Bye Bye Oil Surge (K-Series, Wet Sump)

[Willie.]

Gentlemen,

 

I have been looking into oil supply related issues recently, and have been attempting to cure my surging problems - Wet Sump K Series. I fitted a warning light, set to flicker on hot idle, and could get it to come on when cornering hard. However...

 

I have just run all day with sticky tyres, on track, and I didn't get a single problem due to surge. The reason for this is below.

 

See these photos

Actual Image

or

Image in Viewer

 

This is a photo of the Caterham sump, viewed from the front, as installed in the car. The pulley is the crankshaft pulley (Belt is altenator belt).

 

Key:

Red Line - Approx Sump Outline

Yellow Line - Oil Level

Magenta Line - Low Oil Level

 

Note that there are 2 plates, which are of interest here. Firstly there is the alloy "windage plate", and secondly there is the sump gasket. You can see these in more detail in the album, or here:

http://tinyurl.com/5wcmxh

 

I don't know if the gasket is a Rover part or not (I suspect it is), and I'd be fairly sure the windage plate is a Caterham part. You can see from the photo that oil can get trapped above the gasket, at the right hand side. This can be confirmed by draining oil, then releasing the sump bolts...and mystery oil spews out. In fact, at normal (Yellow) oil level, there is a triangular volume of oil there that cannot be used.

 

During cornering, the oil above the gasket must travel left, uphill on top of the gasket, drop onto the windage plate and then drain through the 3 holes in it to the pickup pipe...which it cannot do quick enough. What actually happens is that the useable oil in the sump, which is the small volume from the red line on the right, up to the gasket, and below the windage plate, simply surges over to the left side, where there is loads of capacity to accomodate it...leaving the pickup pipe uncovered.

 

Drilling holes will not fix this, so I removed both plates and sealed the sump with an appropriate silicone type gasket sealant (Oil resistant). This TOTALLY cured the problem. Oil can now get directly into the sump, and to the pickup pipe on time. Previously I had been able to light up the oil pressure light on decent corners, now even giving it a serious lacing on track, the light didn't flick.

 

If anyone reading this has a K-Series Caterham and is having similar issues, I would suggest trying this.

 

Willie

 

[Englishmaninwales]

Willie

Unfortunately, silicone gasket sealant has a nasty habit of breaking away from the inside of the joint and causing havoc by blocking oil galleries and the oil pick up.

 

Malcolm

[Tonycaterham]

Hi

After searching this forum I used Loctite 574, which only sets in absence of air so no problem with getting into oil galleries.

 

 

Tony

 

L7 EVL

[susser]

A series of statements that I think are relevant to the oil surge debate;

 

One of the perceived problems with the K is foaming of the oil due to the crankshaft whirling round. Removing all the windage plates would make this worse I woild have thought. If your oil pressure is more stable with the plates removed, then this weakens the foaming hypothesis.

I agree with you that 2 holes in the gasket can't significantly affect oil drainage, considering the flow rates. They would help drain all the oil during a change though.

I recently removed my foam baffle and did a TD at Snett. Coram is allegedly a problem with Ks as it a long high speed right hander. I saw no oil pressure fluctuations, but I was looking out of the front most of the time.

 

I'll be surprised if this is the end of the matter. With due respect.

[Peter Carmichael]

Because of the orientation of the installation, the engine will be most susceptible to surge from braking/acceleration. Combined with cornering to the right, the surge will be at its worst. The plates were in the sump to control surge in the North/South direction. If the plates were too effective in keeping oil away from the pickup, then some sort of modification is sensible. I'd prefer a solution that still attempted to control North/South surge. North/South surge will see the oil level get well up into the crank's path.

[Johnty Lyons]

Peter your wasting your time Opposite Lock suffers from what is known in Ireland as a sticking plaster and string approach to everything and a youthfull exuberance of Everybody else is an idiot and I'm the best engineer in the world Leave him alone hes just out of his teens and time will eventually be a great lesson to him.

[Peter Carmichael]

I *am* keeping out of it. I thought a little hint that all may not be exactly as described might be a balancing view for other people contemplating this modification. If the modification is effective then good luck to him.

