NCSUDucker
Senior Member
A little backstory and any input is greatly appreciated as I'm learning all the time here. The truck (39 tonner) was towed to my mechanics this morning but would definitely like to hear any input from all the flathead knowledge here.
I've put about 4500 miles on the truck since the rebuilt motor was installed. Here was how the motor was built.
It's a 59a - Ported & Relieved
Ross Forged Pistions (.125 over) 3 5/16"
Total seal rings to match pistons
Offset grind mercury crankshaft 4 1/8" stroke
N.O.S 21A connecting rods w/full floating bearings
New piston pin bushings
Cam Dynamic "Street Grind" cam
Isky adjustable lifters
Isky 185g (not sure about the g, as I'm reading his notes) Springs
All new chevy 1.5 valves, valve hardware
Offenhasuer 400 Heads
Edmunds 2x2 intake
Rebuilt 94 carbs
Mallory electronic distributor
98% full flow oil filter
PCV system
Also a little note on the side that says .331 lift 207 Dur @.050
Broken in with 10w30 Lucas Hot Rod Break in oil
I do know the heads were used and repaired and cut/resurfaced.
Most of that is greek to me but figured it all might be pertinent.
Anyway I've never had it run hot, dash gauge reads right around 180 once warmed up and the mechanical gauge on the block reads about 195 usually when I stop the truck and pop the hood. I never have any steam or antifreeze from the overflow.
About a week ago, I was running some errands and noticed the overflow was steaming and losing a little coolant. I had smelled some on an earlier drive but didn't seen anything. I stopped and let it cool and added some coolant as it was a little low, none over the tubes. I had a small leak around one of the hoses at the bottom of the radiator and just though that lost some and that maybe I had not checked it recently (as I usually do). I run it about a 1/2" above the tubes and like I said, no problems overheating ever. On the way home I started having some coolant mist blowing back on the windshield. Pulled over and sure enough a leak in the radiator. Let it simmer down just a bit and made it the couple of miles to the house no problem. When I got home it made some thumping/gurgling sounds. In reading I figured that I had overfilled a bit, the motor wasn't completely cool when I added it and in combination with the leak there was some air in the system.
I pulled the radiator and took it a local shop that has been there since the 50s. He said the tanks and the overall radiator were in great shape, just a had split seam in one of the tubes. He closed that one off and had me repaired yesterday. I picked it up and reinstalled the radiator. While I had it off I went ahead and pulled the thermostats and drilled the 1/8" hole in them. I filled the block first through the upper outlets with coolant, reinstalled the thermostats and the upper pipes. Opened the heater valve. Added little more to the tank and backed in on an incline, with the nose up. Ran it at idle with the cap off until the thermostats opened, never saw any bubbles or heard anything abnormal. Blipped the throttle af ew times. Put the cap back on and went for about a mile drive. Looking back I probably should have left the cap off longer. Got back to the house some gurgiling and water draining sound and steam out of overflow. Let it cool down some and repeated the incline process. Took it for another short test run, when I got back, not much in the way of sounds but some steam and coolant out of the overflow for about 1 minute. I took that as a pretty good sign as it was finding it's level.
This morning I checked the coolant and needed to add about a 1/2 gallon to get me to about a 1/2" above the coils. I figured that was air working it's way out of the system. Did the hand test over the radiator fill and felt zero pressure. Took it for a short ride, about 6 miles total. Temps great and no problems. When I got back just a little steam out of the vent that stopped quickly. I had an errand to run that was about 19 miles from the house so I figured I was good. I was planning on stopping at the auto parts store and picking up a block tester just to be on the safe side. Got about 12 miles into the trip and I hear kind of rattle sound that would cease if you backed off the accelerator again no issues with temperature. I start looking for the closest place to pull off. This all happened in probably less than a mile. Suddenly I start losing power and a lot of steam rolling out from under the truck. Coast into the parking lot of a Dollar General and it dies as I pull into the spot. I turn everything off and crack the hood, at this point I have steam coming from everywhere. Still no problem with temp as the mechanical was reading 190 to 195 like usual. From what I could tell I had coolant coming out around the passenger side head where it contacts the block.
I've done a ton of reading on here and the net in general. And while I won't be doing the work myself I want to make sure my mechanic knows what all to look for. He's the one that installed the motor, worked on the previous motor and got me on the road. Good guy and I trust him but I trust the wealth of knowledge on here quite a bit so if there is anything I should relay to him to check or to do when replacing the gaskets it would be greatly appreciated.
