How Far Can I bore A 5S Block Out?

[CLG]

I'm in the planing stage of a future engine build, so with that in mind, does anyone have information on how far you can bore a 5SFE out? The standard bore is 87mm, and yes I'm happy to sleeve, but not to the point of having to "move galleries"!?!

[-Totenkopf-]

Well, I don't know how far you can go exactly, but I've gone 88MM w/ sleeves. Once I lay eyes on the engine I'll let you know if I think there is enough to take out more.

[CLG]

Get "macro" pics too please?!

[The Real Roadrunner]

standard bore is 87.5 should be able to go to 89 easy just check between 2-3 to see if there is enough meat.

[-Totenkopf-]

Still waiting on pictures. The issue with moving upwards from 88MM bore size in the 5sfe block is not really strength but lack of headgasket sealing area. The area between the cylinders gets very slim. I'm still waiting on pictures mate but will upload them as soon as I receive them

Cheers,

James.

[Classique71]

i think i know whats happening here - and all i can say is SCARY SCARY FUN!!

good times good times !

[-Totenkopf-]

Bit of an intro to my plans at http://toyota-mr2.mine.nu/mr2/topic....27&whichpage=1

[Spectre]

Costello... why not a 1UZ 205 :O

[Gabe]

Costello... why not a 1UZ 205 :O

Cause it's too hard for him and he's scared of anything even remotely challenging

[Spectre]

Cause it's too hard for him and he's scared of anything even remotely challenging

5SFTE isnt challenging?

[Joshstix]

5SFTE isnt challenging?

Not at all, you could do it with stock Toyota bits in an afternoon. The 3SGTE exhaust manifold will actually bolt straight up to the 5S head if all you're trying to do is build a 5SFTE.

As to the original question, the stock bore is 87mm, the bore spacing is really quite tight in the S engines. While it is better in the 5S due to the siamesed bores for all 4 cylinders it's still going to be tough to get a decent head gasket seal if you go to more than 89mm I suspect.

Potentially you may be able to get a slightly bigger bore by cutting the cylinders off centre from there standard location and then sleeving. The reason I suggest that is that the wall between cylinders 2 and 3 is about twice as thick as that between 1-2 and 3-4. If you move the bores towards the middle of the block and then sleeve you may be able to get a more even bore spacing and slightly larger bore.

Having said that it is an arse load of extra work for a feww extra cc's of capacity. Personally I'd go with 87.5-88mm bore in a good condition 5S block and avoid needing to screw around with sleeves and "experimental" bore placements.

[mtp_69_i]

^^^ agreed. plenty of people have done it in the states.

another option would be 3sge head on 5sfe block. It's also been done a bit but there are some specificities about which generation 5sfe block will match up to the 1st gen 3sge head.

celicatech.com has a couple of people that have done both of these conversions.

[Joshstix]

I would assume that the plan in this situation is to build a 3S stroker using a 5S block, most likey running a Gen3 head. There is no point spending the time and money involved here and keeping a rubbish F head on it.

[CLG]

No, there was never a plan to keep the economy "F" head - I have a gen 2 GTE head and a 5S short motor, so will start playing around with those items first.

[mtp_69_i]

all good. should be a bunch of fun! Not sure what sort of tolerance the 5S bottom end or conrods have for high power though...