Ideal O2 levels?

[DODGEN1]

So what vacume readings do you have at WOT?
this is in park and running up to 4 grand?
idle?
at engine break?
i assume this is one foot on the gas and the other on the break? power break?
and cruise?

i dont think your mixtures are that bad. idle problem your going to have to adjust to with out so much of the readings. engines very.

what are the mixtures at 3000 say pulling a small hill? thats what i would set the load ratio to.
if you 425 is that slopply i wouldnt even play with it. use the tightest parts you have and set it up.
return all the original springs to the converter and mixer. havent delt with the model L. always the model E. but with my EC1 cover you changed the blue spring to
the orange spring. what is yours suppose to be? with the standard cover?
ive got a couple thoughts more but lets start there.

[Steptoe]

So what vacume readings do you have at WOT? 1.5 to 3 hard to read accruate and watch the road
idle? in gear 450 rpm 12/13 out of gear 500 rpm 13/14"
at engine break? 23/ 26 +
i assume this is one foot on the gas and the other on the break? power break? no just liftfoot off throttle higher the speed higher the vac
and cruise? open road 18/20
what are the mixtures at 3000 say pulling a small hill? @3000 thats over 90 mph 60 mph 2100 around 14 to 16."

if you 425 is that slopply i wouldnt even play with it. use the tightest parts you have and set it up.
return all the original springs to the converter and mixer.

Do that and Im back to 9 to 11 O2 mixtures and stinging eyes....
This was just an excersise playing with a very worn 425 mixer, confirm what a lot of old threads comment on re changing spring weights, lever heights, collect that info and put in one place...till I sourced a new mixer and put it on
I note here some of the spring changes to achieve these O2 readings are extremely dramatic....like a green vapouriser spring, with 3 coils chopped off, then stretched...in the top of the mixer

always the model E. but with my EC1 cover you changed the blue spring to
the orange spring.

I know the EC1 was obsoleted back in the 80s...my understanding , because unstable....with a worn mixer its bloody unstable...which i learnt way back up.

the orange spring. what is yours suppose to be? with the standard cover?

Will have to look up later, currently it makes the O2 run in the 12/14.5 range 11 at ildle.

When I get time to re set the sec butterflys on the new base plate, sortout correct gaskets, mod the throttle and kick down linkages, sort the crankcase frsh air thru air filter on the new mixer etc...and throw it on...I will return everything back to factory, springs, lever heights etc....then start from scratch.

Till then its rather gunty again, economical, and still do the shopping or a trip knowing its on what i understand from old posts, a little on the power side of economy O2 readings

Its not worth playing any further, because changing anything now (except maybe dropping the lever a couple mm) just screws it up....and its not realy worth changing the lever height again...the time far better spent at this stage getting the new mixer ready...and time is in short supply at the moment.
I have a new engine/gear box in the Bradford (see my avatar) building new floors, new lay rubs in the drive shaft, and having trouble getting time to do that.

[Steptoe]

Averaging out the above patch/compensating for the worn 425....and I must emphasise, patching is now way to fix a problem,as an interm temp fix yes,long term Not,..... milage increased from around 10 mph LPG to around 13.8 mpg
Thats short stop start cold runs to open highway, to towing the trailer , shopping.
UPDATE:
I got around to getting the new 425 on a QJet spreadbore base to replace the worn (rattles ) on a Holley sq bore base and adapter to the old performer spread bore intake.
I also increased the L converter lever height from 1/16 below to 5/32 above and put the blue spring back in.
Part of compensation for the worn 425 see posts above.

high lighted below for comments/ what to adjust/look for please

Fired straight up...
The 425 just of cruise whistle has gone, and so has the damn rattle.
I dont have full adjustment on the idle speed....cant get to isle below 700 in Netral??? secondariies are the tinyest smiggen off fully closed????????
I now have adjustment for idle mixture.....set at 17.5 AFR
Took for a spin.
30 mph cruise 17.2 / 17.8 AFR
light load low 16s (bit lean????)
heavy load/ full throttle middle of 15 AFR (bit lean???)

60/70 mph cruise, high 16s thru low 17s.
light load high 15s low 16s
heavy load WoT mid 15s (bit lean???)

Engine brake....high 17s low 18s AFR is this OK?

with the old worn unit engine brake was in the 12s /13s same as the idle....now I have idle mixture adjustment, is the engine brake AFR related to the idle AFR?...I can see how it could be.
Engine 'feels' as if needs a little more advance espec at 30 mph 1000 rpms tru to about 70 mph under full load...maybe another 3 or 4 degrees in the curve max.

