hi can anybody help

ive rebuilt a engine tt

with acl race bearings

npr rings

honed out bores

uprated turbos (new)

660 injectors

lapped in valves

full engine gasket set.

ive been running it in for around 700miles now and its started to smoke,

it only smokes when its in park and you rev the engine,

it seems ok when driving though and ok on tickover

 

i have put the datascan on and have no faults

also taken off egr and blanked them off

tryed new maf

new aav

new plugs

tested compression

etc etc

and still cant figure it out

can anbody help please

Over fueling maybe?? Have you had it set-up

What chip are you running that set up on?

yes i am overfueling slightly but was set that way.

chip been done to spec by john dixon, but would this cause blue smoke i thought if anything it would be black if it was fuel

sorry forgot to say it was blue smoke

i know of a few people after doing a rebuild having oil in the exhaust, takes ages to burn off causing smoke?

 

might be worth doing a compression test to make sure everything is sealed on the bottom end?

Is it decated??

 

Jeff

done a compression test and all ok

and it didnt smoke untill id done around 700 miles then it started

thats why im banging my head against a wall lol

cheers

yes been decated

You running stock pistons with new rings i take it,you inspect the old pistons carefully for cracks?

You running stock pistons with new rings i take it,you inspect the old pistons carefully for cracks?

 

You thinking along the lines of they wont be sealing properly and letting gasses past the rings?

 

Wouldnt a compression test confirm if they're leaking?

You thinking along the lines of they wont be sealing properly and letting gasses past the rings?

 

Wouldnt a compression test confirm if they're leaking?

 

A leak down test is a better way of diagnosing ring / valve issues.

 

Jeff TT

A leak down test is a better way of diagnosing ring / valve issues.

 

Jeff TT

 

Noted. Cheers bud :duffer:

^^^totally agree. Leak down tests are way more accurate than compression tests and help to isolate the cause more effectively.As the old pistons have been re used it makes me doubt them.Im also not an advocate of lapped valves on engines with new rings or pistons.They will never seal good enough to withstand the higher combustion pressures.Especially the exhaust valves,They get such a hammering and the seats pit badly i dont see how you could ever lap one back in.The only cure i find is to have the seats and faces re cut.

cheers for that will look into that leak down test

You have not mentioned the PCV valves, were they changed......??

yes ive also run car without them connected and no change

Good call Jimmer, it is difficult to diagnose a cracked piston land with a compression test, I haven't heard of NPR rings, do they have any rep with 300ZX's, does is smoke on acceleration or overrun?

 

On a tangent did you reconnect all the breather hoses with the correct restrictors in the right place?