Burnt Valve + Oil On Valves? (update)

[1400r]

cost to fix guesses to if possible ?

pulling the engine apart today to get the head faced ready for Tomei H/G saw this

I have limited Tech knowledge when it comes to engines and these sorta things

someone told me that the cyclinder may have just not been running right i.e coil pack issue or something

Edited September 8, 2007 by 1400r

[benl1981]

is that just soot or a shandow? and isnt that where the exh manifold bolts up. Probably just a leaky gasket casued that!

[1400r]

looks to be burnt oil the other openings are very clean

"burnt" one the other pic is how all the others are

sorry there not in focus camera's playing up

Edited September 3, 2007 by 1400r

[RB30-POWER]

check valve stem seals for those valves

[rob82]

looks to be burnt oil the other openings are very clean

"burnt" one the other pic is how all the others are

sorry there not in focus camera's playing up

You must be a photographer!!!

[Simon-S14]

may as well chuck a set of new valve stem seals in while the heads off, from the first pic it looks like it had a manifold gasket leak out the side, which would not indicate any valve damage.

but yes, do the stem seals and check the valves and seats out that chamber that looks sus for any damage. If you do then a reseat might be needed./

[1400r]

Well just had the V8/truck engine builder from the shop next door tell me he thinks the rings are shot in my motor

due to the amount of oil covering the valves

he said if it was him he would through in a set of rings and bearings and maybe linish(sp) the crank if it needs it

he also didnt like the look of the oil on number 1 valve either

yippee

my bosses business partners are happy to through in above items in for me

just wondering if I should put in a little extra cash for better bearings or rings than standard Nissan items?

Im leaning towards ACl race bearings but Im not sure on the extra cost seeing as were I work will have to foot the bill for the repairs

I would love to go forge bottom end but I dont think the budget will stretch that far and I dont want to complicate this for the guys putting together the motor for

me seeing as they mainly work on commerical vehicles

plans are to skid the motor already have h/g for it one hoping to make 280rwkw out of it but for now standardish power

Edited September 8, 2007 by 1400r

[T04GTR]

she does look pretty sad.

hows the bores. any scratches? how was it running prior to pulling it down? and was it smoky? there is a lot of oil in all the cylinders from the look of things. did you do a comp test?

doesnt look like a burnt valve. more like 300000k old motor gunk build up.

[1400r]

nice thanks that makes it worse lol

just bought the motor s/h so no idea on how it was running

engine builder said the bores looked ok probably just need a hone

unfortunately a mate cleaned the bottomend before the engine builder had a chance to look at it

but he did the push on the piston left to right thing and you could seen the oil moving around the rings

[T04GTR]

pull the pistons out and have a look see. (10min job now the heads off)

[T04GTR]

nissan rings are the best. bearings are all much the same so long as the clearances are ok. ie 2-2.5 thou on the mains and 1.5-1.7 thou on the bigends.

standard pistons with 1.3-1.8 thou piston to bore clearance.

from the sounds of it its got busted ringlands. but pull the pistons out and have a look.

[Cubes]

1400r,

Out of curiosity have you been running that united 10% ethanol fuel?

[Duncan]

ACL bearings will be cheaper and better than nissan ones, and they do cheap forged pistons too.....might as well do it all now its apart

[1400r]

got the motor s/h through my work so doubt it was running ethanol in Japan

I like to do forgies but will see dont want to over complicate things for the engine builders and it may be asking a bit much

of them to put it together for me

seeing as its only a free freshin up job

[Duncan]

mate, putting forgies will make the job easier.

when you put second hand pistons back in, there will be 6 different pistons, and 6 different bores, all with different wear. If you put new forgies in you get much easier and more consistent clearances

[Cubes]

Reason I asked is recently I pulled the head off mine. no oil in the inlet ports, exhaust ports just a light soot over them.

Bores perfect, no scuffing or glazing.

The combustion chambers and pistons were clean, inlet valves clean but the exhaust valves where a slight tan colour.

I was told it was due to myself driving soft and the car tuned fairly lean (due to ethanol I was running and pushing 10.5-11litres per hundred), the same thing was asked of myself.. Did I run ethanol.

My initial thoughts were possibly oil but was told yes it can be caused by oil but if it were oil everything would be as dirty as crap.