forced

The problem is probably your head that's toast. Best fix would be to look for another one. Cutting them too much weakens them, Some types of head are weak to start with. To be totally realistic the Isuzu Piazza was a lemon from the day it left the factory. Lots of them ended up at the wreakers cos the dizzy crapped out with no spares available. Steve

I've only just come across this thread. Were you going to use the GTO computer or something else? Maybe I missed it? Steve

I wasn't going to bother as I agree totally, it's called "planned obsolescence", or to put it another way, a built in time bomb, to ensure that you keep spending. Just like having a DVD player with the vital capacitor in the power supply installed so that it's touching the heat sink of the biggest transistor in there. Guaranteed to crap out after 15 months. Anyway RCAs are normally outputs (headunit) not inputs. An input for ipod or whatever is stereo normally a 2.5 or 3.5mm socket. Steve

So who's the dickhead that deleted my post? Which said....... A "pro" would check for faultcodes at the ECU. If you don't know how to do it...... jump over to toyspeed. If it doesn't have built in diagnostics then manual diagnostics would be the way to go by reading the ECU pins with a voltmeter, you'd need a workshop manual though. There's easier things to check first, like sparkplugs..... wet, dry, black or white. That will give an idea to whether it's fuel or spark problems. The igniter as mentioned would be a real possibility. Unlikely to be a temp sensor, you'd expect in that case for the cold start injector to stay on all the time, or at least run crappily when running. Steve

The RB 25 turbos are'nt too bad, it's the RB26 turbos that fly apart badly ....... but only when spun too fast. Steve

That's hardly an intelligent answer. If a "pro" was setting up a turbo on a car, they'd check the compressor map. 12PSI on a 2.5 is probably getting close to the edge of the map, 12PSI on a smaller motor probably isn't. The main problem these days is that people choose turbos that are far too big and so the car drives like a POS cos it's got no bottom end power.They don't know how to read flow maps. Steve

I don't think it's the boost that kills them, it's the revs, if you overspeed a turbo, it dies sooner. So, it depends on the size of the motor you're running it on. Steve

There's plenty of "stock" jap cars that use electronic speedos, just get a sensor from pick a part,. The sensor just screws into the drive gear in the same place that the cable would go to. No electronic speedo runs off the ECU, the pulses go INTO the ECU for the speed limiter, from the gearbox. If you've got an old pommy car (imperial) then the thread will be wrong but could be made to fit. Magnets on the driveshaft...... that went out about 30 years ago along with the first ever car computer that measured fuel useage, time, speed etc. I think reliability might be a bit of an issue , at least compared with a proper sender. Anyway, 78 shoveit, they might have been metric? Steve

So how did you set up the gain so you know that it's not distorting? Genuine question, I'm sure others would also like to know. Steve

I've been thinking again, yes dangerous. Suppose you've got an external power amp that uses + - 30V supplies. Then the maximum power that it can output into a 4 ohm speaker is 30 x 30/4 watts, just very roughly, so that's 225W per channel. That can only happen when you've cranked up the input to the max so that it's outputting squarewaves. That particular amp , if setup correctly would output a sinewave with a peak of + - 30V maximum. The RMS voltage would be .707x 30 so that would be round about 21v RMS and the RMS power output would be 21 x 21 /4 or close to 110W. Hmmmm maybe I've made a mistake but it's pretty obvious that as you pump too much input into it, the power output rises dramatically. So, when the amp is clipping, the speakers crap out..... of course they do, they can't handle the power. So, if you've got a 110W amp you need speakers with greater power handling capacity. It makes me wonder how these "pro" installers actually set them up.Guesswork? A proper qualified tech would use a scope if it were his own setup, a test disc or tape with a tone at the right level and one scope input to the signal input, the other scope input to the speaker output, then lay one trace over the other to check for distortion. Getting OT but it pays to never listen to salesmen. Steve

You're obviously on the right track. I started off thinking that aftermarket parts were the way to go. Soon learned that stock parts are usually but not always better.Unfortunately you can't get roller rockers and roller cams/lifters for every motor as stock. Steve

As far as the hardened pushrods go, my understanding is that they're hardened so that when they rub on the guide plates, they don't get worn away where they run. Nothing to do with bending. I'm sure that the likes of the big block chev, thicker ones are available, along with the guide plates. Or maybe it was clevelands? Anyway, bigger ratio rockers will give more valve lift. The knock sensor is only a monitor, the sensor itsself get from a wreck, it's only a fancy microphone, the Knocklink, I forget now the cost but there's a row of LEDs, when the top one comes on, you've got a problem so you lift your foot. Handy for setting the timing on the road, a dyno is a waste of time & money. Only good for bragging numbers, besides, it would need to be retuned for the road. Bast dyno tune isn't the best road tune. Oxygen sensors have limited life. If you get one from a late model car that's crashed, you should be OK. Those universal ones from the wholesaler are rubbish. Same goes for a wideband if the calibration hasn't been checked. Same for avgas, my car runs better on 98. Higher octane burns slower so needs more advance, without more advance you're loosing unless you've increased the CR. Bikes have (get away with) more CR due to more radical cams. Steve

It's no good advancing the timing and having to rely on guesswork. Fitting a knock sensor and knocklink would be worth it's weight in gold, likewise an oxygen sensor and monitor display. Steve

