Vacuum leak test results on GQ RB30 Patrol

[mudnut]

How did you go with this;
http://www.nissanpatrol.com.au/forum...ght=rb30+carby

Have you tested the vacuum advance,
choke break and pre-heat diaphragms
for holes or splits?

If it was me, at this point I would look at
all of the simple stuff first. I would make
sure all of the ignition components are
in excellent condition. I would then tune
it to run on petrol fuel first, to eliminate
any problems, before trying to get a
compromise for both fuels.

[dom14]

How did you go with this;
http://www.nissanpatrol.com.au/forum...ght=rb30+carby

Have you tested the vacuum advance,
choke break and pre-heat diaphragms
for holes or splits?

If it was me, at this point I would look at
all of the simple stuff first. I would make
sure all of the ignition components are
in excellent condition. I would then tune
it to run on petrol fuel first, to eliminate
any problems, before trying to get a
compromise for both fuels.

I rebuilt the carby back then. I have cleaned the carby couple of times ever since.
When you say pre-heat diaphragms, I' guessing you are referring to heater at the bottom compartment of the carby?
electric auto choke is(was) working fine.
I need to double check again.
Vacuum advance confuses me.
Sometime it appears to be working ok.
Other time it isn't.
Let me follow the procedure from the manual and test it again.
I'm suspecting an electrical issue(pretty sure) as well.
LPG related I think. The blown fuse(as in my previous post) was for a reason, and I still don't know the reason.
I started cleaning and replacing earth connections and rewiring the bad ones.
I bought conduits from Jaycar to replace the old dodgy LPG wiring.

I totally agree with you about the simple approach.
It's quite possible I'm missing out something basic here.
ignition coil, leads, spark plugs are ok.
Distributor and the points I'm not so sure.
Vacuum advance I'm also not sure.
I also did the "Brake booster test" as pointed out by the Haynes manual, and apparently vehicle brake system failed it.
I'm hoping to start another thread for that.
And of course, focus on one fuel type(petrol) to start with.
When I was doing the carby I was told that it's not possible to fine tune a carby for both petrol and LPG at the same time.
Some sort of ignition adjustment unit is necessary.
It's available from a place in Campbellfield(They are made in US).
I didn't buy it. I decided to put up with the different quirks of power & other engine behaviour between LPG and petrol(by manually adjusting the ignition timing when
necessary).
I was advised by "Altis(George)" to go for the EFI conversion. Still haven't got around to do it. I thought keeping a backup carby will do for the time being, while
I'm hunting for EFI+turbo gear.

I think carby's are old school technology for the most of the techies out there.
They prefer not to do deal with, while few new generation old schoolers like me still sticking with it.

Thanx mate.

[mudnut]

The pre-heat flap on the intake switches the
air from the normal intake to the "stove pipe'
which draws warm air from the exhaust
manifold during a cold start.

If you do go for the EFI, I may be interested
in buying one of your carbies. I believe simple is
best in the bush, and I would rather carry
a carbie than a whole swag of
delicate components.

[dom14]

The pre-heat flap on the intake switches the
air from the normal intake to the "stove pipe'
which draws warm air from the exhaust
manifold during a cold start.

Are you referring to a pre-heat flap in the carby or in the air box?

If you have a look at pictures, you might notice that I have removed the 'snorkel pipe bit',
as well as the foil pipe that connect the warm air from the exhaust manifold to the air filter air intake(via the 'snorkel pipe bit').
I was told a quite a while ago, the warm air intake from the exhaust to the intake pipe is not required in Melbourne climate.
The foil pipe bit that connects the exhaust hot air to the intake pipe was badly tarnished anyway.
Since you mentioned, I might connect the hole thing again and see how it goes.
I will have to buy the alluminium foil pipe bit. The rest is in the garage somewhere.
I know, it's useful during the cold winters(like right now)
From memory, I removed it years ago, when the engine was coughing a fair bit during red hot summer days.
Also, part of the rubber flexi hose bit on the snorkel pipe bit was gone out of shape from the heat over time.
So, i probably need to wrap it with heat resistant duct tape for the time being.

If you do go for the EFI, I may be interested
in buying one of your carbies. I believe simple is
best in the bush, and I would rather carry
a carbie than a whole swag of
delicate components.

I will be going for EFI as well as turbo at some stage. I can't see myself doing it this year until pretty late this year.
You don't want my backup carby. I paid $100 for it and put a kit through as well, and still idling at around 2000 rpm like crxp.
I haven't had a chance to tear it apart and fix it. I think I know where the problem is(some of the throttle butterfly shafts may be
jamming, as I was pointed out to by one of the blokes here).
Running carby is ok. I've done careful work on it with patience(yet still not like a brand new one).

