4G30 main jets & gasket kit

[75GC]

Looking for comments about engine timing. I have a 4G30 with an unknown reground/lumpy cam. Previous owner told me engine has heavy duty springs, flat top pistons, 10.5-1 compression ratio, port polish etc. I checked compression and 4 cycles/cranks gave about 720kPa, which when averaged per cycle is above stock, so I believe the conpression ratio. Anyway, cam shop told him get "get as much advance without it pinging", which he said was 14 deg BTDC, rather than stock 8-9 deg BTDC.
So, the engine runs very rough and I think poor power under load. I checked the timing at 800rpm with vacuum advance disconnected, and it was about 25 deg BTDC! Worse than that, when I adjusted the distributor and Mitsubishi advance unit, to retard the timing, it stopped at 22 deg BTDC! I think the distributor has been installed incorrectly or on the wrong gear, otherwise I should have been able to get 10-15 deg advance. What do you think? Also, it has electronic ignition XR7000 from memory, but that shouldn't impact timing, although related. Maybe the electronic sensor disk is installed wrong? Sorry for the long post, just looking for ideas here.. Thanks!

[75glnt]

I think you mean xr700 from crane cams.. I have the updated xr3000...

The circle plastic thing you're asking about is the "shutter", and can only be installed one way.. The one you should have, should have 4 little notches cut out of it... What it does is, allows the optical sensor (little light thing that sits off the side of the shutter), to break the circuit until it reaches each notch... They're pretty straight forway and I'd recommend it to anyone.

With your timing issues, I have no idea! but it does sound it's a tooth out or so

[geezer101]

I'd tend to agree with 75glnt. Pull the distributor out and retard it one tooth. It should give you enough scope of adjustment after that to dial in your ignition timing and kill your rough running issues.

[75GC]

Yep, think I will. XR700 sounds right. I didn't think the shutter could be shifted. Never removed a distributor before, but presume it's not too difficult. Hopefully it makes a big difference coz at the moment it makes a lot of noise and that's about it! Thanks

[75GC]

By the way, is there any adjustment with the XR700 unit? Or is the dwell angle / spark duration set by the gap size? Or is the shutter gap just a trigger for a pre-selected spark duration? Just curious, never used one before.

[75glnt]

Hate to say, but I have no clue

I know how to put it in, and how everything but the module works.. But nothing else.. Had to figure it out myself how to install the bugger!! Instructions were absolute rubbish! Had to mod the shutter, and for nothing... Had to rip it out... Now I've misplaced it

I went back to points to make sure she ran. This might be youre issue?

Try and put the points back in her, turn her a tooth on the dizzy, and see how she goes? If it works, re install the ignition, and try again.... Come to think of it... It would most likely be easier swapping the two around try the tooth outer god before the points method elimination process I guess...

Either way, I hope your issue is easy and painless

[geezer101]

Pulling a distributor out is easy but if you want to make life easier on you do the the following - turn the crank over by hand so the distributor is set to fire on #1 cylinder, get a white marker and mark the spot on the body of the distributor where the indicator mark in the centre of the rotor button is pointing. This will be your starting reference point (if you pull it out and you screw it up somehow you know where it has to end up pointing when you put it back in). Take note the bottom driving gear in the distributor is helical cut, so as you pull it out the centre shaft and rotor button will turn to the right until it disengages. You'll be right

[75glnt]

My g32 dizzy is straight cut... With a flat point on the end (like a blade screwdriver), which slots into the oil pump drive

[geezer101]

...ah, o.k. It's a chain drive and driven off the crank. My bad... So how do you alter the distributor position to correct it - pull the timing cover off to get to this?

[75glnt]

Nah just undo it, pull it out until its free of the gears, then turn it until it sits back it... On mine it's 180deg.. But I can turn the oil pump drive and move it any amount I need

[75GC]

Hey, well I cautiously removed the distributor today, and rotated the rotor shaft by one gear tooth, and after working out that I needed to use a screwdriver to turn the oil pump groove at the bottom of the shaft, managed to get it installed. I checked and re-checked that I had about 10 deg BTDC before starting the engine, and it started first time and ran quite smoothly. I put the timing light on and set it to about 12 deg BTDC, did a quick idle setting change and air/fuel mixture tweak then took her for a spin. And... what a difference! So much more power than before, and it just revs more freely. Very much like my first and only Galant from 1997-2002 (GC sedan, twin carby). I've booked it in for a full diagnostics/tune-up at a local engine tuning place next week so at least now he can focus on fine tuning and carby settings etc rather than the gross engine timing issue. So thanks for your comments to make me give it a go!
Cheers,
Andrew

[75glnt]

Glad to hear mate!

And yea, I just used a blade screw driver to turn the oil pump drive, should've mentioned that

[geezer101]

Good stuff 75GC. There's a reward for getting your hands dirty - you learned something and took a big step to getting it running well.

[tandanus]

I like it when folk take a risk and it pays off
T.

