4AGE block differences explained (incl. some eyecandy)

[Bean]

Here some info that recently came up again, I condensed it to post it here (click the pictures for bigger versions) - thanks to the involved members for sharing:

In this picture 3 defining things can be seen
[list] 40mm crank, distinguished by the shape of the counterweights (comparison pic will follow)

12point rodbolt nuts common on 20V blocks, early (3rib) 4AGE are regular hex (like the maincap bolts)

the "extra meat" in the block wall @ #3 journal was also only introduced later with the 7rib generation.[/list:u]

so why is this intriguing? this is a changeover block from Toyota (probably from around 1987) as pointed out above it has many features from the newer generations but one important one from the first generations which is the 40mm crank. Also something that can't be seen very clearly is the above block doesn't have oil squirters.

As mentioned before here is a pic of a 42mm crank notice the difference on the counterweights which are equally shaped on the 42mm but not on the 40mm (this is one reason why the 42mm is 1kg heavier).
here's a better picture for comparison
and a nice collection I guess Dan put together as well


next we have a close up of the 10:1 pistons, you'll notice the flat are is higher than the outside edge. The 9.4:1 pistons have this area lower.
here the comparison, thanks Dan and some more specs

next the 7 ribs, clearly seen in this picture
compared to 3ribs

now to add to the confusion my own block, which is a 7rib WITH oilsquirters doesn't have the additional "meat"


Now want might to want to jump to conclusion and say easy 7ribs without squirters had this additional meat and the others don't. As usual it's never so easy as I found this picture:

7ribs no squirters and no meat - this particular block is a late model MR2 1987-1989

I also came across this picture from Ben Willson back in 2007
20V left and 16V right... now I'm not a 20V expert but I know they use different oilpan patterns and there's supposed to be a slight difference in the openings on top where the oil drains back from the head too...


Connecting rods - I also dug up these pictures from the internet showing the different connecting rods used in the 4AGE series.




I'LL EDIT THIS FIRST POST WHENEVER SOMETHING WORTHWHILE COMES UP - SO PLEASE CHIME IN

[Bean]

PLACE HOLDER IN CASE I RUN OUT OF SPACE ABOVE

[ZDoman]

the extra "meat" at #3 cylinder was introduced around 1991! I've seen a lot of smallport engines, and only the last ones had this strengthening! And this version had the thinner "silvertop" conrods! so this engine (shortblock) must be produced after 1991!!

[Bean]

ZDoman Wrote:the extra "meat" at #3 cylinder was introduced around 1991! I've seen a lot of smallport engines, and only the last ones had this strengthening! And this version had the thinner "silvertop" conrods! so this engine (shortblock) must be produced after 1991!!

might be - as far as I could dig up so far this block (11400-16061) replaced 11400-16060 which was one of the 3rib 40mm versions.

the last production use of the 40mm crank was in late 1989 when they switch the FWD Corolla to the smallport and 42mm cranks. AW11 7rib block I've seen so far (1987-89) didn't have it.
I'll have to dig up some information on a 1990 modell to see if they had this extra "meat".

[Alex170984]

This kind of falls into the block category...

Do you know if there are any dimensional differences between low and high comp 4AGE pistons?

[Bean]

Alex170984 Wrote:This kind of falls into the block category...

Do you know if there are any dimensional differences between low and high comp 4AGE pistons?

well for starters there are two different pin sizes that have been used.
18mm on 9.4:1 and 10:1 bigport pistons
20mm on 10.3:1 smallport and 20V pistons

and then there's actually a third which are the Formula Atlantic (Mahle) pistons which use a 19mm pin

the rest of the dimensions are the same disregarding the differences due to the dome design.

[Project D]

I don't know why almost everyone forget the redtop bigport (AE92 mk1, before they had the smallport)

7 rib block, 42mm crank, bigport, no oil squirters and 9.4:1 pistons.
I have a recap table (in Japanese) if you want :wink:

[Uzelac]

There must be difference in height since dome is a bit bigger at HC pistons.

[Alex170984]

Are they 20mm on 10.3:1 smallport and 20V pistons high comp?

[Bean]

Project D Wrote:I don't know why almost everyone forget the redtop bigport (AE92 mk1, before they had the smallport)

7 rib block, 42mm crank, bigport, no oil squirters (and I think 9.4:1 pistons since they where rated to 120hp)

I do know about it and if it had a 42mm crank then the pistons were 10.3:1 th only sub low comp (sub 10) piston with 20mm pin was the 4AGZE and they are 8.9:1
anyway I wasn't really listing all the different versions merely the oddball OEM block at the top compared to others.