gze vs. age pistons

kennyb01
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gze vs. age pistons

Postby kennyb01 » Mon Feb 11, 2013 11:08 am

So the 4agze has a compression ratio of 8.1 and the regular has low 9's as I recall. Does anybody know if the physical length of gze connecting rods are shorter than typical age or is it the pistons? Or is it both? Just curious before I start buying parts for my engine.

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Re: gze vs. age pistons

Postby oldeskewltoy » Mon Feb 11, 2013 1:42 pm

kennyb01 wrote:So the 4agze has a compression ratio of 8.1 and the regular has low 9's as I recall. Does anybody know if the physical length of gze connecting rods are shorter than typical age or is it the pistons? Or is it both? Just curious before I start buying parts for my engine.


it is all in the piston crowns. Comparison of similar year GZE to AGE: block, rods, crank - all more or less the same....
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Re: gze vs. age pistons

Postby kennyb01 » Mon Feb 11, 2013 8:43 pm

I see. Thanks for the info anyone know what kind of power the pistons can handle with say some decent connecting rods?

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Re: gze vs. age pistons

Postby yoshimitsuspeed » Mon Feb 11, 2013 11:26 pm

There are no 4AGE rods that are prone to failure. The ones found in the 7 rib 16Vs (NA and GZE are the same) are very stout. And have been proven to very high power levels in both NA and boosted form. More importantly boost is not that hard on rods. The most stressful moment in a rods life is under tension on the exhaust stroke when there is nothing pushing back. On the compression stroke the compression actually pads the rod relieving stress.
The stock rods have been proven to 500+ HP and failures of any sort are very rare.
The OEM GZE pistons have also been proven over 500 HP.
People always come in thinking as with other motors that you need to replace a bunch of stuff with aftermarket components so it won't fall apart. This is just not the case with the 4AGE unless you are chasing crazy numbers.

You should know if you have a 3 rib you have a different crank, rods and pistons, pre 88 motors can have mix and match blocks and internals. It is rare for a 7 rib to have 3 rib internals but it's possible. If you have the smaller internals you will need a later crank and rods to run GZE pistons. If it's a later 7 rib then the only big difference is the pistons. Small differences are things like having the knock sensor drilled for the GZE and SP, having the oil drain drilled for the SP etc.

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Re: gze vs. age pistons

Postby kennyb01 » Tue Feb 12, 2013 10:15 am

I have a 7 rib block and conponents. Not sure on the year. I was hoping to get about 10 to 12 lbs of boost off my turbo without blowing my block to pieces. More what my current concern is getting some agze pistons for the lower compression ratio. But it sounds like they'll likely mate to my rods which is a relief. By different size are you talking about rod journals? I ordered some rod bearings a while back. I measured out the crankshaft and as It was within spec. The bearings were too small. Same thing happened when we were going through my buddies 7 rib weber engine. But we found some random japenese bearings amidst his stuff and they were the right size. At work when I run part numbers for different years the later rod bearings are a different part number. Would I be safe to assume the 7 rib later journals where bigger and therefor stronger? Also which side ia the knock sensor? Is it on the exhaust side?

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Re: gze vs. age pistons

Postby oldeskewltoy » Tue Feb 12, 2013 11:14 am

knock sensor hole is on intake side high on the block close to cyl 3

4AGE bearing tolerances are VERY tight.... you want to make sure the tolerances remain in spec or you may get some noise....

Interesting to note that although the standard clearances vary to a small degree.. the MAXIMUMS... never do ;) Check that... the AE111 mains are a slightly tighter minimum spec.

Rod clearances AE86 and AE92
Image

Rod Clearances AE111
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Mains...

AE86
Image

AE92
Image

AE111
Image
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Re: gze vs. age pistons

Postby kennyb01 » Tue Feb 12, 2013 12:59 pm

Thanks for the info. I plastiguaged bearings from japan. (Still dont remember which ones they were) and they were good. What I meant by small is they wouldn't even fit around the journals. It was odd. Especially since it happened twice. My block doesn't appear to have a knock sensor port drilled into it. Unless I am blind lol. It's also a hideous blue color for some apparent reason.
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Re: gze vs. age pistons

Postby yoshimitsuspeed » Wed Feb 13, 2013 9:49 am

Yes the later rods were a larger diameter.

The stock knock sensor bung is the undrilled one below and between three and four freeze plugs. I forget what goes in the hole right to the right of it in stock form but you might be able to use it.
I have two knock sensors on my car. One goes to the GZE ECU, it's in the stock hole. The other one goes to my knock light and it is in the hole right next to it.
For moderate power levels it's not even the compression that is the benifit. it's that the pistons and especially ring lands are much stronger. For under 250 HP I would try to find the later 8.9:1 GZE pistons to start with.
For around 200 HP I would try to get at least up to 9.5:1. Compression is a really good thing for many reasons so it's best to have it as high as possible for your goals. The one exception is if you don't fully know your goals and may want to grow a lot more in the future.

12 PSI is nothing to the 4A. The later GZE came stock with 10 PSI. Your goals are very mild for this motor.

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Re: gze vs. age pistons

Postby kennyb01 » Wed Feb 13, 2013 2:31 pm

I'm aiming low because I'd like to get used to the slight power increase over a conventional 4age and gradually move up getting used to the car. Instead of dumping a bunch of money and HP into it which doesn't yet suit my developing driving style. I've always felt that one should build their car around them not around HP. No sense in having a 500 hp car if you don't know how to deal with it. I'm new to boost so trying to get everything straight before I go nuts spending unecessary money and wasting my time fabricating, wiring, etc.

