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bobbybelair
09-03-2015, 03:44 PM
I think I need to fiddle with the timing on my stock 283. I get a bit of rattle sound when I get on it just before shifting into second. Too much advance on the timing? Another clue is sometimes when it is hot and I have stopped for gas, when I turn the key the engine will turn a bit, basically go dead stop, then fire up. Too much advance in general?

I'm going to unplug the vac advance - do you plug the vac going to the distributor or the carb? Also, set the advance to 36 at 2500 revs (don't have a tach so will have to guess revs, I'll get a timing tape and glue it on as Rick_L suggests), then check what the advance is at idle for reference, with the vac plugged back in. No distributor genius here, I assure you, so any help appreciated.

bobbybelair
09-03-2015, 04:21 PM
Just cracked the manual, and it calls for 4 degrees at 1000 rpm. Assuming the distributor is still in decent shape, I guess I should start there. Not having a tach handy, I will probably end up setting it by drive and feel anyway.

Rick_L
09-03-2015, 04:59 PM
When you say it's "rattling" on the 1-2 shift, is that with your foot on the floor, or some other driving condition?

The initial timing spec of 4* was recommended back in the days when gasoline wasn't as good as now. You may be able to use more.

Don't worry about not having a tach, it's not really required. What you want to do when checking at rpm's above idling is just to slowly increase the speed until the timing quits increasing. This with the vacuum advance hose removed and plugged at the carb or manifold.

Tuning by feel and by ear (listening for pinging) is fine, but you want to use a timing light to know where you stand once you get it right. And you must isolate the vacuum advance from the mechanical advance to understand how both are working.

You have a good start and must have read some other posts.

bobbybelair
09-03-2015, 05:32 PM
This rattle has elicited a a different opinion on what it is from a few observers. It occurs when I get into it pretty good (doesn't have to be wide open) from a stop and becomes noticeable just before the Powerglide shifts into second, say between 35 to 40 mph. Quite a mechanical sounding clatter, mostly from the right passenger side in my opinion. It can occur in second at higher speeds if I get on it but not as noticeable.

Another point, but not sure if this is relevant - linkage needs adjusting because it doesn't kick down from 2nd to 1st at speeds that it should, say 35 mph. Or any speed where it should.

I figure taking a good shot at setting the timing one more time to eliminate it as a reason.

My old time mechanic friend says he thinks a cam lobe is somewhat wiped. Says it reminds him of the good living he made off replacing cams and lifters on the early 305s (and maybe 267s?) which had a bad grind and didn't rotate the lifters properly. That's possible too. I could pull the valve covers and watch the rockers to know for sure

chevynut
09-03-2015, 06:23 PM
Your symptoms sound just like a friend's 62 Impala did years ago...rattling, then hard starting after stopping at a gas station for gas. We never tried to figure out what it was. ;) I'd back off timing and see if it goes away.

I guess I don't understand what a cam lobe would have to do with it. It's either pre-ignition or detonation, imo. What is your CR? Have you tried using higher octane fuel?


back in the days when gasoline wasn't as good as now.

That's funny....lots of guys claim gas isn't as good as it used to be. LOL

Rick_L
09-03-2015, 06:37 PM
Certainly the hard starting when hot is usually an indication of too much initial timing. So that's what should be diagnosed and fixed first if needed.

If you have a bad cam lobe then that's another situation altogether. It's also possible to have a burnt exhaust valve seat.

A compression test can isolate these kind of problems, as will using a vacuum gauge.

Both the cam lobe and burnt exhaust seat will get worse pretty quickly.

But bobby don't let us discourage you into panicking, work through diagnosing all this.

bobbybelair
09-03-2015, 07:28 PM
No panic here, I've been nursing this old 283 since I pulled it a long time ago and did some backyard work on it. I sent the heads out to be done a couple years ago and put them back on after I broke 3 pushrods if you recall. I'm gonna pull it again someday and see if it can be saved. It's already 30 possibly 40 over I think. I won't rebuild it without a sonic test though - I'll be asking questions about that later.

It runs ok, and it is not hard starting, it always starts easy, just sometimes when I start it hot it turns briefly, does a quick interruption stop, then starts right up. All on the same key turn, it's a brief pause is all but it starts immediately. But I will do the timing and let you guys know.

chevynut
09-04-2015, 07:31 AM
To me your hard starting when hot problem sounds like it might be heat soaking of the starter solenoid. Have you tried to address that with a remote solenoid? It may not even be related to your timing, especially if it doesn't do it cold.

bobbybelair
09-04-2015, 08:55 AM
Anything is possible with this old boat, cnut. I'll tinker with the timing but don't think it is the problem.

Rick_L
09-04-2015, 11:16 AM
About 95% of the time or more, this "heat soak" problem is either timing related, or a bad starter. battery, or connections. The heat soak deal is overrated.

bobbybelair
09-04-2015, 02:14 PM
Diameter of those 57 balancers was 6 1/8" I think. Just want to make sure I get the right timing tape so I better measure it in case.

chevynut
09-04-2015, 02:19 PM
About 95% of the time or more, this "heat soak" problem is either timing related, or a bad starter. battery, or connections. The heat soak deal is overrated.

It wouldn't be hard to check out with a temporary fix. All you would need to do is put a long wire on the solenoid, cap it, then connect it to the battery when the problem occurs and see if it goes away. If it goes away, you need to figure out why the solenoid isn't getting enough current to it.

