23 votes

Do pistons keep moving when the car stops?

The answer to your question is both yes and no. Yes in majority of the conventional vehicles, the pistons keeps moving even when the vehicles is at a stop light. The idle RPM, which is usually ...
Vish_evo's user avatar
  • 576
16 votes
Accepted

What's gonna happen if I disconnect 'single piston'

As you saw with your test, it is possible to disconnect the ignition on two pistons and still have the engine run. The vibrations have nothing to do with engine knock or detonation though. The reason ...
Zaid's user avatar
  • 39.1k
12 votes

Do pistons keep moving when the car stops?

In most cars, yes the engine continues to rotate and the pistons go up and down in the cylinder bore due to combustion and the engine continuing to run. Some vehicles have an "auto stop" feature which ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
9 votes

3 rings vs 4 rings pistons: which design is better?

There are trade offs, so no clear answer here. First of all, just to be anal and clear something up ... what you have is actually a 4-ring and a 5-ring piston. The oil control ring at the bottom ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
8 votes

Where does the piston stop after the ignition is turned off?

It isn't completely random, as there will always be one piston that is approaching TDC, and the compression building in that cylinder will ultimately cause the engine to stop. Any cylinder that makes ...
SteveRacer's user avatar
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8 votes
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Where does the piston stop after the ignition is turned off?

It's random. Usually won't come to a stop at top or bottom dead center because theres nothing to drive it to that point, and one of the pistons will be building compression at any given time of the ...
user608804's user avatar
6 votes

Cleaning pistons and cylinders with oven cleaner

Why chance it when some carb cleaner will do the trick for you. It should take carbon off of the piston without any worry of damage to the piston. Use an old, broken piston ring to clean out the ring ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
5 votes
Accepted

Is it really necessary to resurface cylinder and substitute piston?

You can absolutely reuse the piston if it isn't damaged. There are piston compressor tools dedicated to slide the piston back into the cylinder.
Zaid's user avatar
  • 39.1k
5 votes

Do pistons keep moving when the car stops?

To add to the other answers, in a manual vehicle, the road wheels are usually disconnected from the engine when at a stop either by putting the transmission in Neutral, or by depressing the clutch ...
James Hyde's user avatar
5 votes

Pivoted curved-path piston engine

The only curved bore designs I am aware of are toroidal I have been unable to find a match to the drawing, not even close. I took a hard look at steam engines as well. Here is an example of a ...
DucatiKiller's user avatar
  • 32.9k
5 votes
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Fourth piston isn't sparking so car is losing power

I am pretty sure the spark plug is broken but I am not sure That's almost certainly the issue. Replace the spark plug and try again, if the problem is fixed, you're all set. If not, then there are ...
jwh20's user avatar
  • 12.1k
4 votes

How much force is needed to push a piston down?

I apologize if my question wasn't as technical as you want. I would like to add I have no knowledge of cars and I'm just learning. I thought it was common sense to ask questions if you didn't know ...
zipzit's user avatar
  • 6,539
4 votes

Rebuilding an engine: pistons installed, crank rotation "very" stiff

I am concerned with you description of the oil ring - the ones I have fitted come in 3 parts : 2 scraper "flat" rings and a "top hat" mounted on its side that locates the other two. Fitted correctly ...
Solar Mike's user avatar
  • 34.6k
4 votes

Extracting piston rod's "wire" C clips

Those gudgeon pin clips are the fiddly type! .. Get a sharp engineers angled scribe or similar, and try to lever one end of the C-clip away from the piston just enough the get a small narrow blade ...
Orb's user avatar
  • 5,067
4 votes
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1986 El Camino: deprecation

6 months won't have done much damage. It might be worth changing those tyres if it's been sat on them flat for months. It started so battery and fuel system are probably OK. Sometimes brakes will ...
Dave Smith's user avatar
3 votes
Accepted

piston damage impact

The piston will be fine - it is the rings that provide the seal with the bore. As long as the rings move freely side to side then it will seal as it should. If the rings stick then that should be ...
Solar Mike's user avatar
  • 34.6k
3 votes
Accepted

Can the bottom of a piston be scratched and not damage the cylinder?

