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Choke

What are everyone's thoughts on choke with twin carb set up?
Mine are both fixed open with no choke. Seems to start alright as it is getting plenty of fuel so not sure whether to worry about coming nbevting it or not.
Cheers and a Happy New Year

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The basic rule with a choke is:- If you can start & drive a car without the use of a choke, then it must be running too rich.

In other words it's always best to have a fully operational choke.

By the way what does "nbevting" mean ?

Dr Terry

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do you know how well it starts in winter? Ive only got a single barrel - if engine warm or a hot day no worries but if cold and in winter I need choke to start
Andrew

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I'm with Dr Terry.
If it will start cold without the choke it's getting too much fuel.
I'd get a choke cable and get it sorted properly.
Out EH with triple Dellortos won't start cold without the choke.
I'm getting a bloke in town to custom make me a120" cable with the original EH knob and dash bits on it. He can make up any length cable so if you can't get an X2 choke cable he could help.
I've got currently a Kombi choke cable (120") for the Dellortos. It goes up across in front of the radiator and back to the carbies - the chokes work the opposite way to a Holden.
David
David

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Old is good.

Starts fine when very cold without a choke. A couple of pumps of the throttle and give it a few revs for 30 seconds and it will idle and keep running fine. The plugs were very black. Might need to get some smaller jets and get the choke wired up.
Seems to run well when hot so if it ain't broken I might not fix it.

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does it start easily when very cold? I've only got a single barrel but when it's cold (esp winter) I need the choke to get it started - I can get away without it or only need a little bit of choke in the hotter weather - but irrespective once the engine warms a little I need to open the choke right up to avoid it running rich. I would think that if you don't need any choke at all and you live in an area where the temp can fluctuate a fair bit then you would not be getting optimum performance when the engine is hot.

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Andrew

if its running all right don't worry about it, you obversely don't care how much fuel it uses. Does it have a big cam to use the fuel thats getting poured into it?

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A taxi named after a fish blew my 5 litre Vn to the weeds.

It has a 186 high comp head on it but everything is standard. Might be worth getting head worked and a new cam to match it

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There's not really such a thing as a 186 high comp head, a regular high comp 186 engine is fitted with an open chamber (L) head, so putting a 186 head on a 161 engine will give you a low comp 161. What is the is the actual cast number on the head?

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This is the confusing bit. The engine number is 161 7233. The casting number on the head is 7249477 which matches a 161 from what I have found, however it also has E 186 X 8 "H" on it as well.
Inlet matches HR X2 as do the 2376050 BXUV - 2 carbs.

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Is anyone able to confirm the below head? I was sure it was a 161 head but have confused myself with over googling.
Casts 7429477 E 186 x 8 H

Thanks heaps guys

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T

My Shed

Holdenpaedia, they're the brakes Mate.

E186 will be the casting date. 18/5/1966
E = may 18 the 18th of may, 6 for 1966
8 is just a casting id, maybe the 8th time the mould was used that shift etc??
H for high comp

477 is what i recall as a 161 head.

who really cares what it was off??

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Thanks for clearing that up. I was certain it was a 161 after reading the casting number but the number 186 threw me abit!
Thanks heaps guys

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I'd be concerned about the darkening of the oil.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

Why is this T? Carbon build up? Has just had all main seals replaced so I'll
monitor the fresh oil. I bought the vehicle from an old Holden enthusiast. He recons this set up goes a lot better than his 186 in another vehicle.
Anyone have a recommendation on what sort of cam I should run? Will get a head port and larger springs etc eventually.
Cheers

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An overly rich mixture will blacken the Engine Oil and impact Engine life. I've also seen it caused by Chokes that were stuck half on.

I'm scanning for Holdenpaedia images.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

Do you have an aftermarket rocker cover and a PCV valve?
An aftermarket rocker cover that isn't baffled (like most of them) can give you black spark plugs because it can suck oil through the PCV valve.
I always had black plugs until I tossed my aftermarket cover and went back to a stock cover. Black plugs and oil consumption gone instantly.
If you don't have an aftermarket cover, it is most likely to be getting too much fuel.
Do you have a HEI distribuitor? If yes, do you have the proper HEI spark plugs, if not you aren't getting the full HEI spark and it won't be burning as good as it can.
David

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Old is good.

An original steel cover is on its way to replace the current aftermarket chrome one. It does however have pcv pipe which sucks air on from below the engine. Still has original distributor and correct plugs.
Has anyone used one of the kits from eBay which is supposed to turn original distributor into an electric one by replacing its internals?
Cheers

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find a closed chamber (high comp) head, get some xui sized valves installed, get quality valve springs and get someone to open and shape the inlet ports and valve castings. don't touch the exhaust ports other than a clean up of the carbon.

