TB42 (On gas) blowing some smoke :(

Post by **Jimbo** » Sun Dec 30, 2007 5:55 pm

I went away yesterday for a camping trip and because i run a fridge and dont run 2 batt i start the car later on in the night and let the battery charge up.
Anyway i had the motor reving at about 1200-1400rpm for around 10 mins when my g/f jumped in the drivers seat and gave the throttle a few bleeps and thats when i saw blue smoke come out and could smell the burnt oil. I have no idea how long this has been happening but its the first time i noticed.

I just did an oil and filter change last week and used the same oil as usual Penrite HPR15.

Can anyone tell me what they think the problem is? Rings? Valve guides?
Should i try a different oil? Additve?

The head was replaced 50,000km ago by the previous owner after it cracked

Cheers

JIMMY

Post by **mikmav** » Sun Dec 30, 2007 6:31 pm

I'm no expert.. but I'd say valve stems..

Post by **BowTieGQ** » Sun Dec 30, 2007 7:36 pm

Valve stem seals. The vacuum sucks the oil down them into cylinder. Head time. Welcome to the club.

Post by **Jimbo** » Sun Dec 30, 2007 7:38 pm

Ok...any reason why this has happend so soon after top end rebuild?

Post by **BowTieGQ** » Sun Dec 30, 2007 7:46 pm

Not inserted correctly or damaged. Take it back and ask them to take a look.

Post by **Jimbo** » Sun Dec 30, 2007 7:58 pm

It was done 10,000km before i bought the car.

Post by **Jimbo** » Tue Jan 01, 2008 4:11 pm

Well i haven't been able to get it to blow smoke again!! I have repeated what i did while camping and also checked if it blows smoke on start up inthe morning and so far nothing.

Post by **tweak'e** » Tue Jan 01, 2008 4:39 pm

i wonder if you got a bit of oil up through the breather, mayby a sticky breather valve.

Post by **love ke70** » Tue Jan 01, 2008 5:45 pm

how long had the car been sitting for since last being started?

having run for 10 minutes thats a bit late for vss really, they are usually characterised by oil on startup. i woulda said rings.
compression test it and see what you get.

if its stopped smoking now though, and if it had been sitting perhaps for a few weeks you could ahve had a few dry vss that have softened themselves up again...

Post by **Jimbo** » Tue Jan 01, 2008 7:32 pm

When it blew smoke the car had been sitting for around 3 to 4 hours.

I have been running hpr15....do you think next oil change i should run something different like Hpr 30??

Post by **love ke70** » Tue Jan 01, 2008 7:45 pm

HPR 15 is 15 w 50 isnt it?

thats quite thick, i dont know if going to 30 will be beneficial or not to be honest...

Post by **Sterlo** » Tue Jan 01, 2008 9:03 pm

It could be rings. It is most common for oil to come up past the rings at a constant non loaded speed. Then as soon as you give it a bit the accumulated oil burns off.

Valve stem seals are more evident when going down a hill with no throttle then hitting it at the bottom you will get a puff of blue smoke that doesnt last long. Or like you stated it smokes atfer sitting for a while.

Sterlo

Post by **christo400** » Tue Jan 01, 2008 10:40 pm

Hey Jimbo - just a thought have you got an upper cylinder lube kit fitted ?
if so check to see if it is metering properly they will blow smoke if flow rate is too high !!

Post by **tna racing** » Tue Jan 01, 2008 11:04 pm

christo400 wrote:Hey Jimbo - just a thought have you got an upper cylinder lube kit fitted ?
if so check to see if it is metering properly they will blow smoke if flow rate is too high !!

x2 on that, and if you dont have one, i would buy one

Post by **Jimbo** » Wed Jan 02, 2008 7:27 am

Thanks for the replies. I think i will have to keep an eye on it.

I dont have a lube kit fitted, are they worth it? Do they actually do anything.

Cheers

Post by **tna racing** » Wed Jan 02, 2008 9:28 am

flash lube, it lubes the valves and so on,becuase gas is such a dry substance, it dry's every thing out

Post by **PGS 4WD** » Wed Jan 02, 2008 7:34 pm

Forget the lash lube, make sure the tune is correct. Incorrect mixtures cause high combustion temps that burn valves. Keep you valves set correctly and make sure the mixture and tune are OK. If you idle any car with an older engine at 1200 rpm for 10 minutes you are likely to get some smoke, the high vacuum draws oil past the seals and guides, if you are not using any more than 2 litres per 10 000 klms don't worry about it.

Joel

Post by **frby69** » Wed Jan 02, 2008 7:58 pm

i run a gq 4.2 carb on gas all you need to do for upper lube is flick it oce to petrol once a week for a few km's a week i live on the gold coast and work in brisbane so once a week i run petrol on way home for around 10 km's i's all that s need if really concernd start it on petrol first thing every morning to warm it up then flick over before taking of

Post by **frby69** » Wed Jan 02, 2008 8:00 pm

frby69 wrote:i run a gq 4.2 carb on gas all you need to do for upper lube is flick it oce to petrol once a week for a few km's a week i live on the gold coast and work in brisbane so once a week i run petrol on way home for around 10 km's i's all that s need if really concernd start it on petrol first thing every morning to warm it up then flick over before taking of

morning warmup will use around 5-10 ltrs of petrol depending on how long you run on petrol for per week

Post by **Jimbo** » Wed Jan 02, 2008 8:55 pm

Thanks for that. My patrol has never really used any oil at all between oil changes. I tend to run it on petrol every day for a couple of mins on startup.

I had it tuned around 30,000km ago but have not gone for another tune as my km have not changed at all and everything seems to be running as good as ever.

Hey Joel what oil rating thingy do you think i should be running for an engine with 270,000km??

Cheers

Post by **PGS 4WD** » Thu Jan 03, 2008 7:42 am

Tappets should be checked and adjusted every 20 000klms on LPG, exhausts I set at .040 not .038 as the additional heat from LPG combustion causes the exhaust valve to grow and not seat, this is where the valve wear comes from.
I use 20w-50 in large capacity, big bore and old styyle pushrod engines and 10w-30 in late model multivalve engines unless a particular oil is specified like some Nissans of the late 90's that needed 5w-30 or the valve train oilers blocked up.
All engine use some oil, petrol cars dilute the oil with unbunt fuel that passes the rings on cold running (called dillution) and this gives the appearance that no oil is being used. Many people are under the impression that LPG engines use more oil than petrol, this is untrue, LPG being a vapour doesn't dillute the oil so the level drops as some oil is consumed, it is not being topped up with fuel. This is also why a vehicle that appears to use no fuel in regular driving around town may suddenly use a lot of oil on a long trip, the oil temperature gets hot enough to cause all the dilluted fuel to evaporate out.

Joel

Post by **Jimbo** » Thu Jan 03, 2008 8:35 am

Thnks for that. I adjusted the valves around 10,000km ago.

cheers
jimmy

Post by **MyGQ** » Fri Jan 04, 2008 2:23 pm

I ran 5W-50 in my Dual Fuel Maverick and it was perfect, no oil usage or nothing

When i first got it, i ran Shell Helix Gas in it, 15-40, burnt it cause its too thin, Patrols in petrol require 20W-50 according to the book.

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TB42 (On gas) blowing some smoke :(

TB42 (On gas) blowing some smoke :(

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