rebore question

[superchargedsam]

How much overbore is safe on rev 3 blocks if its unknown if its thin or thick wall ? I know fensport do 86.25 which I guess would then allow a further rebore if needed at later date but is it safe to just go to 86.5 ?? Dan, Adam any views ?
Is 86.5 the max bore you can safely go to ?

[djdna2000]

Depends on what you want to do with it, i.e. how much power. I would say that stock power will be fine on 86.5.

[superchargedsam]

Dan what about if your pushing power to mid 300 then ?

[adamh]

i,d say it would be fine, but to be sure, id ask the engine shops / ring makers. as it happens, i have a buddy who recently offered me a set of ross racing piston rings for a 3.405 bore (86.5mil) interested?.. they have allready been gapped professionally by toolmaker.
we know that 86.25 is fine tho, it would be first stage of stock re-bore.

u know, dependant on the condition of the cylinders, you could get away with just a hone.. and standard 'sized' rings.

[djdna2000]

Once you get to mid 300s I would say you are getting outside the comfort zone. Of course it isn't power that will crack it but det, and det can come at any power level, but more likely at more extreme levels.

[superchargedsam]

nope this will defo need a rebore ! Are standard pistons not reaching limits at about the 300 mark (altough the celica is running at 320 quite happily at 1.2bar) ! I know alot of people are running high boost and power levels on standard internals but I really want to aim for longevity from the engine so rather build it right first time rather than build it then it blows then rebuild with additional cost that could have been done first time round if you know what I mean !

[superchargedsam]

Dan totally agree with the detonation issue and wondered what the best way at higher power levels to best avoid issues with det as there are so many views on this !

[djdna2000]

Good ECU, properly mapped, simple as. Of course you need the basics in place like a good fuel supply, good intercooling etc.

[adamh]

well, if it needs a bore it needs a bore!. there is no reason to go to 86.5 straight aaway, it makes negliable difference to the cc (2021) im sure it will clean up with 86.25, thats plenty to take out any wear or lips.
get some good bearings in there. are you keeping the standard crank & rods/pisys?

[superchargedsam]

not sure yet what the plan is on this one hence the questions ! will defo need some bearings from you soon adam if you still have your contact. Will need new pistons but will stick with the crank but will have a look at options for rods as some are quite pricey but tohers seem more reasonable so dont suppose you have any contacts for good I or H beam rods then ? Also what piston options are availabel without going to fennies and paying fenny money for them ?

[djdna2000]

Stock rods are good for big horsepower, no need to worry about changing them. Just a good set of forgies :)

[adamh]

on that matter sam, its going to be the luck of the draw, they are expensive premium items, if anyone could get them cheap, i think we'd all have a set :D

bearings i should still be abled to get, dont worry, nearer the time, you need to strip & measure everything first check stamp sizes , mic journals and stuff. mic your bores.

what about your head?.. are you going in deep?

[djdna2000]

he obviously needs his head examined if he's a TB member :D

[superchargedsam]

i have a flowed and ported rev 3 head and standard rev 3 head so I will strip both and then use the ported one for comparison to see what they have done to it ! have fully adjustable fidanza cam pullys so top end is more or less sorted ! this engine plan isnt for the 1.5 I am currently working on but is a long term project but means I wont bother with a full tear down on the rev 2 unit going in the car at the moment but will just clean the engine up and change all the consumables on it !

[adamh]

he obviously needs his head examined if he's a TB member :D

sams sane :freak: , its the rest of us.

[superchargedsam]

dont think there is a sane one on here....oh yeah theres always.....nope even he lost his marbles....erm nope no one sane left !

[adamh]

have ye taken off the rockers? got any cams?

[Driftin_AW]

you could always overbore and sleeve down to stock size if you're worried about the block cracking. You can also have the block ultrasonically tested for thickness, apparently.
:)

[superchargedsam]

i had my 4age overbored and svleed down once so I guess thats a possibilty, my main reason for asking was really du to the fact there are so many debates about this its always good to get more views on it to either clarify the situation or muddy the waters further ! This has all given me food for thought so will try and decide whether to go forged rebuild on the rev 3 block or go 5SGTE to be different !

