NZConvertible

It only takes a few seconds cranking to get a compression reading, so that's not an issue.

Like I said above, you need to let the starter cool down after a long crank. As long as you do that each time, you can keep cranking the motor over until the battery's flat if you really want.

In my experience unflooding rotaries, if it hasn't started after two attempts, it will never start without outside assistance (i.e. oil or ATF). Doing it over and over is just pointless.

Net Seven

iTrader: (5)

Then my experience is different than yours. On multiple rx7s including my own, my friend's, and some at the shop, I have gotten them to start by having to do it to more than twice. Maybe you havent cuz of your "method" that is non sense messes everything up making you have to pour ATF or oil down into your engine.

So you say all this crap about starter going to die and blah blah.. where is your proof? I have proof that our way doesnt blow starters.. never have we had a starter go bad on us. The whole idea is just dumb, just like the mazda book says not to pull start your car.

FC Alex

I've flooded my motor several times in the past. I just kept trying and got it running. It ussually several attempts before it started up. One time, it wouldn't start so I had to push start it. That was with my old 13BT, with my new RE I haven't experienced any of these problems. BTW I'm relocating my battery next weekend.

HAILERS

A classic example of why I do my own maintainence If this example isn't enough to prompt you to do your own work......the thread I read today about how a certain fellow reuses the water seals when breaking down an engine...will. It's scary out there in the real world.

Net Seven

iTrader: (5)

Well lets see if we break something on your car at work, we replace it for free. Whats there to be scared of? You think all cars start with 5 seconds of cranking? Ever try to start a car with bent valves? Gatta start it up to see whats wrong with it first you know. Obvously you guys dont own a shop or dont work as mechanics. If you did then you would get so fed up with your useless precautions and throw them out the window because they dont mean **** in the real world. They are only theories.

Net Seven

iTrader: (5)

And im not saying to crank it for a minute straight. After cranking for a while yes we do let it sit and cool down. Duh of course it can overheat, but with your 5 second only BS thats just plain stupid.

WAYNE88N/A

NZ's right again...I've seen aircraft starters smoking hot, and some damn near melted internally, because the mechanics didn't follow the proper starter cool-down periods. Those things are just scaled-up versions of our car starters, they're nothing more than electrical motors, wired in reverse. I know we have some damn good starters, because of all the cranking I've done on floods, but I always give it a cool-down period between crank attemps (at least 30 sec after a 5-10 sec crank)

Net Seven

iTrader: (5)

Once I again I didnt say cranking for minutes at a time. We do like 15 second cranks sometimes when needed, and we let them cool off a bit. I said the 4-5 second thing is BS.

NZConvertible

Yeah, switching off the fuel pump and cranking the engine with the throttle open is just nonsense. Me and the rest of the world will stop doing it that way because you said it just messes everything up.
I listen to the advice of experts, like the people who design and build electric motors. I listen to the advice of auto electricians who've shown me the internals of overheated starter motors. When I read (gasp!) the same advice in several technical manuals, I conside this worth remembering. Your "proof" proves little; it just means you have no idea what happens to a customer's cars weeks or months later.
Why would you need to crank and engine continuously for 15 seconds? If you think that isn't doing permanent damage to the starter's internals, you're kidding yourself. At the very least you're shortening its lifespan.

If a customer's starter dies a few weeks after you found some reason to crank it over for so long, because the heat generated weakened solder joints or damaged bearings, do you replace it for free? Or do you just tell them nothing you did could have caused that? More likely they wouldn't even realise that it was because of your abuse of their car, and just put it down to bad luck.

Just because it's running okay when it leaves the workshop, doesn't mean you've done nothing wrong.

Net Seven

iTrader: (5)

"Yeah, switching off the fuel pump and cranking the engine with the throttle open is just nonsense. Me and the rest of the world will stop doing it that way because you said it just messes everything up. "

Please find in my post where I said switching off the fuel pump is bad? I just said that cranking it longer helps, usually with the fuel turned off on rotary engines. We rarley get rotary engines at work, so nothing floods out unless something is seriously wrong with the ecu and keeping the injectors open the whole time. Anways ill call up the guy that rebuilds all our starters and alternators and see how long he thinks cranking a starter is ok for. I will post that tomorrow.

NZConvertible

You didn't, you said my unflooding method was "nonsense" that "messed things up". Which of course is complete BS...

