I was just installing new plug wires to the new distributor on my 4.3 engine swap when I realized that there is no degreed timing scale anywhere. The engine came with electronic ignition that used a crankshaft position sensor to control advance. I've change over to Carb with vaccuum advance distributor, but now I don't have a marked scale to set the advance.

The new distributor:

The damper has the TDC mark, but there is no scale on the timing cover or block.
I put a different distributor, wires, and coil on my boat with a 4.3 yesterday and it only took about 10 minutes to get the engine running and timed, but it had a timing scale to go by.
I need some help!
Thanks, Egor.

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"Of all the things I have lost during my lifetime, I miss
my mind the most."

Turn the crank over until the No.1 piston is at full stoke. (take the spark-plug out to see and make sure the piston is at the top)

Once that is done, drop the distributor in the hole and start the engine. If you can't get it running, turn the engine crank another 180 degrees and position the no.1 piston at full stoke. Again, drop the distributor down in the hole and start the engine. I now should be able to idle on it's own, but then you have to rotate the distributor to adjust the timing.

Make sure the distributor is pointing at the No.1 post firing position. Once you have the engine running you can paint a white mark on the harmonic balancer. Just make sure you have the engine at TDC before painting the mark.

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fierogt28

88 GT, loaded, 5-speed

Set the timming enough to get it running (if you haven't already). Keep advancing the timming until it kicks back when starting, then of course retard it untill it quits. Drive it & make sure it dosen't ping under load; if so retard it a little more untill it quits.
HTH,
Paul

All you really need is a marked location for TDC. Many timing lights have a built a degree dial where you turn it until the TDC mark is lined up and then read the dial for how many degrees of adjustment it took to get there.

Autozone and other parts stores also sell bolt on timing tabs if you want the degree marks.

I am pretty sure you have the plastic timing cover, and many people have installed it on older engines, so you should be able to install an older metal timing cover with the tack welded timing tabs on it. The plastic cover uses far less bolts than the Metal one, but I believe the common holes between them are in the same location and could be installed without issue.

During the engine mockup stages, I always remove the timing cover and find TDC based on the marks on the timing chain. Then slide the cover back on and make my confirmed TDC mark on the balancer and timing tab on the cover.

I am also sure there is a part # for what you need, but, that said, to time a carb'd engine it is not much of a mystery.

Figure out the #1 position for the distributor. #1 wire goes from that one to #1 cylinder. Rotate the assembly to TDC. You can check that two ways. Look at your rocker arms to determine both valves are closed, or stick a screw driver down the spark plug hole, or put some air into the spark plug hole to make sure the valves are closed.

You now have a "basic" timing position and you can start the engine. Choose a vacuum port on the intake manifold. There should be one there or on the carb body. Use a Large face vacuum guage and with the engine idling, move the distributor until you get the highest vacuum. Something along the line of 15 to 17 lbs/ft. You now have good timing.

Try driving it. If you get ping it is too far advanced. Set up your carb idle circuit and do it all over again.

Good luck

Arn

[This message has been edited by Arns85GT (edited 07-06-2008).]

Best way to locate the timing mark on an engine.
Crank the engine with your finger covering the #1 cylinder spark plug hole. When you start to fell pressure and you start to hear it leaking from around your finger you are on the compression cycle. Insert a dail indicator so it hit the top of the piston. Carank engine by hand using a wrench on the bolt on the balancer and watch the dial indicator When the dial indicator no longer keeps increasing in reading and just starts to go the other way by a few thousnads, you are at TDC. Mark the reading on the dial indicator and put a chalk line on the balancer. Now cycle the engine two roattions and finsih by hand to get to the TDC (highest reading) position. Now mark the balancer at the point where it aligns with the TDC pointer. I put a dimple in it with a hammer and punch and also use white out to paint a line. You've found the TDC position. Only accurate way to do it.

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87GT - 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

Thanks for the suggestions guys!

I already had the engine set at TDC from when I pulled the original computer controlled distributor, so when I installed the new vaccuum distributor, it is already within a few degrees of being right. I just need that degree scale to get it perfect.
Arns85GT suggestion to use a vaccuum gauge to set the timing would probably be good except that this carb was never used on this 4.3 engine. The last two applications were on a 360 Dodge V8 and a 460 Ford big block. It is not jetted for the 4.3 yet.
Fieroguru's idea to change out the timing cover from the plastic one to the older metal cover, unfortunitly, is the way I'll probably have to go to get the timing scale on this engine. It's just a real p'er because I am ready to slip the cradle back in the car and do some driving except for this small setback.
I've had more trouble with these kinds of little things on this swap than on the big things. Plus, I just don't get the time to work on it.
One of these days!
Egor

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"Of all the things I have lost during my lifetime, I miss
my mind the most."

quote Originally posted by Tha Driver: Set the timming enough to get it running (if you haven't already). Keep advancing the timming until it kicks back when starting, then of course retard it untill it quits. Drive it & make sure it dosen't ping under load; if so retard it a little more untill it quits. HTH, Paul

This is how I always have done it. Every engine runs slightly different and official specs are only an average. This method works no matter what kind of mods you make and is far more accurate for your specific engine. I had a car one time that ran far better with timing over 6* off what spec was.

Excellent information from all of you.