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Anyone recommend what size jets twin stromberg carbs should work on a 161. It's obviously getting too much fuel with black plugs and starting with no choke. It has umbrella style pcv so no oil would be getting sucked in through.
Cheers

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I would get a mechanic (old bloke who actually knows how) to tune the motor before I started mucking around with new jets. It could just be tuned rich, which just needs a simple adjustment to fix.
David

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Old is good.

I did think this might be a good idea however was told these carbs aren't adjustable apart from their idle mixture?

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Read here: http://holdenpaedia....
Idle speed, mixture, float level, accekerator pump are all adjustable.
Just a thought. How are the needle and seat in your carbies? If they are old and past it they could be letting too fuel into the carby and making it rick.
David

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Old is good.

After replacing the chrome rocker cover with an original red one, i realised that their was no PCV valve hooked up to the umbrella style pipe which goes to the rear of the vehicle. Would this cause the engine to burn oil and be contributing to the black plugs?
cheers guys

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The umbrella handle system doesn't use a PCV valve.

The umbrella handle will reduce the likelihood of oil burning by relieving the crankcase pressure. The dark oil is over rich mixture somewhat similar to diesel "black death" caused by injector leak.
The umbrella handle does not use a connection to the inlet manifold.

The umbrella handle needs a breather type filler cap to prevent road grime from being sucked into the rocker cover when the engine is not making power ...

http://holdenpaedia....

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T

My Shed

Holdenpaedia, they're the brakes Mate.

no. you should be able to workout what jets were in the x2 from std then jet down a tad for the 161. on the side of the carb is a circle with the size of the carb. from memory 161std is a 1 and 3/8ths? 186 was 1&5/8ths, 202 1 &7/8ths. each had a bigger main jet. findout what the carbs are, what jets are in it then talk to a carb shop. they should have a range of jets available to suit the strommy's drop a couple of sizes and see what happens. if all the rest of the carbs are good condition,(accell pumps etc) a flat spot suggests you are too lean as a rough guide. grab a reco kit for the carbs as they will have a jet spanner in them (check first)

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I do understand this. What sort of fitting/valve should the umbrella plug into the rocker cover? The previous chrome rocker cover plug for the umbrella appeared to be a blank with no way for air to get out through the umbrella.
Cheers

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It looks to use a grommet similar to the PCV valve grommet used in this picture ...

http://holdenpaedia....

The PCV Valve Grommet is FuelMiser Part Number PCG-20.

No PCV valve is used with the umbrella handle.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

"The previous chrome rocker cover plug for the umbrella appeared to be a blank with no way for air to get out through the umbrella."

That sounds inadvisable because the crankcase cannot breathe properly.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

That's what I thought. All vented properly now. What are the problems with no PCV?

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1. Road dirt may climb the Umbrella Handle, typically under engine braking.

2. No PCV means reduced crankcase vacuum that means less control of oil leaks which includes the rear main seal. PCV keeps the engine cleaner.

3. Reduces upper cylinder, valve seat and valve stem lube.

4. Increased emissions.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

Is anyone running twin carbs on a stocko 161? Wanting to know what main jet size they are running?
Thanks in advance

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Ive been certain that the HRs 161 with X2 carbs is running rich, with the plugs being fuel fouled and very black. I consulted an old race car mechanic whom is highly recommended around here for working on old cars. Before I could start discussing jetting etc with him he asked if I used fuel additive. I use flash lube and was adding 50ml every time I filled up. He recon's the stuff is [Naughty Pottyword], and the oil in it has a real problem with blackening plugs. He was importing some fuel additive cylinders from England which you put in your tank and they last 500,000km and that I should try this before I worry about the carbs.
Anyway I have run it for 25 km and it is already changing my plug colour.
Photo attached shows after a trip to the shop and back this morning after fresh fuel and adding the cylinder of what looks like lead chunks in a basket to my fuel tank.
The plugs were pitch black before hand.
Anyone got any input?
Cheers

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It looks like a plug from properly tuned engine that's just done a cold choked start followed by a short run.

How are the float levels on the carbs?

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T

My Shed

Holdenpaedia, they're the brakes Mate.

As they are old plugs I will put some new ones in it and see what they look like. These lead pellets have turned the plugs white/grey instantly. Ill check float levels today (5/8 - 11/16). I might lower them abit?
Might keep my eyes out for an original manifold and carb set up and see what i think about difference in performance.

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An HEI Conversion will turn the centre electrode white.

