Alfa Pages

[Sprintervention]

I have always found No1 big end to be the one that gives way first, this seems to be due to oil starvation. Has anyone had any success with dry sump lubrication, crank scrapers, extra sump baffling or any particular oil or additive to help prevent oil surge.

I have now stopped using fully synthetic as it appears to be too thin and tends to slosh about too much and find its way out of the engine too!

I have come accross some boxers that have been dry sumped in the past but never got any details and I have a few sumps that I would happily have a go at modifying if anyone has any details of mods that work.

Any help gratefully received, currently have 2 spare engines just in case, 1 is waiting a crank regrind to No1 big end, need I say more.

Many thanks Chris.

[Eddie W]

A bit expensive except for racing but well worth while for that application. Drysumping not only increases reliability but also has HP gains in the region of 10-20 HP depending on engine size and output.
In the case of the alfa, you would probably be looking at an external belt driven pump and the tank MUST operate as a swirlpot. That is, the returning oil is angled to spin around the wall of the tank which separates the lighter air to the inside where it can be vented to atmosphere. There is usually a 50mm or so sleeve in the centre of the lid, extending down to say 25mm above the normal oil level and this prevents oil being thrownout the vent, also helping the swirlpot action. Without this action the volume of oil gets greater and greater as it gets more airated. This can not only fill the tank to overflowing but also negates one of the main benifits which is supplying dense oil to the motor consistently.
The sump itself should preferably have a twin pickup ( although our Escorts only used one) and a removeable windage tray curved to the crank throw. This has slots where it meets the L/H side of the sump as the spinning crank throws the oil against this side and it runs down the wall into the sump.
The details of where you retun the oil to the block you will have to work out by studying the oil system in the block. This can have quite an effect if there is a tendency to starve one part of the motor.
The HP gains come from the negative pressure generated by the suction side of the pump so that the crank is not acting as an air compressor, which takes power.
Regards Eddie
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[Guest]

Do you really believe, that you gain 10-20 HP from dry sump lubrification?

If that was wright, it would be one of the main tuning items - and it is not!

The reason for a dry sump is that you want reliable lubrification (during cornering and braking), and you can easily incorporate much more oil in the system (good for cooling).

I once had an aluminium sump with inside plates for my boxer (made by Dieter Gleich in Germany). I sold the car with this sump, but unfortunately could not get another one for the following car. So it had to be fitted with a plain normal sump.

The following boxer was fitted with supercharger in 1988 and has run until now without opening the engine! (it has now been opened after 70.000 km)

The car has been raced and used slick tyres which give better braking and cornering, but I remember to keep the oil level slightly (0,5-1 cm) above max. This has been enough not to have problems with lubrication.

This is not to say, that dry sump is not a good idea, only that it is possible to run without it.


Peter (DK)

[Peter D]

Sorry.

It was me who wrote the above text.

I was logget on, but before I had finished the reply I was obviously automatically logged out again and did not discover that.

Peter (DK)

[Eddie W]

Hi Peter, yes there are many texts that stipulate HP gains with dry sumping. It may not be the original motivation for the mod but is a definite byproduct if you like. 10 HP was an average gain for an Escort rally motor from 1.8-2ltr on dyno. The spinning of the crank attempts to compress air against the sides of the crankcase acting somewhat like a centrifugal compressor and that is work that the motor is doing that doesn't go to the wheels. A properly designed windage tray will also be of benifit with this in a wet sump application and every dry sump that I have seen (and made) has had one. A windage tray is of more benefit controlling surge in a wet sump than all the baffles and swinging gates etc in the world. Been there, done that. I've made a lot of tanks and sumps etc for custom dry sump applications from rally cars to speedway cars.
Be aware that if the standard sump is overfilled too much then the crank can scoop oil and this can be a power loss as well as increased oil burning.
Regards Eddie
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[Sprintervention]

Hi Eddie,

Looks like dry sumping has a multitude of befefits, not least the benefit of increased power available. I will have to look into it further, shame the cost is quite high. The main cost appears to be on the pump, there is also the need to fabricate a custom sump and oil storage tank. Any details that you have on dry sumping the boxer engine will be welcomed. I may have to see if I can get another look at the dry sumped boxer engine that I saw about 10 years ago, doubt if the same guy has still got it though!

Regards Chris.

[Peter D]

Hi Eddie

What is a "windage tray" (not in my technical dictionary).

Could you explain further or send/show a photo/drawing?


Peter (DK)

redaktoer@alfaklub.dk

[Eddie W]

Hi Peter, I'm finally getting around to answer some of your questions. I should really define between a windage tray and a surge tray, the windage tray generally being used in drysump applications and a surge tray in wet. Usually but not always as I think the Nissan SR20 has a windage tray as standard.
Windage Tray::
A curved tray sometimes mounted off the mains and sometimes in the sump. The tray closely follows the curvature of the crank throw and restricts the turbulence created by the spinning crank thus reducing the HP loss from this effect.
Surge tray:
Basically a flat traymounted in the sump above the oil level with a lip around the pickup hole to within say 20mm of the sump bottom. If the tray has a slight V shape then 4 or 5 10mm holes should provide enough oil return in conjunction with the pickup hole. Very effective against surge without any extra complication. A winged sump may require swinging gates etc as well.
When my IT dept. gets back from Australia I'll see if she can tune me up on our CAD programme and post some drawings. But for now I'm getting a bit tired so Ill try to answer any further questions as they arise.
Regards Eddie
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[Eddie W]

Further to the above, I was just having a discussion with my buddy Glen and he mentioned a drag car that one of his boys works on. It is wet sump but a powerful vacuum pump was added and that alone lifted the HP from 1100 to 1200. The gains from the negative pressure effect are usually in the range 3-7% but an extra 100 hp for a vacuum pump can't be bad.
With the BDA Escorts we used to work with even a 3% gain would equate to 8HP so the 10 HP gain I mentioned is well within the usual range.
Regards Eddie
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[Peter D]

Hi Eddie

Sounds like the boxer engine already has a kind of surge tray, a horisontal plate in the sump.

