Timing??

[Kasey 1977 K10]

I have a 1977 Chevy K10 with the 350 small block. I just had the intake and carb replaced. While that work was being done we noticed the distributor was in pretty bad shape so we put in a new one. I didn't noticed the following issue prior to that work. For the issue.. When the truck is in park under any RPM I dont have any issues. However, when in Drive if I aggressively accelerate I can hear what sounds like a tin can full of nuts and bolts being shaked gently. At first I thought it was my transfer case shifter. If I accelerate slowly I dont notice it and if I hammer down on it I dont notice it. I have done a bunch of research and to me it sounds like my timing is too advanced. Does this sound right to you guys too or do you have any other suggestions?

 

[HotRodPC]

Are you trying to say it's pinging? Cuz normally a timing issue whether retarded or advanced doesn't cause any noise, with the exception if pinging or detonation knock. But you say when you hammer down on it, it doesn't make the noise. If it was detonation, it would be even worse when you hammer down on it. Unless of course when you hammer down the exhaust gets louder and you're just no hearing it.

 

[Kasey 1977 K10]

Are you trying to say it's pinging? Cuz normally a timing issue whether retarded or advanced doesn't cause any noise, with the exception if pinging or detonation knock. But you say when you hammer down on it, it doesn't make the noise. If it was detonation, it would be even worse when you hammer down on it. Unless of course when you hammer down the exhaust gets louder and you're just no hearing it.

I think thats the case. I think its still happening I just cant hear it. I've been watching additional videos and it sure sounds like detonation. I've been driving it for a few days now since the carb swap so I hope I haven't done any permanent damage. I certainly wont continue driving it till I get it ironed out. I can try to retard the timing but I may just have someone who knows more than me adjust the timing appropriately. I dont really want to do guess work.

 

[HotRodPC]

I'd just retard it about 2 degrees at a time until it quits and call it done. That's if it's a stock dizzy that hasn't been modified. If someone has played with the weights and springs then maybe it's just advancing the timing to quick and it needs a bit heavier spring set in it. If you bought the dizzy and just installed it, then that's not the case and I'd just retard it 2 degrees, take it for a drive.

 

[Kasey 1977 K10]

I'd just retard it about 2 degrees at a time until it quits and call it done. That's if it's a stock dizzy that hasn't been modified. If someone has played with the weights and springs then maybe it's just advancing the timing to quick and it needs a bit heavier spring set in it. If you bought the dizzy and just installed it, then that's not the case and I'd just retard it 2 degrees, take it for a drive.

Thanks, its a stock distributor with a brand new NAPA cap, rotor and coil.

 

[rich weyand]

Here's some reading for you.
http://www.gmsquarebody.com/forum/showthread.php?t=14508

Be interesting to see which vacuum can is on it. Look down at the bracket between the vacuum can and the distributor cap (use an inspection mirror or take a pic with the cellphone) and look for the markings there. Those numbers should be visible:

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[Kasey 1977 K10]

I have a 1977 Chevy K10 with the 350 small block. I just had the intake and carb replaced. While that work was being done we noticed the distributor was in pretty bad shape so we put in a new one. I didn't noticed the following issue prior to that work. For the issue.. When the truck is in park under any RPM I dont have any issues. However, when in Drive if I aggressively accelerate I can hear what sounds like a tin can full of nuts and bolts being shaked gently. At first I thought it was my transfer case shifter. If I accelerate slowly I dont notice it and if I hammer down on it I dont notice it. I have done a bunch of research and to me it sounds like my timing is too advanced. Does this sound right to you guys too or do you have any other suggestions?

Thanks for all the advice folks! I had someone come help with a mobile tack and timing light. The timing was somehow set to over 20. Dialed it down to 10, adjusted idles, fuel mixture and the choke and it is running like a champ!

 

[HotRodPC]

Yep, so you just had a detonation ping from the timing being to far advanced. Glad you got that fixed pretty quick.

 

[Kasey 1977 K10]

Yep, so you just had a detonation ping from the timing being to far advanced. Glad you got that fixed pretty quick.

I believe so. I took it for a test drive and couldn't get it to ping again so pretty confident it was timing detonation. I drove it like that for maybe 20 miles so hopefully didn't do any permanent damage. Doesn't sound/feel like it but who knows if the pistons are in as good of shape as they were before.