A MetroMPG.com reader has been buying up XFi's and offered to sell me a set of used pistons. (The XFi pistons were different than the garden variety ones - they had a single compression ring, vs. 2, to reduce friction losses.)
I have a couple of q's...
1) I'd only be interested in this if I knew in advance if I could re/re the pistons out the bottom of the engine, which might be a relatively easy job. Anyone know if that can be done?
2) Any idea what they'd be worth? He left it to me to make a fair offer (said they were in "good" condition - but how would I know?)
3) Any general advice? Is this a bad idea - what kind of problems could I get myself into?
Iono if you can re-ring an engine just by pulling the crank/pistons. Every in the car ring job I've seen involves pulling the head. IMO, don't even bother w/ it unless it burns a lot of oil now. Can you inspect the XFi pistons first to make sure they're within spec?
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Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
1) I'd only be interested in this if I knew in advance if I could re/re the pistons out the bottom of the engine, which might be a relatively easy job. Anyone know if that can be done?
Not likely. A lower connecting rod bearing maybe, but the crank (bolted to the flywheel and accessory pully) will be in the way of the piston and rod.
I have never seen a car that you can do that with. but if you could it would not come out without removing the crank. To do that you need to pull the motor. Easer to pull the head. Most cars it's pretty easy anyway.
Or I could just be lazy and take a ring off my 2-ring pistons
Truth be told: I'm not really into pulling the head. Too much stuff to disconnect & remember to reconnect. Plus I'll need a more (& more expensive) gaskets than if I could have done it through the bottom.
Thanks for the replies though.
(Can you tell it's been a while since I had an engine all apart?)
The pistons won't fit out the bottom, they will have to come out the top. You can get the head gasket kit off ebay pretty cheap compared to an auto parts store but it is still more than just the oil pan gasket.
I don't really think it is worth doing if you are just going to swap pistons only. If you have the head off and have it shaved .030 and cut the grooves into it and deburr and port match the head and intake manifold then maybe it would be worth it. While you are at it you can get the stainless swirl polished exhaust valves that don't burn up as easy as the stockers. My guess with just the piston swap alone would maybe get you 1mpg on the highway until the engine gets fully warm if you are lucky.
The extra compression in my car without the grooves didn't really seem to help much with the stock computer so unless you are really ready to dump about $750 total into the project to go Megasquirt, Wideband, knocksensor, and lots of head grinding I probably wouldn't raise the compression without the grooves.
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