Could you folks help me determine...

[dadsgreentruck]

...The condition of my 40 year old motor?

It's the 307 in my '70. The truck came into the family in the early '80s. As I recall, the odometer showed 17K. At the time I assumed it was actually 117K. It's now up to 128K (It spent about 10 years mostly sitting in my dads garage). Back then we had the heads re-built with new valves, added a steel timing set, and a cam that yields a slightly loping idle (don't remember what it is). On top we installed an AFB on a Performer manifold. Oh yes, and a Mallory dual point distributor with copper core wires. It was great fun to drive.

Fast forward 15K miles and 25 years. It just doesn't seem to have the "oomph" that it used to so I went out this weekend and did some diagnostics:

Compression: Cylinders 1-6 show 132-139 psi, while the 7 and 8 in the back are 119 and 121. Seems kind of odd the two in the rear would be that much lower since they are not adjacent.

Vacuum: fairly steady with a little wobble 14-15 in. at 850 rpm idle, leveling off at about 23-25 in. as rpm increases.

Advance: 10 degrees base. Don't know how much total I have as I don't have an adjustable timing light.

I also have a tick-tick-tick noise that I can't seem to determine the source. It seems to coincide with the wobble on the vacuum guage. I've also included a couple of spark plug pictures. They all look pretty much the same (Old bosch platinums). Reddish tan insulator with carbon depsits on the threaded end, though number 6 has some kind of tan colored build up on the ground strap. The pictures are fuzzy because I couldn't focus well that close.

I wonder if she could take a set of 305 416 casting heads?

Tim

[Sammy]

What about oil? Does it use any between oil changes? How is the drips from the pan area? Something to also think about when you consider changing the heads out is over powering the rings from increased compression with something that has that many miles. You may suddenly cause a huge increase in oil consumption in just a couple of thousand miles. Just some points..

[fine69]

Change over to a HEI ignition, some new AC plugs. New plug wires. Go from there. Add some Marvel Mystery oil to the crankcase. The tick is probably a gummed up lifter. Should go away.

See what happens.

[Hottrucks]

I agree^^^^^^^

marvel will help ...also add some to the fuel tank and fill it up with some MOBIL super its the highest detegent fuel and will help to clean up some of the inside carb stuff.....looks like its runnig well .....just in need of a tune up...

as far as you comp #'s they are all pretty good...but to address 7-8..well due to the slight tilt of the motor any fuel that drips (when you shut off a hot engines sometimes it causes fuel to leak out) it will drain the the back 2 holes...it doesn't make for an issue so to speak, but causes the back 2 to start dry ..over 40 years of starts it does wear the rings a little...

[dadsgreentruck]

Originally Posted by Sammy

What about oil? Does it use any between oil changes? How is the drips from the pan area? Something to also think about when you consider changing the heads out is over powering the rings from increased compression with something that has that many miles. You may suddenly cause a huge increase in oil consumption in just a couple of thousand miles. Just some points..

I haven't really kept track, but I would say I uses about a quart in 2000 miles. It doesn't smoke or leak. Spark plugs are dry too. I seem to remember putting a new front seal in along with the pan gasket back when we did all the work on it.

I said it doesn't smoke, but I did see smoke once when I started it up in 25 degree weather after it sat and cold soaked for a week. For some reason, the cold idle was set way too high. It smoked for about 30 seconds or so before I shut it down. I backed out the cold idle screw, restarted it, no more smoke.

Tim

[PanelDeland]

I agree with the above.Tune it and see what happens.I don't doubt it will run great with a tune.

[69 longhorn]

Its burnin clean Looks like a runner to this old man! I agree with the rest, give her a good tune, run a little Marvel, or Rislone through the crankcase.....a few easy miles, then let her run. You can live with 10-15% spread highest to lowest on the comp pressure, & after things "free up" after the long nap, it may get better crazyAL

[dadsgreentruck]

Thanks for all the replies!

A couple of more questions though:

Do I have to be concerned about cam wipeage with todays oils?

Is HEI *that* much better than the dual point unit I have? Its only got about 15K on it...
How about a Mallory Unilite? They look pretty nice and looks like it's the same size as the one I have.

Tim

[Sinister]

Originally Posted by dadsgreentruck

Thanks for all the replies!

A couple of more questions though:

Do I have to be concerned about cam wipeage with todays oils?

Is HEI *that* much better than the dual point unit I have? Its only got about 15K on it...
How about a Mallory Unilite? They look pretty nice and looks like it's the same size as the one I have.

Tim

Todays oils suck for flat tappet cams. I add some ZDDP Plus when I change the oil. I had swapped to an HEI from a fairly new points distributor, and really couldn't tell much of a difference. HEI is nice as far as maintenance though. Can't help on the Mallory question.

[Hottrucks]

run rotella diesal oil and as far as the HEI...I would stick to the stuff you have just due to the Kool factor but HEI's are zero maintance

[Fitz]

Sounds like you have several problems. A stuck lifter will tap and , since it is opening and closing a valve, your vacuum meter would dance in time with the tap. Good way to find out if it's a lifter is take a long screwdriver, put the screw end against the valve cover and your ear on the handle end. Try this in several places and stop where the tap is loudest.

Since it smoked when you started it after laying up for a while AND you have low compression on two cyls (but not too low) you might have worn or incorrectly installed valve guides on those two cylinders.
Installing an HEI wouldn't hurt, either but I suspect it'll be mo-bettah to fix the other stuff before going that way....just an opinion.

[mike16]

bad/old gas will cause a stuck valve. not correcting the problem and coninuing to drive the vehicle will lead to more damage and perminent damage. Fix whats wrong befor you go throwin money at somethin else