Hot answers tagged

7

I use brake part cleaner on lots of things. It should be fine. Note- this is just personal experience. If someone pops up and says it's detrimental, I'll certainly listen.


6

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 engine cycle. So without some powering source to force it to a high compression location, it'll stop somewhere mid-stroke. Plus the crank wants to roll off from ...


5

Too long for comment, but I suspect wastegate linkage or door not closing fully due to distortion from heat (it's really hot around there). You could try and get it hot enough to duplicate the problem, park, and attempt operate the wastegate manually with pliers or gloves... but it's tricky to get to without removing the turbo heatshield. Also make sure ...


5

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 toroidal design Here is a modern mock up of a similar design.


5

Yes, it does lead to a loss of a power, but your compression is not worth worrying about. Every engine will loose some compression after a few years. New rings wear out faster at the beginning and later they wears out slowly, so probably you won't see a difference for another 2 years.


5

Those numbers do not seem horrible, unless the 140psi is low. You might want to repeat the test with the engine warm. I generally feel that a cold test only reveals inter-cylinder differnces (in your worst case only 18psi), but dynamic compression after everything is warmed up and expanded might be much better.


5

If I had to guess this sounds like a four cylinder engine, with one or even two cylinder's misfiring. Best guess is a problem with either a spark plug wires, or an ignition module. I'm looking at high resolution photos of your engine compartment and its not clear on what type of ignition system you have. Generally there are two types of systems. One has a ...


4

I encountered a similar problem with my Honda D15 engine. The car would start fine when it was cold, but have trouble starting warm, stumble under acceleration and sputter/die at idle. I had also tried replacing the fuel filter, plugs, wires, and an o2 sensor to no avail. I then purchased a coil pack and distributor rotor/cap. I had just enough time to ...


4

I assume you mean that when the engine is cold, it requires the choke, but then if you stop and try to restart, then you have to turn off the choke. This is by design. The choke is a tool to allow a cold engine to run by enriching the fuel/air mix through restricting (or choking) the air supply - once the engine is warmed up, this is not needed any more. ...


4

It depends on the exhaust system. If it is a road bike with an exhaust system designed for the road, you need to keep the silencer/muffler/mute on it for optimum performance. Only a full race system, designed to run without a silencer (pretty rare these days with all the noise restrictions even on races) might suffer by having a silencer attached, but that ...


4

If you can turn the engine over using the starter, the engine is not seized. Just because it died after such an event, doesn't mean it is going to do that. Definitely not good for the engine, but it doesn't mean it's seized. It really depends on how the engine died to tell you what exactly happened. If it just quit without any loud bang or loss of engine ...


4

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 it over TDC, will have a "spring" action that will tend to maintain RPM, as the compression energy is now released. This is critical to the brilliant and ...


3

Depending on the cause of the fluids mixing: buying a new engine would be the most extreme of the possible repairs. The simplest repair for this would likely be a gasket replacement, which may still be quite costly, since (for example) head gaskets require taking apart most of the engine to replace.


3

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 BMW has the nikasil coating. I would not simply hone your cylinders, attempt to the coating, it may be required to put then next overbore size of piston in. If ...


3

This is an interesting question, though it is probably way too broad. Honda claims that there has never been a warranty claim against their VTEC systems - as in, the solenoids and variable valve/timing system is quite reliable. This isn't at all to say that these engines don't fail - of course they do - however they have a very good track record for ...


3

Your oil pressure is lower I think the big issue with lugging is a considerably lower oil pressure along with high load. You don't want your connecting rod breaking the hydrodynamic lubrication layer of oil between your connecting rod and crank pin thereby causing damage to the bearing and the pin. This could cause permanent engine damage. Doing this at ...


3

The longer you run it, the more damage you are going to cause. This will incur more cost when you do go to get it fixed due to the parts involved. Depending on which valve(s) is (are) sticking, you could be doing damage every time you start it up. I'm talking about the exhaust valve, as if one is open during the combustion cycle, you've damaged a valve and ...


3

It's your valves or the cam chain If you have a ticking sound, those are your two options. You haven't provided much data or info at all. Adjust your valves .004 inch clearance for your intake valves .005 inch clearance for you exhaust valves OR Check your cam chain tensioner to ensure it's putting the proper tension on your cam chain.


3

How cold is very cold? The outside temperature when you go to start it is key. But in general, unless you are more than twenty or thirty degrees F below zero, I would say the answer is "no damage"... provided you have used an engine oil and an antifreeze mix that is appropriate for your climate. Your owner's manual should contain the information you need. ...


3

I'll start with the bad news - if it's the CD100 model without electric start then it's a no-go unless you replace the engine (I'm inferring this from your statement "customize my old bike with a self start"). You won't be able to retro fit a starter to it as the cases and internals will not be configured for one. However, if the engine does have electric ...


3

It is OK to used a metal tool on the valves. They are very hard and difficult to scratch. It is also OK to use oven cleaner on the valves. The steel is a relative of stainless and will be little affected by harsh cleaners. This is not true for the aluminum head and the valve seats are usually softer than the valves but are still hardened steel.


2

I shaved .060" off the head gasket surface using a 8" wide belt sander at work. This increases the compression and REALLY provides more torque when the grass gets thick. I use 93 octane gas and have no heating problems. It Really works great! I even installed this modified head on the Brand New lawnmower I bought Of course a clean filter and sharp blade are ...


2

Someone mentioned rotaries and oil. 5w20 conventional is recommened most likely for fuel economy benefits but this is not the issue with durability. Rotary engines do infact use oil. Typically 1 quart every 3000 miles is normal. This is because the engine has a metering oil pump that directly injects oil into the rotor housings to lubricate the apex seals. ...


2

I think all the major points have been made, but there's one more to consider. Your engine probably idles between 750-900 RPM, running your engine below this under-drives your alternator, water pump, and most importantly your oil pump. Frequently letting your engine run under this starves it of lubrication. Over time this will reduce your engine's life. -...


2

Yes, absolutely. Can you port tune a Mazda 13B on your kitchen table with a dremel tool? Yes. I've done it. Better said, I tried it. Can you expect the apex seals to last any time at all using "free" instructions from the internet? Not a chance. I'm sure there's plenty to be gained, but I doubt nearly as much as an Otto cycle due to the speed and ...


2

Oil consumption in the LM7 engines is pretty common. The L33 in my '06 Silverado is around the same amount, maybe a little less. What you are talking about sounds more like a stuck/leaky injector. Oil smoke will usually last longer than 10 seconds, if that were the issue. And it would be distinctly blue, not black/dark. The way you could tell if this was ...


2

You can boost away almost indefinitely until the AFR goes lean or you start pre-detinating (knock). At which point you'll need a new engine. But once you get outside your turbo's compressor efficiency map, more heat, less VE, and a whole bunch of other concerns. Time for a bigger turbo. Are you going to run 93 pump, E85, meth/water spray? First post is ...


2

Honda used VTEC for two applications: Fuel economy. For example the F18B engine with peak power of 136 shp. Rev limit of about 6000 rpm. Sometimes called i-VTEC. Performance is decent but not spectacular (many have low torque at low rpm so you need to shift down for overtaking). Performance. For example the F20C engine from the S2000, with ~230 shp. ...


2

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 assume like with most wear items, you'd want to remove it, then put new ones on after.


2

From the pictures, that does appear to be the block. As for what would cause this damage, I'm not sure, but it doesn't look good. Usually damage in this area means a new engine is in order. If you really want to know what happened, pull the oil pan.



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