Lotus Elan and Lotus Elan Plus 2 Forums

Hey dudes

Dashed if I can find the crankcase breather on this S130. I see a stubby "thing" under the carbs near the bulkhead in the manual which is called a breather, but it doesn't look like a pipe and there is nothing going into my airbox. I don't think it has a "road lubrication system", either, being a later car, and I didn't see any dangling pipes under the engine.

So, for the avoidance of doubt, could you tell me what breathers this engine should have, and where they are, please? I have leaks all over the place and would like to check the breathers are clear.

Cheers
JonB

Hang on... item 22 : http://www.lotuselan.net/wiki/EA_-_Engine_-_Block_%2B2 ?

And ..

Items 11,12,13 here http://www.lotuselan.net/wiki/EJ_-_Engine_-_Airbox_%2B2

OK, move along please.. nothing to see here!

No22 is more of an oil drain than a breather.

The pipe should fit into the airbox just behind Inlet 4 . It also should have a brass filter in the metal bit to prevent nasties going down said inlet. Mine was rattling about in the airbox.

Jon
You should definitely let the engine breath, there will be internal pressure which can exacerbate leaks if not relieved.
Whether you ingest, collect or dump is arguably a matter of choice depending on how much oil comes through.
Apparently the gauze filter gets blocked - which may explain its absence.
Edit - It would seem that the breather pipe is available. SJ Sportscars are now listing it. Possibly others?
Mark

As mentioned by vincereynard, there's supposed to be a screen filter of sorts inside the breather pipe.
I have a foggy recollection that in my S2, said filter was clogged and broken down many years ago, and I have have not had a filter in there probably for a couple of decades.
What exactly is the purpose of that filter? to prevent what from going where? The air inside the airbox is already filtered.
Or is the purpose to prevent oil mist or droplets from entering the airbox? I really don't see a lot of oil inside the airbox.
Always bothered me not being able to figure this out!

Carlos g.

I believe that filter to be a flame arrestor. The large surface area cools the flame front and stops it entering the crankcase should a backfire occur in the air box. Much like a PCV valve which is one way only and prevents flow back into the crankcase.

Flame arrester/filter may look like this one from my Stromberg S4 ..... soldered into the engine end of the breather tube.

It would be easy to make such a thing, should it not be present.

So now I know where it is, I can look closer. I do believe it's working, because when I first took the airbox apart, there was some oil in the join which must have come from the breather tube. I'll be dismantling it soon anyway, because I have a new set of O rings, Thackeray washers (lovely name, like a Victorian novelist) and nylocs. Just waiting for the imperial feeler gauge to arrive.

JonB wrote:I'll be dismantling it soon anyway, because I have a new set of O rings, Thackeray washers (lovely name, like a Victorian novelist) and nylocs. Just waiting for the imperial feeler gauge to arrive.

Jon, don't get too stressed over trying to achieve the 40 thou gaps in the thackeray's, it's virtually impossible anyway. Concentrate more on getting uniform parallel gaps between carb, misab plate & inlet stub, with a reasonable amount of flex. I always just do it by eye & feel, never put a feeler gauge anywhere near em

Regards, Tim

Yes, because of carb weight top washers always seem to be too tight.
Even gap and some flex is indeed the target.

flame arrester... now, that makes sense!
feels good to be a little less ignorant
thanks,
Carlos G.

As stated by Orsom, the actual measurement is less important than keeping them even and square. As it happens 40thou is almost exactly 1mm anyway.

Bit of a "hopefull" system really, especially as the bottom at 3 / 4 cannot even be easily seen, let alone measured accurately.

Remember to instal a plain washer twixt nyloc and thackety.

I also smear a spot of silicone grease on the O rings. (As I believe someone else mentioned as well!)

(And on the pipe going into the head grommet.)

As a guide taking up all the slack in the Thackeray washers evenly and lightly then backing the nuts off one turn gives a nominal 1/24th inch gap = 40 thou near enough.

Orsom Weels wrote:

JonB wrote:I'll be dismantling it soon anyway, because I have a new set of O rings, Thackeray washers (lovely name, like a Victorian novelist) and nylocs. Just waiting for the imperial feeler gauge to arrive.

Jon, don't get too stressed over trying to achieve the 40 thou gaps in the thackeray's, it's virtually impossible anyway. Concentrate more on getting uniform parallel gaps between carb, misab plate & inlet stub, with a reasonable amount of flex. I always just do it by eye & feel, never put a feeler gauge anywhere near em

Regards, Tim

+1 that's what i do.
Alan

MarkDa wrote:As a guide taking up all the slack in the Thackeray washers evenly and lightly then backing the nuts off one turn gives a nominal 1/24th inch gap = 40 thou near enough.

+1