Questions about recently refurbished 1965 GTO

[starfireelvis]

I am asking this on behalf of a friend, who owns the 1965 GTO Coupe that he and his Mom placed a special order for back in February of 1965, and picked up at the end of March that year.

After being garaged and not started since 1991, he started refurbishing all of the mechanicals two years ago, with extensive work just short of an engine rebuild being done by a shop with experienced old-car mechanics, and drovethe car for the first time in many years a couple of months ago. For the most part, the car runs well and is very responsive, but he has a couple of questions of concern.

He is having problems with the temperature gauge reading 3/4 hot and then starts hearing some ping, once he reaches and drives a short distance at high-speed (65 mph and above). He uses high-octane fuel with an octane boost, and an ethanol inhibitor, and also uses oil with ZDDP. He also uses a proper mix of conventional anti-freeze.

Pertinent info would include that it is a 389 4-barrel with a manual transmission (not the Rock Crusher), and that he had the original radiator replaced with a four-core radiator and a six-blade fan. He also had the water pump replaced, as well as all of the hoses, and has a 180-degree thermostat in place. Should he change to a 165-degree one? He says the gauge should be accurate, as it is also from a new cluster,and noted that with the cap off, the thermostat opens right at 180 degrees.

Is it a timing issue? He has a conventional distributor installation (choosing for now, not to fix the cost-prohibitive transistorized system that the car came with, though he still has it and may do so in the future), and naturally the car has been tuned up to specs. Could the water pump be the incorrect one for the car(he does not have A/C, don't know if there is a difference in pumps between cars that do and don't have air)?

Just looking for answers on troubleshooting and where to look to resolve these issues. Thanks in advance for any advice.

Mike

[Guest 1arunem]

I would look at the timing first based on running hot and pinging..

[GARY F]

radiator cap, is it correct & new

[Guest DRM500RUBYZR1]

1- Is the spring in the lower radiator hose to prevent it from collapsing during high speed flow?

 

2- Does it have a clutch fan, although i doubt that it should, but if it does when you shut off the motor is the fan locked due to the heat?

 

3- Are belts tight, any slippage,

 

4- is radiator the same temp at top and bottom, as well as left and right? any cool spots, is it new or was it cleaned?

 

5- does it stay cool idling and get hot while driving? or does it get hot both ways

 

6- is the pressure 12-15 lbs? check the cap at an auto parts store.

 

7- any bubbles in the coolant while running?

 

8- any coolant in the oil?

 

9 - were the heads done by a pro?

 

10- timing, timing timing!!!

 

p.s.

 

putting in a 165 stat will not improve your situation at all. opening the tstat 15 degrees sooner will have no material effect on an engine temp rising to the point of pinging. such symptoms state that you are going well beyond 180, so opening at 165 might delay the rise for a couple of minutes, but it will rocket right by 165 then 180 etc.

 

was the engine comlpetlely disassembled and known to be free of all stop leak, rust grud etc in the passages?

 

could some stuff have been trapped in the radiator and or heater core?

 

are your heater hoses properly connected and flowing

 

please report your findings.

 

good luck

 

while it is hot, spray cold water from a hose on the radiator. temp should plummet and remain low while being sprayed with water. if it does the radiator is cooling properly, if temp does not plummet either the radiator is malfunctioning, or you have some thing significant within the engine causing the heat such as blocked flow, combustion leak, failed gasket etc., or any headwork done around the water passages may have breached one passage.

 

Marty

Edited August 5, 2015 by DRM500RUBYZR1 (see edit history)

[TexasJohn55]

Confirm temperature with an infrared temp gun or leave cap off and warm it up with another guage bulb in the top of the radiator.

Premium fuel does not have the high octane rating as it did in years past before no-lead. It likely requires at least 93 octane. Todays premium needs a timing adjustment. Check timing by the book, back it off 2* and drive it. If necessary, back off another 2*. Start first at factory spec and retard until it quits pinging. Be sure you check the vacuum advance unit to be sure it advances and retards with change in vacuum.

Edited August 5, 2015 by TexasJohn55 (see edit history)

[GMPARTSMAN]

Another possibility is the water pump installation. Behind the water pump is a stamped metal plate. The assembly sequence starting from the timing cover outward is as follows:

Timing cover housing

Water pump gasket

Steel divider package GM P/N 9793131 (now discontinued by GM, aftermarket maybe?)

Water pump gasket

Water pump.

Not uncommon for a installer not familiar with Pontiacs to remove the old water pump AND leave the divider stuck between the old gaskets to it.

 

That is why there were two gaskets in a lot of water pump kits. If that divider is not there the water will not circulate correctly in the housing.

A real common problem in Pontiacs.