Craigs New Datsun Sunny

mera red gti said:
il bet it is fella, only so much careful run-in one can do right. could be a number of lil things....................
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yeh well i mean it's done 800 odd miles now so thought it'd be run in, HG shouldn't let go anyway, unless head lifted, or both matingsurfaces weren't perfectly clean or it just got too damn hot with the comp and sitting on the drive revving with no air around it. hmm, tomorrow will tell.

gonna measure c/r properly too and see, there's an ebay seller selling 1.5mm cosworth gaskets so may go for one of those seeing as it'll be cheaper and quicker, unless my comp is uber uber high.

do valve seals while it's off too, check rings

hmmm
 
weeeeelllllllllllllllllllllllllllllllllllll

the headgasket that went.......didnt!! lololol. what a tit :tt2: so i dunno about the gurgling and water loss, cant work it out at all. before i loosened the headbolts i tried tightening them with the torque wrench to see if they were to spec, they all turned a tiniest smidge, but not sure if i set the torque wrench exactly the same...

P9080059.jpg


worse though is that it appears my piston rings may not have seated evenly and i think i have some ring end scratches down the bores slightly :( MAJOR FUCKED OFF, so could be expensive and take me a while to sort. but i need transprt too, anyone got a £50 shedican have or some old banger i can borrow lol????

here's some pics for the guru's, think i can just about feel the ring end scratches with my fingernail :(

cylinder 3

front wall

P9080062.jpg


cylinder 2 front wall,

P9080063.jpg


cylinder 3 back

P9080060.jpg


2 back

P9080061.jpg


so what we thinking boys, seems odd they'd wear unevenly but directly opposite on both? although the scratches from ring end gaps are obviously not good :(

best case is what? pistons out, a fresh DIY honing or by someone who'sgood at it preferably, then back in and see how we go?

I'd take it all out and do it right if i wasn't looking to work and travel in japan or south jorea in the new year, but ifeel pressed for time and ust want it to work....

on a positive the pistons look good which considering all the det jez was worried about is a positive

cheers
 
im gona be honest i wouldnt care about those slight amrks.. i bet they were done at first startup.. all cylinders have slight vertical marks.. what head gasket was that?
 
i wish el, that'll be my next build, a 23ve goin in a different car ;)


Raceworx said:
im gona be honest i wouldnt care about those slight amrks.. i bet they were done at first startup.. all cylinders have slight vertical marks.. what head gasket was that?
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no i dont think so either really, dunno though. i can only just feel the worse looking scratch with my finger nail and only for like 5-10mm of the scratch, more like 5 - so it doesn't give much chance for oil or blowby

what we think about the shiny patches runnin up the bores? uneven wear? you think i should whip the pistons out and get someone who knows to give ita diy hone?

also need to look at bores 1 and 4, i was defo geting blue smoke at high load and revs, could that be valve seals too or isnt that normally on cold start up?


EDIT: oops sorry ian it was a metal ve gasket off greg - looks fine still
 
mera red gti said:
i'd have contacted the engine builder, to voice your concerns before stripping anything
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lol, i built it :P

i knew something was up so stripped it, needed doing and i been thinkin bout a slightly thicker HG too. might measure my combustion chamber properly and work out my c/r for proper and can do valve seals too

all good fun innit lol
 
i tihnk most engines wear uneaven.. there not gona polish out the bores all at the same time youll get one bit start wearing first and as that goes it moves to the next high point..
 
Those marks look quite minor tbf..

Space your rings further away from the thrust surfaces next time though.

http://arrc.epnet.com/autoapp/9306CIR/chiltonimages/7000/7922AG05L.gif

Also, (i dont know if you did this before) clean and lube the bores with mineral oil when you assemble the block.
As Ian said, those scuffs were likely caused on initial start up.

If you want to lower your CR a bit, you're best option is to remove the pistons and get the dome shaved. Putting a thicker HG in is probably cheaper, and will work...but you will loose the effect of the quench pads on the pistons and head. Quench is supposed to improve the burn and reduce det.

And while the pistons are out, i'd also take the sharp edge off the piston valve reliefs. Sharp edges = Hot spots = DET
 
youve got me slightly worried as im going for even more compression in mine im using un modded SR16's 13.2:1 baby.. just whack more fuel in :P
 
You could of done the valve seals with the head still on. And was the coolant primed properley? I didn't know you had a 20V gasket, lifting the head would of been my last resort.
 
