Lotus Elan

Engine to airbox breather photos

PostPost by: mbell » Sat Oct 12, 2019 3:12 am

Hi,

I am planning to make a new breather tube (Weber head and carbs) as am missing mine. I've had a look around but not found many clear pictures of the tubes to go off.

Anyone have clear pictures? I am particular interested in the bend/shape and the location and type of mesh used as fire screen.

Thanks,

Mark
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
mbell
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1432
Joined: 07 Jun 2013
Location: Austin, TX (UK Ex-pat)

PostPost by: oldelanman » Sat Oct 12, 2019 7:43 am

Hi Mark,
Did you find these images ?
breather-assembly.jpeg
breather-assembly.jpeg (28.79 KiB) Viewed 356 times
breather-pipe-003.jpg
breather-pipe-003.jpg (35.34 KiB) Viewed 356 times
breather-tube-mesh-screen-002.jpg
breather-tube-mesh-screen-002.jpg (51.3 KiB) Viewed 356 times


It's basically a 5/8" diameter steel tube, the copper mesh screen is soldered inside the cylinder head end.
Roger
S4 DHC
oldelanman
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1521
Joined: 02 Jan 2008
Location: Dorset UK

PostPost by: Nickm » Sat Oct 12, 2019 9:31 am

You can get a NOD one from eBay,. No affiliation

Item number 193146329224

Hope it helps
Nickm
First Gear
First Gear
 
Posts: 23
Joined: 06 Oct 2014
Location: Sutton, Surrey, UK

PostPost by: Grizzly » Sat Oct 12, 2019 12:02 pm

I'm really tempted to modify mine so it doesn't vent back to the airbox, bit sick of the oily mess it leaves...... my engine was rebuilt recently so has well within spec crank case pressure / blow by etc but even so i find i get oil in the air box especially after aggressive right hand turns. I suspect the Head to block pipe is protruding into the head too much causing a bit of an oil pool which in turn gets thrown against the side of the head / breather tube hole during hard cornering but it's one of those things that really bugs me.

I was going to buy one of Clivey boys bypass tubes but he's stopped selling them so i might have to knock some thing up myself.
Chris
User avatar
Grizzly
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1918
Joined: 13 Jun 2010
Location: Cheshire/UK

PostPost by: nmauduit » Sat Oct 12, 2019 1:06 pm

The early breathers were venting to the road rear of the engine...

I have tried a breather scheme for increasing venting capacity, with one 3/4" port from the head which is the air box port, and an other one from the block where the rubber oil drain would plug (crossflow venting point). I had experienced too much oil from blowback during a track day, though later found a small head gasket leak which was causing the extra blow back and had pushed me down that slippery slope...

The final version has a condensation chamber in the middle above the mechanical fuel pump location, so that oil can return to the sump a bit like on a crossflow (the bottom hole in the head has been plugged, the top one has a tube press fit into it so that oil from the camshaft does not get into the original chamber as much). An oil catch with a purge at the bottom is in the fender, and is connected to the top of the condensation chamber (hand made in a rush with material at hand as a tall alloy box filled with mesh, two input ports at the bottom and one exit to the top).

p1050240.jpg and
two stage engine ventilation with oil recuperation (not complete on the photo)
S4SE 36/8198
User avatar
nmauduit
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1232
Joined: 02 Sep 2013
Location: France

PostPost by: mbell » Sat Oct 12, 2019 6:31 pm

oldelanman wrote:Did you find these images ?


I had seen the top two but not the bottom one. That's really helpful. Thanks.

I have bought some 5/8" Ali pipe that I plan to make one from. Looks like I need to get some Cooper mesh too.

Nickm wrote:You can get a NOD one from eBay,. No affiliation


Thanks Nick, I had not even thought to check given these are meant to be hard to get. TBH I want to make my own as a fun project and even at current prices it will likely be cost effective.

Grizzly wrote:I'm really tempted to modify mine so it doesn't vent back to the airbox, bit sick of the oily mess it leaves......


And

nmauduit wrote:I have tried a breather scheme for increasing venting capacity,


At the minute I think the standard setup seams to be working ok, not much oil or leaks I've noticed. So not planning to mess around with it to much.

I am thinking about adding some piping in side the air box to move the exit further forward. The reasons for this
1) see if I can find a lower pressure area to create more suction and increase flow (Bernoulli principle)
2) spread the flumes across the cylinders more evenly.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
mbell
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1432
Joined: 07 Jun 2013
Location: Austin, TX (UK Ex-pat)

Total Online:

Users browsing this forum: No registered users and 3 guests