302 timing change when hot

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tndt1

Active member
Joined
Aug 18, 2011
Messages
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Location
Biloxi, MS
My Car
1973 white/white/white convertible, 302 V-2
Hey All, 1st post, Im having a problem with my 1973 Conv, I have a 191 degree thremostat and the temp goes up to 210-220 after driving for about 45 min. (I've never let it get any higher) As I get off the freeway and drive around town I have a very noticable ping when I accelerate. (Timing ping) until the engine cools down. However it never pings when its cold or with the temp going up, The car runs great.

Any body else ever heard of this or anyone have an idea on what to work on???

Thanks in advance

Ted

 
Try retarding your timing just a hair. Without knowing what build you have, could be low on octane also. The temperture issue is a unknown. Be aware that coolant under pressure does not "boil" at 212 degrees. That being said. Did you just rebuild your engine? Paint it? And lastly. What was the "normal temperature before ? Look forward to hearing from you.

 
Try retarding your timing just a hair. Without knowing what build you have, could be low on octane also. The temperture issue is a unknown. Be aware that coolant under pressure does not "boil" at 212 degrees. That being said. Did you just rebuild your engine? Paint it? And lastly. What was the "normal temperature before ? Look forward to hearing from you.
I Just have a standard 302, V2 I think it was rebuild previous but I dont really know. The only thing I have done to it is replace the left side head gasket. and had it painted (Exterior) When I had a 160 degree thermostat in it seemed to run cooler. I also recently replaced the Carb, manifold and distributor and put in electronic points. The car runs really good when its cold but when it heats up is when I have the timing prob. I'l try to retard the timing and let you know. What is the "Normal" running temp supposed to be? My truck (2007 Chevy) runs at about 210 normally.

 
::welcome:: The normal temp is dependent on your thermostat and coolant mix. Pure water will behave the same way as pure coolant/antifreeze and tend to run hot. 50-50 is typical. Was there a reason you put in a 190 deg? I think it originally came with a 180 deg.

BTW why don't you go and put a post in the introductions forum so the group can give you a proper welcome. Hope this helps.

 
Just took the 73 out on the hwy after readjust the timing, no go. the temp still went up to 230, within 15 min of driving at 70-75, and the pinging was still there. When I shut it down, the gage went past 250 and the car wouldnt start. I let it cool down and after readjusting the timing it started without a prob. The temp went back to 200-210 and I drove around town and did some erands, no probs. The car never "Overheated" per-say but I did have some fluid in the overflow. I hate that I cant take it on a road trip.

 
What kind of fan are you running. If it is a clutch fan have you checked that?
It is a 5 blade fan w/o a clutch
Have you checked temps at the top and bottom hoses for actual temps? to rule out the gauge and make sure the radiator is doing

No I haven checked the actual temps yet, but I know that its very hot LOL
 
The pre-ignition is occurring because of the excessive engine temperature. If the Ported Vacuum Switch is still operational it will advance the timing when the engine gets hot to increase engine speed and therefore fan speed in an attempt to cool the engine down. What symptoms were present that caused you to change the head gasket? Did it get too hot after you changed the head gasket or only after you changed the thermostat? What is initial and total timing now? Is the fan shroud in place? Is the lower radiator hose collapsing when the engine gets hot? Chuck

 
When you say the car wouldn't start. Was it acting like a dead battery (turning real slow)until it cooled? If so, you may want to drop your pan and have a look at the mains, especially the thrust bearing.

 
The pre-ignition is occurring because of the excessive engine temperature. If the Ported Vacuum Switch is still operational it will advance the timing when the engine gets hot to increase engine speed and therefore fan speed in an attempt to cool the engine down. What symptoms were present that caused you to change the head gasket? Did it get too hot after you changed the head gasket or only after you changed the thermostat? What is initial and total timing now? Is the fan shroud in place? Is the lower radiator hose collapsing when the engine gets hot? Chuck
Thanks for the Ideas Chuck, I have no idea where or what the OVS is or if it's operational, all the smog and orginal air cleaner have been removed. I changed the rt side head gasket because there was a leak between the #7 & #8 cyl. I dont know if the car was overheating prior to changing the HG, but I never noticed. I changed to the 190 thermostat because the auto zone guy told me that that was the correct one, The timing at idle is on the 1st mark. I removed the vacume line and plugged it and increased the rpm to about 4000 rpm the timing went past the middle mark and almost to the 3rd mark. The shroud is in place and the lower hose is fine when it's hot. when I Changed the HG I also flushed out the radiator, got alot of crap out of it and with only water in it it stayed pretty clean. I run a 50/50 antifreeze mix.

