#1  
Old 08-28-2013, 09:52 AM
zeebo's Avatar
zeebo zeebo is offline
Chief Ponti-yacker
 
Join Date: Jan 2007
Location: Lapeer, MI
Posts: 766
Default largest factory rad for 73 lemans

hi there..anyone know the brand of a copper/brass radiator that is the largest one the factory used in the 73-77 cars? i need a new rad for my 73 and would like to install a 4 row..currently a 3 row is in it...also, it looks like the tanks are pretty thick..could a thicker core be added to the 3 row tanks? thanks!!!

  #2  
Old 08-28-2013, 10:46 AM
BillyGoat73's Avatar
BillyGoat73 BillyGoat73 is offline
Member
 
Join Date: Mar 2008
Location: Elma, New York
Posts: 73
Default

I'll throw my 2 cents in on a larger radiator for what it's worth.

When I put my 73 GTO together over 25 years ago I found large side tanks and had a 4-row core put together without the tranny cooler (my car is a 4-speed). Here are my lessons learned as I struggled with a hot running engine:

1. 4 rows reduced velocity of water flow through radiator (more tubes meant slower flow for same gpm out of water pump). This caused uneven flow between top and bottom tubes and reduced efficiency.
2. I painted the radiator, which turned out to be bad because I was actually insulating the fins and the tubes reducing the heat transfer rate.
3. I was missing the air deflecter under the radiator, which was required on all air-conditioned cars to improve heat transfer. I added that in 1995.

The car ran hot with the A/C on warm humid days, even on the highway. It ran normal temp when not using A/C. The air deflector helped a little.

In 2004 I was getting ready to go to the GTOAA Meet in Pontiac and the radiator started leaking. I pulled it and took it to a local radiator shop that my "car guy" friends have used. The owner asked why I had such a large radiator and went thru the reasons above for my problems. I installed a smaller tank 3-row based on what his book said I needed and the car runs just fine all the time, even with the A/C on.

The moral here is that the cooling system main components are the water pump, thermostat, radiator fan (clutch or non-clutch) and the radiator. They are designed as a SYSTEM for the application of the vehicle. Throwing a bigger radiator in is not always the best thing to do.

Just my thoughts...

__________________
1973 GTO 400 4-spd
1973 LeMans GT
  #3  
Old 08-28-2013, 12:43 PM
BR57's Avatar
BR57 BR57 is offline
Chief Ponti-yacker
 
Join Date: Jul 2006
Location: Toronto, On - Canada
Posts: 648
Default

I also received similar advice as Bill when upgrading my radiator to accommodate the swap of a 454 into my LeMans (Canadian car) I too asked the shop for a 4 row and the owner with 35 years experience told me why a 3 row would be more than adequate. Frank came recommended from a friend who raced in CASCAR now NASCAR Canada and he had Frank build all his race car radiators.

Like Bill I have a clutch fan, air deflector and proper shroud in place with the three row. I think BBC are well known to be a cooling nightmare and mine runs pretty consistently at 180 might see 200 when crawling along in heavy traffic.

__________________
Ray White
Toronto - Canada
  #4  
Old 08-28-2013, 06:18 PM
77 Canamman's Avatar
77 Canamman 77 Canamman is offline
Ultimate Warrior
 
Join Date: Aug 2006
Location: PA
Posts: 4,022
Lightbulb

I am one who prefers 4 core large tank radiators. Pontiac put them in these cars originally, and for the added capacity. All of my A/C cars have them, and no issues with cooling, even on 95 degree high humidity days with the A/C on. The main issue with a Pontiacs ability to keep cool is the water pump impeller design, condition of the pump tube seals, and the plate to impeller clearance.

I bought one of these for my 455 police car. NO issues in the last 3 years with it.

http://www.ebay.com/itm/SPECTRA-PREM...item4d1135cd84

__________________
1976 LeMans B09 Freeway Enforcer, 455/M40 Smokey

1977 Trans Am, 400/M21 Black/Gold Bandit. 44K actual miles

2017 Sierra SLT 1500 Z71 4X4

2019 Canyon SLT Crew 4X4

  #5  
Old 08-28-2013, 07:28 PM
zeebo's Avatar
zeebo zeebo is offline
Chief Ponti-yacker
 
Join Date: Jan 2007
Location: Lapeer, MI
Posts: 766
Default

thanks rick..i have never heard of a 3 row cooling more than a 4 row before..in my schooling, a larger radiator has more capacity for coolant, and the coolant is exposed to more air, hence it is cooled more. (that is why the factory used large capacity radiators on big block engines, wagons, cars with ac, motorhomes etc. if a tiny radiator would have done the job, they would have used one..

The Following User Says Thank You to zeebo For This Useful Post:
  #6  
Old 08-28-2013, 08:16 PM
77 Canamman's Avatar
77 Canamman 77 Canamman is offline
Ultimate Warrior
 
Join Date: Aug 2006
Location: PA
Posts: 4,022
Default

If GM could have saved a few pennies on each unit, they would have done it.

__________________
1976 LeMans B09 Freeway Enforcer, 455/M40 Smokey

1977 Trans Am, 400/M21 Black/Gold Bandit. 44K actual miles

2017 Sierra SLT 1500 Z71 4X4

2019 Canyon SLT Crew 4X4

  #7  
Old 08-29-2013, 02:46 AM
rexs73gto rexs73gto is offline
Suspended
 
Join Date: Apr 2011
Location: Niles MI.
Posts: 4,319
Default

Zeebo , 2 years ago I was having a cooling problem with my new engine a (462), I took the old T-stat & replaced it. Didn't work. Put in a new 4 row Alum, that helped but still not good enough. Lats I replaced the water pump & made sure the didvider plate was clearenced correctly to the impeller. That made the most difference & it now runs around 160-165 in or out of traffic under load or not. I guess what I'm saying is to make sure the little things that need to be done are done before you go out & spend $ 300.00-$ 400.00 or more for a new radiator. Some times the little things that we over look are the the same things that fix the problem. A lot of the time when a Pontiac over heats or runs hotter then it should is caused from improper clearences in the water pump & divider plate. Try that first before you spend all that money.

  #8  
Old 08-29-2013, 10:06 AM
BR57's Avatar
BR57 BR57 is offline
Chief Ponti-yacker
 
Join Date: Jul 2006
Location: Toronto, On - Canada
Posts: 648
Default

Quickly, on how a 3 row has same or more cooling capacity. A modern three row recore has more cooling passages in its 3 rows than a traditional 4 core has. Both rads can do the same job, it is a matter of preference, cost and fitment/parts. .

__________________
Ray White
Toronto - Canada
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:45 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017