QUESTION.
I recently competed at a Supersprint with my Lotus Elan S4 and when I came back to the pits, the front valance had (I guess) 0.5 litre or more of oil in it.
The engine oil had been deposited there courtesy of the piping connected to the carburettor air box.
I presume (in full ignorance of these things) that oil deposited in the airbox was poured down the intake pipe under braking.
I have the standard connector from the engine to the back of the airbox.
Under road conditions I get a smearing of oil iin the airbox but his was something else.
Clearly doing 5-6000 rpm for some 7 minutes upset the applecart.
Any suggestions please?
D.B. - NSW
ANSWER.
If you rev any Lotus twin cam engine hard you will soon discover it wants to breather oil and vapour out of the head breather hole.
I am guessing you probably have a standard sump and as a precaution may have over-filled the sump by 0.5 litre to minimise oil surge?
If you have a tired engine then it will certainly manifest its self in the way you have described.
As the engine wears then piston ring blow-by gradually increases.
In turn this also increases crank-case pressure and can cause the front and rear crankshaft oil seals to leak.
So with extra revs, hot oil and an over filled sump, this can quickly lead to oil being readily ejected from the twin cam cylinder head breather hole.
The best way to stop all the mess is with a catch tank
A race engine requires a breather hose with 1" bore to dump the vapours etc in a tank that has a vent to atmosphere via a filter.
Before you have any more excitement and race track outings, I would recommend carrying out a leak-down test to check the wear/condition of the piston rings and bores in your engine.
Copyright © 2012 Lotus Marques
I recently competed at a Supersprint with my Lotus Elan S4 and when I came back to the pits, the front valance had (I guess) 0.5 litre or more of oil in it.
The engine oil had been deposited there courtesy of the piping connected to the carburettor air box.
I presume (in full ignorance of these things) that oil deposited in the airbox was poured down the intake pipe under braking.
I have the standard connector from the engine to the back of the airbox.
Under road conditions I get a smearing of oil iin the airbox but his was something else.
Clearly doing 5-6000 rpm for some 7 minutes upset the applecart.
Any suggestions please?
D.B. - NSW
ANSWER.
If you rev any Lotus twin cam engine hard you will soon discover it wants to breather oil and vapour out of the head breather hole.
I am guessing you probably have a standard sump and as a precaution may have over-filled the sump by 0.5 litre to minimise oil surge?
If you have a tired engine then it will certainly manifest its self in the way you have described.
As the engine wears then piston ring blow-by gradually increases.
In turn this also increases crank-case pressure and can cause the front and rear crankshaft oil seals to leak.
So with extra revs, hot oil and an over filled sump, this can quickly lead to oil being readily ejected from the twin cam cylinder head breather hole.
The best way to stop all the mess is with a catch tank
A race engine requires a breather hose with 1" bore to dump the vapours etc in a tank that has a vent to atmosphere via a filter.
Before you have any more excitement and race track outings, I would recommend carrying out a leak-down test to check the wear/condition of the piston rings and bores in your engine.
Copyright © 2012 Lotus Marques
