18R and Weber 32/36 settings?

[MarkIIRx12]

Hi

I put on a Weber 32/36 on my corona markII with 18R engine. The car runs fine, but it feels less powerfull now compared to the old carb. maybe thats to be expected from this weber carb?

i wonder if anyone have any experienze in jet sizes and ignition timing with theese webers on a 18R.

i found a website that had jet sizes listed for use of this carb with 18R's but now i cant seem to find that website again, maybe someone else knows of a simular site or place where i can find out whats correct?

Thanks for your help and suggestions .

[Ben Wilson]

Are you sure you're getting 100% throttle?

I'm using that carb on a 2.4 Nissan and the secondaries make a big difference.

[timbosaurus]

Hey Mate,

I've got no idea what jets are in mine.

It's an 18RC with no internal work, just a 32/36 and extractors. It also has all the pollution gear gone... at a rough guess, maybe a similar power out put to a stock old 18RG. Significantly more responsive and revvy than a stock 18RC.

Ignition timing is advanced until it pings, then backed of a tad

Sorry I can't be of more assistance, but I haven't pulled the carby apart yet. I bought a rebuild kit, but it's still sitting there as i don't think I could be farked with this motor.

I'll try to find jet size this weekend and post it.

There might not be much power, but you certainly feel the kick in the back when the secondaries open up. Sounds good too.

Cheers,
Timbo

[bnicho]

These carbs should give superior results over the Toyota ones, so something is definitely wrong. If your linkage is home-made, check you are getting full throttle.

If the carb is a DGV (not a DGAV or DGEV) and it is new, out of the box, it will carry a really odd 140 primary, 135 secondary main jetting. Switching to a 150 or 155 on the secondary will improve things straight away.

Regardless, you should really take the top off and see what jets are in there now. The main jets are in the bottom of the float bowl and screw in on an angle. The air correctors are above the mains and screw in from the top. Mains control most of the fueling, where air correctors alter the mixture at the top end - basically when the throttle is almost fully open and beyond.

Your idle jets should be roughly 45 or 50 on the primary, 50 or 55 on the secondary. Primary idle affects engine idling and just off idle. Secondary idle is only used briefly when the secondary throttle is opening, so it's not so critical.

Not all 18R engines in different markets are equal in fueling demands. You will need to experiment with a few different main jets and air corrector jets to get them exactly right.

As for timing, I've always done what Timbo suggests. Start with the factory seettings, then advance it but by bit until it pings then back off a bit.

Hope this helps,

[MarkIIRx12]

Hi again

Thanks for all ur answers.

I have checked and i get full throttle. i have done as suggested and advance the timing a bit until it started pinging and then back off. it runs nice and clean now, but still it has lack of power in high revs, but improved power on low-mid-range.

I took off the carby top and looked at the jets. main jets are 135/165 and secoundary is 130/160..

what exactly should i switch to to get improved power? it is enough to just switch the secoundary jets?

i have also been looking at pertronix ignition kits, have anyone here experienze with them? looks easy and cheap, but i wonder if its any good to use.

Thanks again for your help.

[Screamn_Sleeka]

Make sure its not a 32/36 DFV, because that means the primary is on the wrong side, and it wont deliver fuel equally to the cylinders.

[bnicho]

Hi,

It's not really clear from your post which jets are which. If your main jets at the bottom of the float bowl are:
primary: 135
secondary: 130
... then they are very lean and would be causing power loss!

I'd switch to:
primary: 140
secondary: 150
... and you should see an immediate improvement.

Air correctors sound about right if they are:
primary: 165
secondary: 160

Get the mains right first, then you can increase/decrease the air correctors to fine-tune the top end. Smaller number air corrector = richer top end. Larger number = leaner top end. ie: the Opposite to Mains.

Cheers

[MarkIIRx12]

Hi again

Its a dgv, the jets are located correct isnt they?

to make it clear, bowl jet main, 135, secoundary 130, airjets main,165 secoundary 160.

its good that its lean/economic on main, but can i keep it like it is on the main and go down to 150 on secoundary, and get more top end power and still get economy when im driving slow? or will this mess everything up?

Thanks again for ur help

[bnicho]

Hi,

Based on the info you have given, if you keep the same primary main jet and fit a 150 secondary main jet, you will have more power under full throttle with similar fuel economy. Provided you're not enjoying the extra power so much that you mash the pedal all the time.

But I would still try a 140 to try in the primary. You don't want to burn valves from being too lean.

