.5 over what are teh benifits

General engine questions/issues that aren't specific to the other categories
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.5 over what are teh benifits

By Classiccarsrule85
- Thu Sep 09, 2010 6:01 pm #212917 well when you ask that parts dealer for pistons and rings he asks you 75mm or 75.5 /5over depending on what your engine is...

I am wondering what are the benifits of going .5 over i am looking getting a set of 75.5mm vitaras and well i am wondering if i should just go ahead and get the 75mm ones instead....if there is a benifit of getting .5 over what is it???
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By blk92hb
- Thu Sep 09, 2010 6:12 pm #212921 More displacement, more power due to more air and fuel going into the combustion camber. But weaker cylinder walls because you have to bore the block to get the pistions to fit. Imo i would do it because "there is no replacement for displacement"
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By Classiccarsrule85
- Thu Sep 09, 2010 6:22 pm #212922 So lets say i was to turbo it i should thusly get a block guard??
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By blk92hb
- Thu Sep 09, 2010 6:36 pm #212926 I would just for peace of mind knowing im not going to blow out a cylinder wall. How much boost would you run if you do go boost?
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By Classiccarsrule85
- Thu Sep 09, 2010 6:53 pm #212931 no more than 13psi but im building with safety and peice of mind eagle rods arp headstuds etc....
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By ikon
- Thu Sep 09, 2010 7:08 pm #212933 i hear block guards are a no no. they only reinforce the one area at the top where they sit and they can cause warping in the lower levels of the sleeve, thus creating catastrophic engine FAILURE........ anyone else hear that. i wouldnt go cheap on the block especially if its gonna see some boostiez. get new sleeves. :thumb:
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By teal_dx
- Thu Sep 09, 2010 7:26 pm #212938 boring is a good thing to do on a higher mileage block where the cylinder walls may be slightly out of round or have deep scratches.

Boring is done before honing.

Boring a D16 .020 (.5mm) will mean that you will need to use 75.5mm pistons instead of 75mm.

On big v8 engines, boring has a greater affect on displacement which translates into more HP. But many of those are closed deck iron blocks which can take a lot more boring than our open deck aluminum blocks. Plus you are removing a lot more material on 8 cyls than on 4, so you're going to see better displacement results on a v8.
So it's not really done with horsepower gain in mind on our D series engines as it is for a fresh piece of mind when you want a fresh start block as the base for your build.

Block Guards are a controversial topic. Some people swear by them because they strengthen the area around the top of the cyl. Others say they retain more heat around the top of the cylinder which can lead to pre-detonation in the combustion chamber.

I would not use one unless you're going all out on a crazy build.
Last edited by teal_dx on Thu Sep 09, 2010 7:30 pm, edited 2 times in total.
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By 93hatcheg
- Thu Sep 09, 2010 7:27 pm #212939 the reason the dealer askes you for 75 or 75.5 is only because when a oem motor is beinbg rebuilt if the cylinder walls are damaged then they must be bored bigger to get past the imperfections in the wall. its a standard overage and really has no effect on hp, it may a tiny bit the only way to get hp outta a bore is to go big usually 2 or 3mm over (on a b-series at least).
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By Classiccarsrule85
- Thu Sep 09, 2010 7:35 pm #212940 yea im just trying to get my options sleeveing would probaly cost more than everything ive bought so far as a rough estimate is 800+

would "posting" the block help??

I guess if worse came to worse then i could save up 800 over winter but i really do not know as im only shooting for 200-250hp

*i think since its a packaged deal then ill just eitehr sell or try and trade the 75.5 vitaras for 75mm vitaras....
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By JUICE
- Thu Sep 09, 2010 8:36 pm #212948 you do it cause....

say you have a block with 100,000+ on it, if you got stock size pistons for it, it's a good chance the rings won't seal well. especially after it's been honed. always a good idea to go .020 over on a old block :thumb:
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By Classiccarsrule85
- Thu Sep 09, 2010 9:19 pm #212955
teal_dx wrote:for that HP goal you don't need sleeves at all. Get a reliable tune, nothing too extreme and you will be fine without a block guard as well.


Alrite thats what i thought now i know if i was going 300hp id definately get a sleeve done but yea im getting a reliable tune most definately
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By d-mon
- Thu Sep 09, 2010 11:11 pm #212966 aftermarket sleeves are for forged pistons.
they beat the f*ck out of the cylinder walls.

ppl make 500+ hp on stock sleeves and v-tatas

Suzuki has slightly different clearances than Honda, and their 75mm pistons are 'loose' in the d-series cylinders. (noisy on start up)
using a 75.5mm piston allows the shop to bore to a new size with the correct piston to wall clearance for the vitara, rather than oem honda piston.

another issue is that the intake and exhaust valve reliefs are backwards to honda engines. not a big deal with the huge dish of a vitara, but also the piston pin offset is different. so you put the pistons in backwards (arrow points toward flywheel)
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