Manifold Gaskets

[53 Truck-O-Matic]

Began replacing manifold gaskets today as part of solving a vacuum leak. There are two bolts, and when I loosened the left hand one, coolant poured out. Is this normal??

I sure hope so!!

 

Also, noticed some exhaust leak in #6 exhaust port, seen in photo. Ordered new gaskets from Roberts.

[mechresto]

Do yourself a favor...have your manifold planed. That should cure any recurring exhaust leak.

The coolant leak is normal,  the bolts go into the water jacket, put some #2 permanent on the threads when reinstalling.

[53 Truck-O-Matic]

Whew! Thanks for that word "normal"!

[53 Truck-O-Matic]

Manifold planed, new gaskets installed , vacuum gauge purchased and connected to intake manifold. See attached video of meter. Vibration is not good, is it? It otherwise reads well and does the right thing when I blip the throttle. But the vibration? Keep in mind this is a rebuilt engine on it's first hours running.

Also, it still won't idle with out some choke. Just stalls out immediately.

 

Any thoughts?

 

 

 

[53 Truck-O-Matic]

Manifold planed, new gaskets installed , vacuum gauge purchased and connected to intake manifold. See attached video of meter. Vibration is not good, is it? It otherwise reads well and does the right thing when I blip the throttle. But the vibration? Keep in mind this is a rebuilt engine on it's first hours running.

Also, it still won't idle with out some choke. Just stalls out immediately.

 

Here's another wierd issue. Timing light shows me set at a few degrees before TDC, but it comes and goes, that is - the TDC mark disappears then reappears. As if it goes 180º out, then returns. Sometimes gone for as much as a minute, then back, then gone. 

What up wit DAT??

Any thoughts about any and all issues??

THANKS

 

 

 

[53 Truck-O-Matic]

Sorry, I submitted the first note along with the second.

[DJ194950]

Try testing your timing light itself by hooking up the spark plug lead to say the #2 plug then others without paying attention to the TDC mark just aim the flash at the block to see if it does the same thing, going off etc. If it does the same thing then the timing light is the issue, if not then the #1 plug is only firing occasionally. Check the cap at #1 position and change plug wire and plug.

Hope I am making sense.

 

 

DJ

[kencombs]

 

The choke issue is obviously a fuel related issue if you're sure there are no vacuum leaks, and gauge seems o indicate there are not.  Idle circuit plugged maybe?

 

The vacuum 'bounce' may be related.  What is the idle speed?  Another source of that is a tight valve.  But, add the timing mark issue and I'd take a look at the distributor.  Either the vacuum or centrifugal mechanism may be at fault.

[The Oil Soup]

My gauge flutters just like that at 19" and the engine has 62k original miles on it.

[53 Truck-O-Matic]

I think timing light issue was operator error/iffy connection to #1 wire. Seems okay now.

Idle circuit is clean as far as I can tell.

It needs to idle in the 900-1100 range to not stall, accomplished with a some choke.

re: Kencombs:

"Either the vacuum or centrifugal mechanism may be at fault."            How do I check those? I have electronic ignition, by the way. Could the vacuum  be bad if the meter reads good at the manifold? Remind me, (he said as if he once knew!) what the centrifugal mechanism does.

 

[kencombs]

1 hour ago, 53 Truck-O-Matic said:

I think timing light issue was operator error/iffy connection to #1 wire. Seems okay now.

Idle circuit is clean as far as I can tell.

It needs to idle in the 900-1100 range to not stall, accomplished with a some choke.

re: Kencombs:

"Either the vacuum or centrifugal mechanism may be at fault."            How do I check those? I have electronic ignition, by the way. Could the vacuum  be bad if the meter reads good at the manifold? Remind me, (he said as if he once knew!) what the centrifugal mechanism does.

 

I don't have my manuals handy, but that idle speed is almost double what I recall as the spec.  So, something is wrong the the carb's Idle mechanism, plugged, misadjusted or something.

 

the reference to the advance mechanism was part of the timing issue, and it looks like you found at least part of that.

 

the mechanical advance springs have been known to break and cause timing jitter and/or vacuum pulsing.  Not likely since you found the cause of the timing light disappearing.

[mechresto]

Since you've covered the ign fault, and it's now holding steady spark.....

You're not going to like the next part....

There's only one more thing that's going to cause both symptoms you describe. No idle situation w/o choke and a fast fluttering vacuum.

The valves are leaking or mis-adjusted, or too loose in the guides, from what you've said all things point there.

It could be valve timing, however, the ability to achive high rpm smoothly negates that almost 100%.

 A head gasket leak on adjacent cylinders will show as a slow pulsing of the needle as those try to fire. 

I'll dig up the vac gage testing chart for you.

It will explain in detail.

Edited May 25, 2018 by mechresto
Wrong wording