Craigs New Datsun Sunny
- Thread starter craiGTi
- Start date
thats not what my instructions said i'm sure of it, i'll check on them in the morning.
only thing i didn't do was retorque them after heat cycle. but it didn't let go anyway
had a chat with my mates bout this ...
basically saying, either piston doesnt match piston ring, ie too big for ring
or, gudgeon pins arent correctly connected into piston, would explain the play in the piston, scouring, and oil burning, but as i said, there should be a rattle :zoidberg: maybe very slight, looking at how deep the score is
honestly dont see how tight the head is on makes a difference, maybe oil can seep through? can you explain rowdy?
nline2long: plus wouldnt you see evidence of oil leaking around head to block gap?
Steve
basically saying, either piston doesnt match piston ring, ie too big for ring
or, gudgeon pins arent correctly connected into piston, would explain the play in the piston, scouring, and oil burning, but as i said, there should be a rattle :zoidberg: maybe very slight, looking at how deep the score is
honestly dont see how tight the head is on makes a difference, maybe oil can seep through? can you explain rowdy?
nline2long: plus wouldnt you see evidence of oil leaking around head to block gap?Steve
had a chat with my mates bout this ...
basically saying, either piston doesnt match piston ring, ie too big for ring
or, gudgeon pins arent correctly connected into piston, would explain the play in the piston, scouring, and oil burning, but as i said, there should be a rattle :zoidberg: maybe very slight, looking at how deep the score is
honestly dont see how tight the head is on makes a difference, maybe oil can seep through? can you explain rowdy?
Steve
hmmm, don't hear a rattle and really don't think it's any kind of piston slap, and even if the piston was loose in there the rings are whats sealing it, the pistons just carry the rings. I think the sscratch is just a ring end on first start up as ian said, the polishing of the cross hatchin i'm not sure about or how severe or important it really is
i think rowdy's mentioning the head bolt torques re. me thinking the HG had popped or head lifted and the water issue i had
was mapped on road due to unforeseen circumstances, is way down from where it should be due to detonation jez was hearing so timing is backed way off. i'm goin back with my clutch thing sorted, hopefully oil issue sorted with valve seals, and possibly a thicker HG, some v power and octane booster or toluene in the tank. Next time will be on dyno with no det fingers crossed.
S
sr20bud
Guest
i doubt the head would lift at that much torque of the bolts mate 2 secs i have a fsm
S
sr20bud
Guest
ffs i cant find my fsm but i found this http://www.gtirworkshopmanual.com/default.aspx?v=207 should be the same for the vvl i think plus check yours anyway
S
sr20bud
Guest
strange no leaks? i know i have noticed with nissans ga's sr20's and the diesels if you pull the rad cap off after a few miles when shes cooled the water level sinks and it looks like you need to top up then you do and it takes half a liter ish then its ok for a bit im not sure why this is but be careful cause this happened on my gti n14 and when i pulled the head off there was a massive gouge between the head and block mating surface on the bore wall top. is it missing at all even a hint of a missfire?
I agree it could have been an air lock. Were your heaters in the car blowing hot? We've had them at work before coming back after a few days for a top-up of coolant.
Definitely not a water leak? Like from the pipes at the back of the engine?
i thought airlock but id bled it for ages with the rad cap off, heaters on, and like spook said did hundreds ofmiles and it was fine
havent seen a water leak corbs but it needs checking thoroughly
and i definitely saw no steam, i didn't see much smoke either tbh, jez said he saw some on overrun into bends, i saw some what looked blueish, black smoke at high rpm but my lambda had worked itself unplugged so it couldabeen a bit rich too.
anyway, smoke wise, valve seals make sense cos the head was sat for a year at least in the cold damp shed so the rubber coulda perished.
Main thing, what do people think i should do now - speakin to ross last night i was saying about removing the pistons fora fresh hone hopefully removing those scuffs, he said just do the valve seals, put it all back together and see what happens...
Lastly, what oil would people think i should use? i riginally went with fully synthetic 5w 40, butis 5w a bit thin? or would semi synth help oil usage?
havent seen a water leak corbs but it needs checking thoroughly
and i definitely saw no steam, i didn't see much smoke either tbh, jez said he saw some on overrun into bends, i saw some what looked blueish, black smoke at high rpm but my lambda had worked itself unplugged so it couldabeen a bit rich too.
anyway, smoke wise, valve seals make sense cos the head was sat for a year at least in the cold damp shed so the rubber coulda perished.
Main thing, what do people think i should do now - speakin to ross last night i was saying about removing the pistons fora fresh hone hopefully removing those scuffs, he said just do the valve seals, put it all back together and see what happens...
Lastly, what oil would people think i should use? i riginally went with fully synthetic 5w 40, butis 5w a bit thin? or would semi synth help oil usage?
