Assume I don't know what I'm doing...because most of the time I don't. Walk me through how to check timing. I read about base timing, advance timing, what time is it timing....and I'm confused. I want to check the timing on two of my engines. 1) 354 Hemi with an MSD distributor (with a vac advance) and an Edelbrock Thunder 650 carb. 2) GM 400 block with a similar looking, but no-name distributor and a Holly 750 double pumper carb. Tried a search last night and can't find the steps laid out clear enough for an idiot to follow.
From MSD website TIMING FUNCTIONSBefore continuing with the installation, here are a few definitions you should be aware of:Initial Timing: This is the base timing (also referred to as idle timing) of the engine before centrifugal advance begins. Centrifugal Advance: The centrifugal advance mechanism is made up of weights, springs, advance cam, and an advance stop bushing. The amount and rate of advance that your distributor is capable of is determined by the centrifugal timing. If you ever wish to lock out the centrifugal advance, refer to the centrifugal advance section. Total Timing: This is the total of the initial timing plus the centrifugal advance added together. Example: 10° Initial + 25° centrifugal = 35° Total Timing
Vacuum advance also adds to time at cruise. Disconnect while checking. Also, it is good to pull spark plug one and check to be sure that top dead center matches your timing pointer. Sometimes folks mismatch balancers and pointers and your timing is way off. Engines vary on what they can accept for total timing. This depends on your cam and compression. I have a very good worksheet on this that I googled up from a Corvette board. A timing light with a dial makes checking your total time easier. All you need to do is turn the dial until your balancer mark is on zero and take your reading. You can do this at idle and various RPMs to see how this all works.
Do leave the vac line plugged it at first, or pull it out? Is that checking my initial timing at idle? How do I check total timing? Do I have a partner rev up the engine? To what RPM?
First unplug your vac line from the distributer and stick a screw in the end of it. At idle your timing should be set according to the book. Or to whatever spec your cam manufacturer is telling you. You will do this with your timing light. Right? Now plug the vac line back onto your distributer. Your timing will change a little or should. Now rev it up you should be all in by about 2500-3000 RPM that would be your total timing. Your timing marks will probably not go that high so unless you have a special timing light your are pretty basically SOL. Normally if you are spot on at idle you will be OK unless your life is lived in thousandths if a second.
Operate the motor to running temperature. Turn off the motor. Remove and plug vacuum line at the distributor. Hook up your timing light to #1 spark plug wire and make sure you can aim it at the timing market.make sure you are going to get the cables caught in the fan Start the motor. make sure it is at the factory recommended (or desired RPM) Aim the light at the timing mark and take note of the reading Compare with the factory (or otherwise recommended setting). If it is not correct, loosen the distributor hold down clamp and adjust until it is correct. re-tighten the clamp Recheck to make sure it didn't move when you tightened it. If you do not have timing tape on the balancer or a dial up timing light, you are pretty much done. If you do, you can rev the motor until the advance quits moving (should be around 3000 rpm), take the reading and note the RPM. This will be your total timing. Shut it off, re hook the vacuum line, put the tools away and have a beer and congratulate yourself on a job well done.
Don thank you I couldn't remember what one of those timing lights was called. Let me ad to Don's instructions that you may want to make sure that your fingers also do not get tangled up in the fan and no I won't tell you why I know that.
Start engine, Advance timing a smidge, go for a ride, notice if it has more power. If it does and doesn't knock, stop. Stop engine. Restart engine, if it starts without dragging, leave engine running and advance timing another smidge. Repeat ride, does it knock? is there more power? if it doesn't knock, stop, turn engine off. Restart - does it drag? no? get out and advance another smidge - repeat until it starts to knock under full throttle or is hard to start. Once you hit either condition, retard slightly until it doesn't knock and starts correctly. Then get out your light and make note of initial and total advance settings so you can put it back there if you need to take the distributor out.
setyourtiming.com has some good information complete with a video tutorial hosted by David Freiberger.
On one of the engines, it runs a bit hot. Cooling system checks out though and no indication of leaks (water or head gaskets) IF it's a timing issue, would my timing be too far advanced or too retarded?
Timing can affect temp, but from the sound of it, you are a bit new to this. Make sure the timing is correct along with vacuum advance and carb adjustment. To check vacuum advance, Start engine, then rev and hold it at a steady ~2500 RPM. Disconnect and reconnect the vacuum advance. The engine should rev higher with it connected. After the basic tune is checked, drive the car noting WHEN it gets hot and what the temps are. Before you go, make sure the fan belt is tight, the coolant is full, the radiator, hoses and fan are in good condition. Heavy stop and go traffic, low RPM cruise, Highway speed? Report back what you find.
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