Regards Peter

[Eddie W]

Hi Peter, I finally got around to having a look at my spare sump and the tray you mentioned. Yep that is a surge tray but not the most sophistocated I've ever seen. It appears that it would only be really effective on braking mainly and on L/H cornering. I would definitely want to improve it for racing but at least it shows Alfas thinking was on the right lines. If I remember right from when I had my 1.5 in bits the pickup is fairly central and the standard setup wouldn't do much on righthanders or acceleration. When I next have one of our motors down I'll look at how to improve it and do a post with some pics. A vertical lip around the pickup hole is very important to stop the oil climbing out and starving the pump under extreme cornering.
Regards Eddie
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[rallyboy77]

Hi Guys,
My Alfasud has a standard sump with additional baffling added. If I remember correctly it continues the original baffle around the side an also closes the "hole" in the original baffle plate a little. Nothing additional right at the back though I don't think we have problems under acceleration

The car is setup for club gravel rally and runs a completely stock "95hp" 1500 boxer with 150ks on it, (other than the baffled sump and lightened flywheel that is) but it still does fairly well.


jez

[Eddie W]

Hi Jez,I'm really intruiged at the use of a 33 on the loose( if I remember right you're running a Sud) I've only driven RWD ( Escorts) on gravel and they were very easy to set up sideways before the corner and power out as straight as possible. On a sweeper you could hold the tail out all day on the throttle. I believe the technique for FWD is different although I remember watching Erickson winning our international some years ago in a FWD Opel and he seemed to be able to throw it sideways when he wanted. Do you use left foot braking to set it up before the corner as I believe you need lots of wide open space to learn this technique? Presumably an LSD is necessary for good times but what other mods do you have to make it work?( ie suspension, quicker steering, toe in/out etc) Obviously the Junior WRC cars make it work pretty well.
Be interested to hear from you.
Regards Eddie
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[rallyboy77]

Hi Eddie,
Yes I run a Sud. I've taken my (rwd) Falcon out on khanacross once and yes it is quite different to a fwd. The Sud can be made to go very sideways although it is power off sideways as opposed to power on sideways. I do left foot brake a lot and use the handbrake in all the tighter corners.
The car itself is an '83 Ti shell, seam welded with a full rollcage to front strut mounts / extra plating on top of strut mounts. Uprated springs with an extra 30mm ride height on the front, revalved koni sport shocks up front and spax gas shocks up the back. We generally run -1.5 camber on the front and even toe for the events we do. It may be advantageous to have a bit of toe out on the tighter stuff but it gets a bit hairy on the fast straights then. We have a sprung plate LSD or phantom LSD which is 25nm static load. Have you seen these LSDs?
The Alfasud can be quite a handful even though it doesn't have much power, most other fwd cars with see have powersteering. Imagine the old F2 kit cars without powersteering, 300+hp and upwards of 100nm LSD driving through the front wheels!!

The junior wrc cars are great. I've witnessed the Suzuki Ignis at the Rally Canberra, 215hp 1600cc motor screaming through the forest is awesome to watch!!

We are planning some upgrades over christmas for next year, on the cards is brakes (twin master cylinder and balance bar conversion) and maybe a new engine as the current one is nothing special. I may have a bunch of questions for you if that is alright??

Jez

[Eddie W]

Hi Jaz
Thanks for the info. Anything I know is yours for the asking although my knowledge is probably a little out of date now. We used to run a hydraulic handbrake with a flyoff conversion which is really easy to do if you haven't already. I used to make balance bar pedal boxes years ago and found they were at their most usefull with a cable linked to a knob on the dash. The cable needs to be of a type that has the wire layers in alternating directions so that it transmits motion in iether direction unlike most speedo cables. Some cars with hydraulic handbrakes used to run a limiter valve in the line to the handbrake with a knob for adjustment. The factory Nissans of some years ago used to run that system quite successfully.
I'm not quite sure what your LSD type is but I used to run a Salisbury in the Escort. I would have thought that 25 nm was a little light.
I used to run quite a lot of castor on my car(4.5 degrees) and that made the turn in really sharp.
The Sud/33 chassis looks like it could do with some stiffening from the engine firewall forward even more than the S3 type braces. Some thing I intend to experiment with.
There are more ideas I would like to explore but I have to sign off now as It's getting a bit late so I'll catch up with you later.
Regards Eddie
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[Serpent33]

Can I add that the pump is located as closely as possible to the bottom as possible and right in the middle. For oil to surge away from the pump is rather difficult a G to generate.
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Each time I speed I say, "Dear lord, make me fast and accurate..."

[Eddie W]

Take a half full bowl of milk (or a similar viscousity fluid), hold it over the sink and make a quick movement left then right. As you are moving the bowl right the fluid will still be climbing the l/h side due to inertia. The same can happen in your sump under hard cornering. Now try the same with a lid on the bowl (ie a surge tray in your sump). The 33s sump has a surge tray that leaves a gap on the l/h side which can allow the oil to climb away from the pickup under extreme load. Under these circumstances the iol will also travel along the underside of the tray and a vertical lip around the pickup hole will minimise this. You could make it near bullet proof but it becomes impossible to fit the sump and this is where you have to comprimise.
Either experiment when wife/partner is absent or grovel suitably and clean up.
Regards Eddie
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