Heres what i would do: (because i dont know what clearances you are running)
Remove the pistons and inspect for further vertical scoring on the pistons and get the crowns cleaned
Measure the bore (near BDC should be the smallest so this is what P2W clearance should based on)
Measure the pistons
Check P2W is in spec for your Piston (If it isnt, then get the cylinders bored to correct spec)
Check Ring end gaps are within spec ( If they arent, file them until they are)
Re-hone block
Install new rings on pistons
Send head away for pressure testing and skim
Check Valve guides for wear/play
Replace stem seals
Replace HG
Since you said you cleaned and coated the bores in oil on assembly..I can only suspect those minor marks have been caused by running an ever so slightly too tight P2W clearance and ring gap. Essentially even just a fresh hone should bring your P2W to a level that it wont scuff.
Whether its the pistons themselves, or your rings butting together and causing them marks really depends on where your ring end gaps are located when you installed them.
I didnt build it so i dont know mate, im just trying to cover all the aspects... maybe you should get an opinion from an engine builder about those vertical marks and shiny spots before proceeding further.
BUT if you dont want to delve into what caused those marks on the cylinder walls:
Check Valve guides for wear/play
Send head away for pressure testing and re-surface
Replace stem seals
Replace HG
Clean Piston crowns
Remove the pistons and inspect for further vertical scoring on the pistons and get the crowns cleaned
Measure the bore (near BDC should be the smallest so this is what P2W clearance should based on)
Measure the pistons
Check P2W is in spec for your Piston (If it isnt, then get the cylinders bored to correct spec)
Check Ring end gaps are within spec ( If they arent, file them until they are)
Re-hone block
Install new rings on pistons
Send head away for pressure testing and skim
Check Valve guides for wear/play
Replace stem seals
Replace HG
Since you said you cleaned and coated the bores in oil on assembly..I can only suspect those minor marks have been caused by running an ever so slightly too tight P2W clearance and ring gap. Essentially even just a fresh hone should bring your P2W to a level that it wont scuff.
Whether its the pistons themselves, or your rings butting together and causing them marks really depends on where your ring end gaps are located when you installed them.
I didnt build it so i dont know mate, im just trying to cover all the aspects... maybe you should get an opinion from an engine builder about those vertical marks and shiny spots before proceeding further.
BUT if you dont want to delve into what caused those marks on the cylinder walls:
Check Valve guides for wear/play
Send head away for pressure testing and re-surface
Replace stem seals
Replace HG
Clean Piston crowns
hmmmm
the ring end gaps i checked and all were ok
and the p2w was supposedly done by the engine shop when they honed it and fitting the rings and pistons to rods for me
the ring end gaps on the back wall were about there and correspond, but the ring gaps round the front weren't so it does seem to correspond with the piston skirts
hmmmm
EDIT:
just had a proper look in daylight and theres a fair few small vertical marks around where the ring ends would be and where the cross hatching has been polished a bit. It looks a lot to me like purely ring ends, but i checked the gaps and it doesnt really add up thatif it was too small a clearance on those it'd be the top of the bore where it was worse does it.
Also very much doubt it's the piston skirts as the polished areas go higher than the skirts would reach.
AS ian said i'm hoping/thinking it was just the ring ends on the initial startup. Maybe i didn't have the bores as dripping with oil as they should be
the ring end gaps i checked and all were ok
and the p2w was supposedly done by the engine shop when they honed it and fitting the rings and pistons to rods for me
the ring end gaps on the back wall were about there and correspond, but the ring gaps round the front weren't so it does seem to correspond with the piston skirts
hmmmm
EDIT:
just had a proper look in daylight and theres a fair few small vertical marks around where the ring ends would be and where the cross hatching has been polished a bit. It looks a lot to me like purely ring ends, but i checked the gaps and it doesnt really add up thatif it was too small a clearance on those it'd be the top of the bore where it was worse does it.
Also very much doubt it's the piston skirts as the polished areas go higher than the skirts would reach.
AS ian said i'm hoping/thinking it was just the ring ends on the initial startup. Maybe i didn't have the bores as dripping with oil as they should be
but i don't see how a too tight p2w would cause oil burning, if the rings had butted together they'd most likely cause a lot more damage than this.
out of interest i just looked at my fisher price engine build thread for pics of the blocks i had when i first stripped them...
they are the bores of a p11 gt block having just been stripped - first time it'd been opened since it'd done like 100k odd after leaving the nissan factory...looks very similar in terms of position of the polished areas and vertical marks, but probably worse than mine
out of interest i just looked at my fisher price engine build thread for pics of the blocks i had when i first stripped them...
they are the bores of a p11 gt block having just been stripped - first time it'd been opened since it'd done like 100k odd after leaving the nissan factory...looks very similar in terms of position of the polished areas and vertical marks, but probably worse than mine