K series oil surge prevention

[John]

Has anyone got any good solutions other than dry sumping for oil surge prevention on a K series wet sumped 1600 race car. Are Apollos / Accusumps the only answer or is there a demon sump mod that can be used?

 

John

[V7 SLR]

Anything other than dry sumping is a compromise, one which will only serve to make you wish you'd gone for a dry sump to begin with.

 

If you really have a race car, then you'll be pulling serious "g"'s which means you can ill afford to have surge. Both the Apollo and Accusump solutions will not prevent that. They will only reduce it.

 

What is you objection to dry sumping? Is it price? If so, then there's a cheaper solution for dry sumping K's coming up from Pace. Someone on this forum and/or the Se7ens list is looking into it. It could end up a better solution that Caterham's for about half the price.

[garyedwardc]

What's wrong with Caterham's system apart from the bell-housing tank and the price?

[murph7355]

Apart from price (1700+VAT) I've heard that the racers are removing it in favour of Apollos as a number have failed (don't know why but can point you at people who can tell you from experience).

 

The Caterham bell housing is, I think, a compromised design due to space issues in the engine bay which are avoidable. Possibly. The pumps are also a big compromise, partly (again I'm no expert) because they retain the internal pump and try to fit around various fittings rather than be designed specifically for the job.

 

I'm looking at the Pace system so mail me if interested. Unlikely to be available before Autosport 2002 (ie Jan/Feb) but it's at least started now.

 

The Apollo has two advantages - removes air from the oil so whatever turns up in the engine is oil and not Mr Whippy's finest. It also gives 2l (approx) more capacity. But as V7 says, it's a compromise.

 

The Accusump is probably not worth the hassle/expense. I know of at least one K that has died with one fitted. Which isn;t to say the Accusump caused it, but it obviously didn't prevent it.

[Peter Carmichael]

The Accusump is a cure for a problem that noone has. Under conditions of surge it will supply *AIR* at high pressure to your bearings rather than *OIL*. Whoopee for the high pressure, but what sodding use is that?

 

The Apollo tank is a very good interim solution.

 

Where do I start on explaining what is wrong with the Caterham dry sump system?

 

The scavenge pump is half way up the block. It has a single pickup. The tank capacity is small. The tank shape is compromised. The pickup in the tank is an inch and a half above the bottom of the tank. The configuration as a sealed engine restricts drainage from the head. The belt tensioner is crap and the belt falls off.

 

Need I go on. I have fixed some of these on my installation with:

 

1. A warning switch for when the belt falls off.

2. A filtered breather to the head

3. Fitting the Apollo tank as well

 

I also plan to:

 

4. Shroud the pickup so that it is effectively lower.

 

After that I will seriously consider a different pump arrangement possibly with an extra stage to scavenge directly from the head.

[Peter Carmichael]

IMO the internal pump is fine. It certainly has the capacity and it has the advantage that in a system where the belt is prone to falling off, the pressure pump still keeps the engine alive for a few seconds during which you can shutdown.

[Rob Walker]

The Accusump is a cylinder that has a Piston in it and as the oil pressure rizes the cylinder compresses the air behind the piston until a time when there is a drop in pressure ( under surge ) the piston will then move with the compressed air behind it pushing the oil in front of the piston around the engine and maintaining oil pressure for the duration that is determined by the size of Accusump you have fitted. It does not pump air.

 

Peter was the cause of your dry sump scavange going AWOL not that you were trying to run a four grooved belt on three grooved pulleys??????????????

 

The Apollo tank picks its oil up in exactly the same way as the stock system and as such will not help with oil surge, in fact due to the bleed off of a the top of the tank it will help to loose oil pressure.

 

Edited by - Rob walker on 21 Nov 2001 09:35:26

[John]

Dry sumping is not allowed in the series that I intend to compete in, hence my query.

 

John

[John]

Dry sumping is not allowed in the series that I intend to compete in, hence my query.

 

John

[Rob Walker]

Accusump is your best option then. You could also fit an Apollo along with the Accusump this will get rid of the airiated oil.

[WDervish]

I raced with a wet sumped 1600 K for two seasons on A032 tyres & had no problems. The main trick - i think is to have plenty of oil capacity.

 

To that end i had a 13 row oil cooler in teh circuit as well - not for cooling necessarily, just for oil volume. I had a std Caterham wet sump, the foam baffle and the windage plate (all from Caterham). The other thing that i did was to take the oil filter off the side of the engine fitted a take off plate and ran a remote filter. All oil lines were -10 size (5/8 in)

 

Chris

 

 

 

[Jason Plato]

Whats stopping us fitting a seperate 5 litre oil tank , in place of the belltank and reverting back to a std bellhousing ?? - Vx's have been doing it for years !?

