K series dry sump

[Andrew Dent]

Been pondering whilst having a few spare hours travelling.

 

Caterham sell a dry sump kit for the K series for about 1500 quid (DT catalogue price). Can anyone give a price for what it would cost to put it together on your own.

 

Andrew

[Peter Carmichael]

You are getting into can of worms territory.

 

The components of a dry sump kit don't actually cost very much. An external scavenge pump, a tank, a sump which allows external feed to the existing pressure pump, mountings for all of the above.

 

If you start trying to do this yourself, none of the parts you source will fit without custom work of one sort or another.

 

Most one offs start by abandoning the Caterham bellhousing integrated dry sump tank. Finding the extra room usually involves chopping off the passenger footwell extension or some other drastic measure. Probably any neat solution will use the Caterham dry sump casting.

 

The Caterham pump is mounted quite high, which is not as good as it could be. The pump and sump design mean you have a single pick up which is again not as good as it could be. The belt drive to the pump is not particularly clever - several failures have been recorded, but pretty much only by R500 owners and myself where we are using 9000+ rpm.

 

The Caterham sump expects all the connecting pipework to run on the RHS of the engine. The passenger footwell location for the tank will require long pipe runs.

 

In other words:

 

It will be a lot of work and it will be even more work to make a neat job of it. Which on balance may justify the cost of the Caterham kit.

 

Alternatively, an Apollo tank will prevent most of the damage and has fewer points of failure. Having experienced the dry sump system I am almost longing for the good old days of reliable running with the Apollo tank.

[V7 SLR]

"Almost" Peter..?

 

In 9000 miles I've not had a chirp out of my dry sump. Been great. Is your problem due to the belt speed you get from your new engine. If so, can't you put a smaller diameter pulley on the crank to lower the belt speed or would this mean not enough scavenging at those revs. I'm not sure if the scavenge pump overpumps and so could be slowed down a little or whether its gearing is entirely right & proper for the revs that the engine does.

[Jason Plato]

I've got the caterham dry sump kit , and I've not had a problem in 10K miles , on road , track and competition .

I havent heard of an failiers from the race series cars either .

 

I woud agree that the position of the scavenge pump is far from ideal being above the base of the sump , which could result in air being drawn into the pump instead of oil and , the pump having to drag the oil up instead the oil being fed to it .

 

At a Roger King lecture recently , he mentioned that he modified a crossflow dry sump system to run on a K series with ...... maybe it would be worth you having a chat with him ??

 

The cost of the sump base plate as used in the caterham system alone is £350 . I cracked mine once , I have since fitted my sump guard which has saved my bacon twice so far !!

 

Dave J

[Peter Carmichael]

V7:

 

can't you put a smaller diameter pulley on the crank

---

 

er....

 

NO. The scavenging MUST maintain a ratio of extra capacity above the pressure pump delivery. No ifs or buts about it. The original purple k-series pump gave way to the gold one for exactly this reason. Can't remember where I saw it but there is a very good web site on general purpose dry sumping gear which gives you the lowdown on multi-stage pumps and the whole theory.

[Wallbanger]

Peter,

 

What are the differences between the Purple and Gold pumps (apart from price)? I ran my K on a purple and did have some problems, but we could never tie it down to either an engine fault or the dry sump kit.

[Mike Bees]

The gold pump was part of a package of changes intended to solve the problems of the VHPD-engined race cars grenading their engines due to oil starvation. IIRC the total package was:

 

* Gold scavenge pump (higher capacity than purple)

* Revised pickup for scavenge pump

* Bigger bore pipe from the pickup to the pump

* Swirl tower (incorporating breather) for dry sump tank input

* Tappet bucket feeds blanked off

* Cylinder head sealed (only relevant on a non-plenum setup)

 

I think it was generally understood that the problem stemmed from an excess abount of oil accumulating in the cylinder head, i.e. resulting in a lack of oil elsewhere. Maybe just the tappet bucket blanking would have been enough to solve it, I suspect that the package of changes was a sledgehammer attempt to solve the problem quickly.

 

I ran my car for a year on the purple pump with no oil pressure problems. I think some of the 1.6K race cars ran the purple pump too, it was only when they started testing the VHPD that the problems occurred.

 

If you do change to the gold pump then you must have the swirl tower fitted to the tank, without it it will chuck all the oil out of the filler on the tank - BTDT! The swirl tower does increase the effective capacity of the tank - separating the oil from the air as the oil/air mix is fired into the tank means you can get more oil in before it starts chucking it out of the breather.

 

Mike

 

Edited by - Mike Bees on 18 Dec 2000 10:34:31