Strange question, been told by Leeds specialist reboring...

[caldridge7]

Hi guys had a short conversation with a Leeds specialist over the phone and asked if the engine I'm buying has been rebore to 86.5

I already know it hasn't and is 86mm

The reason he asked is that he said if it's been rebore to 86.5mm then the block would crack in a month...

REALLY????????

Must be crazy or is he?

True or false and reasons why please!!

[Dale_V]

Plenty of people run 86.5mm bores, some run 87mm . the bigger the diameter of the bores the thinner the wall thickness will be, meaning less strength and easier to crack.

Thats why its best to try and keep the walls at maximum thickness to give the block a fighting chance of lasting.

But saying that a 86.5mm bore will crack within a month is unfair. It might last years, it may never crack! it might last a week!

A good tune/map is also a major factor. A thicker (unbored) wall block will cope with a bit of detonation better than a bored block.... then I guess you could even give a 86.5mm block a better chance of surviving with a bit of water/meth injection

Its a minefield tbh, theres no right/wrong/proven answer

[androo007]

Not using a rev 3 block gives you the best chance.

86mm is preferred, but 86.5mm is just fine.

[caldridge7]

Why would it be better to not have a rev 3 head or block is rev 2 better? Also quick question I'm getting 880 sard injectors and the specialist said the won't fit the standard injector rail.... Will they not?

[androo007]

Who is this "specialist"? 800/850cc SARD side feed injectors drop right in. Unless you have top feed?

Rev 3 head flows best stock, but bottom end most likely to have poor casting, increasing risk of cracking between 2/3 cylinder walls.

I opted for rev 2 bottom end and rev 3 top. Opinions are divided on whether it's any better but have a look around and makr up your own mind

Many many 86.5 engines out there. Yes, sticking to 86 is best, and u less you have excessive scoring it's likely not needed to be bored out, but many people do without issue.

[C35Rob]

Why would it be better to not have a rev 3 head or block is rev 2 better? Also quick question I'm getting 880 sard injectors and the specialist said the won't fit the standard injector rail.... Will they not?

if you mean SARD/Denso 850cc side feeds (red top) then no, they aren't a direct fit as they require adapter collars for the bottom of the injector, which are slimmer than the oem injectors. the collars are readily available though.

the 'other' two common sard injectors (tea/brown and blue 800's) are a direct fit into the fuel rail but the brown/tea injectors require the resistor pack to be bypassed, as do the 850's

beware there are lots of fake sard injectors around, especially the blue drop in 800cc's which are all over ebay, and even being punted on by some 'specialists' at the moment.

for what its worth, and the price difference it's worth going for a top feed set up.

who is this 'specialist' you're getting advice from?