Will do milage over the next few weeks.
Would appreciate comments on highlights above please.
Cheers
Steps

[Steptoe]

Bump Help required.
Comments please on AFRs....
Being on the lean side I dont want to put up any big miles yet.

upped the timing a shade over 2 deg... power change dramatic.

I dont have full adjustment on the idle speed....cant get to isle below 700 in Netral??? secondariies are the tinyest smiggen off fully closed????????

I suspect I have a air leak...but not between carb and intake....Im not familar with the Qjet base...I suspect I have a port or something that goes between above the butterflys to below....leaking enough air as required for the idle....
Would this be possibe thru something like the petrol idle ports or something?
All Qjet base plate vac taps are blocked as in car vac gauge , brakes, Vac advance etc are all take direct from the inlet manifold.

[DODGEN1]

I screwed the idle jets in all the way on mine. found this on one i converted the bushings were bad on the primary shaft but you had to spray
carb cleaner directly into the shaft to get it to stall. never noticed a problem with it running.

[Steptoe]

Just come in from pulling the carb off.
Yes checked with engine start (either ) for leaks, and also a small LPG torch not lit.
Did not find anything
Removed the carb, re centerd the butterflys...was not quite happy how they where sitting, slight improvement when put up to the sun.
Checked channels bleeds, make sure nothing leaks past /around the butterflys....anyway all the gaskets block everything off...brakes, in car vac gauge shut off are all from manifold taps..except VA.
Butterfly shaft bushes have no play...would have picked up with the LPG torch.
Reassebled and have a slight drop in idle from 700 to 650/600.

I screwed the idle jets in all the way on mine.

???? idle jets....Im not familar with Qjet....are these on the base plate? where?

[DODGEN1]

front of the base plate. about an inch and a half apart. but depending on year you may not have them. i'll post a pict of mine this weekend.

[C3H8]

Steptoe. Dependimg on the year of the QJ you have the idle jets might be covered to be tamper resistant. Look for two small round steel or aluminum caps about 1/4" in diameter swedged into the body. They restrict access to the adjustment screws. They will be located on the front of the throttle body. pop a small hole in them with a drill and pry them out with a pin punch. Once removed you can crank down the gasoline idle mixture screws.

By the way thanks for the thumbs up in a previous post.

[Steptoe]

Thanks....
Hopefully this thrad can be used for reference what to do not to do in the future...
I will post up a pic of the Throttle body carb soon...
my AFR WOT has come right 13.9 14.2 Sweet.
Idle AFR Sweet 18.9 17.2
But out today...open road cruise...60mph is 2000 rpms cruise below 1600 /1700 and AFR around the mid to high 17s
Above that right out to 90 mph cruise (ran out of road lol) AFR is mid 15s....
I can understand when getting up over 45 80 mph .....but around 60 mph I would expect mid 16s at least.

The questions are...are my expectations of the AFR correct?....right thru all of the above.
If so, where would I look to increase AFR above 1700 rpms (about 50 mph to around 70 /75 mph cruise?
L Converter lever height current setting 5/32 above edge
The spring? put the orange back in?.

Had another issue happen....planted WOT and AFR went out 20 plus...stopped, engine cut out, couldnt restart
Removed air cleaner and the mixer diapham pist was stuck high???? bit of a flick with the fingure and dropped free...
Thats a bit of a worry...any ideas?
Will take off and look inside in next few days when get a few spare minutes.

[Steptoe]

Save u guys posting up pics..
here is my Qjet...
sry not as close up or clear as wanted but alot of water hoses etc in the way to get clear shot.
inside the holes is a flat plate thing...like a heavy bit of wire that is flatened out.
I can just get to the left one with the long nose pliers and it appewars can turn about 1/8 turn...after that i dont know as dont have the room to get a good grip...
maybe a special tool or pick up an elcheapo small chinese pair long nose pliers after Easter.???

Trip yesterday 17.4 mpg LPG releates to 34.4 mpg of 96 octane petrol...and got tied up in the easter holiday traffic a bit to.

[C3H8]

Spent half an hour making a nice post and lost the dam thing at submit . Here's an abbreviated version.

Try the orange spring. The mixtures should richen up but the down side is it will richen all over. The hih 16's low 17's are OK during light cruising. If the AFR did not change with the orange spring better check your meter. Somethings up

Have you ever tried a VPV. The AFR you show is OK at cruise. You just need to make sure you richen during acceleration and heavy pulls. VPV's will work well when engine vacuum drops below 3" Merc.

