I have seen figures of as much as 80% aeration.
Strewth - I start getting nervous at 30% (FEV Aerometer scale).
Perhaps we should put one of these engines on the rock and roll rig at work and see what they do with the equivalent of 1.0-1.5G of lateral acceleration… or perhaps we dont want to know?
I dont have any issue with recommending against the Caterham dry sump, but the wet sump is worse WRT to aeration and the wet sump is difficult to baffle effectively.
I always recommend the Pace 3 stage pump system, even to those who have the stock Caterham dry sump setup already, the Caterham setup has only a single scavenge pump and uses the existing pressure pump, it is not unknown for the scavenge pump to fall behind the delivery of the internal pump. It also has a realtively low capacity tank. It is important to note however that there are two systems, one based on a ‘purple’ pump which is a lower capacity pump and is underdriven WRT crank speed and a later ‘gold’ pump which is of a higher capacity and is driven at crank speed. The gold pump based systems are less prone to failure.
Aeration tests have already been undertaken with both the dry sump and the wet sump, Simon Thornley has some interesting data. 80% Aeration seems a bit high to me, I would expect the tank to overflow at around 20-25%. I think Simon has seen 30-40% aeration on a static test rig with the stock wet sump.
Dave
I know this is all about the K series, but as someone considering the purchase of a new R400 (Ford/Cosworth) should I be worried about the same problem from the dry sump?
The Duratec based system is very different. Check the details with Caterham but I believe that it may be a multi-stage pump based system.
Dave
Wet sump,dry sump,1800,1900,2000,all this is good.and productive,and stops the K being lost
Well I would expect you disagree completely with everything I have to say.
The Caterham sump is very different to the Elise sump Simon… and the orientation of the engine is different too.
I have seen many bearing failures on wet sumped Caterhams, probably more than 50, I have seen around a dozen oiling realted failures on DS systems. The fitment of an Apollo de-aeration tank can act as partial protection against the affects of surge on a wet sumped engine. Fact is that most Caterhams that compete under duress have the Caterham DS system, hence you will see a quite a few failures.
Have a good look at a Caterham wet sump and then tell me that it is easy.
Baffling the wet sump has been done, but space constraints limit the fitment of proper one way trapdoors, the orientation of the trapdoors is different from the transverse installations and the lack of any well around the pickup and the nature of the sump mean than baffling is rarely effective.
The best solution is the PACE 3 stage setup which has a generous tank, two scavenge stages and an adjustable pressure stage.
Dave
Simon E - I know exactly what you’re saying re Judd and Elise sumps but the Caterham wet sump is a law unto itself. I mean, its got a block of foam in there to try and stop it surging.
Simon D - The Caterham duratec dry sump is a properly engineered and proven system and you cant argue with the value of the new R400 though. You’ll love it.
Well I would expect you disagree completely with everything I have to say.
And that is rather troubling chaps. There surely can’t be complete opposites for every item on every issue that you discuss, can there? I have no problem with you not getting on when the information is of interest, but when it becomes plain confusing you just end up damaging the reputation of K builders in general. How would anybody know who to pick when it seems that there is no right way of doing anything?! Makes alternative engines seem more attractive if anything and I doubt that’s good for either of you.
Just an observation.
Ian
SimonD and Bob,
The Cosworth R400 scavenge pump is indeed a multistage pump. The scavenge pumps themselves and variants of the sump supplied to that Caterham have proven to be extremely reliable and are used without issue on Duratecs across the board, including the entire grid of 300bhp Formula Atlantics, CSR260’s and a number of privateer cars.
Cheers,
Chris
IDG,
I agree entirely.
However I have considerable experience with all of the various sumps fitted to Caterhams going back some 9 years or so. Any advice I give is based on practical experience of many engines over a considerable period of time. The advice is no different than I would give to anybody. I have agreed that the Titan type dry sump system is flawed no question and I have consistently said so for a number of years. The alternative Pace system however is excellent.
Scarcely a week goes by without me advising a wet sumped Caterham owner how to fix his rogered big-ends, and these are mostly road cars with stock engines. Show me a Caterham wet sump, with or without baffles, a set of slicks and an average circuit and i will show you a costly rebuild. True there arent many with rods thru the block, primarily because these are mainly rpad cars who’s owners see the signs early rather than track cars where the owners see the red mist and have little or no mechnical sympathy.
