hi there I have a question please.

I recently bought a 300zx dooer upper, guy i got it from says he had it looked at, they said it was the nearside turbo, I have only run the engine very breifly and it ran sweet but chucking lots of whitish smoke out at the drivers . I took out the plugs and compression tested each bore, each was bang on 100 so dont think there is a gasket problem, and the plugs on the driver side looked good (nice brown / biscuity) and the plugs on the nearside were all oiled up.

by now i was convinced it was the nearside turbo but on dropping the intercoolers the nearside (suposed bad one) and it was very clean, on dropping the drivers side that one was full of engine oil!!! so now i am confused.

 

Can both turbos be done without taking the engine out?

andy

xx\

any help / load of spanners etc would be much appreciated, lol

100 PSi per cylinder ?That's way down. Ideally should be up near 160....suprised your is running TBH. Try another gauge.

 

Oil in the intercoolers hints at blowback through the manifold. Poor breathing due to buggered PCV valves or worse, knackerd pistons/rings.

take a look at your plenum bud... from the nearside tub it goes to the nearside intercooler, then in the nearside of the plenum, BUT, the design of the plenum is that the inlets cross over into the opposite bank (offside)...

 

therefore, if your neasid tub is buggered, your offside would smoke first :)

 

btw.... 100 psi is very low on the compression chap :confused:

With 100psi compression i think you should be looking at fitting a set of rings or getting a replacement engine, thats very low for one of these engines, the manual states a minimum of 142psi

 

Baz

unless your inspector gadget with some special and rather odd tooling, you cant change both tubs with engine in :(

take a look at your plenum bud... from the nearside tub it goes to the nearside intercooler, then in the nearside of the plenum, BUT, the design of the plenum is that the inlets cross over into the opposite bank (offside)...

 

therefore, if your neasid tub is buggered, your offside would smoke first :)

 

 

Well surely that would depend on where the turbo is leaking oil. If it goes straight down the exhaust then it would be on the same side.

yeah i thought 100 was low too but, the engine aint been run for nearly a year and when i started her up she fired up on the first turn of the key, maybe it would improve after a decent run, dare not do that tho till i sort out which turbo has gone.

 

Andy

IMHO, you should see what's wrong with the compression. A good run won't really improve anything to much of a degree

Can't imagine that ALL 6 cylinders are that bad and also it still starts easily. Sounds like a dodgy guage to me. I wouldn't be quick to start stripping it down.

Well surely that would depend on where the turbo is leaking oil. If it goes straight down the exhaust then it would be on the same side.

fair point, but he was referring to oil in the intercooler pipework :) just making sure he was aware that they crossed over

lol and its very true that i hadent noticed that it crossed over, lol, next time i look at it i will ware my glasses promise.

 

Andy

test again with a different gauge, if the compression really is that low, then then the rings are shot completely, the air will be blowing straight past. quite strange for the comp. to be down on all cylinders though, if that is the case then you'll most probably have to have the engine out.

If your n/s turbo is dying then Ive got a good un you can have and Im just down the road from ya too it would seem ;)

what psi are you boosting at?

It looks to me like your gauge just needs calibrating mate. Its almost impossible that every cylinder would be down by the same amount. I've used different compression testers and had huge differences like that on the same engine. I'd either get a known good tester, or try the tester on a different engine to check it.

Sounds more likely to be your turbo as you suggested to me. Check the return hoses on the bottom of the turbo as if they are kinked they can also back oil up and out the exhaust (not sure if this happens much on Zeds though).

The nearside can be removed with the engine in-situ if you've got hands and arms like ET but its probably quicker to remove the engine, and definately advisable to replace ALL the hoses around the back of the engine (turbo coolant ones in particular as this one is a b*gger to get to and is probe to going).

yeah royal i must admit thats what i thought, i was more pleased that they were all the same and no major differences between them. i havent got hands like ET but i have a son, lol he is eager i will let him have a go, not convinced now it is nearside tho as the all the n/s intake hoses were clean and nothing in the intercooler, (and o/s plugs were clean) however the o/s intake hoses had lots of oil in them and the o/s intercooler had loads of oil in it, (also the n/s plugs were very oily) does this make sence? lol not sure it does to me. if GaiJin has a n/s turbo anyhow and it can be swapped without taking engine out, is it worth trying it? the PO said that a garrage had told him it was the n/s turbo,

as for the boost Carlz i have no idea i bought it end of last week as a project, so have never had it on the road yet.

 

Appreciate all your help thus far if i am in wath GaiJin how far are you away?

 

Andy

Well surely that would depend on where the turbo is leaking oil. If it goes straight down the exhaust then it would be on the same side

 

But he said the plugs were oiled. If it goes straight down the exhaust then the plugs would be OK

however the o/s intake hoses had lots of oil in them and the o/s intercooler had loads of oil in it, (also the n/s plugs were very oily) does this make sence?

 

Yes. It's the o/s turbo.

Hi Andy, hope you get her sorted, if I can help in any way lemme know...Im not mega technically capable but have owned my car for a good while and can offer some help & bits n bobs to try/replace when fault diagnosing...as you will likely have to at some stage, all part of the joy of owning a Z :D

 

btw Im at Brinsworth

 

John

thanks very much john, nice to know someone will share my pain, lol, could you drop me your details on my email which is brian@rich-tec.co.uk and i will give you a shout

 

thanks again