F355GTS Posted December 23, 2002 Share Posted December 23, 2002 Having had my Gearbox serviced by Road and Race I now have a natty breather on the top instead of a hole 😳 Phil suggested routing a pipe to end a bit higher than the box however I've just installed a Mocal oil catch tank for the dry sump breather which has two inputs, does anybody have any views about connecting the Gearbox breather to this? Mark Edited by - F355GTS on 23 Dec 2002 23:34:57 Link to comment Share on other sites More sharing options...
Trevor Phillips Posted December 23, 2002 Share Posted December 23, 2002 Mark, I normally run a gearbox breather into a catch tank but then vent the other side to air [in our case a second open catch tank]. By keeping the catch tank above the oil levels some of the expelled oil drops back into the gearbox through gravity. I obviously run 2 lines - 1 from engine, 1 from gearbox. An alternative on the breathing side is to fit one of the natty little K&N filters. Racing pics and items for sale here Link to comment Share on other sites More sharing options...
captain chaos Posted December 23, 2002 Share Posted December 23, 2002 Mark, I have an identical set up, breather added by phil, dry sump and the Mocal tank. (where have you located it?) last year i did a Ring trip and a couple of track days and never got any oil from the breather, so, rather than find a way of upsizing the breather line dramatically to fit into the Mocal, I've blocked off one of the catch tank fittings and run the breather along the top of the tunnel from the gearbox to the back of the car. Any droplets can find their way back in and if it becomes a problem I'll fit a container behind one of the seats at the back end. Link to comment Share on other sites More sharing options...
Fred Posted December 23, 2002 Share Posted December 23, 2002 Don't you think having the breather from the gear box coconnected to the catch tank, you run the risk of moisture from the tank, running back down the tube and in to the box. i.m.o. this is a bit risky and no benefits gained by this lenth of tube.ect. Link to comment Share on other sites More sharing options...
captain chaos Posted December 23, 2002 Share Posted December 23, 2002 I must admit, i did get a problem when I first fitted the breather in that I originally plumbed it into the catch tank for the dry sump system. I then accidentally over filled the engine with oil which then filled up my catch tank (previous set up), and excess oil found it's way out of the 'to air' vent and also into the gearbox breather. It was a crude set up, no one- way valves fitted for example, but this still encouraged me to run the breather separately from the catch tank. How much oil is going to come out of the breather if you top the g/box up to the right level anyway? Link to comment Share on other sites More sharing options...
F355GTS Posted December 23, 2002 Author Share Posted December 23, 2002 Captain I changed the fittings on the Mocal using Sealy Air line connectors (1/4 BSP thread and a smaller push on tube connector), they're perfect for the job for the tube size from the dry sump breather. At the moment I've got one blocked off and therefore had thought of routing the Gearbox Breather to it. I've moved the Battery to sit on it's side on the Scuttle (it's a Hawker Gel type), the Mocal is now mounted on the end of the Passenger footwell. Fred See what you mean although I doubt much would travel down the tube. BTW if anybody is about to buy one of these 1Ltr catch tanks (Demon Tweeks 2003 page 229) I know a place locally that sells them in various different colours for £50, Demon's price £69.99 plus VAT! Mark Link to comment Share on other sites More sharing options...
captain chaos Posted December 23, 2002 Share Posted December 23, 2002 Mark, Are you running the Cat/integral dry sump system then? (allowing space infront of the pasasenger footwell). My Mocal is infront of the pedal bbox but attached to the frame where the old battery mount is.Mocal tanks for 50 quid....great, now you tell us! ☹️ Anyway, DaveK helped me put the TB's on and he also felt running the breather in this way would not be a problem. Link to comment Share on other sites More sharing options...
Fred Posted December 23, 2002 Share Posted December 23, 2002 My consern is not oil coming out. but condensation going in to the box. as the vapour in the catch tank is hot from the engine, as it cools down it will turn to liquid some of this must run down the tube even if the tube is at the top of the tank due to gravity Link to comment Share on other sites More sharing options...
Fred Posted December 24, 2002 Share Posted December 24, 2002 good price on the tank mark Ifound that you are better to keep the connectors to 1/2 inch on the tank.if you seal the top. on mine with the 1/4 connectors the engine was not breathing right this is what gave me all the noise from the scavenge pump. 1/4 is ok if you use the mocal cap . Link to comment Share on other sites More sharing options...
F355GTS Posted December 24, 2002 Author Share Posted December 24, 2002 Captain Yep using the Std Caterham Dry Sump system, the car is an ex race SLR so passenger footwell is shorter Fred I'm using the Mocal Cap so hopefully breathing will be OK, I understand your concerns on the Moisture and therefore will leave the Gearbox Breather going to air or get one of the Mini K&N's Mark Link to comment Share on other sites More sharing options...
Jason Plato Posted December 25, 2002 Share Posted December 25, 2002 Another option is to run the breather from the gearbox to a catch tank mounted near the fuel pump , this tank can also be used for the diff breather - essential for MIRA sprints . Dave Link to comment Share on other sites More sharing options...
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