[75GC]

Engine tune update:
I took it for an engine tune yesterday and found out some other problems. Firstly, the coil wasn't producing high enough energy sparks, so new coil installed. All my spark plugs are blackened/carbonised due to the WAY to rich mixture being supplied by the carburetor. With the carbon monoxide and hydrocarbon analyser in the exhaust, the carburetor jets must be so large that there's always way too much fuel entering the cylinders. Secondary vacuum system completely missing, which I did know about. Previous owner had connected a spring to the secondary throttle valve so it opened as soon as the accelerator was pressed passed ~ 65 degrees. Normally the secondary should only open as the rpm reaches higher levels (higher vacuum) but this system would completely flood the engine with fuel when you press the accelerator down at low revs.
So, recommended a complete overhaul of the carburetor and starting with original spec jet sizes. I managed to install a vacuum diaphram so now the secondary should only open with the vacuum rather than just accelerator position. And I also changed out the primary and secondary slow jets to original spec. Just need to decide whether to pull off the top cover to access the primary/secondary main jets which I suspect are way too big for this engine. Then I can take it back for an engine tune and reduce the crazy carbon-monoxide / hydrocarbon levels in the exhaust.

[geezer101]

The carby might have been off a 4G32 Saturn which would explain the jetting. Smaller displacement engines are more sensitive to fuel delivery changes. Always frustrating when you find stuff like that... It would've run like 3 legged donkey with the secondary vacuum disabled too. You should have it running smooth and strong in no time.

[75GC]

I keep changing the heading to suit my latest question...
Should I overhaul my current Solex carby (now with working secondary vacuum system) back to original spec jets, or should I try to buy a 2nd hand carby from someone in Sigma-Galant world? Since I've never pulled apart a carby I was quoted $250 for an overhaul (original jets, strip down, clean, new gaskets, not sure what else). Anyone have a spare "standard" solex carby I could bolt straight on? At this stage I'm thinking it might be worth the overhaul so I know it's working like new rather than an unknown 2nd hand one that may need an overhaul later anyway. What do you think?

[geezer101]

$250 for a basic overhaul is a good price (as long as there's nothing else that has failed on it). Be aware that the age of the carby is against it. The butterfly shafts can oval out the locating holes and suck air through them and the throttle plate can warp (and more than likely has...) Rebushing shafts can be a costly job and requires a carby specialist to perform it.

[75GC]

So I've decided to give this a go myself just for fun. I can always get a professional to help if it doesn't work... I now have the secondary vacuum working which makes a big difference to the engine's performance under load and higher revs. But the engine tune clearly showed the jets are too big because the spark plugs are all black and carbon fouled, not to mention the huge CO and hydrocarbon readings out the exhaust (and black soot/oil out the exhaust). I installed the correct Slow jets (Primary 0.525mm and Secondary 0.60mm) because they are accessible from the side of the carburettor, however the main jets are under the top cover. So my plan is just to install smaller Main jets and see if the performance is improved, and take it back to the engine tuner.

Where would I find Main jets for my 4G30 carby? I need a 0.875mm for Primary and 1.65mm for Secondary jets, and possibly a 0.45mm enrichment jet (according to my Gregory's GA/GB Galant manual). And I will also need a gasket kit for the carburettor (I presume this would be required, although I guess I could try just reusing the gasket, as I'll probably just be opening the top cover anyway). It should be a Solex dual throat downdraught model 28-30DIDSA-1 (again, according to Gregory's).

Thanks, Andrew

[75GC]

This looks promising for a gasket kit.
http://www.ebay.com.au/itm/Chrysler-Gal ... 0534242302
Now to find some jets...

[75wagon]

This any help?
4G32 solex/ mukini twin carbs close up shots and info......

Just for the record on jetting for the Saturn engines, 1400's, 1500's and 1600's are all jetted the same with a single stock carb. The 130's single carb runs the same jetting as what the twin carb set up do.

Dave...

[75GC]

Thanks for the link Dave, yes helpful. In the link you provided someone suggested you can buy the jets from motorbike shops? Maybe I misread it with a quick scan. Interesting, the Gregory's manual I have suggests the 1400 and 1600cc engines have different jets (Main jet primary and enrichment jet) than the 1500cc. But I'm thinking I'll start by taking mine back to original 1300cc spec then see if I need to try one size larger, depending on tuning results with the exhaust analyser.

[75GC]

I opened up my carb last night to check the main jets. the primary jet said "107" and the secondary jet head was blank. so my next step is try to source a few different jet sizes as ive booked in for a diagnostics with a dyno / carby tuner.alternatively it could be the enrichment jet/circuit. will keep you posted.

[75GC]

Update: I just ordered new jets from MikuniOz in Townsville, should arrive this week so I can try them out over the weekend.
I got 4 main jets: Primary 87.5 and 90, Secondary 165 and 167.5. I also got an enrichmentstarter jet 50. Only $6.60 each, not bad.