Dave
“The other significant issue is that all the steel cranks previously available used an OE or similar oil path through the block and crank. This route is circuitous and marginal and though it works well enough in a standard production engine, why it was not improved on the steel aftermarket cranks I do not understand. - Just one reason I consider all the previously available non OE cranks so poor, In fact I would never use one.”
Revised oiling is commonplace on aftermarket cranks, it’s simply that your experience of these is limited. when fitting these it is necessary to modify the block, and /or main bearing shells to provide transfer grooves in all the appropriate positions and to ensure that the main bearings are cross drilled. I hae done these modifications to many engines to ensure improved oiling. These modications are made in tandem with the correction of the awful std oilways in the K block and ladder.
Windage plates are also commonplace, again, it;s just your lack of experience of them…
Dave
You are losing the plot Simon.
Diecast or no you should open your eyes and you will see many anomolies in the ladder and further anomolies in the block where the oil feeds are inadequate and misaligned, the main passages to the filter housing have casting flash on the both turns which will rob the pump flow of energy. similary inside the pump galleries oil is forced around some pretty poor perpendicular drillings which need improving.
Oil is the lifeblood of the engine, poor oilways are like blocked arteries and cause similar problems. Attending to the oilways is no different in principle than porting a head except that the transported medium is far more viscous and therefore more affected by anomalies. It is a practice that I have used going back more than 30 years.
Oilways don’t have to be blocked to give problems they only have to be marginal. On the OE system, the feeds to journals 2 and 4 are the same size as those to the remaining bearings even though they require more oilflow since they also service a pair of crankpins each, if either of these is marginal then oilflow to the most important bearings in the engine will be compromised.
Casting/machining shift on the ladder and block often causes the oil delivery holes in the bearing shells to be misaligned with the delivery holes/grooves by up to 1.5mm, this compromises the oil delivery to the most vulnerable part of the engine, to ignore these failings is lunacy.
What would be the point of cross drilling main journals 1,3 & 5 when on an OE type crank there is no oil feed to a crankpin? or do you not understand why journals are cross-drilled?, both main and big-end? Strike a light Simon, you do talk rubbish sometimes.
The revised oiling goes further than x-drilling which is just an expedient, it’s simply that you haven’t yet seen sufficient crank variants to know what you are talking about. Nor do you seem to understand why cranks are x-drilled.
As I’ve said before about the oiling issue, the question isn’t about whether a stock engine with relatively low rev limit and relatively low rod loadings can survive marginal oiling, but whether a higher revving engine with much higher bearing loads can. If there is any doubt about whether the standard galleries can deliver then they should be corrected… no question, being pig-headed about it just because I mentioned it is just plain daft.
Dave
Same old same old… there are an awful lot of my engines out there that have not ‘totally failed’ and as yet I haven’t in this thread or any other blamed the engine.
As with any production engine there will be areas of the manufacture that are less than good, liner heights, liners themselves, casting quality, alignments of oilways in head, block and ladder, tolerances of guides, valves, head machining etc.etc. That’s what blueprinting is about, correcting these and bending the tolerances to give the best possible output.
There is a very good description of the problems in my text, you just have to read it. I dont need to prove any ‘claims’, my suggestion is that the oilways should be inspected and if necessary corrected. In my experience it is often necessary. I would expect that to be a natural part of any complete build. As it happens I keep a photo log of most builds, but there would be little point in posting any pictures of the mods, since you would simply refute, deny and rake up the usual mindless rhetoric.
You say you are at a loss to understand what I consider to be appropriate modifications to the crank? That depends on what is there to start with. I consider cross drilling of the main bearings that deliver to the pins to be a worthwhile modification, even with transfer grooves in both top and bottom shell (which the ‘K’ does not have in factory trim) I believe that you will see fluctuations in delivered pressure to the big-ends without cross-drilling.
With only a single transfer groove and no cross drilling you will see sufficient lack of oiling continuity to see failures.
do you seriously believe that I knew nothing about crankshafts before being ‘blessed’ with your regurgitated information… please…
I’d would be interest to know what ‘totally failed’ means and also the extent to which I was involved in these engines, I assume they got further than the rolling road before ‘totally failing’.
Yawn…
Dave