 

Simple question for Opposite Lock is: would you warranty club-members' engines with this modification 🤔

[Johnty Lyons]

 

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jj

N.I. L7C AR 🙆🏻

Membership No.3927.

240BHP 1900cc K Series 40th Anniversary

 

[simonbell]

 

Continue

 

Simon Bell - Caterham 7 Duratec R

I`ve seen the future.....and it`s powered by duratec Check out the website here

[SLR No.77]

I fitted a QED windage plate to my last Seven whilst fitting a dry sump. This is much more substantial than the standard jobbie and includes 4 "fingers" than run at approx 45º up the wall of the block, reducing the crank wind that is opposing the oil running down the block wall. Although QED did tell me it would be fine with a wet sump, it's impossible to fit unless a hole/slot is made for the pickup pipe fitment. It would be interesting to know whether this eliminates any problems with north/south windage whilst still allowing maximum oil to flow back?

 

Willie is actually approaching this from a similar angle to where I was coming from with my "reduced oil pressure" idea, where I found there to be less air scavenging if the pressure relief valve was adjusted to drop the oil pressure a little which allowed more oil to pass back to the sump from the relief valve, offset against a compromise on operating pressure. The oil capacity becomes limited due to not only sump depth, but the ability of gravity to get the oil back there. We flow pumps etc etc who aid oil getting to the bearings but the down side is that at the end of the day, unless enough gets back to the sump then starvation will occur. Willie's approach makes perfect engineering sense, but maybe just needs fine tuning as suggested by Peter C.

 

At the outset the Hellier sump baffle was thought to work, but then owners noticed shortcomings - every issue with wet sump starvation is related to there not being enough depth of oil in the sump (obviously!). Either we control what's there (Hellier idea), or we increase what's there (as Willie has done). Or a combination of the 2?

 

IIRC Willie's car has VDO gauges so there's certainly no damping of the readings. The slightest pressure drop and the gauge would register it immediately.

 

Stu.

 

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Joint Area Representative MAD Sevens (Merseyside And District)

www.superse7ens.co.uk..........the rebuild 😬

 

 

[Johnty Lyons]

The retention of oli above the sump gasket is well known and Documented There is nothing wrong in removing the gasket [don't like the silicone would tend to use an anerobic material] However the complete removalof the windage plate is NOT IMHO a good move BUT time and Willies shell bearings will tell.

I just feel that to rush into Print after just one track day on a short CCt is possible a bit premature Further long term testing would be a good idea before advising folk on here who may not have thought it through to modify their engines.

Willie is very very keen and has lots of Good ideas but sometimes just sometimes his enthusiasm carries him away. Everything in moderation young man. 😶‍🌫️

[Casbar]

Better sell my dry sump setup then 😳

[Willie.]

Casbar, I'll buy it

 

Peter C, I wouldn't warrantly anything related to other members. I wouldn't even put their own bonnets on...I'm not taking the blame when something goes wrong.

 

I have VDO gauges (As Stu rightly says) and a very bright (shift light) oil pressure warning light, set to flicker at hot idle.

 

Previously I could light the light, and simultaneously drop the gauge on corners, but having removed the plates...the gauge is rock steady and the light never blinks.

 

I can see your point regarding north/south surge, but this has never affected me as far as uncovering the pickup pipe, and I haven't seen any evidence of crazy amounts of frothing.

 

My engine has always got tappety when trashed for ages (Hence the previous post on cavitation). I noticed at the track day that it took alot longer for it to get tappety, and it settled down again MUCH quicker.

 

For anyone interested in this, I am 23, have no qualifications in engineering but tend to be up half the night thinking about things to make. This has stopped my surge issues, and I am definetly glad I did it. If you follow suit...on your own head/sump be it.

 

Willie

p.s. The sealant gaskety stuff was purely temporary as I didn't know if I'd have to put the gasket back in. I'm intending to cut the middle out of the existing gasket and re-fit it.

[Englishmaninwales]

I'm intending to cut the middle out of the existing gasket and re-fit it.

 

Did that. Doesn't work. ☹️ In fact, made windage worse with an increase in noisy cam followers.

 

Malcolm