Excess oil drain modification...

[gussay]

Hi, I'm a new member even though the elan I have has been in the family since 1980.
It's a '69 S2 and it seems to produce a lot of smoke on first start up. Apart from that she goes like a dream. I've heard a rumour that there is an engine modification available that drills through the block and allows excess oil sitting on the head to drain away. Is this true? and if so does anyone know any details of it?

Thanks,
Gus..

[types26/36]

It's a '69 S2
an engine modification available that drills through the block and allows excess oil sitting on the head to drain away.
Gus..

Welcome Gus,
Is this the mod you are refering to:
http://www.gglotus.org/ggtech/tc-oilstu ... lscave.htm

......and on an other note, a 69 S2 ??? ........

[bill308]

Interesting. Can anyone read, or do they know the lieaar dimensions, from the reference lines drawn through the cam cap studs to the hole center line?

Bill

[rgh0]

Gus

Later twin cam heads had a cross drilling at the rear from the exhaust side cam chamber to the inlet side chamber. This enable oiled pooled at the rear of the exhaust side where there is no drainage to flow across to the rear of the inlet side where there is drainage via holes that go down via the redundant push rod holes in the block.

An S2 with its original head probably does not have this cross drilling as I think it was first introduced sometime during the S3's production. You can test if this is your problem by parking your car on a slight downhill nose first for a while and then starting it. If the oil smoke on start up goes away then lack of drainage at the rear of the head is contributing to your problem.

However with the right valve guide clearances heads without the cross drilling do not smoke and cars with worn guides and this cross drilling do smoke so it is not the complete solution.

regards
Rohan

[MintSprint]

As Rohan says, with unworn, correctly reamed valve guides the engines should not smoke excessively on startup, even when they have been standing for several days.

In the longer term you would probably be better investing in a rebuilt head with new valve guides.

When I did the engine on my first Elan - which smoked on start up, but not to an alarming degree - the amount of play in the valve guides was astonishing. With the valve springs removed, you could take a valve between your fingers and rock it like a loose tooth!

[lotuselanman]

Gidday,
Worn guides is the normal reason for smoke on start up but as has been said the early heads had a very poor oil drainage system for the head which was changed when the heads were crosse drilled. In the past with early cars I and others have drilled the back of the head into the floor of the oil area and fitted 90degree tapped fittings with 3/8 or 1/2" tube draining in the sump. This is easy if you have an electric fuel pump, run them into the cover plate. Works like a charm.
If you want to check to ascertain the guides are leaking due to wear, slip the exhaust off the head and look into the exhaust ports, if there is a clean oily track from the tip of the guide then that is your problem.
See ya, Les.

[Quart Meg Miles]

This has been a subject close to my heart for decades! With another rebuild forced on me and a head full of oil to mop out on the exhaust side I had a close look. Behind the cam there is a deep gully suitable for a drainage port to be drilled into and on the inlet side of the head and lower down there's room for another port into the breather cavity with a path to the sump via the rubber oil tube..

A few inquiries found me a machinist prepared to drill and tap the two holes and shallow rebates suitable for Weber banjos and two straight-piped ones and a scrap of fuel pipe completed the job
.

There hasn't been a whiff of oil smoke out the back since and there is no oil lying below the filler cap after a run. I'm hopeful that the exhaust manifold ports 3 and 4 will not coke up again but I may never see them.

[rgh0]

A nice modification that replicates the function of the cross drilling done by Lotus in the Later heads.

cheers
Rohan

[nmauduit]

This has been a subject close to my heart for decades! With another rebuild forced on me and a head full of oil to mop out on the exhaust side I had a close look.

Would the engine work include valve guide replacement ? then the question remains about to what extent the situation will be improved when they get worn out again...

For other reasons (excessive blow back which eventually turned out to be due to head gasket leak) I've pursued a somewhat opposite route : plugging the bottom ot the chamber and making its top inlet higher with a tube, then venting the engine (from the back of the head where it used to go to the carbs, as well as the block from the bottom outlet where the rubber hose would go) to an oil condensation chamber with return to the sump and excess to a catch tank. So in effect the head oil return path is mostly to the front: so far so good, minimal amounts in the catch (say a tea spoon after several track days) and no smoke.

Then the valve guides are quite recent as they were changed when the head was out...

[Quart Meg Miles]

Yes, the exhaust guides and valves were changed though that, by itself, did not usually stop some oil smoke after standing for a while. The rear two plugs habitually showed sooty deposits and sometimes oily ones but now the oil level is below the guide tops I don't anticipate that behavior any more.

Thanks Rohan, that was what I was hoping to emulate.

[vstibbard]

That what I’ve done in past when replacing guides etc, I’ve used 90deg fittings and copper pipe with is fit and forget.
It’s always worked a treat allowing the pooled oil in exhaust side to return easily.
I’ve posted photo of it in past.
Cheers Vaughan