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Re: gze vs. age pistons

Postby yoshimitsuspeed » Thu Feb 14, 2013 9:00 am

kennyb01 wrote:I'm aiming low because I'd like to get used to the slight power increase over a conventional 4age and gradually move up getting used to the car. Instead of dumping a bunch of money and HP into it which doesn't yet suit my developing driving style. I've always felt that one should build their car around them not around HP. No sense in having a 500 hp car if you don't know how to deal with it. I'm new to boost so trying to get everything straight before I go nuts spending unecessary money and wasting my time fabricating, wiring, etc.


That's a great approach. As long as you tune it right and take that care while upping the boost you should be able to get quite a lot out of a GZE longblock.
One of the first tuning tools you will want to get is a wideband gauge so you can monitor AFRs.
I am a huge fan of knowing as much as possible. While they may not be absolutely necessary starting out a pyrometer and knock sensor/monitor are extremely helpful in allowing you to more safely tune closer to the edge.
If you keep those three sensors within safe ranges then it's pretty unlikely you will seriously damage your motor. If your tune starts wander to the dangerous side they should let you know before you do serious damage.

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Re: gze vs. age pistons

Postby kennyb01 » Fri Feb 15, 2013 9:00 am

Thanks for the tips. Out of curiousity how'd you wire up the other knock sensor to your light? I'm under the assumption that when predetonation happens the knock sensor complete's a circuit. Therefore when knock/predetonation occurs, when wired directly to the light it lights up. Acting like a switch.

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Re: gze vs. age pistons

Postby ga_goosh » Fri Feb 15, 2013 9:25 am

the knock sensor is basically a very sensitive michrophone. it is not a switch. the ecu will turn on the engine light
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Re: gze vs. age pistons

Postby yoshimitsuspeed » Fri Feb 15, 2013 9:47 am

Yeah it's a piezoelectric mic. Narrowband knock sensors like on our old cars are tuned for a specific frequency dialed in to the freq of that motor when it detonates. It still picks up a lot of noise all the time though. It's up to the ECU or the knock lite to listen to all that noise and decide what is actually knock.
I got a knocklite and wired it into my old GZE sensor. Ultimately I realized this wasn't a very good idea. They recomend you use a newer wide band sensor with the light. My knocklite goes off like a christmas tree over 4k RPM so it's only any good below that. When I started advancing my timing it did start catching low end knock before it did damage.
The knocklite is no longer available but looking for it one day I found this. http://tunertools.com/proddetail.asp?prod=K-Lite
I don't know how good it is but if it works at least as well as the knocklite it's definitely better than nothing.
You can also build what is called a detcan. The good ones use a knock sensor and some very basic electronics and a pair of headphones so you can listen to knock. Many of the best tuners still say the human ears and brain still make one of the best knock sensors.

If you have big money you can get a J&S safeguard. This actually wires into the ignition and pulls timing if it detects knock. This is by far the best option but starts around $500 last I checked.

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Re: gze vs. age pistons

Postby kennyb01 » Fri Feb 15, 2013 1:19 pm

Do you know of a way to use a wide band knock sensor and wire it up to a light manually? There's got to be a way instead of buying a kit. Most sensors have a positive from ignition, a ground or two, and the actual signal going to the ecu. I'd like it to still be on a budget and would prefer not to be using headphones. Not that it isn't a good idea. But the advantages of having a light mounted in my dash is I can see it at higher rpm's and while I'm driving. If at the track it starts freaking out on me it's probably good to know so I can pull to the pits and assess the situation at hand. You know how it is with tuning. Just as soon as you get everything sorted out something else is brought to your attention. As goes aftermarket improvements. Doesn't mean you did something wrong, engines are just finicky.

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Re: gze vs. age pistons

Postby yoshimitsuspeed » Sun Feb 17, 2013 10:07 am

Since the knock sensor is basically a microphone you need hardware that will listen to the signal and decide when it hears knock. It then sends that signal to a light or the ECU or whatever.
There could be some DIY options. Megasquirt users often use a GM knock module. http://www.megamanual.com/ms2/knock.htm
You may be able to use something like this but send it to a light instead. You would need to find out what kind of signal the module puts out though and see if it will work with a light or if you could make it work.
It's been a long time since I looked into this module but one thing I don't remember them addressing is using the right module for your motor. It uses a wideband sensor to it's up to the module to detect the frequency it thinks is knock. If the module is from a different motor I would expect it would be looking for a different freq. I could be wrong. The biggest thing that effects freq is bore so ideally you would want to find a module from a car with as close a bore as possible. Stroke doesn't matter, number of cyls doesn't matter ect. You just want one from a motor with the same bore or as close as possible.
This is another one you might be able to get to work. http://www.viatrack.ca/
I tried to get in touch with them a couple years ago and after no response for a couple months I ended up going with my knocklite. At the price of the knock light it's kind of hard to beat. DIY would cost a good bit and it would take a good bit of time too.

One thing to think about though is if you will want to tie it into your engine management when you get to that point. The GM module and the knocksense could both be used for that and may save you some time and money down the road if you go MS or something else that requires an external module. MS3 is supposed to have some built in knock monitoring ability but I haven't followed up on it lately to see how well it's working.

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Re: gze vs. age pistons

Postby kennyb01 » Mon Feb 18, 2013 7:45 pm

Thanks again for the info. If I find a simple and relatively cheap way to do it way to do it maybe I'll try ro make a write up for it. I'll check on the mspnp unit to see about said possible knock monitor.