Questions tagged [piston]

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1answer
53 views

What effect would a hole out of the bore at the bottom be?

My end cap bolt dislodged from the piston and ended up in the sump, it broke right through the bore at the bottom making a small hole about 0.5cm^2. I was intent on replacing the piston and bearing ...
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4answers
77 views

Do you have to machine the crankshaft after a spun main bearing?

I had a spun main bearing due to low oil, the crankshaft journal is pretty scratched, no dents just looks spun on the surface. To the inexperienced diyer it's hard to imagine this would be a huge ...
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0answers
24 views

I have a 2008 Ford Expedition XLT

I have a 2008 Ford Expedition XLT. While changing my spark plugs I didn’t push them down as far as was required therefore on two of them the hook broke off and now it’s making a clacking metal sound. ...
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1answer
51 views

How does enough oil remain after combustion to lubricate during exhaust stroke

To my understanding, cylinder walls are lubricated by retaining a tiny amount of oil in the honed or otherwise manufacturing prepared cavities in the cylinder walls, so that when the piston rings ...
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0answers
51 views

What is the plastic plug for on the bottom of an SU HS4 Carburettor Piston?

Please could somebody explain the purpose of this plastic plug on the bottom of my SU HS4 carburettor piston? The lip of the plug protrudes very slightly from the bottom of the piston (shown bottom ...
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1answer
85 views

Can missing two oil changes cause piston rings to crack?

Car is 4 cylinder Astra. !.4 engine no turbo charge. Last service 8500kms. Missed 2 services, rings in number two piston failed at 44000kms. Oil level always maintained. Car only driven on sealed ...
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1answer
204 views

1986 El Camino: deprecation

I have a question about my 1986 el Camino, as relates to how much it has or hasn’t been damaged after a 6 month hiatus from action. Last July I bought a 1986 el Camino from a private seller. The ...
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0answers
43 views

Does a 2-stroke engine needs “break-in” after replacing cylinder and piston?

I just replaced cylinder and piston (with new gasket, rings, etc) in a 2-stroke 52cc string trimmer engine. It started at the first pull and sounds great, I let it run for 5 minutes, adjusted the carb ...
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1answer
49 views

Fourth piston isn't sparking so car is losing power

What are the possible reasons that my fourth piston is not sparking. I am pretty sure the spark plug is broken but I am not sure. The car is a 2006 Scion XB. Thank you.
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1answer
57 views

Bought a damaged used 2SZ‑FE engine in Sweden. How to check if piston ring is damaged without using a borescope?

Despite using https://en.bildelsbasen.se things weren’t Utan anmärkning as described. We found some engine parts filled with water (which by the way means the generator no longer works so we took ...
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0answers
306 views

Bent push rod, valve bent as well?

so i finally got around to opening up the head of my lawn mower and found out why it wasnt running. the intake push rod is bent. and the exhaust is straight. obviously my valves were way out of spec ...
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2answers
51 views

How to clean up carbon

I was wondering what the best way to clean up carbon off of the Pistons and valves is since I have to change 2 head gaskets I heard abrasive cloths and cleaners aren't so good for the piston heads, ...
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0answers
86 views

Does this piston look normal?

I noticed a slightly reddish color on my pistons. Is it normal? It's an '08 Mercedes-Benz E350, gasoline (petrol), with 35k miles. Here is a little color correction:
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3answers
2k views

Is it possible to repair a piston in an engine

Continuing from my previous question (here) one of the pistons have no combustion and so the car is only working with three pistons, and there is a sound like a piece of metal smacking against ...
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1answer
586 views

How are compression rings lubricated?

My question relates to the lubrication of cylinder walls and piston rings. It is my understanding that pistons in cars consists of 3 rings; two compression rings and the oil/scraper ring. As far as I'...
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1answer
97 views

Removing Cylinders from engine block

Trying to take apart my bmw n51 motor for fun and not trying to rebuild it becuase it toast. Took evetthing atchatchet to block off and finaly got the cylinder head off. The big end bearing is exposed ...
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2answers
432 views

Lancer 2004 Piston Slap Concern

So yesterday i figured out my car has a piston slap because it keeps ticking during a cold start and goes away after warming up. Car is a lancer 2004 and has 260k KMs. I changed the engine oil to 20w-...
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1answer
78 views

Compression test

I have a 2002 Toyota Corolla (1zz-fe engine with 236k miles on it) and did a compression test on a warm engine. My readings are: 150 - 150 - 140 - 175 I've read that the difference should not be ...
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2answers
655 views

piston damage impact

something got in and caused these scratches. can/will they cause blowby if reused? I figure if the placement of its .018 mil piston ring gaps matter, then the gaps from these scratch just may as well....
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1answer
536 views

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

I went to a mechanic and he showed me this custom piston made out of molten car pistons (there was no other option in this case). My question is: Is the scratch from the side of the piston going to ...
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0answers
543 views

Modify (cut) piston skirts: does it also cuts its lifespan?

