump itself rather than over the ends/sides and provide a easier return path?

James.

[Jamesh]

John - you beat me to it! Thanks, ill review and add the holes as shown.

[John Vine]

...I presume that they allow the oil to flow more directly down through back into the sump itself rather than over the ends/sides and provide a easier return path?

Exactly so.

JV