Craigs New Datsun Sunny

i think he was gettin at the swap between you 2 not workin cos his are 87mm lol

hmmm, if ian's right mongo u'll be pretty low comp, bit ghey that given the monster cams etc, what'll you do skim your head loads?
 
Well i'm trying to work out the CR so i know exactly what it'll be before i decide what to do. Any ideas about the measurements i gave above? i need to know the piston dome volume and deck clearance in cc
 
de=46cc
ve=41cc

carnt help you with the dome unless you work it backwards.. as you know the compression in a VE as 12.5.. so if you can do abit of maths and switch the formular around youll get the Pisstond dome CC's
 
well sticking what we know in and messing about till it comes out at 12.6:1 in a VE makes the piston CC's 7

putting the DE head voloume in makes it drop to 11.4:1
 
iv just stick all the details into a calculator a 16VE piston is around 11cc's aparently this makes it 13.5:1 in a 2.0VE and 12:1 in a DE
 
Right so going on what you've worked out ian it should be 11.4:1 which isnt too bad, i've had the head faced which has taken off a litlle bit and i dont know what has been taken off before, so it would be safe to assume i'm looking at 11.5:1 as it stands. How much volume would be lost if i get the head skimmed say 0.5mm or even 1mm?
 
one i found on SR20 fourm.. i tihnk there all the same lol iv closed it now :( never used on before actually first time messing about with one..
 
i like to workout compression ratio when im shafting...

the dome of my purple headed piston and the depth of her bore, the bore height from bore opening to the diaphragm and the compression chamber volume in the diaphragm

voila
 
yes christophe but its not the block that raises the comp, its the DE pistons. this car has VE specific pistons

we had this confusion at first with craigs build (i'll mention your car as we are in your thread darling, all these fuckers spamming it up :lol: )
 
I think lets just leave it at 11.5:1 and stop spamming craigs thread up lol. In all honesty 11.5:1 is a nice increase over stock and i'll be happy to be able to use 99ron and whack the timing right up.
 
Right, now you boys have deliberated about your pussy boy comp ratios :clown:

I was lookin for some advice/opinions/discussions....

The car is all back together and running well, no water loss etc... However, i believe i am still burning oil :no:

Soooo, does a leakdown test pinpoint the problem? presumably not cos it shows compression? which with my comp rings being ok will show fuck all if it's rings?

While the head was off i changed my valve stem oil seals, so can tick that off the list.

I have cleaned my pcv valve and fitted a small filter in place of the oversized pipe i had running from the cam cover to intake, so i'll see shortly if that helps.

I'm drivin 300+miles to scotland and back at the end of the week to drop off and pick up some parts from Martyn so will see how much it uses, but the main question being is there any sure fire way to tell if it's my oil rings before i demolish the bloody thing yet again?! And why the F would the oil rings have gone in any way? My comp rings are good so you wouldn't think there was any kind of installation issue, and they're not worn, and if they were proper broken it'd be a bit more obvious by now lol.

Main problem with this oil burning being it could be bringing the fuel octane level down when it mixes in the combustion chamber and adding to my problems with det.

So in short, is there any way to tell for sure it's my oil rrings? Why the hell would they be the problem anyway already? and if it is would it be most sensible to postpone final mapping til November and re-ring the fucker this month when i have the cash for the rings?! - rather than going to Jez on 18th with the car as it is.

Thanks soap opera viewers, opinions appreciated if you still give a shit :)
 
mongo_tuned said:
How much oil is it using?
Click to expand...

i'll confirm that on saturday but seeing as the blue smoke i think i can see at high revs, if it's as it was before about 1litre+ to 500miles ish :eek:

pissing me off, looking like a right comboy engine this but i did everything by the book, why would rings be gone?!!
 
my VE sucked a litter of oil up when i first put it in.. a later oil change showed the oil had settled somewhere in the engine.. i dropped it a few months later and got all t=5.5 litters back out.. the oil was always on the full mark.
 
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