Dale said:
Those marks look quite minor tbf..

Space your rings further away from the thrust surfaces next time though.

http://arrc.epnet.com/autoapp/9306CIR/chiltonimages/7000/7922AG05L.gif

Also, (i dont know if you did this before) clean and lube the bores with mineral oil when you assemble the block.
As Ian said, those scuffs were likely caused on initial start up.

If you want to lower your CR a bit, you're best option is to remove the pistons and get the dome shaved. Putting a thicker HG in is probably cheaper, and will work...but you will loose the effect of the quench pads on the pistons and head. Quench is supposed to improve the burn and reduce det.

And while the pistons are out, i'd also take the sharp edge off the piston valve reliefs. Sharp edges = Hot spots = DET
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yeh i lubed the bores loads beforehand, and i spaced the rings to CPs instructions but i was reading earlier the rings move around loads at first?! lol

i know i should shave the pistons to do comp but i'm not bothered, i'm gonna use v power and some nf octane booster. i'm contemplating getting a 1.5mm cosworth gasket though....

Raceworx said:
youve got me slightly worried as im going for even more compression in mine im using un modded SR16's 13.2:1 baby.. just whack more fuel in :P
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and bore wash y0000


so what we saying then? i stripped it for no fucking reason whatsoever?? lol what about the burning oil at high rpm before istripped it, and apparently when letting off throttle jez said he noticed?

and the scratch i can just about feel with my fingernail for 5mm? nothing to be too fussed about?

could the shiny patches directly opposite at either side of the walls be from the piston skirts? somehow?!
 
GTi kurt said:
You could of done the valve seals with the head still on. And was the coolant primed properley? I didn't know you had a 20V gasket, lifting the head would of been my last resort.
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20v gasket? that same as the ve metal gasket you mean? yeh opted against the cometic

yeh i bled the coolant with the cap off, topping it up if thats what you mean, fans wouldn't come on after ages but that happened on my mera too so didn't worry once the level stopped dropping.

i know i was hastey but i knew something wasn't right, and was already thinking of the cosworth gasket. also was interested in seeing the condition of the pistons after all the det. easier to dovalve seals this way for me too without a compressor and stuff
 
What was the piston to wall clearance when you had the block honed?

Forged pistons expand more so you should run a looser piston2wall clearance.
 
Dale said:
What was the piston to wall clearance when you had the block honed?

Forged pistons expand more so you should run a looser piston2wall clearance.
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dunno, the machine shop honed it, fitted the rings and gudgeon pins for me, and said measurements were good to go, ie piston/wall

i trusted them...

its the oil burning i'm bothered about, my good comp test doesn't show the oil ring condition does it

it does make sense tthat my valve seals could have deteriorated in the at least a year the head was sat in a cold damp box in my shed...
 
could you hear any slight rattle when it was cold dude?

blue smoke im guessing would be normal due to the forged pistons not hot enough to seal the rings against the bores
depends what your wall clearances were

Steve

EDIT: when did you test the compression?
 
steve55 said:
could you hear any slight rattle when it was cold dude?

blue smoke im guessing would be normal due to the forged pistons not hot enough to seal the rings against the bores
depends what your wall clearances were

Steve

EDIT: when did you test the compression?
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what kinda rattle? not really i don't think

tested the comp a few times, latest just after the bubbling coolant, when it was hot. all have been around 250psi
 
craiGTi said:
what kinda rattle? not really i don't think

tested the comp a few times, latest just after the bubbling coolant, when it was hot. all have been around 250psi
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my thoughts would be the piston to cylinder wall clearance is too low, meaning they are too close to each other, therefore high compression readings when hot, as the forged piston expands and creates an even TIGHTER seal, but then that wouldnt explain the oil burning :(

Steve
 
steve55 said:
my thoughts would be the piston to cylinder wall clearance is too low, meaning they are too close to each other, therefore high compression readings when hot, as the forged piston expands and creates an even TIGHTER seal, but then that wouldnt explain the oil burning :(

Steve
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but surely the expansion of the piston itself woldn't affect compression? the rings will stay as they are just closer to the piston if you see what i mean

rowdy-GTi said:
What torque did you set the ARPs to?
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104 lb/ft iirc
 
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