Lotus Elan

cured my oil leak, but now have another problem

PostPost by: tdafforn » Sat Apr 22, 2006 11:05 am

Hi guys,
The twinc on my +2 has always leaked a fair amount of oil (Those of you who saw it at stoneleigh will know what I am talking about, an oil puddle big enough to attract green peace!). Anyhow I have known for a long time that most of the oil is being blown out of the dipstick tube.
I have tried a number of schemes to stop this, but with varying levels of success.
On sunday a checked the oil (which was low) and refilled as usually, drove the car to my parents and back, and then noticed a trail of oil on the road.
Knowing that it was coming from the dipstick, I felt I had had enough and took out the dipstick, connected a pipe and ran it to a catch tank.
Then ran the car for the week (20-30 miles), and checked the catch tank and there is abot 100mls of oil.
Seems like a lot!!
Then ran for another 30 miles and the amount seems not to have changed..
I am planning on running the car like this for the rest of the summer (I know it isn't curing the problem, but I am planning on fitting a 711m block) as in all other terms the engine seems fine, good oil pressure, no oil smoke appart from on startup, reasonable power (110-120bhp on the dyno), good compression...
Does anyone see any problem in this?
I am also still puzzled how and engine with steady compression figures 160-170 lbs (w and wo oil in the bores) manages to push so much oil out..?
Cheers
Tim
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PostPost by: twincamman » Sat Apr 22, 2006 11:37 am

this could be a sign of over filling the sump ---or keep the revs below 8 thousand ----ed :shock:
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PostPost by: tdafforn » Sat Apr 22, 2006 4:23 pm

I had wondered that, but it shows full after I have filled it...
I suppose the dipstick could be something other than correct!
tim
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PostPost by: john-c-elan+2 » Sat Apr 22, 2006 4:26 pm

Has someone fitted a high pressure oil pump by mistake ?
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PostPost by: marcfuller » Sat Apr 22, 2006 4:38 pm

"Has someone fitted a high pressure oil pump by mistake ?"

Why or how could a high-pressure oil pump cause so much oil to be "blown out of the dipstick tube"?
-Marc '66 Elan DHC (36/6025)
http://www.lotuselan.us
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PostPost by: elans3 » Sat Apr 22, 2006 5:17 pm

My bet would be that the dipstick tube could be set at the wrong level. Very significant that it gets to a certain level and then doesn't increase ! Next time you change the oil, don't fill it up to the mark on the stick, but accurately measure what you put in, ie as per the book, then check the stick and make a new mark. Could be you're overfilling.
Only time I've ever come across a really bad case of blowing oil out was in my (and other's) Twincam rally cars that were constantly at high revs.
Tweak then was to use a breather on the front of the cam cover, piped to a catch tank.
I still have a cover with that very breather !
The twink was well known for it in competition, and Vegantune in the period, made a cast breather elbow to fit.
Compressions and everything else make it sound like a vgc engine. I wouldn't strip it until you're absolutely convinced you're not overfilling,
Good Luck
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PostPost by: cliveyboy » Sat Apr 22, 2006 6:00 pm

Tim
I have a similar problem. Engine totally rebuilt. The oil blowing out of my dip stick I put down to a very poor sloppy fit of dip stick in the new front casting for the water pump conversion.
Although "Elan3s" suggestion of over filling might be worth checking as it is a new casting and the dipstick tube could be set wrong.
I know the dip stick is not supposed to be a pressure seal but take a dip stick out of any car and it usually blows out some oil especially at higher revs.
If the new better fitting dip stick I make stops the problem I will let you know

Clive
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PostPost by: poiuyt » Sun Apr 23, 2006 11:40 pm

I suggest you get a straight spark plug boot and cement/ty-wrap it to the sipstick so it acts as a plug. I have not had any oil come out of the dipstick hole since I did this.

Steve B
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PostPost by: tdafforn » Tue Apr 25, 2006 7:25 pm

Discovered why my twink had turned into an oild fountain!
The DPO had modified the breather pipe that goes from the head to the airbox by welding on a pipe that vented to atmosphere..
Over my ownership, I had run a rubber hose from this to under the engine as the oil vapour would get into the cabin.
A couple of weeks back a blocked the pipe as an experiment as I resoned that this shoudl force the fumes back on their original route into the air box.
What I didn't know was that the welded tube (at 90 degrees to the orginal) infact block the original path.
So now the engine could only breat through the dipstick tube, hence fountain!
unblocked the tube and alls well with the world.
(still going to build a 711m based short block, as I have nothing else to do on the car!)
Cheers
Tim
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