 

The Appollo tank also increases the temperature of the oil ( reduces the cooling capability ) , as it is sited directly behind the radiator .

If you want oil / air separation fit a proper seperator or create swirl into the "new" oil tank .

 

Just my 2p worth .

 

Dave

[Peter Carmichael]

I think the bleed is irrelevant to the oil pressure. It is very low volume.

 

The siting of the oil pressure sender relative to the Apollo installation is probably responsible for the pressure drop, but I haven't looked into it.

 

I don't know of any wet sump Apollo engines that have expired. In the first year of SLR racing the dry sumped ones tended to expire and the wet sump/Apollos were fine.

 

My panic attack over maybe having had a 4 row belt was because I found one kicking around at rebuild time of exactly the right length for the dry sump. I now recall that I bought a 4 row for the alternator believing that to be the right spec (should have been 5 row) and it just happened to be the same length. I (and several R500 owners) have had the three row dry sump belt fall off. Cr@p design yields cr@p results.

[Peter Carmichael]

The Apollo tank temperature effects are more likely to be down to crank windage. Overfilled wet sump k's run high oil temps even without the Apollo tank, but the Apollo tank comes with the temp sender that tells you there is a problem.

[John]

Thanks all. A few pointers to be looking into.

 

John

[garyedwardc]

As Rob says most of Peter's Accusump criticisms are incorrect (is that blasphemy?) I can't see why it will not reduce or if of sufficient capacity eliminate surge. Is doesn't pump air into the engine it releases the oil it was charged with, back into the system when the engine runs out of oil to charge it. The system's oil capacity is also increased and the whole arrangement is much simpler than a dry sump, with no belt to fall off, far fewer joints to leak etc. Another advantage is the ability to isolate the stored pressurised oil when the engine is turned off so that as soon as the key is turned, on start up the crank gets lubrication while it is waiting for the conventional oil pressure to build.

An Appollo tank does not reduce surge and in peter's dry sump system is only needed because the dry sump tank in the bell housing is a far from optimal design with little or no attempt to reduce aeration. I can't see the problem with a K series version of the Xflow set-up. I don't think the position of the scavenge pump is critical and although more scavenging from another point in the sump is desirable it's the limited capacity of the tank that demands more scavenging in order not to run dry. A bigger external tank would provide a resevoir to iron out lack of oil returned. from the sump.

[Rob Walker]

Peter,

 

Bleed off is 0.5 Bar up to 90C using 4W 40 Synergy.

[oilyhands]

I'm sure there is plenty you could do to the stock sump to minimise surge in the sump, there are also mods you can make to improve drainage from the head.

 

I have an article on sump baffling/ surge minimising somewhere, if you applied the techniques outlined it would certainly help the surge problem.

 

If anyone would like a copy, let me know.

 

Oily

[Peter Carmichael]

Rob,

 

I'm not saying that you don't see a lower pressure. I just haven't been convinced that it is down to the bleed off. Have you proved it is the bleed off, for instance by blocking it off temporarily and seeing the pressure pick up?

 

If the pressure stays above the pressure relief valve operating pressure then it is fine. Any more pressure is waste.

 

The pressure is a measurement of the oil pumps ability to keep up with the oil demand. The point of the oil pressure relief valve is to vent excess volume (not pressure) of oil and it does it by using pressure as an indication of how much needs to be bled away. The gain of the pressure relief valve is quite high - a small increase in pressure results in a large bleed of volume. By contrast, the Apollo tank uses a 1mm restrictor which has a very low gain - you need a signifcant increase in pressure to see more volume being bled through it and the resistance goes up (roughly) as a square rule of the volume being passed. If you really are worried about losing 7 psi you could fit a smaller restrictor and the Apollo tank would still function.

[John]

Oily,

 

Yes please ;-)

 

John

[John]

Oily,

 

Yes please ;-)

 

John

[Rob Walker]

Yup Peter, I have blocked the bleed line on my 1600 SS when hot and noted a pressure increase. AFAIK the Rover pressure relief is set to 4.1 Bar and my engine used to run around 4 Bar before fitting the Apollo when hot and between 3.5 and 4 with the bleed off connected. At idle the pressure loss was greater.

[Peter Carmichael]

OK, I stand corrected.