timing for a stock 350 with mild rv cam [Archive] - Team Camaro Tech

: timing for a stock 350 with mild rv cam


fjas67
Aug 22nd, 10, 07:52 PM
i'm having some timing isuses with my 67 camaro, has a 350 with a mild rv cam and a th350 trans, 3:73 gears out back... the car has NO power whatsoever, i don't think the motor making enough vacuum because my trans is not shifting right (th350) and my power brakes are not working right, i have a T coming off the intake manifold to supply my vacuum to the power booster and vacuum mod on trans...

i tried timing it today and seen better power with the brakes and trans was shifting better but still have no power, and crappy throttle response...we tried timing it at 4 degrees before tdc but couldn't get it so my neighbor kinda timed it by ear, what's the proper way to time it and what should it be timed at??? i really don't wanna take it to a shop to get timed, and i'd really love to be able to do it myself...any recommendations???

TJS69
Aug 22nd, 10, 08:56 PM
Try about 8 to 10 and see what happens.

Z15CAM
Aug 22nd, 10, 08:58 PM
Sounds like you have a severe Vacuum Leak or Valve train problem. 4 Degrees isn't much you should be around 10 Degrees BTDC with a RV Cam.

Disconect and plug all Vacuum Sources Tranny Mod, PB, PCV, Vacuum Advance ... etc and put on a vacuum Gauge on her. It should be Stable; if not, you have Leaks in the Intake or a cam going south. Ensure Carb is Set up with Primary Throttle Plates in the Idle Circuit and Secondaries Set Per Mfgr's Specs - Turn Air Screws approx 1 1/8 off Seat and Start the engine with No Vacuum Advance by turning the Dizzy to establish Initial Timing. Once you have the engine Starting and Idling nicely begin connecting the Vacuum Items. Start with the Vacuum Advance and adjust Carb accordingly for Idle followed by other Vacuum Dependant Devices, noting Vacuum Readings. If you see a discrepancy in the Vacuum Gauge you found the leak. You should have a steady 12 Hg or better Vacuum at Idle and an Initial of approx 8 to 10 degrees without Vacuum Advance and approx 20 to 24 BTDC with Vacuum Advance connected.

Steptoe
Aug 22nd, 10, 10:59 PM
it so my neighbor kinda timed it by ear,
Oh crap...timing by ear is imposble to do..no matter what the old school guys say, it will end up way over advanced..
Why time by ear?

Basically set the timing , disconect/Block the VA by taking the rpms up till the timing marks do not move higher....and hold at that rpms...will be somewhere in the 2800 to 3800 rpm range (if you have a dizzy that is in the ball park specs) then turn the timing so set around the 34 to 36 deg mark....this mean marking off the balance out to 45 to 50 degs
What you have at idle is determined on what is in the dizzy...should be around the 8 to 14 range.
Reconnect the VA..if this is the correct specs for you engine it will be all in at idle and the idle advance will go higher and run stable....then when increase rpms to when the cent is all in the total will be in the high 30s to high 40s..maybe even low 50s.

How to mark out with out buying a tape (and make sure the tape is for your size balancer) in many old posts.
If still the stock dizzy for that engine, dropping 1 or 2 lighter springs will give u a bit more power in the low rpm range...but do not go so light that they bounce around at idle...have come off about 200 to 300 rpms above idle.

i don't think the motor making enough vacuum because my trans is not shifting right (th350) and my power brakes are not working right, i have a T coming off the intake manifold to supply my vacuum to the power booster and vacuum mod on trans...
Re check and re check again the HT leads are on the correct plugs

Z15CAM
Aug 23rd, 10, 02:59 AM
Oh crap...timing by ear is imposble

I beg to differ. Over the years with a timing light and vacuum gauge to refer too, I pretty well hit what the engine needs for Initial Timing before looking at the gauges and every engine is different. What is important is that the Carb has to be setup and there must be absolutely NO VACUUM LEAKS which the gauge does an excellent job to diagnose.

If the motor will only run with 4 degrees timing meaning it will baff out with more timing then he more then likely has vacuum issues, provided the carb is set properly.

I doubt he has an EGR Valve or plugged Catalytic's but you never know, maybe the cam was not degreed properly, did this engine ever run right ?

fjas67
Aug 23rd, 10, 12:47 PM
thank all of you for the helpful info...and no, the car has never ran right since i've had it...i bought the car from a gentleman in bakersfield...he put the motor in, said it was a rebuilt motor and has a small rv cam...most of the work he did on the rest of the car was sooo crappy i feel like re doing everything, seriously it was that bad, when i went to move the distributor it was already loose and the bolt he used to hold it in place was too long so it was bottoming out before it even tightened up the bracket that holds the distributor, the cars never been timed correctly and i don't even know where to start. ill take your suggestions and hopefully that will help me get this thing dialed in, I CAN'T WAIT TO DRIVE IT WHEN IT'S RUNNING LIKE IT SHOULD!!! right now it has less balls than my grandma's wheelchair!

Steptoe
Aug 23rd, 10, 04:00 PM
From your description..just start from scratch..even down to stripping the engine, re measure everything etc
Chances are tollerances havnt beed 2x ckecked , torques at best a gessamate

reelknots
Aug 23rd, 10, 04:29 PM
I agree with Ron that you have to get the vacuum reading corrected before you go any further. You should have more than 15" of vacuum at idle. Plug all the vac ports to the dist., brake booster and trans. Hook up a vacuum gage to the bottom port of your carb and see what it is when the engine is idling. If it's still low, pull the carb and see if the gasket is bad or even missing. You gotta get this right before you worry about timing. Post what you get and we'll work you through the timing issues.