thermostat question
Thread Starter
Racer
Joined: Feb 2006
Posts: 428
Likes: 1
From: West Des Moines Iowa
thermostat question
I have a completely stock/original 327/300 hp HO engine in my 68 vert. It has the original steel shroud and smog pump also. My question is: Should I be running a 195 deg thermostat in it, or just keep the 180 I stuck in their about a year ago???? Right now on the highway it runs between 180 to 190 constantly, but in town, or barely moving in traffic for over 30 minutes it will CLIMB to about 230 to 240. I'm wondering if this was because I altered the thermostat to a 180 deg one. I know that the stock unit was 195 deg, and I bet it was for a damn good reason.... Radiator, timing, shroud, coolant, water pump are all new and working great.
Gonzo
Gonzo
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Originally Posted by gonzo14
I have a completely stock/original 327/300 hp HO engine in my 68 vert. It has the original steel shroud and smog pump also. My question is: Should I be running a 195 deg thermostat in it, or just keep the 180 I stuck in their about a year ago???? Right now on the highway it runs between 180 to 190 constantly, but in town, or barely moving in traffic for over 30 minutes it will CLIMB to about 230 to 240. I'm wondering if this was because I altered the thermostat to a 180 deg one. I know that the stock unit was 195 deg, and I bet it was for a damn good reason.... Radiator, timing, shroud, coolant, water pump are all new and working great.
Gonzo
Gonzo
Make sure you have all of the insulation and barriers in place to isolate the air flow to go JUST through the radiator (and NEVER around it). This is the biggest cause of cooing problems. Is there an air dam on your car on the lower lip of the body? That will also help.
Thread Starter
Racer
Joined: Feb 2006
Posts: 428
Likes: 1
From: West Des Moines Iowa
Originally Posted by pws69
Changing the T-Stat to a 195 will have no impact on how high the heat will climb - I think you should keep the 180 in there.
Make sure you have all of the insulation and barriers in place to isolate the air flow to go JUST through the radiator (and NEVER around it). This is the biggest cause of cooing problems. Is there an air dam on your car on the lower lip of the body? That will also help.
Make sure you have all of the insulation and barriers in place to isolate the air flow to go JUST through the radiator (and NEVER around it). This is the biggest cause of cooing problems. Is there an air dam on your car on the lower lip of the body? That will also help.
Gonzo
Burning Brakes
Joined: Mar 1999
Posts: 1,047
Likes: 3
From: CA
Originally Posted by gonzo14
Yes, the air damn is in place fine, thus it runs around 180 on the freeway. I understand that the thermostat has absolutely no effect on any overheating problem (unless the thermostat itself is bad!!). I was just thinking that it is not shutting properly since the car runs constantly at 180 to 190 all of the time (except in traffic--a little hotter). I thought that increasing it to a stock 195 unit would help it to close more often, thus giving the radiator time to do its intended job----lower the temp of coolant, before the thermostat opens again.
Gonzo
Gonzo
A couple things that weren't mentioned...is your vacuum advance hooked up and working properly to give you advance at idle? How is your fan clutch? And your radiator...you mentioned it was changed, but my last so-called "new" radiator was a piece of garbage. Sometimes the fins in the radiator and condensor get plugged with stuff...have you tried rinsing it with a hose. Just a few ideas...good luck.
Thread Starter
Racer
Joined: Feb 2006
Posts: 428
Likes: 1
From: West Des Moines Iowa
thanks fer' yer' input Paul....Yes, clutch is ok, vacuum advance works great and radiator is clean. I really dont know if changing to a 195 deg thermostat is the answer either, but I'm gonna give it a try and let you folks all know what happens with this here dude!! Thanks for everyones input. By the way, I am getting a high flow thermostat, you know, the Robert Shaw type that fails in the open position.
Gonzo
Gonzo
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
AS PaulH indicated...your overheating at idle could be due to timing...if it's over 11º advance then dropping it down to specs might solve your problem. Specs for your engine from the Chilton's Repair Manual says a 68 300HP 327 should have 4º BTDC at 700RPM. Check your points as well...they should have a .019" gap and a dwell around 30º.
If that isn't the problem then if you have a fan clutch then check it to make sure it doesn't spin by hand (with engine off) when it warms up. If you have plenty of air flow then your problem will be in the cooling system...possible lower radiator hose collapsing, clogged or rusty radiator. The thermostat opening at 180º or 195º won't change anything for you except the lower operating temp. You might want to try removing the thermostat and testing to see if the extra flow volume changes anything.
If that isn't the problem then if you have a fan clutch then check it to make sure it doesn't spin by hand (with engine off) when it warms up. If you have plenty of air flow then your problem will be in the cooling system...possible lower radiator hose collapsing, clogged or rusty radiator. The thermostat opening at 180º or 195º won't change anything for you except the lower operating temp. You might want to try removing the thermostat and testing to see if the extra flow volume changes anything.
Thread Starter
Racer
Joined: Feb 2006
Posts: 428
Likes: 1
From: West Des Moines Iowa
Originally Posted by Rockn-Roll
AS PaulH indicated...your overheating at idle could be due to timing...if it's over 11º advance then dropping it down to specs might solve your problem. Specs for your engine from the Chilton's Repair Manual says a 68 300HP 327 should have 4º BTDC at 700RPM. Check your points as well...they should have a .019" gap and a dwell around 30º.
If that isn't the problem then if you have a fan clutch then check it to make sure it doesn't spin by hand (with engine off) when it warms up. If you have plenty of air flow then your problem will be in the cooling system...possible lower radiator hose collapsing, clogged or rusty radiator. The thermostat opening at 180º or 195º won't change anything for you except the lower operating temp. You might want to try removing the thermostat and testing to see if the extra flow volume changes anything.
If that isn't the problem then if you have a fan clutch then check it to make sure it doesn't spin by hand (with engine off) when it warms up. If you have plenty of air flow then your problem will be in the cooling system...possible lower radiator hose collapsing, clogged or rusty radiator. The thermostat opening at 180º or 195º won't change anything for you except the lower operating temp. You might want to try removing the thermostat and testing to see if the extra flow volume changes anything.
Gonzo
