[goldgtr35]

Sorry if this has been covered before, but here goes,
Going stage 4 with down pipes, so stage 4.25476
I know the benefit of fitting new rods, if going over 630 lbs of torque
But I've never heard of a piston letting go, I've heard of burn holes in pistons if a plug has been too hot,, I might be thinking of my karting days on that one,
But can some one clarify why pistons need changing,
Regards Goldie

 

[MattGTR750]

Why you've got the block open makes sense to do pistons as well ? Stock pistons will max out at 750hp I think also

 

[goldgtr35]

That's what I'm saying,, guessing at 750 BHP,,,, Has there been any failures,
Can't see why pistons are changed if they aren't a week point,
Saying because the engines apart don't cut it with me,
I paint cars for a living, like saying while it's in the oven give it a repaint
Sorry,, Regards Goldie

 

[Voyager]

comparing paint to engine mods is a bit of a fudge tbh.

on the one hand fitting new pistons while you have the engine apart is a small price for piece of mind.

on the other hand, aftermarket pistons are quite a bit lighter than std so you will stress your new rods far less, and with reduced rotating mass comes faster pick up and higher rev limit.

not to mention better ring sealing, cooler quench area, shorter piston skirt, better flame propogation (depending on piston design ofc)

 

[Adamantium]

If you can be bothered to read my mod thread you'd see I felt the same way.

I didn't see the point and was concerned about noise on cold starts and oil consumption.

Iain then showed me pictures of engine failures due to piston ring land failure rather than poor mapping. Basically directly attributed to exceeding the operating limit if the stock rather brittle pistons . It was enough to cincince me.

Now my build has been done I'm over the moon. It's the wuietest forged engine ice ever heard with no oil consumption at all.

 

[goldgtr35]

"On the one hand fitting new pistons while you have the engine apart is a small price for piece of mind"


This is what in trying to get at,, piece of mind,, of what,,, do the original pistons fail, or just fitting new, because some one states theirs is better that Nissans

 

[goldgtr35]

Hi Adam,
sorry hadn't read your rebuilt post,, so there has been piston failings before,
That's all I was getting at, can't see the point in changing things that aren't broke,
The old saying if it isn't broke don't fix it,,
Cheers Goldie

My cars covered 12 k now and never used a drop of oil.

 

[mindlessoath]

pistons can shatter and have. recommend doing both.

 

[Ja5on]

I would do both

 

[Adamantium]

Hi Adam,
sorry hadn't read your rebuilt post,, so there has been piston failings before,
That's all I was getting at, can't see the point in changing things that aren't broke,
The old saying if it isn't broke don't fix it,,
Cheers Goldie

My cars covered 12 k now and never used a drop of oil.

Your rods aren't broken but you're changing those.

 

[Trevgtr]

Slightly off topic, but how much engine oil should a standard GT-R use per 6000 miles?

I read in the handbook up to 1 litre per 1200 miles but that seems excessive! And why would some use more than others? There can't be that much piston ring slack?

 

[MattGTR750]

Mine hardly uses ANY oil...

 

[goldgtr35]

Your rods aren't broken but you're changing those.

I've owed and driven big BHP cars since I was 17 and I'm not at the old age of 53..
Rods are the first thing to bend in most modded cars, my only question from the outset was are the pistons prone to failure,
I've got a new shape mustang running a Saleen super charger just over 600 BHP and that at it limit with out changing the rods, never heard of pistons being change, but never too old to learn,
Goldie

 

[MattGTR750]

I cracked a piston on my 450bhp focus RS ... Rods were fine when took the engine apart ...

 

[goldgtr35]

I cracked a piston on my 450bhp focus RS ... Rods were fine when took the engine apart ...

Cheers for reply Matt,
Sound like pistons and rods by the sounds of it then,,,
Regards Goldie