Slight flicker in my vacuum gauge. Questions. (1 Viewer)

[ColoradoFJ40]

77 FJ40 2F. 87k original miles. Since I’ve owned it and driven it about 1200 miles I haven’t adjusted the valves. Prior to my ownership it hadn’t been driven 1000 miles in the last 20 years. So I don’t know when the valves were last adjusted.

The truck has really been running well. Starting well. So I figured I should mess with something and see if I can screw it up.

I’ve got a perfectly tuned oem carb. I had the manifold and intake machined together. New manifold gasket etc.

From reading other threads and seeing the flicker in my vacuum gauge (noticed it when I was tuning the carb) that I might need a valve job. Now I’m a new mechanic so when I read about flickering vacuum gauges I don’t know how to put it in perspective. Mine twitches but does not fluctuate widely.

So would the experts review my video and let me know if this is nothing to worry about or point me in some other directions?

Btw. All new vacuum lines. Factory emissions still intact.

Thank you
Mark

 

[lcwizard]

good news is there's probably no vacuum leaks or weak piston rings and the carb seems to be adjusted well... but I'm on the fence about those gloves.
However, you may have worn valve guides or seals. When mine were worn in the number six cylinder it would smoke profusely from the exhaust
on nasty climbs. The oil would run down the guides into the piston chamber

 

[Splangy]

Adjust the valves before you start dumping time and money into it.

 

[ColoradoFJ40]

So to be clear. I adjusted the valves Friday for the first time ever .I had never done it before in this vehicle or any other . I think I took too long before I rotated the engine 180 when I did the last valves so I decided to redo things today .

Again, the truck runs strong. No hesitation or fumble . Idles beautiful .Starts easy. Absolutely no issues .My question is this....in an old engine like this should that much fluctuation of the vacuum be acceptable or should I keep at the valves .

Could having one valve wrong cause the irradic vacuum?

 

[coonassjohn]

Nothing to worry about, if you had a problem it would not run as well as you say. that is more of a vibration than a flux.

 

[thebigredrocker]

I have a cheap handheld vac gauge and a in cab autometer vac gauge. Neither flickers like yours.

Did you check valves while your engine was hot and running. If not, get some Go/ NoGo gauges and give it one more try.

 

[coonassjohn]

Had the same flicker in my gauge once, blew the carbon out the engine and it went away.

 

[Spike Strip]

Adjust valves.

Vacuum 101 - Land Cruiser Tech from IH8MUD.com

 

[ColoradoFJ40]

Adjusted twice in the last two days

 

[1969FJ]

Maybe, the gauge is an issue. I would try another gauge to confirm results.

 

[ColoradoFJ40]

It is a cheap harbor freight .

I also wonder since I'm still smogged if I have a small leak coming from somewhere . I replaced all vacuum lines but there is a ton of old crap still on the engine .

 

[ColoradoFJ40]

I'm going to try a different vacuum port first .I used the brake booster port and I wonder if that has anything to do with it or not.

 

[Martyt]

Sounds like it is a great running engine— call me when that changes

 

[Solace in Solitude]

You’re barely fluctuating... seems more like a spark issue.

Pull your plugs...make sure they’re clean... check the gap.

Are your points good... and set properly?

Are your plug wires good?

Good dissy cap and rotor?

 

[coonassjohn]

hook the gauge to the engine, not anything else.

I'm going to try a different vacuum port first .I used the brake booster port and I wonder if that has anything to do with it or not.

 

[ColoradoFJ40]

I pulled all the plugs tonight and all of them could have been wrenched out by my 6 year old.

I didn't have a spark plug gauge to check the gap but I will get one tomorrow and check them all.

You can see from the pictures that some of them look a little different. The plugs are Denso W14EXR-U. They only have 150 hours on them but some were from tuning and adjusting the timing with long periods of idling.

I have new plugs on the truck but I believe I just cleaned the distributor cap and rotor contacts. I left the points alone too.

My thought process was it ran when I tore it down but then I rebuilt the carburetor and pulled the dizzy out and I wanted one less variable for me to screw up if it didn't start. I have new points but since it has been running so good I've just been holding on to them.

I also got a better vacuum seal tonight and will post another video. Vibrations are less than before but I want to know what you guys think of the spark plugs.

 

[ColoradoFJ40]

The rest.

 

[ColoradoFJ40]

Last ones .

 

[ColoradoFJ40]

 

[Solace in Solitude]

Densi W14EXR-U are hot plugs... this is what @FJ40Jim recommended a few years back.

Jim recommended they be gapped at .32, rather than the .39, that the FSM states.

There are many plug diagnostic sources on the web... just search for “spark plug diagnostics”.

Here’s one Spark Plug Fouling