VX Wet Sump breathing

[I reply to every thread]

Following on from my earlier "oil level" query I'd appreciate a description of the standard wet sump VX XE oil breather system on cars with carbs.(I've not got one handy)

 

Is it simply crankcase to cam-cover alongside dipstick, & one from the cam-cover front offside to catch tank?

[Harry Flatters]

Matthew,

 

Not 100% sure about carbs, but mine runs TB's and has exactly the breather system you describe. I presume when you say "along the dipstick" you mean the large bore pickup pipe from the crankcase up to the 90 degree elbow union in the cam cover. The smaller outlet on the offside of the cam cover is blanked off.

 

 

 

Edited by - Steve Mell on 26 Nov 2001 13:26:01

[I reply to every thread]

Thanks Steve.

Does yours blow out any oil? Where do you fill to on the stick? Made any mods to inside of cam cover?

[Andrew Russell]

Aves

 

I run the same breathing system on my car with no modifications to the 'plate'. Engine is on 45's and puts out about 205 bhp. I use Comma Syna G oil and fill to about 1 cm above the standard mark on the dip stick. If I overfill beyond that level, oil is thrown out into the catch tank, but then stabilises.

 

How much oil is yours throwing out and is it still doing it? Has it stabilised once a certain level is reached? What did it do before your recent mods?

 

Andrew

[EFA]

Before the mods it blew the oil into the injection system for emission frinedlyness.

 

DOesn't seem to want to stablise even on the dipstick mark. WOuld add that it only blows out when he uses high revs!

 

Fat Arn

The NOW PROVEN R500 Eaterid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[I reply to every thread]

"He" uses high revs. Seem to remember that you accounted for the first quarter litrewink.gif

As Arnie says, previously vented back into injection system (but didn't burn any oil)

Now blows out at least until 1-2 mm below max level on dipstick - but seemingly only with plenty of revs. I'm reluctant to find it's natural stabilising zone - that might be off the stick!

[Harry Flatters]

Matthew,

 

I do run with cam cover mods. The usual closed in oil channel is completely open (ie plate removed) except for a small plate where the breather exits on the off-side to prevent excessive cam splash from venting into the catch tank.

 

On filling I usually fill to about 1mm below max - this is with the standard Caterham alloy sump with foam baffle. But to be honest if it goes over the max a bit, all that happens is a bit more in the catch tank.

 

Edited by - Steve Mell on 26 Nov 2001 14:46:17

[I reply to every thread]

Steve, that's interesting. You fill to the max line only? I thought accepted practice was to go over by a few mm. (See Andrew above). I have to admit that I've previously only filled to the max line with the old injection system.

If it's stabilising anywhere it appears to be at around "max" level. You've had no problems then? How hard do you use it?

[Harry Flatters]

Matthew,

 

True to say, up to now this has been a road only car although it does get some serious right foot, revving 7000+.

 

My caution on the oil filling has it's roots in the days when the car was standard fuel injection and was prone to dumping large dollops of oil into the pleneum producing a rather good impression of 007's DB5 smoke screen, and incidentally the first time it happend, making me jolly glad I was wearing my brown trousers!

 

The problem was patially alleviated by the cam cover mods and once the oil settled around the "max" mark the problem eased considerably.

 

It is also true to say that very ocassionally I have had the odd empty hydraulic follower tapping on the bulkhead which is cured by a small top up. It may well be that I have found the optimum level (1mm below max) but that doesn't allow for much venting.

 

From what you and Arn have said I may well try filling a tad higher on the dipstick although as I said before this does seem to induce a bit extra venting.

 

Steve Mell

PTM 88

[EFA]

Matthew,

 

Suggest we try a cam cover with the plate removed and the little (bound top be expensive) SBD piece in to protect the outlet from cam throw.

 

Anyone got a spare cam cover??

 

(Can't use my - it has extra modes for the DS System)

 

Fat Arn

The NOW PROVEN R500 Eaterid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[Andrew Russell]

I think that you should try and see just how long this problem persists. You are not going to pump out all your oil and I think that it will, as Steve said, reach a point where it no longer is a problem.

 

I overfilled my engine to cure the noisey hydaulic tappet problems when using Mobil 1 and altho' I have now changed to Comma Oil which seems to eradicate the tappet problem, I still put a little extra oil in out of habit!

 

The standard Caterham sump doesn't hold a vast quantity anyway and so I feel happier with a little more there!

