sorry if i sound ignorant , im looking for best way to set timing on my 360 with a 671 blower. ive been told different things by old timers and others and im just looking for best method so i dont destroy something.ive had the motor in car for several years havent put alot of miles on it so nothing bad has happened yet this year i would like to drive it more ,want to make sure everything is good. thanks for any help,jeff

To find the best timing for any motor, power adder or N/A you need to know how much total timing you have it set at to start with Do you know how much your total advance is now? If so what is it? If you don't know you need to be able to find out :thumbs :Many things contribute to what the motor will like for total timing like the quality of the fuel being use, the amount of boost being made, the spark plug type and heat range and even the manifold intake temperatures below the blower
Please give us some more information on your combination like static compression ratio, lbs of boost at max RPM, your spark plug type and heat range and your current total timing
Ultimately you will need to set the timing at a safe amount and then watch the spark plugs, all eight of them and thne try advancing the total timing two more degrees at a time until the motor starts to run worst Once you find that you back it down one or two degrees and run that The last blower motor(426 Hemi) I tuned on a dyno liked 33 degrees total timing with 7 lbs of boost at 7300 RPM, we switched the pulleys to go from 12% under driven to 13 % overdriven which made 12 lbs of boost at 6500 RPM, I had retarded the timing to 25 degrees total timing and we had switched it to race gas in it from the pump gas we had used to tune it with the lower boost. It didn't like 25 degrees so we advanced it to 27 degrees and it hated that We put the pulleys back and took it off the dyno as we where running out of time and the owner was real happy with the resuts we had got on pump gas, his car was not going to hook up with 925 HP on pump gas , let alone with 1027 HP on race gas
IHTHs

wow i didnt know there was sooo much involved that makes me feel kind of stupid. im not sure what total timing is right now . is there a easy way to find that.the car is just a street toy so its not real radical im trying to get timing set so it runs good without hurting the engine. as far as boost the pulleys are one to one it has 7.5/1 compression pistons stock heads with a little porting. is there a good way to find a good starting point? ive messed with timing a little ive got it where the car starts up easy and seems to run ok but i want to make sure its set where it wont hurt anything. ive had people tell me all kinds of things like hold gas on at 2000 to 2200 rpms and set timing to where it runs smoothest doesnt seem very scientific to me. thanks

What kind of distributor is it?

that makes me feel kind of stupid
Not at all, quite the reverse - you investigated before you broke something.

As you must have anticipated, the maximum timing will get smaller as boost goes up, high boost engines use as little as 18 degrees.

it has a mallory unilite distr. how do you determine total advance or figure out how much initial timing you have / im really green on this stuff but id like to learn as much as i can.

To figure the initial timing at idle RPM you use a timimg light to see where it is idling at To figure total timing you need either a harmoinc balancer that has timing marks on it from 0 to 60 in 2 degree increments or a after market balancer that is marked that way. Another option is to use a timing tape on a stock balancer but that is a crap shoot if your balancer is on the motor and not absolutely clean before using and applying the timing tape I have had them blow off due to not good enough cleaning and not using a clear varinsh or clear coat of paint over the tape after installing them Once you have a balancer that you can read the timing with the motor revved up you can mark with white marker or something easy to read to mark what you want to see, say mark 25, 30, 35 and 40 degrees so they are easy to see to start with Another way is to use a dial back timing light and see what you have at idle, dial it back to zero and then revved the motor until it quits advancing the timing and then dial that back to zero, that will be the total advance read on the dial on the back of the timing light when revved up beyound the mechanical advance Do you have a decent timing light? Is your balancer or steel blower hub marked like needed to read the total advance? If not on either then you need to get that done to see what you have, it is way better on a blower motor to have to little advance than to much Unless you want to melt the pistons in the motor under boost Just kidding , but please don't melt the pistons while learning

The most important question is... How much boost are you running.?

I would read the plugs

Plug reading,,,,,E/T, and MPH will tell you the sweet spot.

thanks for the answers and patience with my lack of knowledge. im beginning to understand the total timing thing but how do i find ideal initial timing? or the best way to get close to initial timing to start figuring it all out? as far as plugs go if they look like running lean im too advanced right?

As a guy who ruined 3 sets of pistons on a blown 340 back in the day, start conservative. I run 29 total at 12psi/8-1 comp. Dizusters turbo car Runs less than 25 total.
Doug

Do you have a timing light?

yes i have a standard timing light not the kind mentioned with dial.

MPH will tell you something, but it's potentially dangerous.
Pick a conservative figure (like 25), run it a fixed distance, and advance 1 degree at a time, watch for the MPH to go up (if it doesn't, pick a lower number and start over).
When it stops increasing speed (viz. advanced 1 degree but no better MPH), STOP.
Retard to the previous setting.
If the plugs are light, add jet size and try again.

Remember, all of this presumes the same axle, tire OD, chassis weight, boost, water and oil temp, exhaust system, plugs, air cleaner, and jetting.

Okay, does your damper have timing marks on it for the first 60 degrees or so? If not then either buy a different damper or put some timing tape on your damper.

Once you have that set up then just fire up the engine and see where your timing is at. Slowly rev up the engine and watch what the timing does. You should be able to figure out initial and total advance by doing this unless your distributor has a super slow curve in it.

I'm assuming that you don't have vacuum advance hooked up but if you do you'll need to unhook it while you're trying to figure out what your initial and total timing are.

thanks for all the replies kind of everwhelming but it gives me somewhere to start. got one more question .. how do i know whats the best spark plug to use ive read that blower cars usually use a cooler plug but how do i know where to start thanks again,jeff

Start very consertative(low 20s) and adjust for power increase a degree at a time.Carefully read all the information you engine can provide ie: tempature(water and exhaust),plug readings,look for signs of detonation and anything else you can get.Adjust for the max performance desired.
Every engine will not react the same and you must determine the best setting for your application.We set our timing on Don Martiks blower car at a consertative 24 degrees and watched the combos reaction(fortunately we has a onboard computer and moniter each run) we stepped up 1 to 2 degrees on each tune and evaluated the results.As we increased timing we adjusted the other componants such as fuel and boost.We have topped out at 30 degrees complimented by the other adjustments and have achieved great success.
Most tuning is trial and error and you have to find the sweet spots.No one can difinately answer the questions for you but can only give you suggested starting points.

no, timing and A/F ratio are different. if your worried about timing read the ground strap.


http://www.dragstuff.com/techarticles/reading-spark-plugs.html
Joe

so i started easy and looked at my plugs they are carboned up pretty good but not wet. how do i know if i have the right heat range plugs. how do i know what plug to start with ? its a 360 motor do i start with a stock plug for that motor or something cooler?