Sump drop

[22rabbits]

Hi Guys, I'm new to the lotus world and have got a m100 elan that needs a new head gasket.

At the same time as doing the gasket a mechanic suggested doing the piston rings as its compression is very poor an the car was driven and overheated. The mechanic doesn't know before looking, if the sump can be dropped while in place? His aim would be to put new piston rings on that way.

So my question is can the sump be dropped while the engine is in place or is it the more costly option of removing the engine from the car?

Cheers, Niall

[theelanman]

Hi and Welcome
not sure why you need the piston rings.....
I would have thought that your cylinder head need skimming......
just a thought
cheers
G

[22rabbits]

Hi and Welcome
not sure why you need the piston rings.....
I would have thought that your cylinder head need skimming......
just a thought
cheers
G

ye that would have been my thoughts but I was talking to the mechanic that the previous owner (PO) used and he said with the PO having driven the car with gasket gone and lack of coolant, he thinks the piston rings might also need changing and that it would be a shame to have the gasket changed only to find the rings are spent too.

[alan e]

yes you can take the sump off with the engine in place by removing the prongeron.

[Giniw]

Hello and welcome 22rabbits,
I would suggest to replace the head gasket first and then test the compression again.
As your mechanic intends to remove the pistons through the sump I don't think it's worth doing both at the same time.

[22rabbits]

Hello and welcome 22rabbits,
I would suggest to replace the head gasket first and then test the compression again.
As your mechanic intends to remove the pistons through the sump I don't think it's worth doing both at the same time.

I believe he intends on push each piston up from the sump out the top while the head is off and replace the rings. I'm not 100% clear on it but he said that this wasn't labour intensive like the alternative it possible.

if the head is off and the car is on a 2 post lift how would he secure the wheels when removing the prongeron?

Sorry for all the questions but fiberglass lotuses are rare for mechanics to encounter

[CalElan]

Pistons - would be unbolted from the crankshaft and then removed with the head off - They also go back in that way.
Pull the sump and get the mechanic to do a leakdown test. With the sump off you'll be able to feel air coming past the pistons if the rings are shot.

[Fredjohn]

If your mechanic is intent on removing the pistons, the sump can be removed by first removing the prongeron. Follow the workshop manual instructions for this and also the brief guide here on WikiLEC.

The workshop manual is readily available from this website, and states that the pistons can be removed with the engine in situ, but recommends removing the engine completely.

I too would do a test of the pistons before going to the time and expense of sump removal. Also you need to check the availability of new rings, even if you don't know the exact size, before stripping the engine down.

Edit added: I'm not sure a 2 post lift is the safest way to raise an Elan. You must at least make sure the 4 lift arms are located under each of the 4 jacking points, even then with all the weight up front forward of the jacking point it may not be totally safe. I've seen a video of an Elise come off a 2 point lift because of bad loading!

[lotusflasherman]

ye that would have been my thoughts but I was talking to the mechanic that the previous owner (PO) used and he said with the PO having driven the car with gasket gone and lack of coolant, he thinks the piston rings might also need changing and that it would be a shame to have the gasket changed only to find the rings are spent too.

Doesn't make much sense to me. To anneal spring steel (piston rings) you need to get them to over 850°C but aluminium starts melting at around 660° and the aluminium alloy used in pistons is not a lot higher. Combustion temperature is higher than piston melting point but it's cooled by fuel mixture on the induction stroke so hopefully never reaches it - get a weak mixture and it will! If your engine had been seriously overheated you'd have a compression problem due to holes in the pistons before the rings went slack due to annealing ...

Changing piston rings is more mileage related so if you've got a high mileage car it may be worth doing while the head is off. New rings need to have clearance gap checked and carbon & glaze busted off the cylinder walls so needs head off to work from above. Can't think how that or refitting the pistons could be done from below. As big end caps are unbolted to get pistons out there is also the opportunity to fit new big end shells too -- Project Creep on a grand scale

By the way ... I lift my Elan on a scissor lift positioned in line with the front edge of the driver's seat and the front still needs to be lifted and sat on an axle stand. The centre of balance front to rear is almost exactly across the front jacking points - which may have a lot to do with why they left the rear jacking points off the S2.

[Saltire]

Edit added: I'm not sure a 2 post lift is the safest way to raise an Elan. You must at least make sure the 4 lift arms are located under each of the 4 jacking points, even then with all the weight up front forward of the jacking point it may not be totally safe. I've seen a video of an Elise come off a 2 point lift because of bad loading!

Rather like this:

image.jpeg

[atikovi]

someone's gonna get fired

[Fredjohn]

Yes that's the pic: well found Saltire