305E V6 troubles

[charlie8297]

Hey All.

I have a 65 GMC with a 305E V6. It was last started it on Christmas day, start it about once every couple of weeks if not more, and drive it a round to keep things lubed. For now the truck is used as a truck.

Here's the issue: After the truck got warm, I heard for loud pops, dark smoke from the tail pipe, and died. I pulled the distributor, and this is what I saw (pic below).

The motor was supposedly rebuilt in the 90's and only has about 10000 miles on it. Besides the distributor gear being shot (distributor about three months old) and cam gear shot (more than likely), any other things to look for? The motor has always an hot for me. Changed the thermostat to 180 deg, didn't really help. After driving the truck for about an hour and a half or so, if I turn it off, I have to let it sit and cool before it will start again.

Any ideas would be greatly appreciated. I do not know any mechanics in my area that work know anything about this motor.

[BillT]

Never actually heard of a problem like that. I would look down at the Cam Gear the best I could to see what it looks like. Use a Magnafying Glass if possible. If it looks good (you may have to crank it around some), I would just try another Distributor, maybe a different brand. Don't forget to line everything back up, if you crank the engine around.

Keep us posted on it.

Bill

[705jmguy]

hi

do u know if your distributer is a off shore one? some of the Chinese ones may have very soft gears and just disintegrate with some use
perhaps you should get a delco one if u can and give it try
just a thought, that may help you

[abus319]

Charlie
I cant tell from the photo, did it just shear the teeth off in that one spot or are all the teeth distorted? Does the rotor turn freely?

[BobBray]

I saw a Ford do this once. The problem turned out to actually be the oil pump. The oil pump was sucking up broken teeth from the plastic cam timing gear. Now, the 305 didn't use a plastic timing gear, but something else could be binding the pump. Be sure to check the oil pump as well.

[charlie8297]

Bill and 705jmguy, When I replaced the distributor, I had a hard time finding one. I found it at AutoZone, brand name Cardone.

Abus, the gears don't looked to be sheared off, they look like it skipped half a tooth and the cam gear tried to make a new space in the middle of the distributor gear, if that makes sense. The rotor does spin freely with the distributor out of the motor, but in the motor, it felt like normal.

Thank you for the help guys. I might just pull the V6 for now and save some money to rebuild it later, and drop a 350 in it. It is my only truck right now and I need to get it back on the road. As you all know, finding parts is like pulling teeth for these motors. I have had 2 separate fall through in picking up a spare.

Bob, when I pull the motor, hopefully by this weekend, I'll take a look at that too.

[jrmunn]

Charlie,

FYI - I have driven my 1964 GMC pickup with a 305E for more than 30 years. It has never run hot, even when suffering from carburetor, fuel supply, and ignition system problems. In fact, it never gets above about the 1/4 mark on the temperature gauge with a 180 degree thermostat. Besides your distributor problems, I think a look at the radiator might be needed. I suppose a water pump problem could also cause overheating, but having replaced these pumps because of failing bushings, I can't imagine what else could go wrong with them. My only other thought is to check the radiator cap to make sure it holds the correct pressure, but you should have noticed the radiator getting low if the coolant was boiling out.

jrmunn

[Jim A]

I have heard mixed reviews on Cardone distributors. They may make new ones, but are known for rebuilts.
I wonder if you got one with the wrong gear. It would be nice if the cam gear won the battle and the dist gear took all the damage.
I would take it back to AutoZone and lean on them some.

I won't argue about radiator caps and proper pressure, but I have run my '60 305A for over forty years and thousands of miles with a broken cap spring and NO pressure.
It runs nice and cool and has never overheated. The coolant sits an inch or two down and if I top it off, it will go right back down there and stay for several years.

[tommyduncan]

I have a spare distributor laying around if you need it?

[BillT]

My 305 V-6 always ran cool, except when it ran at it idle too long. In about 8 minutes or so, the guage would start to rise and would keep going, until I started driving it again. Never figured out why ?? But I just learned to keep it at short idle periods.

Bill