xstuntman
Contributor
Posts: 131
Loc: west Texas
Reg: 04-13-09
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02-01-23 12:21 PM - Post#2854007
Curious to see if there is any advantage to doing this and if so what size hole is necessary. Maybe two holes?
Saturday I will be installing a new 195 in my iron head 350 and getting my homework done now.
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65_Impala
Very Senior Member
Posts: 4960
Reg: 12-29-02
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02-01-23 12:33 PM - Post#2854008
In response to xstuntman
Not really necessary unless you have a newer block and/or heads and don't have the small bypass passage that goes from the passenger side head to the water pump.
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xstuntman
Contributor
Posts: 131
Loc: west Texas
Reg: 04-13-09
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02-01-23 12:59 PM - Post#2854012
In response to 65_Impala
Hmm...
This is a GM Goodwrench motor that's roughly seven years old so I'm not really sure on the passage.
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 rumrumm
"22nd Year" Silver Supporting Member
Posts: 2133
Loc: Macomb, IL
Reg: 10-18-01
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02-01-23 01:53 PM - Post#2854015
In response to xstuntman
I always drill one 1/8 inch hole in a thermostat I use in my small block Chevy engine. It was something passed down to me by a mechanic many years ago, and I have continued to do it. It certainly won't hurt anything if it is unnecessary.
Lynn
"There's no 12-step program for stupid."
383 sbc, Eagle, AFR, SRP, CompCams, Edelbrock Pro-Flo 4 EFI. Dyno #'s: 450 hp @ 5700, 468 lb. ft. of torque @ 4300.
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Edited by rumrumm on 02-01-23 01:54 PM. Reason for edit: No reason given.
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kingkreeton
Frequent Contributor
Posts: 1726
Loc: Nashville TN
Reg: 04-15-11
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02-01-23 05:47 PM - Post#2854027
In response to xstuntman
I won't hurt anything but not sure you will get the return on your labor. The factory setup worked just fine.
Shane
64 Impala SS:
Chevy Performance 350HO
4 Speed Muncie
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Bad56Sedan
"16th Year" Gold Supporting Member
Posts: 1641
Loc: Texas
Reg: 04-29-04
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02-01-23 07:43 PM - Post#2854034
In response to xstuntman
just replacing an old thermostat?
or a fresh rebuild?
temp gauges in heads?
don't drill the bypass, see what happens
drill the bypass and no harm no foul
VC56S 2 door Sedan, 43 Years
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 someotherguy
Senior Moderator
Posts: 29668
Loc: Texas
Reg: 08-01-03
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02-01-23 09:54 PM - Post#2854037
In response to Bad56Sedan
A lot of thermostats already come with a "jiggle" valve type bleed hole in them. On thermostats without, I don't see any harm in carefully drilling a small bleed hole; I usually go 3/32". Just take care you get it in the flat area of the body where it won't interfere with the gasket.
Richard
| 06 Silverado ISS / 06 Silverado SS / 06 300C SRT8 / 93 C3500 dually |
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Tony1963
Frequent Contributor
Posts: 2057
Loc: Orlando Florida
Reg: 07-09-18
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02-02-23 03:28 AM - Post#2854040
In response to xstuntman
This practice showed up several years ago when I was working on an old Ford 200 inline 6. The book that I had talked about drilling the hole. I did it but it really is unnecessary.
| People fear change because it threatens what they know, or what they claim to know. |
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sz0k30
"14th Year" Gold Supporting Member
Posts: 607
Loc: Oakland Co., Michigan
Reg: 10-12-08
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02-02-23 07:35 AM - Post#2854044
In response to xstuntman
On small blocks this is totally unnecessary because they have a "bypass" hole in the block & water pump.
Big blocks don't have the bypass in the water pump, but instead its in a separate small hose between the intake manifold & the water pump. On my big blocks I've removed that bypass hose, so then it is necessary to have bypass holes in the thermostat.
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bobb
Super Senior Member
Posts: 6249
Loc: paradise
Reg: 09-05-03
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02-02-23 08:34 AM - Post#2854045
In response to xstuntman
195 seems high. fuel injected? i always drill the hole to help get air out of the engine.
| 70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails. |
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 Magnetocheck
Silver Supporting Member
Posts: 87
Age: 68
Loc: Charlotte, NC
Reg: 09-05-22
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02-02-23 08:54 AM - Post#2854047
In response to sz0k30
Curious, Roman. Why did you get rid of the bypass on the BBCs? Better performance?
Bob
Bob
'65 Impala SS 396 Convertible |
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65_Impala
Very Senior Member
Posts: 4960
Reg: 12-29-02
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02-02-23 10:13 AM - Post#2854051
In response to xstuntman
Hmm...
This is a GM Goodwrench motor that's roughly seven years old so I'm not really sure on the passage.
I somewhat miswrote. Vortec blocks/heads do not have the passage. You need some external way to let the coolant circulate. The heater core will do it. As long as the coolant has a circulating path when the thermostat is closed then it doesn't need a hole. But, one smaller sized hole really doesn't hurt anything.
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sz0k30
"14th Year" Gold Supporting Member
Posts: 607
Loc: Oakland Co., Michigan
Reg: 10-12-08
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02-03-23 07:40 AM - Post#2854084
In response to Magnetocheck
1. Many years ago I had a corrugated stainless bypass hose on my Chevelle. Similar to https://www.summitracing.com/parts/sum-390124. On a cool morning I was sitting in line to register for a car show. All of a sudden I noticed my w/shield steaming up & steam coming from under the hood? What the hell? I opened the hood and that &%$^T^&%^ hose had a pinhole leak and under pressure with the engine running and fan turning was spraying anti-freeze all over the engine compartment. So instead of a beautiful clean, shiny engine and a trophy I had a wet, ugly mess.