Cheers,

[MarkIIRx12]

Thanks again for your answer.

Im also thinking about adding headers, will this give me any additional power without re-jetting the entire carb? i mean if i change the secoundary to 150, and add headders, will this be noticeable in the power?

anyone know where i can get headers for my car, that ships worldwide?

[bnicho]

Hi,

Sometimes due to the better engine breathing (= more power) with an improved exhaust, you find that you need slightly richer mixtures. It depends whether you are running slightly rich or slightly lean before you add the exhaust. You may have to go from 135/150 to 140/155 on the mains for example.

If you are considering fitting headers, I would buy a 140, 145, 150 and a 155 main jet now. If you order them at once, you can combine postage and you will have all your future needs covered.

Sorry, I can't recommend a header manufacturer. In Aus these headers are generally readily available via local exhaust shops. Genie and Pacemaker were good brands, but I don't know if either still exist, as I haven't bought them for years.

Cheers,

[MarkIIRx12]

Hi again

I have changed the secoundary main jet now to 150, still i dont feel like it runs very good, not much change from the old yet size 130, maybe a little more powerfull and faster at high revs.

The car has no gas leak anywhere, but after i been driving it for a while, i can smell gas from somewhere, im thinking it can be unburned fuel, and that my sucky point ignitor system cant fire up all the fuel its getting now.

also if i advance the ignition, the car runs better, but it pings like hell under full throttle, so either it pings or it runs slow, its nothing in between, does this also indicate my point ignition system cant handle the fuel?

any ideas what i should do? should i leave the carb with the current settings and look for a electronic ignition system, or should i forget the ignition and change some more jets?

Thanks for all ur help

[oldcorollas]

change the jets methodically...
change one jet at a time..

make sure your ignition settings and parts are correct and up to scratch before you start!!!
new plugs, new/good wires, make sure the points and timing are set correctly.

also, when you tune jets, stick something under the pedal (or use pedal feel) to MAKE SURE you are only opening the primary barrel at first.
to start with, set the idle mixture screw. this can affect the rest of the tune, or your perception, due to the progression from idle to mains.
change jets maybe in steps of "10", ie, 130, 140, 150, 160, and see what feels best. you should notice a difference.

once the main jet is set, THEN start to use full throttle, and again, change the secondary in steps of "10". again, you should notice a difference.
if the fuel you have allows you to read the plugs, do that (properly).

once you have the fuel jets set, then you can think about air correctors to tuen the top end...
but you may have better luck going to a dyno, and changing jets there... or at least fitting an oxygen sensor (even a narrow band will be better than nothing, to see which jet is lean, and then go a step up) to see what the mixtures are doing.

if you will fit headers, do that first. every change can affect jetting.

have fun

and do it methodically

[MarkIIRx12]

Hi again

Thanks for ur answer

I think the main jet is good, its pretty good power low and midrange, and i also think the mixture is good, i checked the sparkplugs several times, and they have perfect color.

its kinda hard to do the plug check on the secoundary jet tho, since i will have to rev the hell outa the engine then, but now it just seem to be the top range left to adjust.

i dont have acsess to a dyno, so thats not an option.

Since there was very little diffrence between 130 and 150 size secoundary jet, can i assume its cuz it dont burn up the fuel its given? my point ignition is timed as good as it can be, but maybe there still isnt enough spark?

I think main jet and mixture screw should be left like it is for now, but maybe i should do something with the secoundary air correctors?

im starting to think just leave the carb alone for now and do a electric ignition converting, but i dont know how much that really helps, or if the problem is that the sparks isnt good enough, or if it has anything to do with not burning up the fuel at all.

if others had good power increase from this carb with the jet setting i got now, i dont understand what other than the ignition could be the problem, the engine is in good condition, with the old carb i also had some problems with the engine misfiring sometimes, mostly at idle.

thanks again for any help

[oldcorollas]

there should be a difference between 130 and 150...

how about go DOWN in jet size until it has problems.. then you know it's too lean. then go up to the jet that stops it stumbling... maybe you are still too rich (for some reason.. idle circuit?)
you should be revving it. the idle progression will still work up to maybe 2500-3000rpm? so when you are testing the main jet, you should be revving to 5000-6000rpm (with only enough throttle to engage the main barrel).
if you are only doing 2-3000rpm, you are still on idle progression and that might be shit rich, which is why the mains don't make much difference.

where is the idle screw set?