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Discussion Starter #1
I am installing a new baffled oil pan and was wondering if I can replace the pistons with the engine in place. I want to put in better Arias pistons

I have done this on other cars and want to know clearance is there?
 

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Listing which Lotus car you speak of, may be useful here.
 

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Listing which Lotus car you speak of, may be useful here.
It's posted in the Lotus Elise segment of the forum, so if I had to guess....
 

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Gamera The Atomic Turtle
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i think i read it was entirely possible and done frequently -turbophil?
 

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Discussion Starter #6
yes lotus Elise is what I am working on.

I am doing the BOE oil pan and figured better pistons would be good idea.
 

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When I had my oilpan off a few months ago, I looked to see if the big end could be unbolted and then rods and piston pushed up (after head removal). It sure looked like it could be done. Sorry about missing the group it was from, I ran across your posting under "active topics", guess I should read more carefully.
 

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Gamera The Atomic Turtle
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When I had my oilpan off a few months ago, I looked to see if the big end could be unbolted and then rods and piston pushed up (after head removal). It sure looked like it could be done. Sorry about missing the group it was from, I ran across your posting under "active topics", guess I should read more carefully.
I'm like 90% sure turbophil has a post out there mentioning this. I've been trying to read alot of the posts and they are blurring together a bit, but i swear he said with the rear clam off (obviously i guess) you could get this done in a day. Or rather HE could get it done in a day. My strength is research, not mechanicals. Although I DID get an oil change done in a day.
 

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I'm not so sure you even need to remove the clam, but it would make the job much much easier.
 

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If the head was off then you likely could. I know it is done this way on some other import engines. Pull the pan, pull the head, pull thr piston/rods. Then swap pistons, do a quick rehone and replace. However you have to buy pistons that are designed for the stock bores and even then you dont have total control over the piston to wall clearance and whatever you end up with is what you get. Not ideal but simple.

My only other comment is that pulling the head may be a difficult task in 2zz lotus, so much so that it might be not much more work to just pull the whole engine at that point. I'll leave it to the 2zz experts to comment there.
 

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yes lotus Elise is what I am working on.

I am doing the BOE oil pan and figured better pistons would be good idea.
Not sure if you are alluding to swapping pistons once the oil pan is off as being just a little more work.

That is certainly not the case. Swapping pistons is significantly more work, money, and takes more skill/tools. It's not a simple thing is what I am getting at, even if it can be done with the block in the car.
 

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Gamera The Atomic Turtle
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stock pistons in our cars have their limitations - many elect to upgrade.
 

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The challenge is finding pistons compatable with MMC coated bores.
 

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I am running the Rev 400 kit so wanted to build some more chance of reliability. I did pull the engine which makes removing the head easier. I put in Mahle10.5 which are compatible with MMC bores I don't think Arias are. I also did rods valves and springs but unfortunately put in Circuitworx oil pump gears which are apparently proving to be unreliable :-(
So if you can get the head off then piston change should not be too dificult in situ.
 

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Plug Whisperer
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The only way to get the pistons out is through the top of the motor. Head has to come off... LOTS of work. I HAVE done it in the car. Wouldn't recommend it. It's actually a fair bit more complicated and requires more skill to do it in the car than it does with the motor on a stand. Does it save time, it can for sure--- but only if you've done it several times before with the motor out of the car. Many more ways to screw things up, scratch the crank etc when the motor is not on a stand...

Good choice on the oil sump ;), but replacing the pistons is an entirely different operation.

Cheers,

Phil
 

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IMO internal engine work with an engine in the car is an exquisitely bad idea unless there is some big emergency. I'd never recommend it.
 

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Kverges,
i kinda agree with you. But the question was "can" versus "should", so I answered it as asked. I have done basic engine rebuilds (pistons, rings, rods, rodbearings) with the engine in place. It did save a little time, but required significant attention to detail and real attention to cleaning the honing grit from the engine. Bummer about the recent problems with the circuitworx oil gears recently. They were on my roadmap for upgrades.
 
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