Hopefully nothing is majorly damaged.
Thanks in advance,
Brad
I've put about 4500 miles on the truck since the rebuilt motor was installed. Here was how the motor was built.
It's a 59a - Ported & Relieved
Ross Forged Pistions (.125 over) 3 5/16"
Total seal rings to match pistons
Offset grind mercury crankshaft 4 1/8" stroke
N.O.S 21A connecting rods w/full floating bearings
New piston pin bushings
Cam Dynamic "Street Grind" cam
Isky adjustable lifters
Isky 185g (not sure about the g, as I'm reading his notes) Springs
All new chevy 1.5 valves, valve hardware
Offenhasuer 400 Heads
Edmunds 2x2 intake
Rebuilt 94 carbs
Mallory electronic distributor
98% full flow oil filter
PCV system
Also a little note on the side that says .331 lift 207 Dur @.050
Broken in with 10w30 Lucas Hot Rod Break in oil
I do know the heads were used and repaired and cut/resurfaced.
Most of that is greek to me but figured it all might be pertinent.
Anyway I've never had it run hot, dash gauge reads right around 180 once warmed up and the mechanical gauge on the block reads about 195 usually when I stop the truck and pop the hood. I never have any steam or antifreeze from the overflow.
About a week ago, I was running some errands and noticed the overflow was steaming and losing a little coolant. I had smelled some on an earlier drive but didn't seen anything. I stopped and let it cool and added some coolant as it was a little low, none over the tubes. I had a small leak around one of the hoses at the bottom of the radiator and just though that lost some and that maybe I had not checked it recently (as I usually do). I run it about a 1/2" above the tubes and like I said, no problems overheating ever. On the way home I started having some coolant mist blowing back on the windshield. Pulled over and sure enough a leak in the radiator. Let it simmer down just a bit and made it the couple of miles to the house no problem. When I got home it made some thumping/gurgling sounds. In reading I figured that I had overfilled a bit, the motor wasn't completely cool when I added it and in combination with the leak there was some air in the system.
I pulled the radiator and took it a local shop that has been there since the 50s. He said the tanks and the overall radiator were in great shape, just a had split seam in one of the tubes. He closed that one off and had me repaired yesterday. I picked it up and reinstalled the radiator. While I had it off I went ahead and pulled the thermostats and drilled the 1/8" hole in them. I filled the block first through the upper outlets with coolant, reinstalled the thermostats and the upper pipes. Opened the heater valve. Added little more to the tank and backed in on an incline, with the nose up. Ran it at idle with the cap off until the thermostats opened, never saw any bubbles or heard anything abnormal. Blipped the throttle af ew times. Put the cap back on and went for about a mile drive. Looking back I probably should have left the cap off longer. Got back to the house some gurgiling and water draining sound and steam out of overflow. Let it cool down some and repeated the incline process. Took it for another short test run, when I got back, not much in the way of sounds but some steam and coolant out of the overflow for about 1 minute. I took that as a pretty good sign as it was finding it's level.
This morning I checked the coolant and needed to add about a 1/2 gallon to get me to about a 1/2" above the coils. I figured that was air working it's way out of the system. Did the hand test over the radiator fill and felt zero pressure. Took it for a short ride, about 6 miles total. Temps great and no problems. When I got back just a little steam out of the vent that stopped quickly. I had an errand to run that was about 19 miles from the house so I figured I was good. I was planning on stopping at the auto parts store and picking up a block tester just to be on the safe side. Got about 12 miles into the trip and I hear kind of rattle sound that would cease if you backed off the accelerator again no issues with temperature. I start looking for the closest place to pull off. This all happened in probably less than a mile. Suddenly I start losing power and a lot of steam rolling out from under the truck. Coast into the parking lot of a Dollar General and it dies as I pull into the spot. I turn everything off and crack the hood, at this point I have steam coming from everywhere. Still no problem with temp as the mechanical was reading 190 to 195 like usual. From what I could tell I had coolant coming out around the passenger side head where it contacts the block.
I've done a ton of reading on here and the net in general. And while I won't be doing the work myself I want to make sure my mechanic knows what all to look for. He's the one that installed the motor, worked on the previous motor and got me on the road. Good guy and I trust him but I trust the wealth of knowledge on here quite a bit so if there is anything I should relay to him to check or to do when replacing the gaskets it would be greatly appreciated.
Hopefully nothing is majorly damaged.
Thanks in advance,
Brad
