High RPM

[livinincalifornia]

another one of my kind of newbie questions, bear with me. I know that these little 4 cylinder engine's can easily rev up to 6, 7 and 8k rpm even with little or no mods, but how good for the engine is it? Can it cause your rings to blow and your car to start burning oil?? Or could it cause one of your valves or some other important part to fail even on an engine that's relatively new? Are the stock piston rings and internals capable of constantely revving to these speeds (non-vtec motors that is).

[Kven]

Ive never heard of rings or pistons failing, but its usually the valves that fail(in a way); the valvesprings cant support the high rpm so the valve starts floating, and sometimes causing it to collide into the piston.

[Scott82]

well, the harder you run it the sooner something can go wrong, but if you take care of it a don't throw it into gears and completly dogg it then it should be OK but when you get to over 7500 RPM you better have everything built to handle it well or it wont last. Its the same as anyother motor. If you try and make it do more than it can do then things break.

[livinincalifornia]

thanks for the replies...one of the main reasons I'm asking is because sometimes I like pushing my car to 6,000 and maybe twice a month I'll get acceleration happy and rev to 7,000 on my D15..I had head work done to it and is extremely clean and almost brand new. Also my old engine burned oil, and being the noob that I was and still am, I had the impression it was because I had pushed it to 6,000 (even though it had overheated to red twice and had warped rings)..I guess my main question is: can revving to 6 and 7k cause my car to start burning oil?

[Scott82]

for the motor yes, if it's stock and it's not the vtec. What is your actual redline. I think mine is between 5 an 6k somewhere, not exactly sure where though

[livinincalifornia]

it's a 6.5k..so revving that high can cause my car to start to burn oil? Why is that?

[Scott82]

Well, redline is a point from the manufacture that is the limit to the motor to not cause any longterm damage, however that is the safe point for the manuf. but if you get things doing what they are not supposed to do and create too much strain on an engine, somethings got to give, just depends on where it's the weakest in the motor, some are differ than others, could be valves, rings, seals, gaskets, you name it, just depends on the motor, for that particular motor i am not sure though cause i am fairly new to 4cyls but they pretty much work the same inside, but i am not familiar with how setups work with eachother but as far a general motor standpoint (Not GM but motors in general), then it can cause probs.

[livinincalifornia]

Originally Posted by Scott82

Well, redline is a point from the manufacture that is the limit to the motor to not cause any longterm damage, however that is the safe point for the manuf. but if you get things doing what they are not supposed to do and create too much strain on an engine, somethings got to give, just depends on where it's the weakest in the motor, some are differ than others, could be valves, rings, seals, gaskets, you name it, just depends on the motor, for that particular motor i am not sure though cause i am fairly new to 4cyls but they pretty much work the same inside, but i am not familiar with how setups work with eachother but as far a general motor standpoint (Not GM but motors in general), then it can cause probs.

thanks a lot, that's kind of what I figured, I'll be keeping it below the redline.

[Scott82]

You'll thank your self in the long run especially w/ that motor, cause it's not like it a race car or anything. That needs to be a daily driver until u can get a built motor to handle that kind of stuff, so keep it reliable

[Hybrid1990crx]

youre motor can rev safely to whatever the manufactor specs are. like i can safely rev my b16 to 8,000rpm without a problem because its built to rev like that, with some work it could rev to 9,000. a stock d15 or d16 revs to like 6500, unless its a hf or std, and they redline at 5500 and revlimit at 6500.

[turtlecrxsi]

Originally Posted by Hybrid1990crx

youre motor can rev safely to whatever the manufactor specs are. like i can safely rev my b16 to 8,000rpm without a problem because its built to rev like that, with some work it could rev to 9,000. a stock d15 or d16 revs to like 6500, unless its a hf or std, and they redline at 5500 and revlimit at 6500.

Exactly. You say you have a d15 which is a swapped jdm motor right? And you say you've had some head work done right? With modifications you can run your car more effectively while still adhering to the manufactuers redline... and with some modifications like Hybrid said, you may actually excede those specs. For example, I have a relatively stock d16a6 with CAI, header, exhaust, cam, cam gear, pulleys, lightweight flywheel and stage 1 clutch and my car revs to the 6500 rpm redline easily all day long, but I can push it to 7000 when I want (rev limit 7200) too.

[Hybrid1990crx]

Yeah, and when I say "build it to rev" i mean valve springs, seats, and retainers to prevent valve float, and if you get up really high you're going to want to build the bottom up. Like for example, on ls/vtecs people roll or spin (same thing) bearings in them all the time because they think just because they slap a head on that can handle 8k that the block can too. Also, if you just have the stock cam, its rather pointless to rev that high beeing that the stock si cam doesnt even make power past 6500-6700, i never took a6 past 6500 when I had it in my car.