I'm temped, as a challenge to a problem that raised when getting ready to assemble my engine, to modify the pistons skirts since one of the pistons got a crack in the skirt, under the pin side. I see ...
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1answer
60 views

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

So, still having problems rebuilding this old engine (Skoda Estelle 120, 70's, RWD, rear mounted engine). First of all: getting new parts is out of the question since I have no access to those. So I ...
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1answer
890 views

Piston deck clearance: is 1.4 mm under deck too much?

I'm installing a piston set in a Skoda Estelle 120 engine. I know this is not a definite way to measure piston to deck clearance, but it jumped to my mind to measure it with a vernier caliper using ...
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2answers
3k views

Rebuilding an engine: pistons installed, crank rotation “very” stiff

As I'm assembling my engine back (Skoda Estelle 120, 70s, RWD, rear mounted engine) I have the following issue: installed crankshaft, camshaft and distribution chain, torqued as manual recommends, it ...
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3answers
3k views

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

The engine I'm rebuilding (Skoda Estelle/120, 70's, RWD, rear mounted engine) was manufactured with two different pistons, depending the fabrication years: one piston kind has 4 rings and a cut from ...
4
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1answer
3k views

Rebuilt engine started, but with strong clanking sounds

So this is another question about my Skoda Estelle engine rebuild project. Now it cranked and started, after a session of neither of those. To fix that problem I released the head bolts and retorqued ...
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1answer
1k views

Do my new oil rings have an excessive gap?

Today I measured the new piston rings I will use while rebuilding my old Skoda Estelle engine. Skoda Set They are new from the Skoda factory (or that's what the box says), but they were ...
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3answers
218 views

Extracting piston rod's “wire” C clips

So now that I'm getting ready (soon :) ) to fit new pistons in my old Skoda Estelle engine, I found that the piston rods have "wire" C clips. I mean, they look like a piece of wire, no "eyes" or tabs ...
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2answers
1k views

Rear brake piston hard to turn back in, uneven wear on pads

2010 Toyota Matrix, Manual, Base model 1.8 L Some context It was time to replace the rear brakes (noise, grinding). When I took everything apart, I found that the inner pads were extremely worn, at ...
3
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1answer
209 views

Is it really necessary to resurface cylinder and substitute piston?

I believe this is common in motorcycle maintenance, I have heard in some places that, once you get the piston outside the cylinder there is no way back, you need to resurface the cylinder and get a ...
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2answers
5k views

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

I saw similar topics but that did not explain my things... As we can see 4 stroke engine with 4 pistons Is there any chance (only for test) to 'switch-off' two pistons? For this example I'm talking ...
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2answers
3k views

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

Compression stroke at TDC or Exhaust at TDC or somewhere else? Is this position fixed or does it depend on other conditions?
7
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2answers
652 views

Safe to buy new piston for your two wheeler engine

I own a Honda Stunner 125 CC motorcycle. I bought it in 2009. Since last year I have observed that it is emitting white smoke. Mechanic recommends that I purchase new pistons or after some time ...
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2answers
1k views

Should I remove the rings when cleaning a piston?

I want to clean my piston in a small ultrasonic cleaner (with distilled water). Do I need to remove the piston rings to do so, or can I leave them on and make sure it dries completely? If I replace ...
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2answers
1k views

Cleaning pistons and cylinders with oven cleaner

Can I use oven cleaner (composition: 5-15% aliphatic compounds, 2-aminoethanol, butane and propane...) to clean the carbon off the cylinders and pistons of my BMW R80GS 1991 Motorbike (without ...
5
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2answers
279 views

Pivoted curved-path piston engine

Years ago, I saw a documentary about engine efficiency where people were testing a pivoted, curved-path piston engine. The claim is that the standard piston engine, with straight up-and-down path, ...
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1answer
5k views

How much force is needed to push a piston down? [closed]

Combustion from fuel and air is used to push a piston down. When they combustion it creates a lot of force, my question is how much force is needed to push the piston all the way down when the vehicle ...
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4answers
8k views

Do pistons keep moving when the car stops?

When you are driving and stop at a light, do the pistons still move up and down due to combustion? If not how will the engine know when to combust the fuel to keep it moving?
10
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1answer
5k views

What exactly is a “knurled piston”?

Recently I came across the term "knurled piston" and I don't know what it means. What is a knurled piston? What is the difference between that and a normal piston? Why should you use a knurled piston ...
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1answer
3k views

Interference vs non-interference engines

What do people mean when they say that an engine has an interference design? How does it differ from a non-interference engine?
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1answer
1k views

Why is lugging hard on connecting rods?

I was researching the effects of lugging and came upon this thread, one of whose answers claims that lugging is really hard on the connecting rods. but without explaining why. Can you explain ...
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3answers
574 views

What is an inverted triangle piston skirt?

The recently launched Suzuki GSXR150 boasts an inverted triangle piston skirt. From what I have been told, it seems to be MotoGP technology which has been stripped down to suit a 150cc bike. Kindly ...
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2answers
3k views

Motorcycle 125cc question about PISTON condition and battery

Last year I bought a 125cc bike, Modenas brand, most likely unknown to you. It is a moped. http://www.modenas.com.my/v2motorcycle.asp?id=70 It can go as fast as 110 km/h enough for the city, ...