Thermostat Mod
Thread Starter
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
Thermostat Mod
Who has done the long forgotten thermostat modification. Wondering if you found any aftermarket readily available shims? My understanding is a 1/8" brass ferrule will work but am wondering if anyone has found something better.
Thread Starter
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Shim under the shaft to reduce the opening temperature. I just picked up a new one to play with, or screw up as the case may be. 
Not too many people doing this any more since there are aftermarket ones available, but all the people I spoke with have found they are very inconsistent with regards to actual opening temp to what it is actually supposed to open at.
Not too many people doing this any more since there are aftermarket ones available, but all the people I spoke with have found they are very inconsistent with regards to actual opening temp to what it is actually supposed to open at.
Le Mans Master
Joined: Dec 2003
Posts: 5,561
Likes: 448
From: Atlanta metro Ga.
Shim under the shaft to reduce the opening temperature. I just picked up a new one to play with, or screw up as the case may be.
Not too many people doing this any more since there are aftermarket ones available, but all the people I spoke with have found they are very inconsistent with regards to actual opening temp to what it is actually supposed to open at.
Not too many people doing this any more since there are aftermarket ones available, but all the people I spoke with have found they are very inconsistent with regards to actual opening temp to what it is actually supposed to open at.
I used a slice from a 10mm aluminum bolt I had laying around (race bike parts). Fit great, easy to file to adjust the length. I should have measured the length, I could have passed it on and saved you the trial and error.
Thread Starter
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
Drifting
Joined: Nov 2004
Posts: 1,650
Likes: 4
From: Ringgold GA
Anyone got a how-to on this? Because I pulled mine apart and cut 2 coils off the spring and reinstalled it and it's now opening at 180? That's what my tuner told me to do, didn't say anything about a shim...
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
Got this information out of my HP Book Chevy LS1/LS6 Performance, page 58. They dont say any thing about cutting the spring. What they say is once you have it apart, is to get a 1/8-inch brass ferrule to work as a spacer because it is easily filed down to the appropriate thickness. Make sure it is a loose fit in the housing to allow expansion. A spacer of approx. .090-inch thickness makes for a thermostat opening temp. of about 168 degrees.This is the minimum temp. that will allow the thermostat to close completely. The book has pictured directions of this process. My question to you is, why not get a new cooler running thermostat? I know I wouldn"t be messing around with this mod on my 03 Z. Too much risk of having a heating problem, and with these motors, you could cause some useless dammage. Hope this helps, Good luck. Bob.
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St. Jude Donor '06-'07-'08-'09
Got this information out of my HP Book Chevy LS1/LS6 Performance, page 58. They dont say any thing about cutting the spring. What they say is once you have it apart, is to get a 1/8-inch brass ferrule to work as a spacer because it is easily filed down to the appropriate thickness. Make sure it is a loose fit in the housing to allow expansion. A spacer of approx. .090-inch thickness makes for a thermostat opening temp. of about 168 degrees.This is the minimum temp. that will allow the thermostat to close completely. The book has pictured directions of this process. My question to you is, why not get a new cooler running thermostat? I know I wouldn"t be messing around with this mod on my 03 Z. Too much risk of having a heating problem, and with these motors, you could cause some useless dammage. Hope this helps, Good luck. Bob.
Burning Brakes
Joined: Oct 2004
Posts: 931
Likes: 35
From: Rowlett, Texas
sorry I missed this post; I just posted about the "shaft-shimming mod" on the other post by Viper.
Making the little shim was super-easy, just cut off a nail to about 0.060-0.080" I just chucked an appropriate-size hardware nail in the vise, cut it off, and filed it a little to get it the proper length - took 3 minutes. I used 0.060", and my thermo opens at 183, curises at 183-187 depending on weather. Don't make the nail too long, be sure the thermo valve still closes at room temp, so you get quick warm-up.
Is this better than cutting the spring - well, it's easily reversible, and easily adjustable, if you have another nail!
Is this better than a Hypertech 180? About $60 better; if you have a vise, hacksaw, and file, and don't pay too much for the nail. And you don't mind taking the thermo apart. Whole deal is maybe ten minutes, including finding the right nail.
Does it do anything for the engine performance?
Heck, I have the throttle-body coolant line bypass and the performance hood seal too, all hand-made. but I still can't outrun a new Z06. I just like to piddle!
Seriously, It's really easy, and it works fine.
Cheers,
DG
Making the little shim was super-easy, just cut off a nail to about 0.060-0.080" I just chucked an appropriate-size hardware nail in the vise, cut it off, and filed it a little to get it the proper length - took 3 minutes. I used 0.060", and my thermo opens at 183, curises at 183-187 depending on weather. Don't make the nail too long, be sure the thermo valve still closes at room temp, so you get quick warm-up.
Is this better than cutting the spring - well, it's easily reversible, and easily adjustable, if you have another nail!
Is this better than a Hypertech 180? About $60 better; if you have a vise, hacksaw, and file, and don't pay too much for the nail. And you don't mind taking the thermo apart. Whole deal is maybe ten minutes, including finding the right nail.
Does it do anything for the engine performance?
Heck, I have the throttle-body coolant line bypass and the performance hood seal too, all hand-made. but I still can't outrun a new Z06. I just like to piddle!
Seriously, It's really easy, and it works fine.
Cheers,
DG
Thread Starter
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
With this approach, I can adjust the thermostat to exactly where I want it to open and it won't be like rolling the dice on an aftermarket unit.
Thread Starter
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I don't like cutting the spring. I know that the stock thermostat is designed to also provide some back pressure (or at least I have read this) to keep the pump from cavitating at higher RPM. I would be nervous about adjusting the characteristics of that spring.
