7 rib big port?

[whips]

ok my 4age had uneven compression accross the cylinders
so i pulled my 87 trueno engine out and stripped it last week
its a 7 rib bigport with 40mm crank and 18mm piston pin,no oil squirters
havnt heard of this combo before(7 rib big port-40mm crank)
could it be the factory engine or a mickey mouse one?
cheers

[stahlz_ae86]

Wierd, I thought 3 rib were 40mm and all 7 rib were 42mm.

[whips]

same,be good to know if anyone else has heard of this

[Nikkojoe]

42mm cranks came into the picture mainly in 88, but 7rib blocks came in before that (in 87) so it's possible to have one with 40mm crank.

The AW11 4age had a 7rib block with 40mm crank according to epc (block change over to 7rib in 08/87 and crank was 09/87 - gze ran same crank from 08/86).

[whips]

sweet cheers! now to check vin to engine number(hopefully its the original engine)!fingers crossed
anyone know where i can do this online?

[Nikkojoe]

I don't think it is unfortunately. Kouki only ran to 04/87 so it's most likely a 4age long motor replaced into it.

No way to know unless you have the original books for it (which you probably wont - if that's the case it makes no difference).

[rthy]

the series 2 AE82 twincams, late mode aw11's and some jdm ae92's came out with the red top bigport 7rib 4ages

[Willofan]

Put some pics up of the block and crank. My TRD factory race motor is the same combo. Is the motor stamped with R-Dot or TTA on it somewhere??

[FoldKing86]

Stripped a AE92 GTI twincam engine many moons ago and it was as per OP inquiry

Seemed a small amount of production engine got made like this between bigport and smallport.

[Matt]

^^^ this.

the fxgt also had 7 rib blocks