Net Seven

iTrader: (5)

Actually i said your 5 second cranking rule was nonsense. Meaning it should not be limited to such a low number. How ever you want to twist my words around is up to you. You seem good at that.

sosofast

settle ladies

now for my question

can i run a wire heading towards the starter and then y block it inot two one going to starter and one going to the relays/alternator? as i wanna replace the old wiring.

can someone draw me a diagram of the rx7 powering. not detailed just where the positive wires that connect to the batteries go. just so i know where to take the new wire form teh positive to.

thanks

JerryLH3

iTrader: (11)

When I get around to it (someday, I promise), my wiring will be from battery to starter, starter to alternator, alternator to MAIN fuse. I believe this is an accepted routing method. And that's it, with the exception of any additional grounds you may choose to add. And of course a breaker as well.

Did I miss anything?

RETed

You're right, but does it translate to real world application?

I'll give you this data point...

We recently set-up another customer car with a battery relocation job, and we dropped down to 150A circuit breakers.  It was a fresh rebuild on top of a Haltech E6K install and tune.  On top of that, we were fighting stupid problems (primary fuel injectors not opening) that allowed us some sustained cranking times on the starter.  No, not continuous cranking, but spurts of 5 second bursts coupled with about 10-20 seconds of rest in between.  These 150A circuit breakers managed to trip within 5 to 10 attempts at trying to get the engine to fire.  Now, it can be argued that this in itself is a "safety" feature that will prevent you from cooking the starter itself, but you can make that decision yourself.

I do run the Phoenix Gold 200A circuit breakers in my personal FC.  I have never managed to trip them like the above.  Yes, the Phoenix Gold label does make them more expensive, but $20 more per circuit breaker is not something I would normally complain about myself.

150A seems to be enough for "normal" use.
I would caution on using something lower.

Circuit breakers (and fuses) are rated for amps (current) per time, as NZConvertible states correctly.  As an *example*, a circuit breaker rated at "100A" or 100 amperes will trip at:
100A @ 0.5 seconds
90A @ 10 seconds
75A @ 100 seconds
150A @ 100 milliseconds
200A @ 10 microseconds
Now, these are *made-up* numbers, but you get the point.

It is possible to trip these things at slightly less than the rated currents if we're talking about a sustained continuous current draw.
As a rule, I always like to run double the maximum current draw the circuit will see, so thus, 100A max current draw would require a 200A circuit breaker.  This is the logic to picking the circuit breaker rating I have used in the write-up.


-Ted

NZConvertible

The trend shown by your figures is pretty much what to expect, but the figures I posted above are the actual specs, not made-up ones. A 100A breaker can handle 100A indefinitly and 200A for 10 seconds before tripping. Realistically nothing in the car should ever draw more than 100A, so tripping a 100A breaker should be very difficult.

If you managed to trip a 150A circuit breaker with only a 1.2kW starter motor (drawing ~100A), don't you think something might have been wrong with it?

I can buy a quality 100A circuit breaker for NZ$42.95 (~US$27) from my local electronics store. A Phoenix Gold equivalent would probably cost twice that over here, and not do it's job any better, so I don't see the point myself.

RETed

Yes, you do have a point here.
That particular starter is getting "intermittent", so it could be on it's last legs.
It's still something that could affect other owners though.


-Ted

WAYNE88N/A

NZ, I've got to give you a little "schooling" on starters & electrical motors...This 100A figure you keep refering to is AFTER the starter has reached it's cranking speed...Granted, it gets there pretty fast, but the instant power hits it, it's acting as a direct short to ground (basically the battery's capacity is shorting to ground). As it spins up, the inductive resistance allows the power draw to settle at that 100A figure. Before it gets there, however, the wiring has to handle that short burst of (I'm guessing here based on educated assumptions) 300-400 amps...And, as the starter gets older & less efficient (like most of ours) it'll draw more current. Also guys, circuit breakers are designed to protect the wiring in the circuit- therfore the rating of a circuit breaker is dependant on the wire size, not the starter current draw (This is arguable, I know- so don't flame too hard!)

NZConvertible

Okay, fair enough. I do know about the current spike you get when an electric motor starts, but I also know how quick it is (tenths of a second, if that). A 100A breaker is still going to have no trouble handling 300-400A for that brief length of time.

You're right about protecting the wire too, but that's really just a case of making sure the wire is sized correctly for the current it's expected to carry.