Altis(George) advised me to ditch the carby and go for EFI, so I won't have to bother about tuning for petrol and LPG all the time,
as well as having to do the carby from time to time.
But, there's a $120 solution for that, which adjust the ignition time(I haven't bothered to fit it in)
I'm trying to find the link for that unit, 'cos it was couple of years ago I was onto it, and then gave up.

Most pro mechanics don't like carbies anymore. I still like them for some weird reason.
One reason is as you pointed out is the simplicity, and the ability to carry another one, rather than carrying a whole lot electronic components.
There's no power or fuel economy advantage from EFI, AFAIK.
Turbo to work properly, it needs EFI AFAIK.
I'm also considering sequential injection for the LPG, which would improve the LPG fuel economy as well as possible power increase.
But, I would have to buy it brand new and fit it myself.
It's available on ebay from China, though need some homework to locate a perfectly compatible one.

[mudnut]

If I had an extra carby, I would
hand it to a mate who dynotunes
race cars. He tuned my RB30 to
perfection after cleaning and
whacking a kit into the carby.
I refitted the pre heat and stove
pipe as the carby really struggles
in the cold, after I had to remove
the heater grid at the base.
The grid was crumbling and dropping
bits into the engine. Also it is
a requirement for a roadworthy that
the stove pipe is fitted.

[dom14]

If I had an extra carby, I would
hand it to a mate who dynotunes
race cars. He tuned my RB30 to
perfection after cleaning and
whacking a kit into the carby.
I refitted the pre heat and stove
pipe as the carby really struggles
in the cold, after I had to remove
the heater grid at the base.
The grid was crumbling and dropping
bits into the engine. Also it is
a requirement for a roadworthy that
the stove pipe is fitted.

Hmmm. I reckon it's upto the individual RWC tester. It can be argued as a fuel emission control related thing.
I'll give another go at the second carby soon and if I can't fix it, I'll take it to dyno tuning.

I need to fix the stove pipe and pre heat pipe tomorrow and see how it goes.
At the moment, after a bit of playing this late arvo in the dark, it's running smoothly with extra power that I can feel.
This happened after I "fiddled" with the distributor vacuum line and the charcoal canister vacuum lines.
Have a look at the pictures and the description and let me know what you think.
Thanks mate.

P.S. I don't know the reason for it's running smoothly now. The charcoal canister vacuum lines are blocked now.
I like to think that's not the reason it's running smoothly now.
When I first removed it(two vacuum lines) and blocked them the engine didn't start.
The second time I did that after fiddling with the distributor vacuum line, the engine started
Weird behaviour and probably not related to my fiddling with the vacuum lines??!!!

[mudnut]

Have the hoses gone brittle
and are letting air into the joins?
I have only just replaced the
air cleaner to tappet cover
hose as it had gone hard
and wasn't sealing properly.

[dom14]

Have the hoses gone brittle
and are letting air into the joins?
I have only just replaced the
air cleaner to tappet cover
hose as it had gone hard
and wasn't sealing properly.

Nope. I'm pretty sure they are in good nick.
During my above smoke test they didn't leak any smoke.
And didn't do anything during the WD40 test either.
I reckon, something else is going on.
There's a temperamental issue, either with electrics, carby or vacuum lines somewhere, etc etc.
ATM, I'm trying the elimination technique, rather than locating the culprit(s).

[dom14]

Or the LPG mixer. There was a bit of smoke coming out of the top of the mixer during the smoke test.
The gasket might be leaking. But, it was in good condition(visually) last time I took it off.

[dom14]

Hey guys,
I'm just updating.
So far the vehicle has been going good.
As in the picture N0-5 above, the two vacuum lines are
NOT connected to the charcoal canister anymore. They both are blocked as in the picture 5.

So far, just under 24 hours I've been experiencing amount of power(on LPG) that I haven't been experiencing for quite a few months.
LPG torque response is practical matches the petrol one atm.
Which really surprises me.
I'm not for a second thinking I fixed the problem. But, it's ok atm.
But, I do know at least the electrical issue is still there, if not other issue(s) as well.
I have no idea whether the disconnection of vacuum lines from the charcoal canister helped or fiixed at least
one issue. It all can be a mere coincidence 'cos I played with the distributor vacuum line at the same time.
I would love to hear some feedback from the more experienced patrol gurus out there.
Thanks guys.