I do not see anything that I would call a "scratch". A scratch would be into the piston ( below the surface ) so should not hurt an iron , steel , or even an aluminum cylinder wall. However , I see a ...
blacksmith37's user avatar
  • 3,678
3 votes

Rebuilding an engine: pistons installed, crank rotation "very" stiff

Ok mystery solved: I have two piston sets, both are identical in look, dimensions and part numbers/marks...only that they are not :) I took the ones I installed and carefully checked measures and ...
Aram Alvarez's user avatar
  • 3,336
3 votes

Do pistons keep moving when the car stops?

I don't have enough reputation to comment, but the small economy cars (K or Kei cars) in Japan also have this StopStart feature, as Mauro commented (for European cars). I think this feature is now ...
Jake Peters's user avatar
3 votes

Cleaning pistons and cylinders with oven cleaner

Dude spend the extra 3 bucks and buy a proper engine cleaner. Spraying sodium hydroxide on aluminum is a bad idea. I would use a nylon brush drill bit to clean off carbon. Although it's ...
Jim W's user avatar
  • 1,935
3 votes

Safe to buy new piston for your two wheeler engine

If the smoke being emitted from the exhaust is white with a hint of blue, it is oil. If the smoke is white with a sweet smell, it is antifreeze. As Anarach pointed out in the comments below, yours ...
MooseLucifer's user avatar
  • 6,007
3 votes
Accepted

Should I remove the rings when cleaning a piston?

You have a nikasil coating on your cylinder walls You can't just bore, hone and assemble. You have to have a nikasil coating applied to the cylinder walls before reassembly. Your model year of ...
DucatiKiller's user avatar
  • 32.9k
3 votes
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How much should you clean dirty pistons and valves when you aren't removing them?

You can do as little or as much as you want, it is your engine. Since you have already done a load of work disassembling the engine, to me it would make sense doing as much as you can while it is in ...
HandyHowie's user avatar
  • 25.2k
3 votes

When switching off the engine, do the cam and crank shafts always come to rest in an initial state?

No. An engine stops where it stops because it is random when you turn the ignition off, and therefore there is no set place for it to end up at.
Pᴀᴜʟsᴛᴇʀ2's user avatar
2 votes

Should I remove the rings when cleaning a piston?

Personally, I replace the rings every time a piston goes back in the cylinder. While I can't speak for motorbikes (*I know they get dismantled a lot more often than a typical car engine) I would ...
Aaron Lavers's user avatar
  • 1,586
2 votes

piston damage impact

The foreign object damage to the piston means there is very likely similar damage to the bore . New rings can not fix that problem.
blacksmith37's user avatar
  • 3,678
2 votes

3 rings vs 4 rings pistons: which design is better?

Use the piston from the "newer" design ie most recent - the engineers most likely made changes to reduce or avoid certain issues.
Solar Mike's user avatar
  • 34.6k
2 votes
Accepted

Rebuilt engine started, but with strong clanking sounds

did a valve stick? when you take the valve cover off is there one that is stuck? How did it seize up? Is the sound a bang, a schlip, a ping, a clank. Is it sharp or long? Did you put all the conrod ...
Cc Dd's user avatar
  • 2,879
2 votes

Do my new oil rings have an excessive gap?

if they are 30+ years old were they kept in oil or some other anti rust / corrosion preservative? if not make sure the rings are still good. Are these gaps with the new cylinder sleeves? if so then ...
Cc Dd's user avatar
  • 2,879
2 votes

Pistons ordeal: more pistons problems; two issues in one question

My suggestion is to go with set #1 without any modification to the pins or adding anything to the pins. While the pins are a bit shorter than what comes stock, they should work fine. The difference of ...
Pᴀᴜʟsᴛᴇʀ2's user avatar

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