Yeh, right..... tui ad. The only amp that puts out a constant DC is a broken amp. Clipping at it's extreme is a low frequency DC squarewave at the lowest frequency of the input signal. A home stereo works on exactly the same principle, there's a preamp stage with volume, tone, balance etc controls, that's fed into the power amp section. In a headunit the power amp runs off 12V and earth, the speakers normally float at a 6V DC with the signal over the top of it, or in the older low power systems, the speakers are earth return with only half the max power (with inbuilt capacitors to block DC to the speakers). A home stereo , like a car power amp will run off dual + and - supplies 30 to 50 volts, depending on power rating. Clipping only happens on a rubbish amp or a rubbish installation. It's caused by 1 of 3 things, too much input signal, too low supply voltage or the amp is too hot. So, you've either got permanent hearing damage or you're telling porkies.... well done. The RCA output is a preamp output, that goes into a high impedence input on the amp, splitting it does NOT reduce the signal level. It's all about signal to noise ratio. A higher impedence speaker will always give a better signal to noise ratio. A lower impedence speaker will give more power output for the same supply voltage. Using a headunit's power amp through an adapter (to reduce the level) to an external power amp will always give a worse signal to noise ratio than using the headunit's RCA output and feeding that to an external power amp. Impedence is dependant on frequency, a tweeter has a very high impedence at low frequency, a bass speaker has very high impedence at high frequency. The crossover network is really a frequency dependant filter. Z squared =R squared + X squared where Z = impedence R = resistance X = reactance. X = 2 pi FL Or something like that. Shit I've already forgotton more that most of you have ever learned. Where F = frequency and L = inductance Steve

Mitsubishi carbys usually have the choke crap out & stay on. There's a plastic gear that splits. Steve

100% wrong.I've read it here before too....... forum BS. Probably started and contiuned by some salesman of speakers to keep the sales going. The speakers should always be rated higher than the amp. Otherwise the voice coils burn up at party time when it gets left at full volume. BTW you don't measure speakers with an ohm meter because the 4, 2 or 8 ohm is impedence which varies with frequency. The resistance is always less than the impedence. Steve. You're an idiot. You're the idiot. I've spent over 25 years electronics repair business.Needless to say I've repaired several hundred amps and I've seen plenty of toasted speakers. What do you do? Salesman? Going back to when people had "real" amps at home, some of my mates upgraded them with "wharfdale " speakers. I don't know the specs but were considered to be bullitproof. So .... according to your theory running say 120 watt speakers with a 50 watt amp would blow the speakers? Wrong. What would happen is that the coils & cones are a bit heavier so need a bit more power to get them going. That in turn means that you'll have the volume on the amp cranked up a bit higher to get the same sound output.You'll never blow them though. Of course if you leave any amp running at full power for too long it will get hot and start to distort....... the amp might blow up, but then if it's a good amp it willl have protection circuits in it. If the speakers are rated lower than the amp and you do the same thing..... the speaker coils burn, go low resistance then take out the amp as well.....unless it's got protection circuits. Steve

Where it says...... reverse the coil connections....... it's wrong, coils aren't polarity conscious and it's important that the common connection stays the same. Where it says ...... reverse the wires to the gauges (fuel & temp)...... also wrong because they use a heater wire wrapped around a bimetallic strip. Steve

100% wrong.I've read it here before too....... forum BS. Probably started by some FW salesman of speakers to keep the sales going. Then continued by the usual sheep. The speakers should always be rated higher than the amp. Otherwise the voice coils burn up at party time when it gets left at full volume. BTW when you measure speakers with an ohm meter the 4, 2 or 8 ohm is impedence which varies with frequency. The resistance is always less than the impedence. 4 ohm speaker will measure maybe 3.5 or so ohms resistance. Steve.

IF it's been running AND there's no oil pressure you'd know because your lash adjusters would be making heaps of noise. Steve

There's 3 postitions accessory ignition start. Some ignition switches kill the accessory feed in the cranking position so if you're powering off the accessory feed, it won't go. Just a case of wiring it up correctly. Steve

That's a trick with old cars. The rockers get slots worn in them where they push on the valve stems. You need a feeler gauge that's narrower than the valve stem otherwise you'll set them too loose. Easy to check the accelerator pump. Just open the throtttle and you'll see fuel squirt out. Don't even need to start it up. Steve

I fixed the tank in the Z. Flushed it out, used detergent. Did it several times, then filled with water, turned upside down with the filler on . Didn't weld it but brazed a patch over the rotten part after grinding it to clean it up. Steve

It'll be worn bearings combined with low revs and hot new oil. Had that myself once, did a low budget rebuild on a dirty old V8, new rings & bearings, oil light came on at 1000rpm when hot. Had to do the job again and replace the cam bearings..... which I was told initially by an "expert" wouldn't need changing. Steve

No it's because "real" tuners needed more skills in the old days and modern technology just makes it easier for idiots to call themselves "tuners". I've personally tuned my car to over 300Kw with a NB and the motor still goes perfectly and there's plenty left in there yet for more. I don't even call myself a tuner. Anyway if it's got a carby and it's running rich, check the choke first. Steve

There's nothing wrong with narrowbands. Widebands just make it easier. How do you think poeple managed before electronic aids? Widebands are just an extra expense which isn't really essential. Steve