 

Can't think of any other suggestions......

 

The SBD mod is just that, it is not a bit to buy. It involves cutting away about 95% of the original plate, leaving just a small segment under the breather outlet. Plan is on their website.

 

Andrew

 

Edited by - andrew russell on 26 Nov 2001 15:47:37

[I reply to every thread]

Thanks for your input Gents. Suck it and see I think. I'll modify a spare cover if I can get hold of one & see if that helps.

[Paul McKenzie]

Arnie/Steve,

I think the little 'bound to be expensive' bit of cam cover (insert?) is what remains after you butcher the insert a la SBD - or am I missing something. Also Steve, what is the theory behind this mod and what should it achieve - better oil distribution inside the cam cover, or what? I'm a bit lost on this one, but all in favour of 'freebie' mods.

Thanks,

Paul

 

Andrew,

I see you've already confirmed the first part of my statement - still interested to understand the benefit of the mod., though

Thanks

 

 

Edited by - Paul McKenzie on 26 Nov 2001 17:00:02

[Harry Flatters]

Paul,

 

As I said, when I first got my car it was fuel injected and the cam cover breathed directly into the plenum. Under certain circumstances like whipping sharpish around a roundabout and then planting your right foot the engine would breathe a big gulp of oil up the crankcase breather tube, into the cam cover, and because the oil channel was closed in, the oil wizzed round the cam cover, out the breather and into the plenum - hence 007 smokescreen.

 

Removing the plate (except for the bit covering the breather exit) meant that the oil was not channelled directly to the breather and just fell harmlessly onto the cams and drained back down.

 

Hope that all makes sense.

 

Steve Mell

PTM 88

[I reply to every thread]

Ahh - So tear-arsing all the way round at least 4 roundabouts on opposite lock may have been a contributing factor!

[Paul McKenzie]

Steve,

Thanks for the explanation

Paul

 

[Harry Flatters]

Matthew,

 

That'll do it every time!

 

Steve Mell

PTM 88

[EFA]

Suggest we butcher it then Mathew.....

 

Its great fun pulling all the VX Silicne sealant off..... Getting the cover blasted and refinshed at the same time might be a good idea!

 

Fat Arn

The NOW PROVEN R500 Eaterid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[Harry Flatters]

Arnie,

 

I'm told it's imperative that you get all traces of the silicone off, otherwise stray bits can play havoc with cam followers etc!

 

Just to be on the safe side, I used Loctite on the two bolts securing the little plate over the breather exit.

 

Sorry if I'm teaching my grandmother to suck eggs etc etc.

 

Edited by - Steve Mell on 26 Nov 2001 17:41:48

[EFA]

Steve,

 

Thats why I suggested blasting it - on both sides!

 

AVES cover has some lovely corrosion around the front anyway.

 

Fat Arn

The NOW PROVEN R500 Eaterid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[Rob Morris]

Running std Vx on 45's and found that the sump only takes 4ltrs of oil any additional amount and its sent straight to the catch tank. I have found the dipstick markings that Caterham retro fitted alowing for the small sump to be very accurate. My engine doesn't use a drop of oil between changes and is driven at reasonable pace, however, due to the carbs I tend to change oil and filter every 2,000 miles rather than wait for the recommended 3,000 as oil is cheap. Don't forget to change the sump foam baffle as this can break-up and FU*K-UP the engine.

 

Finally, if (don't think so from our mailings)you are using hydraulic followers then you will find that they start to rattle if the level drops much below max giving you a good oral indication.

 

Hope this helps

[I reply to every thread]

"Dipstick markings that Caterham retro fitted"?? Does this mean that there are dipsticks out there where "Max" means "max"?? Are there long and shorter dippers?

[stevefoster]

I fill mine to just under the max mark. The car / engine was delivered in 97.

Anymore than this and some is expelled into the catch tank.

 

[I reply to every thread]

Modified Cam-Cover fitted as sourced from SBD (I knew I could spend money on this problem if I tried) Touch wood - all seems to be well. Had a fairly good larruping last two weekends and no breathing probs - cracked screen instead!

[Paul McKenzie]

Aves,

Did they mod the cam cover as per their web site drawing, or something else? How come you didn't do the DIY? - I thought that Arnie was standing by with the hacksaw ready - or was that what persuaded you to give some loot to SBD?

Paul