Gearbox ventilation

[Dag-Henning]

I managed to partly empty my gearbox of oil during last race-out, despite the rear seal being OK. ( - it seems......) Has anyone done the same ?? - can it be due to lack of ( enough) ventilation ?? The box is straight-cut, but would that create a need for more ventilation ?

Dag ( - a bit frustrated..)

[rgh0]

Dag
I have never had any problems just relying on the standard vented bolt on the top of the case. I presume you still have this in place ?

cheers
Rohan

[Dag-Henning]

Rohan, I still do have the vented bolt. Thought I might fit a second one to aid ventilation.......Should there be any need to ventilate the main case separately ??

Dag

[rgh0]

Dag

Check the vent bolt is not blocked. A second vent bolt would not hurt but I have never seen anyone need it or to put a separate vent on the case

Rohan

[elandoc]

Hi Dag,
I run a banjo with a breather tube to a bottle. It allows me to see if there's any loss through the vent

[rgh0]

Hi Patrick

I should have known the worlds most expensive elan would have a fancy mod here as well - do you ever see any oil in the catch bottle?

Missed not seening yopu at Lotus 2007 in SA it would have been good to have another quick Elan to run against. The hot Sevens and 2 litre Honda powered Elises are to quick.

cheers
Rohan

[elandoc]

Hi Rohan,
No, never saw anything and now it runs to its own little fitting on the catch tank for the motor. It probably doesn't do much, but it gives me a warm inner glow knowing it's there.
Sorry I couldn't make it to Adelaide - it would have been great to get Ron Hickman to sign my car! I'd love to run it against yours - I really need the feedback, as I only sprint/hillclimb it up here. It's a little undrivable at the limit - a side effect of stiff suspension and big sticky tyres...
Cheers
Patrick

[paros]

Dag

Interestingly I have been seeing oil vanishing from the box. Not sure how much as the first time I just asumed I had not filled it correctly!
I will now carefully refill mine tomorrow, and after 2 races in 10 days time see what has happened.
I do wonder if the thin modern gear oils [synthetic ] might be to blame ?
Richard

[Dag-Henning]

Thanks Richard, - pls let me know what happens. I'll be racing next weekend myself, and will see if the extra vent-bolt is of any help......!

Dag

[elandoc]

Hi Dag,
Apparently the breather can get blocked by the tiniest bit of goo, which quickly leads to oil blowing out the seal (I've asked around). Too thick an oil in the box causes problems when cold, and it takes the box longer to heat up than the engine, so the multigrade synthetic is still the best, I think.
BTW, I notice you have a Replica 26R. Do you mind if I ask what weight it ended up getting to? TTR claims 580 Kg, but that seems extraordinary. It must be with a half cage. I would feel very vulnerable in anything less than a full cage. Anyway, one of my plans is to build a super-lightweight, so I just thought how yours was going!
Cheers
Patrick

[Dag-Henning]

Patrick, I have fitted an extra vent-bolt, and filled it up with multi / syntetic......Next weekend will show....

Abt, the car ; - it ended up at 594 kgs with abt 10 ltrs of fuel.........I have the "full" cage from TTR, but without the extra side-intruder.....May fit one though, and end up around 600 I guess.......

Dag

[Dag-Henning]

- took me one lap of warm up to conclude that I have a sick gear-box......I get serious vibrations and low frequency rumblings when engaging 4th gear........ Must be the box...- can't think of anything else.....Guess it ran dry for a split second, and that maybe killed the bearings.....
Sleeves up, overall on........

Dag

[grat]

Just out of curiosity what multi-grade do you run? I have settled on Redline Lightweight Shockproof gear oil, which is an all synthetic and is roughly rated as a 75W140. It will be running with a LS. Don't currently have any kind of cooling ductwork to the diff (any ideas?).

My maiden voyage** is aimed at third week of July, where ambient air temps will be in the 90s (F) with track temps >110F I would expect. This oil was recommended by fellow elan owner in the vintage club so I think it is on target.

** two year frame off nut&bolt rebuild from a derelict non-running road car. finally seeing the end of this. I can't wait to get it out on the track.

What/where did you come up with a banjo bolt to fit the vent plug? I need some sort of hose off of the diff as my club requires any atmosphere vents to be into a catch bottle. I was thinking to tap a fitting into the face of the bolt, but if someone knows of a source for that size banjo I'll go that route.

So is the 'the world's second most expensive elan' title taken? I may be vying for it.

fj..

[grat]

What/where did you come up with a banjo bolt to fit the vent plug? I need some sort of hose off of the diff as my club requires any atmosphere vents to be into a catch bottle. I was thinking to tap a fitting into the face of the bolt, but if someone knows of a source for that size banjo I'll go that route.

Sorry a little clarification needed. I was thinking of the diff vent when I wrote the above and you guys were talking about the gearbox vent. I need a vent pipe on both. I think I can find a match for the gearbox. question still stands on diff if anyone has ideas.

fj..

[Keith Scarfe]

My experience may be of help but it looks like you have now identified an internal problem. but...
On my race car (Westfield not a Lotus but runs the Ford type 9 box) I used to get the oil blown out when it got particularly hot. It got blown out of the breather hole (std position ford hole in the top cover) rather than the seals.
What I did was to block up the std breather and put in a big one using a tube welded in onto which a small pipe goes. This pipe leads into the bottom of a sealed container fitted above the box (I used an old brake master reservoir) with a little breather to atmosphere in the top. When the box decides to expel its oil, it blows it up into the reservoir and because it is above the box (and sealed so no sh1te gets in) when it all cools down the oil returns to the box thus no loss. This works far better than a catch tank where you just chuck away the expelled oil and thus have to keep topping up the box.
The solution worked very well indeed for me. No more oil loss covering the underside of the car and you can see where the level of oil gets to in the reservoir and being empty means it is returning to the box ok.
HTH.
Keith.

P.s. I did the same for the diff too with similar excellent results.