4agte piston and conrod question

[lolwat]

ok mr bigport i got a 7 rib block, would that be a small port bottom end or did the bigports come out with 7 rib too???

(sorry not trying to hijack its all on topic so why not ask here )

[mrbigport]

7 rib is smallport, gze, or 20v
all ran the bigger crank
slight variations in pistons between weights, design, and materials used but all have the same hole sizes (as far as i know).
pistons changed between the different variations obviously...otherwise we wouldnt be having this discussion lol

[lolwat]

thank you very much

[sld sho]

what is the beneifit of haveing a 7 rib block apart from beeing able to put gze parts in there, what difference is there if you just get forged pistions and conrods for the other block 40m crank?

[mrbigport]

its a stronger block - short answer...more ribs give it greater reinforcement against both the internal preasures (especially under boost) and the twisting forces aka torque twist



this is a photo of a 3-rib 4age.


this is a photo of a 7-rib 4age block.


ultimately its the stronger bot of gear, and its quite obvious once you see the difference in them

[R&D Mechanical]

200kws on a stock (so i think) bottom gze end, loves it

[Skylar]

Just a little correction:

you can get 7 rib with big port. They were in early AE92 and very late AE82 and look like:


That one's been converted to RWD. The difference between them is that bigports are normally black and blue writing on the inlet cam cover but 7 rib bigpot is black and red with smallport being all red writing with spark plug cover further down the valley and not at the top like bigports.

[mrbigport]

fair call, but as a general guide for someone hunting a 7 rib block...