Third method is not one for all users. The AFR can be changed by polishing the gas valve so more as gets past a specific area. This is time consuming and could be costly. Too much and you have to start again with a new as valve. Also the best place to do this is on a dyno and I suspect these are a rare species in the Aussie suburbs.

Sticking 425. Very rare. Take a look at the gas valve and the mixer body and make sure there are no rough areas or nicks. The only time I saw gas valves stick was when we used a plastic bushing as a guide and if it was not perfectly centered it could jam.

Can't remember? Are you running an EC1

[Steptoe]

oops didnt put the pic in the post above

Spent half an hour making a nice post and lost the dam thing at submit

yep who do we send complaints about that function..I donrt use , and its a pain in the butt.

Try the orange spring. The mixtures should richen up but the down side is it will richen all over.

cool...was also thinking maybe lower the arm a 1/16.

check your meter. Somethings up

yes thats crosased my mind..they are a reliable unit...could need re zero, bit of a hassle to put the sensor out and re calibrate till the host free in the workshop...work picked up.

Have you ever tried a VPV......Also the best place to do this is on a dyno

I will put my hand up...the question what the hell is that?

You just need to make sure you richen during acceleration and heavy pulls

I turned out the power valve 1 turn. I know have enough advance very slighty over....and felt like I should throw a cup of fuel down the carb...well 1/4 of a cup lol

Also the best place to do this is on a dyno and I suspect these are a rare species in the Aussie suburbs.

first off..Im a kiwi , not a bloody Ocker...and Aussie/kiwi..m8 you have got things very wrong down under...serious boy racers, old school boy racers, hot rodders, classic car guys, vintage guys...every suburb, town will have a club, and have at least 10 members....then there are the racers track guys, rally guys.
Yep a lot of people clicked on a long long time ago there is a demand and money in a dyno....and that include motor bike dynos to.

Sticking 425. Very rare. Take a look at the gas valve and the mixer body and make sure there are no rough areas or nicks.

I took the pic above when checking why..could not feel anothing binding or stickig....but when dropped felt it did not drop quite right...think u know what i mean....pulled it and checked roundness etc, but could just feel in places dags in one place on the edge of the machined surace...very very lightly wiped them off with bit of 600 sand paper.
Put back to gether and it dropped looking right.

Anyway...its running ok, picnic tomorrow....enjoy the cruise...

[C3H8]

OOP's Forgot I was responding to NZ. Didn't mean to insults all the Kiwi's . Where did that expression come from anyways

VPV; Vacuum Power Valve. Goes into the secondary port where primers are installed. It is a normally open valve that closes at 3" of vacuum. It has two hoses. A 1/4: hose that goes to the base of a 425 or other mixer. The second hose goes to manifold vacuum. When starting the engine it acts as a primer. some fuel flows through to the engine through the base hose. As soon as the engine starts the vacuum closes the valve. Its second function is to send fuel bypassing the mixer whenever you put the pedal to the metal. As soon as the engine vacuum falls below 3" (it is adjustable) extra fuel flows through the bypass hose. It is really good for engines that need additional fuel if the power valve can't supply enough fuel.

There is another trick to increase fuel flow for high horsepower engines. It should only be used for hopped up engines with power raised to the point where the 425 is marginal. If you look inside the vapour inlet of the 425 you will see a restrictor plate. The 425 was designed to be used on NG and lpg. The original bore was for use with NG and IMPCO put a restrictor in to limit the maximum flow on LPG. This plate pops right out and would allow some increased flow of LPG. The adjustment on the power valve is still the limiting factor, however if you are running lean with the power valve wide open removing this plate should allow some extra flow. For NG users this is very helpful.

Cheers M8

[Steptoe]

Where did that expression come from anyways

JAFA
I dont know the orginal source, but would have been in the last 15 to 20yrs..
Auckland is NZ s biggest city, I believe about 1/2 the population of NZ...so mostr of the roading, inferstructure costs from taxation etc goes to Auckland...the rest of the country sees Auckland as the big fast moving city.
Also JAFAs move to other smaller citying and in particular smaller town...come with their great ideas of supermarkets, relestate devalopements etc..which meet huge resistance to local communties....JAFA poked its head up somewhere and has stuck...
The thingh with Kiwis, instread of throwing ones arms in the air, indignate going off 1/2 cocked and in denial, we reconise the the honesty of the situation, and the humour that goes with it.
Im a JAFA....as much as Im a Kiwi... fine
And why is a Kiwi called a kiwi....because its our national bird...WRONG...because in the NTH African campain against Rommel, the Kiwi troops had a damn good boot polish, highly sourt after by the Poms Aussies...called Kiwi Shoe Polish ..The nickname stuck eversince...
Kiwis can laugh and be honest about themselves...
Im mean ...what about the Yanks? looked yank up in the Websters(American) dictionary...meantion that to an American and they dont think its funny