 
Just a off the wall thought, does your car still have the "butterfly" type flapper on the exhaust that is used for a quicker warm up? If so and that stays shut off would be the same as a stopped up exhuast and could cause this also

 
The pre-ignition is occurring because of the excessive engine temperature. If the Ported Vacuum Switch is still operational it will advance the timing when the engine gets hot to increase engine speed and therefore fan speed in an attempt to cool the engine down. What symptoms were present that caused you to change the head gasket? Did it get too hot after you changed the head gasket or only after you changed the thermostat? What is initial and total timing now? Is the fan shroud in place? Is the lower radiator hose collapsing when the engine gets hot? Chuck
Thanks for the Ideas Chuck, I have no idea where or what the OVS is or if it's operational, all the smog and orginal air cleaner have been removed. I changed the rt side head gasket because there was a leak between the #7 & #8 cyl. I dont know if the car was overheating prior to changing the HG, but I never noticed. I changed to the 190 thermostat because the auto zone guy told me that that was the correct one, The timing at idle is on the 1st mark. I removed the vacume line and plugged it and increased the rpm to about 4000 rpm the timing went past the middle mark and almost to the 3rd mark. The shroud is in place and the lower hose is fine when it's hot. when I Changed the HG I also flushed out the radiator, got alot of crap out of it and with only water in it it stayed pretty clean. I run a 50/50 antifreeze mix.
If I remember correctly, the damper is indexed from 10 degrees ATDC to 30 degrees BTDC in 2 degree increments. Longer marks every 10 degrees with a number (10,20,30). The shorter marks in between the are not numbered and occur every 2 degrees. When you say "mark" you mean the long ones with a number, it sounds like the timing may be retarded a lot. That would make it run hot. Maybe I'm misunderstanding what you said. Did it run hot after changing the head gasket or after you changed the thermostat? Chuck

 
The pre-ignition is occurring because of the excessive engine temperature. If the Ported Vacuum Switch is still operational it will advance the timing when the engine gets hot to increase engine speed and therefore fan speed in an attempt to cool the engine down. What symptoms were present that caused you to change the head gasket? Did it get too hot after you changed the head gasket or only after you changed the thermostat? What is initial and total timing now? Is the fan shroud in place? Is the lower radiator hose collapsing when the engine gets hot? Chuck
Thanks for the Ideas Chuck, I have no idea where or what the OVS is or if it's operational, all the smog and orginal air cleaner have been removed. I changed the rt side head gasket because there was a leak between the #7 & #8 cyl. I dont know if the car was overheating prior to changing the HG, but I never noticed. I changed to the 190 thermostat because the auto zone guy told me that that was the correct one, The timing at idle is on the 1st mark. I removed the vacume line and plugged it and increased the rpm to about 4000 rpm the timing went past the middle mark and almost to the 3rd mark. The shroud is in place and the lower hose is fine when it's hot. when I Changed the HG I also flushed out the radiator, got alot of crap out of it and with only water in it it stayed pretty clean. I run a 50/50 antifreeze mix.
If I remember correctly, the damper is indexed from 10 degrees ATDC to 30 degrees BTDC in 2 degree increments. Longer marks every 10 degrees with a number (10,20,30). The shorter marks in between the are not numbered and occur every 2 degrees. When you say "mark" you mean the long ones with a number, it sounds like the timing may be retarded a lot. That would make it run hot. Maybe I'm misunderstanding what you said. Did it run hot after changing the head gasket or after you changed the thermostat? Chuck
Hey Chuck I Just rechecked the timing and it is set on 10btc



Just a off the wall thought, does your car still have the "butterfly" type flapper on the exhaust that is used for a quicker warm up? If so and that stays shut off would be the same as a stopped up exhuast and could cause this also
Hey, No butterfly , headers

 
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Head gasket on backwards?
I didn't want to bring it up yet but, what TommyK suggested is a possibility. No insult to the installer intended. Chuck
I guess that is a very real possiblity, the guy that put it in for me is an "OLD" shade tree mech. He has rebuilt many engines esp Mustangs. who knows??????? Thanks Chuck and everyone else that has replied

Ted

1973 Mustang 2.jpg

 
OK guys, I talked with a radiator guy today and we pulled the radiator for purging and redoing. I hope this fixes both the overheating and the pre-ignition problem, I will let you all know

 
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