What is a 5S block?

[synXero]

they do use a little more but its not too drastic and yes you can get piston slap until it warms up, but that shouldntt be too bad either.
i haave the 87mm hks pistons in mine. i put maybe a ltr of oil in every 750-1500 miles

It's effectively a continuous gradual oil change! Ha.

[Magic Beans]

they do use a little more but its not too drastic and yes you can get piston slap until it warms up, but that shouldntt be too bad either.
i haave the 87mm hks pistons in mine. i put maybe a ltr of oil in every 750-1500 miles

It's effectively a continuous gradual oil change! Ha.

Exactly how I saw it with my old engine.

[MR2 Rich]

they do use a little more but its not too drastic and yes you can get piston slap until it warms up, but that shouldntt be too bad either.
i haave the 87mm hks pistons in mine. i put maybe a ltr of oil in every 750-1500 miles

That sounds like a lot I thought mine used a bit but it is less than that...

[ashley]

they do use a little more but its not too drastic and yes you can get piston slap until it warms up, but that shouldntt be too bad either.
i haave the 87mm hks pistons in mine. i put maybe a ltr of oil in every 750-1500 miles

That sounds like a lot I thought mine used a bit but it is less than that...

Same here...

[gavinda]

you could go with a forged piston using 4032 alloy, they have tighter clearances than the 2618 alloy as they expand less. The 2618 is stronger if you are going for bigger power/abuse, but for a road car i believe the 4032 is a better piston as it will last longer,( due to less wear from the tighter clearance.) wossners are 4032 alloy.
depends on your goals really

[dawesy]

In fairness I brought this engine off a friend. He speced it and got the machining done and I built it up. His machine shop thought the clearances spec'd by HKS were a bit tight and advised going 1 thousands bigger due to him spec' ing it for 650hp. That could be why mine uses a bit more.

Interestingly I was looking at the BGB today and the service schedule for the 3S-GTE and an oil change is reccomended at 2500 miles so I don't mind my usage really

[greeny]

they do use a little more but its not too drastic and yes you can get piston slap until it warms up, but that shouldntt be too bad either.
i haave the 87mm hks pistons in mine. i put maybe a ltr of oil in every 750-1500 miles

That sounds like a lot I thought mine used a bit but it is less than that...

Same here...

Yup! That's far too much. You have a problem somewhere.

[MR2 Rich]

What piston size do people use in a 5S block, standard 3sgte is 86mm isn't it?

[Peter Gidden]

What piston size do people use in a 5S block, standard 3sgte is 86mm isn't it?

Nominal bore size of 5S block 87mm. 87.5 is first oversize.

All 3S engines are 86mm.

[MR2 Rich]

Cheers Peter, would you only go oversize if the block needs a rebore or is there another reason (power? Better piston options?).

[Peter Gidden]

Cheers Peter, would you only go oversize if the block needs a rebore or is there another reason (power? Better piston options?).

Personally, if you're going to the all effort and expense of building a 5S-GTE, i'd rebore.

[MR2 Rich]

So in your opinion what's the way to go with a 5s build? Rev3 head, 5S bottom end at 87.5mm reborn with a decent quality forged piston, Rev2 sump? Would you be changing cam shafts, crank shafts and conrods or are the standard 5S ones good for decent power (400-500)? Not thinking of turbo options yet...

[Peter Gidden]

So in your opinion what's the way to go with a 5s build? Rev3 head, 5S bottom end at 87.5mm reborn with a decent quality forged piston, Rev2 sump? Would you be changing cam shafts and crank shafts or are the standard 5S ones good for decent power (400-500)? Not thinking of turbo options yet...

Rev3 head
Aftermarket cams
5S-GTE custom pistons
3S rods
5S crank ground to fit 3S rods
Rev1/2 sump

[MR2 Rich]

Thanks Peter, I know there are a lot of variables but what kind of power would that be reliable at?

[Peter Gidden]

Thanks Peter, I know there are a lot of variables but what kind of power would that be reliable at?

Depends how often the max power used.

A 500hp road car will last longer than a 500hp race or track day car, simply because you won't be using the engine's max capabilities on the road very often, therefore the engine is rarely under any real stress.

450 -500 should easily be reliable.

[MR2 Rich]

Thanks Peter, I know there are a lot of variables but what kind of power would that be reliable at?

Depends how often the max power used.

A 500hp road car will last longer than a 500hp race or track day car, simply because you won't be using the engine's max capabilities on the road very often, therefore the engine is rarely under any real stress.

450 -500 should easily be reliable.

Very true, thanks for your input Peter.

[ashley]

Just to add- it's all about service intervals when you start upping the power significantly. You can run 500+ reliably, but expect your service requirements to go up, for example big end bearings start to become a consumable item with big boost due to the increased forces acting on them.

[MR2 Rich]

Interesting Ashley, how hard are they to change?

[ashley]

Not too bad at all mate, you can drop the sump with the engine in the car still (not that I've tried yet).

It's just an example, like having to decrease your oil change durations, etc.

I think the main thing is realising that you have to keep on top of your engine, lots of data monitoring, inspecting etc. Once you significantly increase the power output, you significantly increase the potential for lots of very expensive engine damage if/ when stuff does start to go wrong...so it's key to stay on top of things. The second you suspect something ain't right you need to chase it down and sort it, just in case.

Data logging is vital imo.

Totally worth it though

[Peter Gidden]

how hard are they to change?

With the right workshop conditions, correct tools and patience, they can be changed without removing the engine.

In a fully equipped workshop, IMHO, it would be easier to remove the engine.

I agree with Ashley. Another example is the valvetrain. Uprated cams means uprated valve springs means increased strain on cambelt, so cambelt needs changing maybe annually. Moreso when you consider most high power engines are interference engines.

Also consider requirements of clutch, CV joints etc.