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#121 | |
![]() Join Date: May 2010
Location: Japan
Posts: 3,570
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Always a wealth of valuable details and info Cliff. You mention in other posts that you never drill any holes in the thermostat. Is there any reason why you feel 1 or 2 (or more) holes is not good or will make a difference in the lower rpms off idle or while stuck in traffic? The reason I ask is my area puts me in a lot of bumper to bumper until I can get to the expressway. Thanks!!! Craig Sent from my iPhone using ZR-1 Net Registry
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Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048 ![]() |
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#122 |
![]() Join Date: May 2007
Location: Westminster, Maryland
Posts: 3,687
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Cliff, I agree completely with you analysis of the coolant flow at low engine RPM. I have observed that effect on many different ZR-1's.
With a brand new radiator, there is marginally enough coolant flow and air flow to maintain coolant temperature in the thermostat operating range. But as the radiator air flow is compromised due to fin blockage (ie age), the temperature of the coolant will rise until the larger coolant temp to air temp differential will allow more heat transfer and the coolant engine temperature will stabilized above 200 degrees. Jim |
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#123 | ||
![]() ![]() Join Date: Aug 2009
Location: South Dakota/California
Posts: 3,791
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Also.......Marc suggested at one time the older Stants will deteriorate (Decrease in FUll Open Area) by up to 15% as they age. A thermostat with over 50k miles generally opens 5 degrees later and opens about 85% and that far exceeds the additional Coolant Flow Area created by small 1/8 inch diameter holes. SO......along with replacing Original Injectors, Refurbishing Original Starter Solenoids, Installing Aluminum Radiators in ZR-1s and Replacing ALL Fluids as part of Reconditioning, I also Install New Stant 180 deg Thermostats in ALL ZR-1s. Oh....and I also Install the Starter Relay and Carter Bling as part of Reconditioning and some other things. ![]() See Item #6 regarding additional holes in thermostats. The 180 deg versus the 160 deg thermostat or no thermostat Quote:
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Left Clickable links ![]() -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 04-02-2017 at 10:50 AM. |
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#124 | |
![]() Join Date: Dec 2003
Location: Arcadia,OK
Posts: 3,384
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1. Source-My personal experience; with a new Woods 160F thermostat on the bench, I decided to drill 3 holes in my "old" stat. The results were so definitive, I never replaced it with the 160F. [415ci, Ron Woods Radiator]. 2. Source-Memory, not verified ![]() 3. Source-Memory, not verified ![]() There are more cases of drilled t-stat flanges out there, I simply never took the time or made the effort to document them. I answer quite a few tech questions from Jerrys Gaskets customers, including cooling issues. I have drilled new thermostats by request before shipping to customers. I don't take exception to your mathematics. I just believe the the holes have a more dynamic effect than simple enlargement of. cross sectional area. This is a subject worthy of documentation. In that regard, keeping it simple such as number of holes drilled & results restrained to categories such as "no change," "slight improvement," effective" & "excessive cooling." I think there are too many variables to try & pin it down so the factors can be quantified & calculated. It would be useful to read posts from those who have drilled t-stat flanges.
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Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. |
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#125 |
![]() Join Date: Jan 2006
Location: Niceville
Posts: 997
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I have a good problem to have...I guess. I'll give my experience today...if I get to it after injectors, brake bleed, then thermostat drill.
Ted |
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#126 |
![]() Join Date: May 2010
Location: Japan
Posts: 3,570
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[QUOTE=Dynomite;259697]As I calculated, 1/8 inch diameter holes just are way to small compared to the wide open area available when the thermostat is completely open to have any effect. However, a few 1/8 inch diameter holes would not hurt anything as far as too low a temperature for the same reason and......these small holes will allow some air to travel from the engine to the top side of radiator when thermostat is still completely closed. I just do not bother with the holes and have no issues with air as I have explained in my Coolant Filling techniques discussions.
Also.......Marc suggested at one time the older Stants will deteriorate (Decrease in FUll Open Area) by up to 15% as they age. A thermostat with over 50k miles generally opens 5 degrees later and opens about 85% and that far exceeds the additional Coolant Flow Area created by small 1/8 inch diameter holes. SO......along with replacing Original Injectors, Refurbishing Original Starter Solenoids, Installing Aluminum Radiators in ZR-1s and Replacing ALL Fluids as part of Reconditioning, I also Install New Stant 180 deg Thermostats in ALL ZR-1s. Oh....and I also Install the Starter Relay and Carter Bling as part of Reconditioning and some other things. ![]() See Item #6 regarding additional holes in thermostats. The 180 deg versus the 160 deg thermostat or no thermostat Cliff, Thanks for your thoughts. I did not think the 1/8" hole was for air and thought just to aid a little more coolant flow despite how little. It is amazing to hear how 3 holes can be too much and cause the car to run too cool in certain conditions. I know you spend a lot of time in your analyses and it is valued for sure. Sent from my iPhone using ZR-1 Net Registry
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Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048 ![]() Last edited by HAWAIIZR-1; 04-02-2017 at 07:08 PM. |
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#127 | |
![]() Join Date: Dec 2003
Location: Arcadia,OK
Posts: 3,384
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![]() Acquiring the 160F thermostat was not theoretical thinking, it was to be an experiment. ![]() BTW I noticed several references in your posts pertaining to "up to 15% degradation" in thermostats as they age. That's a pretty broad range & doesn't actually state that any occurs at all. Details would really shine some light on this subject. Is it linear? does it always affect the range of the valve aperature?
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Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. |
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#128 |
![]() Join Date: Jul 2010
Location: Woodstock, Ontario, Canada
Posts: 1,275
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OEM radiator
YEARS 1990-92 1993-1995 Core Thickness 1.34 in. Same Frontal Area 405 sq. in. Same Radiator Cap 17 psi. Same Thermostat Open 180 degree F Same Fully Open 195 degree - 200 degree F Same Coolant pump YEARS 1990-92 1993-1995 Type Centrifugal Same Capacity 12 gpm @ idle 85 gpm @ 7,000 rpm Same Supplier Ace (Casting) Same
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peace Paul ZR-1 Net Registry Member #1494 Last edited by Hog; 07-29-2017 at 04:51 AM. |
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