2. I think its just a cleaner look.
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xstuntman
Contributor
Posts: 131
Loc: west Texas
Reg: 04-13-09
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02-03-23 09:35 AM - Post#2854090
In response to sz0k30
Like a dummy I thought it would be great to run a 165 in it and boy it ran cool all summer even tho we went thru 3 months of triple digits.
After many blown fuses and replacing the relay/blower/resistor last week I got heat defrost back, then the cold front hit and no heat blowing out although everything was working. Looked at the gauge and around 150ish on temp when 25 degrees outside so out the 165 goes. Lesson learned. Probably drill a hole just for fun.
Thanks guys.
Edited by xstuntman on 02-03-23 09:36 AM. Reason for edit: No reason given.
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wagonman100
Site Ambassador
Posts: 15777
Loc: Baltimore, MD
Reg: 11-27-04
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02-03-23 08:12 PM - Post#2854106
In response to xstuntman
The thermostat is not the reason you were running 150. I couldn’t say exactly why it was running that cool if the engine was running long enough. It should have gotten to at least 165. But even if you have an even lower temp thermostat, your car will run at whatever temperature the cooling system is capable of maintaining. The thermostat is only there to hold coolant in the engine so that it heats up faster. Your thermostat may have been stuck open. But even then the engine will get to whatever temperature the system can maintain. It would just take a bit longer to get there.
Jay
Friends don’t let friends drive Fords.
1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon
1957 Cameo Carrier |
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Bad56Sedan
"16th Year" Gold Supporting Member
Posts: 1641
Loc: Texas
Reg: 04-29-04
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02-05-23 03:08 PM - Post#2854159
In response to wagonman100
why are you considering bypass hole?
or is another lost post?
VC56S 2 door Sedan, 43 Years
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65_Impala
Very Senior Member
Posts: 4960
Reg: 12-29-02
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02-06-23 10:43 AM - Post#2854188
In response to wagonman100
Yes, only reaching 150* with a 165* thermostat means something else was causing it.
Some coolant paths can cool the engine even with the thermostat closed, especially on very cold days. Even just running the heater full-on can cool it a certain amount.
One of the reasons GM puts shutters on some pickups is because airflow over the engine combined with the heater running full speed while on the highway combines to not let the all aluminum engine reach full operating temperature.
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Tony1963
Frequent Contributor
Posts: 2057
Loc: Orlando Florida
Reg: 07-09-18
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03-08-23 04:57 AM - Post#2855498
In response to 65_Impala
The primary reason for the active shutters is to improve aerodynamic drag. There is no danger of overcooling the engine as the reason for those shutters.
https://www.sae.org/publications/technica l-papers/...
| People fear change because it threatens what they know, or what they claim to know. |
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IgnitionMan
Valued Contributor
Posts: 4028
Reg: 04-15-05
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03-08-23 03:31 PM - Post#2855531
In response to xstuntman
Point of information:
There are two different valve designs for T-Stats, flat blade, and "barrel" types.
The usual blade is a flat plate to close the orifice down, has worked for eons, for the most part. This type has issues, though.
IF the system is set up to have any increased volume, the added pressure flow past the valve can push the plate closed, rare, but does exist.
The 'barrel' type is just that, valve is shaped like a barrel, and allows higher volumes, and/or pressures to literally bypass the valve to not close it with conditions past operative.
These barrel valve S-Tats were marketed by two different companies, Robertshaw, and Mr. Gasket, under the name "Pressure Balanced" types.
I stopped using flat blade types decades ago, only use the pressure balanced versions, best I have ever used.
Just info.
Added, the "bleed hole" is there, either new, or added, to literally allow air to escape from the system, and coolant to completely fill the cooling system. I have added these holes to flat blade valve Stats, used a .050 drill, one hole, no adverse issues.
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65_Impala
Very Senior Member
Posts: 4960
Reg: 12-29-02
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03-10-23 09:22 AM - Post#2855595
In response to Tony1963
These requirements of maintaining optimal engine intake charge air temperature, managing condenser heat load, engine bay heat and aerodynamic lift balance pose contradicting challenges in finding the optimal energy balance within the control strategy.
It seems to be a little bit of everything.
I know my truck without them runs a little cooler than normal on -30*C days when driving down the highway.
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Magnetocheck
Silver Supporting Member
Posts: 87
Age: 68
Loc: Charlotte, NC
Reg: 09-05-22
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03-10-23 09:43 AM - Post#2855598
In response to 65_Impala
This thread seems to be morphing from "hole in the t-stat" to general engine cooling info. That's OK I guess, but did we ever settle the question about whether or not you need to drill a hole? 
Bob
'65 Impala SS 396 Convertible |
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IgnitionMan
Valued Contributor
Posts: 4028
Reg: 04-15-05
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03-11-23 12:24 PM - Post#2855642
In response to Magnetocheck
So, it appears none of the rest of us should even hazard giving any further info, as nobody needs any of it past the original question.
This should mean that those that have come here after the initial question, do not need any further info about the cooling system, its parts, assemblies, tuning to make the engine run correctly on its operating temperatures, etc.
But, in answer to the OP, drill, don't drill, up to you. All it is supposed to do is help bleed air out of the engine so dry hot spots that impede cooling efficiency, do not develop.
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bobb
Super Senior Member
Posts: 6249
Loc: paradise
Reg: 09-05-03
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03-11-23 06:55 PM - Post#2855661
In response to IgnitionMan
uh, i just fixed a guys overheating problem the other week with, the holes. cheap insurance to let the air out.
| 70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails. |
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