might be a stupid question, but my manual states my engine timing should be at 4 btdc. What is this in relation to? at idle? at 1000rpm? or do I drop the dizzy in rotor pointing at the #1 post while the mark on the balancer is on 4 btdc? Little confused and I'm trying to fine tune my engine. Also, I only have one mark on the pulley and the tab on the block has the marks from 12 btdc to 0 then up to 6 atdc. How do I set the timing to 32 degrees at 3500rpm without any markings? Do I need a degrees strip on the balancer? Sorry for the long winded questions. Any help would be appreciated. Rebuilt stock 283, new petronix flamethrower dizzy, new petronix coil, new edelbroke 500cfm
Idle and vacuum advance disconnected. Measure the distance of 0-6 then mark 12,18,24,30. This will get you close to your 32-34 total. Old stuff Ive had liked 8-12 initial timing. Remember the timing chain probably has some slop in it so you will have to finesse it to get optimim performace. Also remember to much advance will make the engine crank slow . Ron
i like 10 degrees make sure your timing marks are correct....chevy moved them around a bit over the years so if you have a 283 balancer and a later timing cover with a tab it could be off
That's one way to do it. Another way is with a fancy timing light that has a dial or advance display on it, they're pretty common. you set the timing light advance dial to 32 degrees, then rev the engine (vac advance hose disconnected) to 3500 rpm and see if the timing light shows "TDC" on the timing marks on the engine.
I agree with May-Pop, about the timing chain. Remember, a sloppy timing chain alters timing.....Plus, gives you bad gas mileage and limited performance. In my 57' Chevy (High school car) I heard a funny noise under the hood, only to find oil leaking frron the timing cover. Seems that the chain was so sloppy that it was banging against it and made enough of a worn spot, oil was leaking out! Also, check for true top Dead center to validate your timing marks.
I think I need to invest in a good light. So by setting the light dial to 32 with the rpm at 3500ish the mark on the balancer should be alinged with 0 on the degree tab?
Ive actually had customers(yrs ago) and friends that when watching me with a dial-back light thought that turning the dial on the light changes the timing-
Rather than tune to a spec that may no longer be valid due to engine mods, advance the timing till she pings under hard acceleration then back off a degree at a time till the pinging stops. Then measure the timing as stated above and write it down for future reference.
If the timming cover and balancer ae original and you have not yet stabbed the distributer, take the rocker cover off. Now turn the engine until the intake valve is just closing. You should be turning the engine clockwise. When the intake valve closes it is ready to fire. Now look down to see your timming mark and when it rolls around to 4 degrees BTC stop and stab your distributer with the rotor pointing at #1. That should be close enough to get it running. If it is a fresh rebuikld you ware going to want to get the cam shaft broken in so do at according to manufacturers instructions. After that with it idleing grab your light and check your timming. that would be with the vac advance disconnected from a va***m source. I probably would not worry about total timming at this point. Get it to start and run first then worry about total timming.
We cannot know what you actually have there........bone stock low HP, or something else??? Initial timing and full-in timing need to be matched to the engine........for good ***istance off this board you will need to list at least these engine details: compression ratio, cam specs, lifter (solid or hydraulic), valve sizes, intake and carb description, intake/exhaust port sizes, distributor type/specs........ In general, the high compression 283 (with a good "street" cam, heads and headers) likes a lot of initial timing......somewhere around 12 degress btdc, and full-in timing around 38. They also like full advance by around 2200 RPM....you will need to re-curve the distributor from stock. Bone stock low HP 283's run great at 8 degrees btdc, around 36 degrees all-in.
Here's the poor mans timing light and timing tape way of doing things. Takes all lil work and patients but it's free. 1- Line up timing mark at 0 2- Rotate engine CC rotation 10* and mark the balancer 3- Repeat step 2 two more times. That will give you a 30* BTC position on the balancer. 4- Use a hack saw blade and score the 30* mark 5- Paint that mark another color than the zero mark for referance Now you can time your engine off that new mark on the 2* mark and you will have 32* BTC timing. No new light, No degree tape, No money spent
Dane hit it (almost) right on the head. That's the Smokey Yunick method, and it works. Just back it off 2 more degrees from when it stops pinging to give you a little margin (also from Smokey). My 2 cents, Dan
The text book timing you mentioned, is stock. It is done at idle, vacuum advance disconnected, and plugged. You say there is a mark for 10 and 6, go just shy of 6. You may find it likes a little more advance....Depending on your cam and compression. You may not want 32 deg at 3500, try it, but I have had to have a starting timing pull off, to get it started. Other wise it will crank hard. Race cars are fine lke that but street rods, not so much
32 all in on a street motor, should be fine. The earball method that Dane states should get you real close.
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