The solenoid needs 12V to it while cranking. If you have the typical smaller wires, ignition switch, neutral safety switch, and all that garbage ahead of the starter you can get voltage drop which only gets worse when the solenoid is hot and resistance increases. The idea of the remote solenoid is to switch the battery voltage directly to the starter solenoid, bypassing all that stuff.

55mike
09-05-2015, 07:10 AM
I would make double-dog sure the timing mark (at 0 ) is at TDC on #1 cylinder. Often pointers are simply not correct. A method I've used is to pull #1 plug and on the compression stroke (you'll get a puff of air) gently place a wire (a short chunk of a coated coat hanger will work) in the plug hole and rock the engine back-forth (i used the balancer bolt and a long breaker bar) . You'll feel the piston move up then down on the wire. Take some time, work back and forth, then double check yourself. Mark the balancer as "0" when you've determined the top spot. Keep in mind the piston feel like it's staying at the top before it travels back down. I spent some time "splitting the difference" with the travel of the breaker bar until I was satisfied I found the sweet spot. I fully realize this is a shade tree method, but, like I said it will get you very close . As for initial timing I agree with Rick. 4 degrees is very conservative. On a stocker... I'd see how it does at about 8 degrees initial.

bobbybelair
09-05-2015, 11:22 AM
OK, here is the story. I timed it for about 8* at estimated 1000 rpm. Still have the problem. I turned it down to about 4* and I was getting backfires out the carb. I kept turning it up til the advance is basically off the map - what sounds like small staccato backfires out the carb. Beginning to think the distributor is mistoothed.

Spark plug wire for number 1 is on the distributor cap at the right side of the dwell window. at idle and moderate cruising it runs fine.

bobbybelair
09-05-2015, 11:54 AM
But I am pretty sure it is not out a tooth. Else it wouldn't idle and run ok at moderate driving levels. It runs ok at idle and normal driving across a fairly wide range of timings, from 6 to 8 to even more.

bobbybelair
09-18-2015, 06:18 AM
I'm moving my timing/distributor thread back here for a current summary.

I put electronic points and a new coil (Pertronix both) in. Set timing at 10* initial, which is where it seems to run best. Starts easy and fast, hotter coil seems to be helping overall.

Car runs VERY well with normal driving, and under "solid" acceleration. Pushing it brings on the machinegun rattle (or ping?) nearing Powerglide shift to second. Downshifting to first will also cause the staccato rattle. At 50 and up in second gear, if pushed there may be a mild rattling (where it doesn't downshift so revs don't get so high).

Vacuum gauge test steady as a rock at 20. Blipping the throttle brings it down to near zero, rebounds to 25 and settles back to steady 20. Normal readings. Pulling off the hose to the Vacuum canister will make the vac gauge drop to 16 or so, "late timing" area of vac gauge. Vac gauge is tee-ed between bottom of wcfb 4 barrel and vac canister. Indicates to me the vacuum canister on the distributor is working, at least in some fashion.

Is it possible that the springs on the advance mechanism have become weak causing too much mechanical advance under load? This distributor was in the car in 1975 when I got it, and has some considerable miles put on it since, off and on (60k +). I haven't been able to check the total timing yet , trying to get my hands on a timing light, or maybe this weekend I will try to get a good measurement on the balancer diameter to scribe it, which is not so easy while in the car.

chevynut
09-26-2015, 07:38 AM
But I am pretty sure it is not out a tooth.

There's no such thing as being "out a tooth" on the distributor. All that would do is make the distributor body sit in a different position, but the timing would be the same.

chevynut
09-26-2015, 07:53 AM
I put electronic points and a new coil (Pertronix both) in. Set timing at 10* initial, which is where it seems to run best. Starts easy and fast, hotter coil seems to be helping overall.

Did that fix the hot start problem too? Or have you had a chance to get it that hot? Electronic ignition is the way to go, imo, but I personally don't think that was your hot starting problem.


Car runs VERY well with normal driving, and under "solid" acceleration. Pushing it brings on the machinegun rattle (or ping?) nearing Powerglide shift to second. Downshifting to first will also cause the staccato rattle. At 50 and up in second gear, if pushed there may be a mild rattling (where it doesn't downshift so revs don't get so high).

This is where it gets confusing to me. You say "pushing it" brings on the pinging...does that mean when under a heavy load or when RPM is high? When you downshift to first, is that coasting with your foot off the throttle?


Is it possible that the springs on the advance mechanism have become weak causing too much mechanical advance under load?

Mechanical advance works on RPM, not load. The faster the distributor turns the more advance you get up to a point. Can you somehow limit the mechanical advance temporarily to test it out? I doubt that's the problem.


I haven't been able to check the total timing yet , trying to get my hands on a timing light, or maybe this weekend I will try to get a good measurement on the balancer diameter to scribe it, which is not so easy while in the car.

So how have you been checking the timing without a timing light?:confused: And why do you think you need to know the balancer diameter? Do you know your static compression ratio of your engine?

If it was me I'd start a process of elimination. This sounds like preignition or detonation to me based on your description of the problem and not having heard it myself. But some of your description of the problem doesn't seem to fit, like the "downshifting" comment.

I would verify your initial timing and make sure the timing mark is correct s suggested. Then I'd quit messing with the timing. Next I'd try high octane fuel to see if it goes away or improves. If it's mechanical could it be a lifter not working properly at high RPM? Does this sound like it's coming from one cylinder or all cylinders?