Timing my 350

[Lippyp]

Having got my engine running again after a new intake, starter, conversion to a pertronicx ignitor I need to set the timing, what should I be aiming for with a fairly stock 350 with an unknown but not wild cam. Its a long time since I timed an engine but I have a new good quality timing light and I'm ready to have a bash at it. Which direction do I turn the distributor to advance and which way to retard the ignition? Any hints nd tips welcomed, I amy also be back for some advice on adjusting my carter AFB to get it running right as I think its running rich at idle at the moment.

[webfoot]

To advance turn it counter clockwise. I'd shoot for 10 btdc at idle with the vac advance disconnected, for starters.

[piecesparts]

Agree on the direction of rotation, but I like my timing just a little higher than 10 degrees. It is a good number to start with, but look for more advance for better acceleration. I have my timing set by using an advance setting timing light and I set it at aTOTAL advance of 35 degrees, whcih works for me.

The carb is an easy thing and if you want it to be as close as you can possibly get it, then I would use a vacuum gauge to set the idle mixture screws. Connect the vacuum gauge to a fitting on your intake manifold. Once the engine is running at an idle around 700 RPM, then note the vacuum reding on the gauge. Pick one of the idle mixture screws and turn it inward until your idle starts to decrease and the vacuum gauge is showing a change from the first reading. Now turn the screw outward until the vacuum gauge changes stop increasing. Then turn the screw back in a 1/4 turn. Now adjust your idle back to around the 700 RPM and then turn in the other screw until you have a decrease in idle speed and vacuum also decreases. Turn that screw outward until the vacuum signal stops increasing and then turn inward a 1/4 turn.

REPEAT this process one more time to get the idle screws set to their optimim setting and you now have your idle screws set.

IF your cam wild enough and it is causing a rough idle, it may not let you set your idle speed at 700 RPM, if so then your exhaust may smell rich, just due to the carb having to be in the transition area between lidle and cruise mode and you will not be able to get your idle down to a lower number. There are recommendations from the carb people that you can drill a small hole in the butterfly plate of the carb to relieve this issue, but I personally have never had much luck in this endeavor.

My truck has a fairly lumpy cam and I have my idle at 700 RPMs when I am in gear, and it then sits at about 900 when it is in Neutral. I run a 2400 stall convertor, so that I can sit at a stop light and the engine does not try to pull me through the intersection because it is pushing the torque convertor. I do not have any air holes in my throttle plates and it runs quite well on my Edelbrock carb (body design is a match to the Carter AFB carb).

[crazy longhorn]

Originally Posted by Lippyp

Having got my engine running again after a new intake, starter, conversion to a pertronicx ignitor I need to set the timing, what should I be aiming for with a fairly stock 350 with an unknown but not wild cam. Its a long time since I timed an engine but I have a new good quality timing light and I'm ready to have a bash at it. Which direction do I turn the distributor to advance and which way to retard the ignition? Any hints nd tips welcomed, I amy also be back for some advice on adjusting my carter AFB to get it running right as I think its running rich at idle at the moment.

I see that you have a pertronix....I am running mine @10 BTDC. It seems that the old points dizzys had a little more mechanical advance than the HEI did. At any rate I agree, I like a 34-35 total (vac advance unhooked & plugged). You can check this with a dialback lite, or just wrap a cheap balancer tape on. Set the "all in " spot around 3000 rpms& you should be good. After you have that sorted out, you will probably need 10-12 degrees@ the crank shaft for your vacumn advance....hook it to a manifold source(not ported). There is a sticky on the top of the page That can probably explain more than I can(as slow as I type) But you will need an adjustable vac canister to make it right on.... & you may need to limit the pull on the pin to make it right. They all tune just a tad different, depending on combo, but any ?, just ask crazyAl

[dukcaln]

I have a small cam in my 350, typical rv cam so to speak, and I have mine set at 12-14 btdc... seems to run really well there....

[Lippyp]

I had a go at it this morning, got it running pretty well and then managed to second guess myself checking it after tightening up the distributor clamp and went back and fiddled and now its backfiring out of the exhaust. In the end I walked away before I got too frustrated and I'll go back to it with a clear head. I did find I couldn't get the idle speed below about 900rpm reliably but I've not tackled the carb yet as I need to buy a vacuum gauge.