If Im WoT...and the only times I do that is maybe passing a truck/tralier unit on the highway....13.9 low 14 really an issue?....stoichiometric about 15.4 /15.8..I dont know the NZ blend..seems to be a closely held secret here.

It should only be used for hopped up engines with power raised to the point where the 425 is marginal. If you look inside the vapour inlet of the 425 you will see a restrictor plate.

My engine as such is not hopped up...rather the opposite, dropping torque way down low, 1200 to 4000 range, hence why I can run a 1200 stall, 255 diff and still accidentally have the rear break loose.
Even so thats really interesting...will look at that on the old mixer.

VPV; Vacuum Power Valve. Goes into the secondary port where primers are installed. It is a normally open valve that closes at 3" of vacuum. It has two hoses. A 1/4: hose that goes to the base of a 425 or other mixer. The second hose goes to manifold vacuum.......

Also very interesting..got any diagrams or pics on that?
Its funny because yrs ago I spent a bit of time thinking along those lines as a possible mod..never did anything about it because didnt need to.

With a 17mpg lpg mix open road town cruising , very few interection stops (they screw mpg runs up bad)
idle mid 17 in gear (which is 99% of real world idle)
30 mph to about 45 mph (1000 to about 1700 rpms) cruise mid 16s
60mph plus cruise mid 15s
Engine break 16 /mid 17s
Thats pretty good for a cruiser/daily driver isnt it?

Would like to sort that qjet mixture screw (maybe) lack of idle speed adjustment...get the butterflies off resting on the bore.
Hopefully removing those machine dags fixes the mixer dipham stucking up after a Full on WoT burst.
Recheck calibration of the O2 data logger.
Be better to sort and know these sorted before any further fine tuning of springs etc (????)
Anyway feed the 70 odd parrots and off for a picnic with the missus.
Busy tomorrow, and after that sorting new wheels tyrs for the car trailer .......clean avairies...
things on hold for a few more days...again.
thanks.
Steps

[Steptoe]

Pleasant picnic at Piha... mostly narrow winding up hill down dale, steep driving
16.22 mpg...diff to the 17mpg but that was pretty straight level consistant .
The mixture screws... now sussed...chatting in the car to the missus, and she suggested using a spare headboard bolt that has those thumb tags to turn them...thats in one of her draws, and cut a slot in the end....
Perfect..couple cuts with the hacksaw..ready made Qjet mixture tool.

One was about 6 turns out the other about 3.
This has now enabled the primary butterflies to be lifted off the bores..just...650 rpm idle in N.
But not the seconaries...
And took her for a quick spin...accel..not wide open...cant do that in town on home turf....
The AFR dropped down to 13.8 /14.2 lot happier...turned the power valve out 1 1/2 turns.
Cruise upto 40 mph leaned a couple points to mid hi 16s..thats ok
engine brake slightly leaner..high 17s think thats ok to
Dont get that would have expected richer??? on the other hand..with a holley petrol...mixture screws change the power/cruise mixtures basically nothing as the amont of air/fuel is insignificant to what is being used under power and higher rpms..so not a suprise

Im running about the same mpg on lpg as I would expect granny footing on petrol.
96 octane is currently $NZ 2.26 /L
LPG is $NZ 1.14 /L
A modern GM Holden 3,8L fuel injected under the same similar driving conditions would get around 24 maybe 26 mpg
A 5.7 L 40 yr old technology carbed, heavier and far less air dynamic..32/34 mpg/
THAT is significant.

Appreciate the pionting in the right directions guys... little things but do matter.

Will check AFR logger re calibrate to make sure..

OH another side note...I put a 180deg thermostat in from a 120 ages ago...a discussion about converter temps/water temp blah blah..didmt make any difference but that was with worn stuff...putting the 120 back is on the to do list
Also note that with the generally leaner closer to stoichiometric...thermostat opens and doesnt move from there, no matter what....running rich varied about thermostat temp to plus maybe 5 or 7 deg up under loads hills towing etc.