3Y block + 4Y head = what CR?

[2JZR31]

A mate has a $500 hilux with a 3Y and he got a reco 4Y head for it. I said that normally when you fit a head from a bigger engine the CR drops and vice versa so it might not be that good for performance. But it would be great if you want to turbo it! We reckon we can do a $300 suck through system on it.

So what is the stock CR of a 3Y what is the stock CR of a 4Y, and would this block head combo lend itself to a boost friendly CR?

[c2888]

All the y motors i just looked up say they are 8.8:1
2y 3y 4y.
Oh why

I know they ping their brains out just being NA and a little too much timing, tho most are set up so they are borderline pinging, because they need all the power they can muster.

Dan

[2JZR31]

Oh why

You just answered your own question.

because they need all the power they can muster.
Dan

Just wana have some fun doing ghetto turbo conversion. We were hoping the CR would drop with the 4Y head?

[2JZR31]

I have just been told the 4Y head wont fit a 3Y block, well it does bolt on but the water galleries etc don't line up. Can anyone confirm. The car was cheap because it had engine probs despite a rebuild. It came with a 3Y with a reco 4Y head, oil in the water and water in the oil etc lol.

He got a new 3Y for $200 and wanted to use the reco 4Y head on it, but if that was the prob in the first place it might be a very bad idea.

[airfireman1]

I can confirm this, i had to get another cylinder head when I bought a 4y block for a yn57 lux..The water galleries were changed for some reason. Just ask any engine reco place and they will confirm as well
Cheers

[2JZR31]

Cheers. Now we know the cause of the first engine being a POS!

[2JZR31]

So you reckon a dodgy turbo setup running on 98 octane with some advance dialled out wouldn't work on a stock 3Y? Are they meant to run on unleaded?