If the rim stays black and sooty, like it is, the mixture is too rich.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

sounds like your running leaded fuel again...

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That would be lead or tin(?) in the cylinder.
I believe it was common to add pellets to aircraft fuel tanks during WW2. I once read an article that said some Spitfires had problems with pre-ignition, but others had that used fuel from tin or lead lined lined fuel drums had no problems, so the pellets were added to all fuel tanks and the pre-ignition problems disapeared.
It slowly wears away and gives upper cylinder lubricant in older cars.
David

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with out the big cam the 186 that had the twin carbs on it I can't see it ever being able to justify 2 carbs did 161 come from the factory with 2 carbs? If you want to just cruise around reliably and not play with them constantly piss them off. How well really did they stay in tune on the 186 I remember blokes putting them on and pissing them off pretty quick 20 years ago as they drank too much fuel and didn't make much extra power we were playing with 202's. As for any fuel additive or valve saver don't bother it will take a long time to burn the valves out with unleaded.

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A taxi named after a fish blew my 5 litre Vn to the weeds.

everything is pretty "fixed" in a stromberg once jets are right, only the accell pump or the throttle shafts can "go out of tune" and that's over thousands of k's. as for drinking fuel. prob still had the single carb jets in them. pretty common mistake. still, I like the ww better for all the reasons stated above

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lead pellets are different to tetra-ethyl lead used to stop recession AND raise octane. if it was that easy im sure everyone would be doing it with fishing sinkers and the like...

think about it - in this case the plugs are likely burning cleaner NOT because of the adding of pellets but from the removal of the upper cylinder lube.

agree with posts above, it likely is not lead but tin like the old fuelstar canisters - i have seen PROOF these work, they were tin which supposedly worked every bit as well as TEL for anti-recession but the problem being that it did not stay mixed in the fuel, so could not be added at the refinery and be expected to still remain in equal amounts in fuel as it was shipped/stored/sold. adding it in-situ was the solution.

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I just wanted to check that the Idle Mixture is OK.

Since the Idle Mixture can be adjusted to zero, jet sizes are les relevant to the Idle passage i.e you can turn it in until the engine stops so overrich is less relevant,.

I'm saying this because you indicated that it cold starts after a couple of pumps of gas peddle.

If the Idle speed is close to 650 RPM then each Idle Mixture screw should be adjusted for smooth running, minimal number of turns from cutoff.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

Idle mixture was set at 2 3/4 turns out. Ive now managed to get t 1 1/2 turns out and it seems to be better.
Ive done some tests this arvo and it seems to be the idle system which was fouling the plugs. I cleaned the plugs then let the vehicle warm up for 10 mins and checked plugs which were black. I then re-cleaned plugs, drove through town with minimal stop/idle time and the plugs were exactly as they were when I cleaned them. I then went for a drive down the highway at close to WOT and then pulled up at home and the plugs again look just as they were when I cleaned them. Ive now re adjusted the idle mixture to 1 1/2 turns out and after 10 mins of idle the plugs remain clean for now.
Fingers crossed and thanks for your help!!

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I hope you've found the trouble.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

I have noticed that the front carb drips fuel onto the throttle butterfly at idle however the rear carb doesnt. Is this normal?

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It may also be a leaking Power Valve.

They are supposed to be completely shut off at idle.

Remove the Power Valve from the Carb, suck on it to test that it seals properly.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

id suggest its butterfly is open more than the rear one, activating the main circuit.

are the carbs identical, a matched pair??

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I had it running really sweet by ear and getting the idle mixture down to 1 1/5 turns out which solved the black plugs.
This afternoon I used a carb sync tool which showed the vechile was idling nearly wholey from the rear carb. Set timing, disconnected linkages and balanced the carbs and now I can't seem to get it to idle right and horrible vibration through car. The revs rise and drop as the front Carb is putting fuel on top of butterfly.
Wish I had just left it and not fiddled!

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with bigger cams and such, often you need to open the throttle more which on a standard carby activates the main circuit - fuel flows from the booster venturi when ideally it should feed fuel only from the idle discharge under the butterfly.

a simple fix is to drill a small hole in the butterfly to allow extra air into the engine, this then allows reducing the butterfly to its standard position. start small and go up as required. this DOES work.

if the butterfly is open too much, mixture screws are either not very responsive, or do nothing at all. bring the butterfly back and you then have full control of idle mixtures.

in your case i would want to know that both carbys have the correct (or at least matching) numbers on the front of float bowl so you know venturi's are the same, correct (or matched) base sizes, identical emulsion tubes, main jets idle jets etc etc. as any small mismatch here will have one doing different to the other.

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