16V head on 20V block??

[AE86fan]

Im just about to build a mild 4age. I have purchased a 20 valve bottom end and quad throttle bodies. This is what I plan to do.

1.Use the 16 valve blue top head on the 20 valve bottom end.

2.Make a manafold and use the ITB on the big port head.

3.Use the factory MAP sensor and computer.


Does anybody know if I can get away with running the 20 valve pistons to keep the higher compression ratio or are there problems with valve clearences? Is the increased compression on the 20V a result of the pistons or the 'squish' area in the head??

Has anybody had any problems using a MAP sensored bluetop loom/computer running silertop ITBs.

I know I am probably making alot of work for myself and should just use a 20V motor but Im not to keen on having to modify the firewall on my AE86, or having to purchase an aftermarket computer to run a different dissy (I also like the idea of keeping some originality).

[basilae111]

Try here dude, answers some of your questions

http://forums.toyspeed.org.nz/viewtopic.php?t=20647

[AE86fan]

Thanks man that helps a bit.

So going by that, pistons from a small port redtop should have the 20mm gudgon pins and fit sweet as on the silvertop rods.

[matt dunn]

Thanks man that helps a bit.

So going by that, pistons from a small port redtop should have the 20mm gudgon pins and fit sweet as on the silvertop rods.

correct.

[NA Drifter]

also, with the ITB and running stock ECU, you will have problem making to car runs correctly.. 20v use less fuel at idling/low rpm and more up high.
I'm going to put ITB on mine in near future and still sorting out stuff and time for it.. got 90% of the things i needed. Is not as easy as you might though.... I think at the end is cheaper to run turbo setup.. but like ITB so.. yeh