This is not strictly a GT4 question . A friend of mine is about to rebuild her MR2 tubby engine and atm she plans to fit HKS 87mm pistons.

Are these going to be too big for a rev3 3S-GTE engine to safely run.

I know the stock size is 86mm and having done some searching it seems that the normal way to go is for a bore out to 86.25 or maybe 86.5.

Will 87 leave the walls too thin? It is from an L-reg MR2 so i guess it's a trhin-wall block.

Any opinions welcomed.

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JDM ST205 (286bhp and 281lb/ft)
JDM ST202 (Finally sold )
1982 Pontiac Trans Am 5.7L V8 (See my website)

Arnt the 87mm jobbies the ones HKS supply with the 2.2 stroker kits??

Personally I am looking at 86.5's when the time comes, unless I can get some liners then I might look at 87mm.

That didnt help really did it...

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ST205 WRC #0002249

It would seem that the bulk of information in the GT-Four community would say that 87 is too large.

Maybe if she is just running stock power?

I know there are some differences of opinion between the MR2 folks and the GT-Four guys as they seem to be able to run higher boosts than we can without things going pop, possibly the engine is not so stressed in the MR2 setup?

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GT4DC Events Co-ordinator
1996 ST205 UK

Would that be because it doesn't have to push a 4wd system?

Cheers for the answers. I'll pass them on

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JDM ST205 (286bhp and 281lb/ft)
JDM ST202 (Finally sold )
1982 Pontiac Trans Am 5.7L V8 (See my website)

I'd always advocate trying to stick as close to stock size as possible really so that you're as sure as possible that the block has as good a chance as poss of staying in one piece. Being an L reg I would also be inclined to believe that unless it is using an old gen2 style block then it may well have the thin wall issues

My advice - get the bores checked and see what the minimum replacement piston size you could get away with would be when rebored, then get some of those.

Cheers,
Mark

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Mark - 94 Red Jap ST205 WRC - Gone but not forgotten
'06 Blue Merc E320 CDi v6
'89 Mica Blue MR2 Mk1b restoration project
"Don't make me come over there"

I would as well stick as close as possible to the stock size. The biggest gains you can achieve will be in a well treated head.

I have choosen 86,5 mm for my new engine build up.

cheers Joerg

Agreed i am also going for 86.5m CP pistons again,From what i hear 87mm is a no no,adrian just gets rid of his when he buys the stroker kit and just keeps the crank.
Has anyone ever tried a crank from a 2.2 camry in the gt4 block ?
would be a nice cheap 2.2 stroker upgrade for our engines

Cp also do the pistons required to run this crank with the 3sgte head.
Hutch

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Please take your nails out of my dash..........501.1 Whp

they are supposed to fit with slight mods, re grind to the mains i think maybe big ends too.

seen it on a site for an mr2 somewhere, not sure about the strength side of things though

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1990 JDM ST185 Grey.
ST205 head gasket.
ARP head bolts.
ST205 Koyo Rad. (almost)
Front mount intercooler.
Colder plugs.
3" decat pipe.
4 Branch manifold.
Nitrous Oxide Steroids for Cars!

The 5S-GTE is not quite that simple

The crank will fit but then you'll need custom rods and possibly pistons to use it. Otherwise the lengthened stroke will send the pistons out the top of the head

Then there's a flywheel issue although I think it's easily solved with a 165 flywheel

This route will only give 2.1L due to the reduced piston diameter.

The other option is to use a 5S-FE block grafted to a 3S-GTE head for a true 5s-GTE with 2.2L capacity

It needs a very specific block (92-93 camry) to make all the water jackets line up. Then there's some machine work to do (oil squirters/cross drilled conrods, turbo oil feed).

There is a wealth of information including one or two "how to" guides on this subject on mr2oc. Just log on there and search for 5s-gte

This looks like an interesting route which requires further investigation, a guinea pig and a fantastic detailed write up!!

Didn't Patrick Chinsue use a similar route on his 185?

Hear that there may be an issue with the gearbox/transfer fouling the block?

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement

I think this is another reason why only the 92-93 block is useful

There are some good writeups out there