Vacuum Advance on Stock Distributor

[bigfoot72]

I started noticing a tick coming from the engine that I suspect might have to do with timing and vacuum advance. I’m pretty inexperienced with doing the timing though. I run 89 octane fuel at the moment. My distributor is stock and I’ve been wondering how to adjust the vacuum advance on it. It doesn’t have the adjustment for an allen wrench that I’ve seen on others. Can anyone offer any assistance? 

 

[Hemikiller]

When/where are you hearing the tick? 

 

[bigfoot72]

From the heads 

 

[Stanglover]

I'm not the expert here, but if you don't mind, a few questions that will help the guys who know. What engine do you have in your Coupe? Why do you suspect the vac advance? Stock dizzy with points ? Please add as much info as you can about the motor. Has it been rebuilt. 

I do have some first hand experience with my 351C 4V M code. I had a lot of problems at first with timing, but over time, I learned how to sort it all out. Hence the questions.

 

[Don C]

The most common cause of ticking from the heads is loose lifters, which may be caused by stuck or collapsed lifters.

When do you hear the ticking? Just at idle, or all of the time? 

Low oil pressure can also  cause the ticking, because the lifters aren't getting enough oil to pump up the lifters. Have you checked the oil level lately?

 

[bigfoot72]

It’s a 351-2v Cleveland, stock bottom end. I took apart the top half of the engine and got the heads refurbished due to a hairline crack in both. I also added a 4 barrel Edelbrock 650cfm carb & performance intake manifold, along with Hedman headers. It has a stock distributor but with a pertronix igniter. I started noticing the tick when I switched from 87 octane fuel to 89 after the rebuild. I decided to add Seafoam in the crankcase to see if that would help at first but nothing. I was adjusting the idle mixture screws and realized I had the vacuum advance plugged in to the wrong side of the carburetor. This actually solved a rough idle I had but didn’t change the tick sound in the heads. 

 

[timachone]

The above said nevertheless explains the ticking from the heads. As said ticking from theads is normally by the lifters. If yoou have solid one it is a kind of normal (not excessive) and by hydraulic lifters it should be mostly gone when full oil pressure is there by driving it a few miles. But one question first: did you changed the lifters or pushrods? It is not uncommon that they could fail from new on or by a false running-in procedure... Pushrods have the correct lenght, oil channels free? Correct rockers, correct valve lash and rocker geometry to pushrod/valve tip? Also an inadequate oil pressure could be the problem. On the first glance I see no correlation to ticking from the heads and the distributor... 

 

[Stanglover]

Thanks for telling us what you have motor wise. I am far from being an engine guy, but I don't think timing or a vac advance is your problem. A timing tic or knock won't sound like that. Also I can't help with Edelbrook stuff. Have you tried using a mechanics stethoscope to pin-point the tic? Also try 91 or high octane. My 10:1 comp motor does NOT like anything less!

As for timing, these motors like more initial timing than the factory setting. Again, I'm familiar with a 4V M code, but I have 14 degrees initial plus 20 degrees crank timing and about 4-6 deg. vac advance with a Pertronix II and coil, Autolite 25 plugs. The carb is a Holley 670. 

 

[Carolina_Mountain_Mustangs]

Try tightening your header bolts again. Sometimes an exhaust leak will sound like a tick. Pull the valve covers and while the engine idles put a wood dowel on each rocker and push on it to find the one with tick. Lots of things it can be but if just a tick don't worry too much. My F-150 has had a tick since brand new and now has 312,000 miles on it still ticks.

 

[Aus73Mach1]

David, your last comment "Try tightening your header bolts again." made me smile.

Some years ago, my Alfa GTV6 developed this quite loud top end metallic knock but only just when you put your foot down and at idle. With the old stick to the ear, sounded like #1 cylinder was the culprit and definitely somewhere in the top end. I took off the tappet cover, clearances all OK. Compression check also OK. Engine had done about 40K since a full rebuild. I didn’t want to pull the heads off (head gaskets not cheap) without first checking from below, so took a day to pull the engine out and onto the engine stand. Turned it upside down and pulled off the lower sump pan. Inside the motor looked as new, not a mark on the bore, big end bearing, etc. gudgeon pin was nice and tight, so I’m thinking it must be in the top end. Turned the engine back upright to start pulling it apart and only then noticed the 2 nuts from the #1 extractor/header flange had come off the studs. I gave the pipe a bump with my hand and there’s that metallic knock. The knock was the front flange banging on the head. Looking down at the motor in the engine bay you can’t actually see the nuts on the exhaust studs, also it didn’t sound like a typical blown exhaust gasket. So, three days to replace 2 manifold nuts and a few more "names" for the car. :classic_wacko: :classic_unsure:

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