Hi, Just wondering if all 4age blocks are the same head pattern. i.e big port on 7rib block small port on 3rib block can this be done.

Thanks!

all 16v should as there the same head gaskets used

 

I'm pretty sure at least

 

Travis

all 16v should as there the same head gaskets used

 

I'm pretty sure at least

 

Travis

 

I'm pretty sure this is true, ive got 3 rib and the gasket I'm using in rebuild fits both smallports and bigports

Edited March 22, 200917 yr by kiahn

Thanks fellas,

I was pretty sure they are the same but it pays to check

Same.

Yep, interchangeable :) Is it just the 7 rib from the 4agze that has the extra oil squirters?

Yep, interchangeable :) Is it just the 7 rib from the 4agze that has the extra oil squirters?

 

I think 7-rib smallports have the oil squirters too.

correct

Oil squirters???

Inside? I have not pulled it down yet, but I brought a 7 rib block.

I have a couple of big port heads to go on it! But may try and find a smallport head.

What made the extra 14kw in the smallports just the port design??? or was the injection etc updated??

I noticed the different oil filter set up??? I have only ever run 86kw bigport 3 rib engines.

Is there any major difference I should know while rebuilding this engine.

Crank and rods are the bigger stronger ones 42mm I have read.

Will have Twin webers on it are the cam profiles different aswell??

Thanks Guys

They run semi-sequential injection, so 2 banks of injectors, as apposed to the batch fire of the bigport. Compression went from 9.6:1 to a touch over 10:1, and the smaller ports sped up the intake velocity. They also got rid of the TVIS system and went back to single runners on the intake manifold too. The funny part is the smallport cam's have slightly shorter duration and less lift than a big port hey.

 

I should also add that that a JDM bigport ecu is rated at 98kw on good fuel, adm at 86kw or so.

Ok so will bigport cams fit in smallport head???

This may sound really dumb!! but I am new to jap engines

what is JDM/ADM.

Are the piston pin heights any different? How did they bump up compression?

not sure about other questions but jdm is japanese domestic market, ie parts factory in japan and adm is australian domestic market ie parts factory in australia

 

Travis

Yep, bigport and smallport have interchangeable cams. ADM = Australian Domestic Market , JDM = Japanese Domestic market. Pin heights are the same, but bigport have an 18mm gudgeon pin, smallport 20mm.

 

The higher compression is a mix of a smaller volume in the head, and a slightly smaller volume in the dish of the piston. To get the compression about 10 with a bigport head most people run a 0.7mm headgasket as apposed to a 1mm standard one.

 

Oh, I forgot to add the angles between the valves are more square on a smallport too, which apparently is better for power.

Cheers fellas big help!!

So where best to buy pistons??

I have used ACL in the past they seen ok?

The only thing is they have to be cast due to our class restrictions so no forgies etc :(

Is there a speed shop set up for 4age in OZ?

Yeah, I've heard that ACL standard pistons are stronger than a standard toyota ones... seen some pretty wild builds on standard ACL bigport items. My 5S ACL pistons are a much better finish than the standard toyota ones, smoother edges and steel gudgeon pin reinforcement. Yager motorsport are known for some nice engine, but they're pretty pricey.

 

What's the plan for the build?