[Driftin_AW]

I think I would go 5S. There is some extra work to be done, but searching on mr2oc.com will show you what's needed.

[superchargedsam]

Malc since yours and Dans information on the rods and the crank then I am seriously considering that as a long term project so will get as much research info together as I can and then go from there on this one ! Need to get some prices on the work I would want on the roatating assembly as it would defo need balancing and lightning end to end and then need to consider gearbox option and if this is a direct bolt up job and flywheel etc etc. Many variables but would be a nice project and what better car to put such a beast of an engine in but a MK1 !

[Driftin_AW]

IIRC the flywheel is slightly different on the 5S, and you might need to source one from an ST165 GT-Four. ST165 flywheels use the same clutches as all other 3S-GTE's though, so no worries there (and you can use the same gearbox).

I think when Dan said the stock rods are good for big horsepower he was speaking of the 3S ones, the 5S however I have heard aren't so good - but I don't know if anyone has ever really put them to the test either. You wont be able to use 3S rods with the 5S crank because they are too long

[superchargedsam]

Malc yeah I realised the mistake I had made about the quotes for the rods after submitting it but had to sort the dogs out before I could edit it so cheers for putting it right ! Will have to investigate the rods further then but guess having them shot peened (hmm not sure how thats spelt but guess u know what I mean) and balanced will help althought, if they aint up to the power they aint up to it ! Over here getting hold of the 16 flywheel should be straightforward enough ! Are there good options for pistons that will fit the 5S engine then as thats stock with 87mm bore AFAIK as it would need decent ones I rekon as I cant see stock being up to much and could affect the CR (hmm something else that needs big consideration as well I guess) ! Hmmm glad this is long term engine plan as no way this would be sorted for JAE !

[Driftin_AW]

I think the easiest route for pistons woud be 1mm oversized 3S-GTE ones, as the valve cutouts will be made for the 3S head.

[superchargedsam]

yeah that was my initial thought s as I have seen some ross 87mm ones recently but thought that was quite a large overbore to do on the 3SGTE engine but might work well on this set up and I am presuming it will also allow the same CR to be kept (but there is also a niggle in my mind about what the change in stroke will do to this) !

[Driftin_AW]

yeah the stroke will probably change the CR. Will be interesting doing the calculations to make sure you get the CR right!

[adamh]

do we know what the bore and stroke of the 5sfe is?

[superchargedsam]

hmmm bear with me as I am sure I have that info somehwere if only I knew where !

[superchargedsam]

arse cant find the stroke anywhere but will keep trying as love seeing adams calcualtion as pure works of art ! Also rods are available for the 5SFE so thats not an issue and JE do the pistons apparantly if I needed to go that route !

[superchargedsam]

Adam your gonna love me as I have what I think is the correct info but its in good old school imperial but know this ownt phase you at all:

Rods are the same length on a 3S and 5S. 5S has larger big end bore though.

5S has longer stroke vs. 3S. 3.58" vs. 3.39". The difference is in the crank.

5S has slightly larger bore. 3.43" vs. 3.39"

I also believe the 5S has a taller deck height.

The above information is courtesy of toyotanation and it seems that you can but pistons for the 5SGTE in 2 different CR, 8.5 and 9.1 i beleive ! Not sure what dan, malc and adam make of the above information but from what I have read the 3S rods can be used on the 5S crank but the crank neds maching to take the 3S rods so thats always an option i guess but not sure if this would weaken the crank by building up strss points in it from the machining !

[Driftin_AW]

oh no. Now you're really opening a can of worms....

[superchargedsam]

i did notice adam came on line for a while then disappeared a while ago so rekon he took one look at those imperial numbers and did a runner ! Im not too worried at the moment about in depth tech detail as trying to complete ideas in my mind and on paper but the views Ive had of yo(malc) and adam and dan have been most useful as they are pretty unbiased as people on here and striving for different goals hence asking it here and not on other open forums where the opinions can sometime be blindly given which makes picking the well founded answers rather difficult !