7AGZE bottom end question

[nick.parker]

7a @ TDC (using 7A pistons) is in the neighborhood of 0.6mm BELOW the top of the deck.

How far below the deck are standard 8:1 GZE pistons?

[Bazda]

4a pistons will sit around 0.7mm below

[nick.parker]

If you happened to be getting custom rods and pistons with higher pins, this would mean 0.5mm of free extra rod length? So long as your piston dish was adjusted for the correct CR?

[Bazda]

I got my rods custom made 0.5mm taller. And got my pistons done with a big dish.

[PrettyCoolWagon]

Keep in mind.... if you build the 7agze w/sc14 and feel your compression ratio is a bit low, you can always fit a smaller sc pulley OR complete pulley system to reach your intended power goal.

At least this way, if you use a boost controller and get your timing right there's less chance of detonation compared to using boost with a high compression ratio.

I'm assuming most of you guys have come across this page at some stage: ??

Building a supercharger car based on the Toyota A-Series engines | Supercharger Performance and Engine Performance Parts

quote

Engine
7agze
1800cc 7afe block 1996 celica st overbored & decked
4age big port head polished & ported
HKS 1.0mm steel head gasket
Oil cooler pistons jets machined in
Arias 81.5mm oversized forged pistons
Pauter forged rods w/oil feed to small end
Porsche 924/944 1986 117x19mm timing belt
NA inlet manifold
Celica GT 55mm throttle body
Supra 1ggze/previa sc14 1435cc supercharger w/sc12 125mm small pulley fitted
Fensport oversized pulley kit
HKS adjustable cam gears
AE92 4agze dli & ecu
PFC HKS f-con & gcc
400cc black supra injectors
HKS super header 2 s/s 4-2-1 manifold & super drager exhaust
HKS intercooler

Some of the most notable parts on this particular install is the use of the larger SC14 (1.4 liter) supercharger combined with a Fensport 176mm crank pulley and 125mm supercharger snout pulley. The resultant pulley drive ratio is 1.408:1 so with each revolution of the motor we have 1.4 revolutions of the supercharger and a total of 2020.5 cc or air. In comparison, the 4 stroke 1.8 liter 7agze breathes in about 900cc per revolution (half of its displacement) of air depending on its exact volumetric efficiency at that rpm range.

The result of this combination is an easy 18psi of peak boost pressure and a potential peak power figure of 270 horsepower @ 6600 rpms!
end quote

Doesn't say what comp ratio - can anyone figure it out based on the information provided???????

[RogueMoog]

Oil cooler pistons jets machined in

Just a question on the side... this is possible to do with a 7A block? What about for a 4A-FE block?

[PrettyCoolWagon]

Yes, It's cost me $313.50 australian dollars. All you have to do is call some engine builders in your area and see if they'll do it. If they can't just ask them who can and they'll point you in the right direction.

I guess you're thinking of doing something like Old Skwel Toys build. 4afze ...I'm not sure but I think for the money he's spent he coulda bought a 4agze straight up.. but you'd have to ask him..

If you know 'why' you're doing it ... then go ahead..

It's only really needed on highly boosted engines

[RogueMoog]

I was just curious, I don't know if I'll end up putting in oil squirters in the FE block. (For those wondering, my plan is GE head, FE block, GE internals, GZE flywheel, in order to keep my AC, PS & alt where they are, and to avoid grinding down a GE block to clear the transfer case.) Power goal is 170-200 flywheel HP, NA build. Part of my reasoning was that if I could find a smallport, I might as well use whatever I could from that engine (head, intake manifold, exhaust header, oil squirters, whatever).

[PrettyCoolWagon]

It's up to you if you wanna go that way. Save yourself the $300 odd dollars on machining in oil squirters. They're a good idea but.. You won't 'need' them on a NA build.

The FE block is actually quite strong. It has 7 ribs just like late model 4age & 4agze blocks, so no problems there.

But to reach your power figure with your intended set up you face several challenges..., I'd suggest doing some research on the silver and black top compression ratios & to reach your power goals, other things like adjustable cam gears would help too but I'm not sure about the timing marks of an FE crank sprocket with GE head ...you might have some figuring out work to do there...

You'd also need to check that a GE crank will seat properly in an FE block so that you can use the GZE flywheel. Because GE and GZE cranks and flywheels use 8 clamping bolts to attach the flywheel, whereas FE engines only use 6.
This means you'd need to buy new crank and main bearings and get the whole bottom end balanced buy an engine builder, due to the combining of so many different parts from different engines, which once again will cost you $$$.

Keeping in mind you'd also need the GE ECU and loom to run the GE head.

So really by the time you get all that, you will have bought an entire 4age engine package minus the block???!.... It would be more cost effective to buy a 4age engine package of your choice/budget. Keep in mind that any 4age block with 7 ribs (not the early 3 rib blocks) will already have the oil squirters machined in factory standard.

The grinding to clear transfer case has been successfully done by many and there's even 20valve blocks that have the same notch to clear the transfer case, similar to the 4afe ... They do still require some grinding but not as much as GE or GZE block.

Hope all that helps.

[PrettyCoolWagon]

Sits more around 0.7mm. Because of the larger stroke if you have the piston right at the top the compression is going to be alot higher than it was in a 4age.

4agze 8.0:1 piston will be around 8.2:1 with a stock gasket at 0.7m deck height in a 7a. If you made it sit flush its going to be around 8.6:1

So does that mean a similar set up (standard length 7A rods, 1.2mm gasket with 16v GE head) ..but using the later higher comp GZE 8.9:1 ceramic top piston will be around 9.1:1 ?