I had it set around 12 BTDC and it ran well so I need to hook the light back up and return it to there and leave the damn thing alone until I've done the carb. Its more about being a bit unsure of myself as like I say I'm very rusty, did a lot of work on asorted old cars when I was younger but then owning a few modern cars didn't really get into anything other than routine maintenance for a good few years so my mojo is a bit wobbly.

I'm sure with all the great help that you guys have to offer it'll all end up fine. All it needs to do is run well enough to get out of my yard and onto a flatbed tow truck and off at the other end.

I also think the damn waterpump that I spent time cleaning up and painting is leaking now its back on, bloody things never like being disturbed, its just dripping from somewhere underneath, I put sealant on all the bolts and new gaskets with sealant so its not those that are leaking I suspect as its quite noisy its leaking out of the front where the shaft comes out.

[dmack91]

Unfortunately, if the water pump is noisy and leaking, sounds like it is shot (not just a gasket). Water is probably coming out of the weep hole.

Look on the bright side, the new one will be all clean and easy to paint before installing.

[dukcaln]

glad to hear you walked away...works for me too. I think we have similar issues. Mine is set at 12-14 and mine runs well, but is does back fire or pop out of the exhaust when letting off the pedal and coasting from a good speed. I too have to adjust the carb, and just started to venture into that issue. i need to get a vacuum gauge too but right now doing it the manual route....let me know how it works for you...

[Lippyp]

Just had a second attempt and got it running better at around 12 btdc and also had a twiddle with the idle screws on the carb as described above. Getting a good 18 in/hg on the vacuum gauge. It then seems to bog down when I reattach the vac advance to the manifold and I have to up the idle speed to stop it stalling. Its a mallory twin point converted to a pertronix kit, I have no idea what the total advance on the dizzy is. She's still running a bit rough but that could be down to the amount of time she's been stood. I did drain the gas tank and filled it with some fresh gas with a stabiliser in it but even thats been in there since last summer. I may chuck a couple of gallons of fresh gas in on top as I only put a gallon in I think. She would also probably benefit from having the valve clearances set and maybe some new leads/plugs/rotor and cap.

At the end of the day though this exercise was about getting her running well enough to move her out of the back yard and onto a flatbed truck so I can move house and she is (even moved back and forth a few feet today) I'd forgotten just how heavy the manual drum brakes are especially as the back has new shoes that won't be bedded in at all. Thats the next thing on my list, converting to power and all new lines. I think I'll leave fine tuning until after I've got a garage to work in and I can address the other stuff first.

[dukcaln]

thanks for the up date...... mine is getting there, going to adjust the timing one more time then if that don't please me I may look into somebody rebuilding the q-jet

[Lippyp]

I think I may have sussed my problem, I've just looked up the instructions for the Mallory distributor and it says it should be connected to a ported vaccum source, I think I have it plugged in to full manifold vacuum, this could explain why its idling like crap as its getting too much advance at idle from the full manifold vacuum. I have a carter AFB and its currently connected to the right hand vacuum port which I think I'm right in thinking is fulkl manifold vacuum. Am I right in thinking the left hand (as you look at the carb) port is the ported vacuum connection. I';m going to swap them over and see if this helps matters.

[Boog]

Phil it's easy to tell them apart. At idle put your fingertip over one of the ports. If it has strong vacumn it is full manifold vacumn. If it only has vacumn when you rev it up then it's ported vacumn.
You must be moving to a new home?

[Lippyp]

Thanks for the tip, I'll check it tomorrow. Yep, finally sold our house after nearly four years of trying and halving the sale price in the end. I will even have a garage to work in at the new place (well once I make the door big enough to get her in!) I'll have to stick a thread up about the new place in off topic.

[Lippyp]

She's idling much better now with the vac advance swapped onto ported vacuum. However, under load theres an occasional big miss followed by a massive backfire through the exhaust (man that can be loud!), it seems to do it occasionally through both exhausts (duals with no crossover pipe) so I'm beginning to suspect either plugs, cap or wires so I think its time they all got replaced, the rotor is new as the Pertronix kit comes with a new one but the rest are a good few years old and have been sat on the engine not being used. . I'm pretty sure the wires are on in the right order but I'll double check tomorrow after I've changed a front hub on my blazer. I'd forgotten just how much of a challenge getting an engine tuned up right can be as its years since I did one thanks to a succession of modern engines (you know the ones where you open the hood, try and work out where the plugs are and quietly shut it and drive to the garage)