Motor Vehicle Maintenance & Repair Stack Exchange
Motor Vehicle Maintenance & Repair Stack Exchange

Questions tagged [valve-timing]

29 questions
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Changing Firing Order in a 4 Cylinder Car

Backstory In motorcycling you can get cams that change the firing order and time from a traditional 1,3,4,2. It's was very common in American road racing in the 1990's to hear 4 Cylinder engines that sounded like two cylinder v-twins. The way these…
DucatiKiller
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What are the various kinds of tappets / lifters and the advantages / disadvantages of each

A previous question about tappets found here: What are Tappets? covers the basics of tappets. If we go the next step, here are my questions: What are the various kinds of tappets / lifters? What are the advantages and disadvantages of each? Are…
cdunn
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How to test timing chain/belt assembly before sealing engine closed?

I had to take my timing chains (one master and two connecting each V6 sides' double cams) off on my 2007 V6 Tacoma to reach to replace my head gaskets. While I do have relatively specific instructions how to assemble them back together, is there any…
amphibient
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What exactly is Honda's i-VTEC technology

I see that almost all of Honda's cars have an "i-VTEC" logo at the back. I googled it and came to know that it has something to do with different cam profiles. Can someone explain? A diagram or animation would be helpful. And why does Honda do it?
Shobin P
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Is there a risk of igniting the incoming charge with wasted spark systems?

I came across a question about wasted spark systems, and I was wondering whether there is a risk of prematurely igniting the incoming fresh mixture charge with that wasted spark. At the top of the exhaust stroke, the inlet valve is opened already.…
Bart
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Why is there no valve overlap on 1987 V4 Honda?

I have a 700cc V4 Honda Magna motorcycle. The manual states that the inlet opens at 0° BTDC and the exhaust closes at 0° ATDC so there is no valve overlap. This would seem to compromise power. What were Honda's reasons for designing it like that?
Tom Pratt
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1997 Honda Odyssey - How do I know if the valves are still good after both the timing belts broke?

I hired a mechanic to replace my crankshaft pulley sensor. He ended up doing something wrong. We tried to crank it and it sounded like a dead battery and the sensor broke and hit the oil pump. Put a hole in it and both the timing belts broke. How…
beth
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Why does this mechanic change the crankshaft mark, during this timing-belt change?

'Renault Sandero - Fitting A Cam Belt' on youtube 11:14 at first the mark is here. 11:30 then, later, it has changed to being further down. a) shouldn't this mark be at 6 o'clock on the crank gear? b) did he make an error to begin with? In general,…
Jim
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Why don't valvetrains use an idler gear between the cam gears

Related to this question: What would happen if you tried to start an engine with the cam gears meshed Why don't valvetrains use an idler gear between the cam gear to keep the cam gears in sync, to simplify timing? Through this one could either have…
Ceshion
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Tick Tick sound from a Royal Enfield Classic 350 at idle

I own a Royal Enfield Classic 350. At idle, the engine starts to produce a TICK TICK sound. However it vanishes when the rpm rises and when riding the motorcycle. This question is a very frequently asked question in many of the popular firms and…
You_Shall_Not_Pass
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4 stroke valve timing diagram: if valves are open during TDC, wouldn't they hit the piston?

I am studying valve timing diagrams. Many of them show something like (for instance) the exhaust valve stays opens till ~20 degrees after TDC and the intake valve opens ~12 degrees before TDC. Wouldn't this mean that the valves are open and pushed…
midnightBlue
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Is this valve toast or could I possibly salvage it without tearing into the engine?

I have a 2010 Mustang GT with 4.6L engine that started making a ticking sound which at times is fairly loud. The sound is much less obvious at cold start but becomes apparent after it gets hot. The sound is loud enough to be heard with windows…
mark b
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Noisy 4.6L Mustang engine

My 2010 Mustang GT 4.6L automatic with 97k miles on it has a noise coming from the drivers side valve cover. The noise sounds to me like all of the other typical cam phaser noises; a ticking sound about once per engine revolution - getting faster…
mark b
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Meaning of Timing valve is open

What is the meaning that Timing valve is open? A local mechanic told me to change the timing valve to fix P0018 code. But he is not sure if there are othern hidden issues. Is it possible that Timing valve is open due to a stretched timing chain?
precision
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When switching off the engine, do the cam and crank shafts always come to rest in an initial state?

Is it the case, when the engine comes to a halt, that the cylinder/piston/valve phases always finish up in the same starting or initial position relative to each other?
Jim
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