vacuum guage install - The 1947 - Present Chevrolet & GMC Truck Message Board Network

76bonanza · 04-09-2007, 01:08 PM

I am installing a vacuum guage and have to splice into one of my vacuum hoses, was thinking of putting a tee conector in the hose that goes to the tranny? I think it would be the best place.

**Palf70Step** · 04-09-2007, 01:17 PM

Mine have always been teed off the distributor connection, but not sure what the difference is. I have not used one in a long time except for tuneups.

ktlx1 · 04-09-2007, 01:17 PM

I recently did this as well, I connected a t-fitting into the vacuum line that runs from the distributor to the carburator. Works great in my application, using an auto meter vacuum gauge

Blue85 · 04-09-2007, 01:20 PM

Anyone know where the factory gauge was hooked up to?

76bonanza · 04-09-2007, 01:59 PM

I assume you guys are running your advance on the full vacuum port on carb and not the ported one otherwise you would get no reading at idle.

ktlx1 · 04-09-2007, 05:23 PM

Yes, you will know you have the correct vacuum by pulling off the hose to the distributor leading to the carb, motor will run sluggish.

bryanw1968 · 04-09-2007, 05:36 PM

Quote:

Originally Posted by 76bonanza

I assume you guys are running your advance on the full vacuum port on carb and not the ported one otherwise you would get no reading at idle.

Vacuum advance shouldn't be on the port with vacuum all the time?

76bonanza · 04-09-2007, 06:50 PM

Quote:

Originally Posted by bryanw1968

Vacuum advance shouldn't be on the port with vacuum all the time?

Well that is debatable, I for one love it on full vacuum, some will disagree many will not.

*Billla* · 04-09-2007, 06:55 PM

Generally, a completely stock engine is fine with ported vacuum. If it's been warmed over at all, the slight vacuum advance at idle from the non-ported (manifold) vacuum will improve the idle quality and off-idle response.

bryanw1968 · 04-09-2007, 06:56 PM

But typically you don't want vacuum at idle pulling advance into your initial right? Once you crack the primaries you expose the other vacuum port and that is the one that's supposed to go to the dist.

*Billla* · 04-09-2007, 07:20 PM

Quote:

Originally Posted by bryanw1968

But typically you don't want vacuum at idle pulling advance into your initial right? Once you crack the primaries you expose the other vacuum port and that is the one that's supposed to go to the dist.

Yes, you do

Uprated engines typically see much smoother idle with some advance at idle. This is pretty broadly accepted practice, although someone may have different experience.

The "supposed to's" pretty much go out the window once you start re-engineering (i.e. adding horsepower to) the design.

sjarrett71 · 04-09-2007, 07:50 PM

What's the benefit of using a vacuum gauge?

*Billla* · 04-09-2007, 07:56 PM

Quote:

Originally Posted by sjarrett71

What's the benefit of using a vacuum gauge?

It fills that blank spot in the gauge package

**Palf70Step** · 04-09-2007, 10:11 PM

Quote:

Originally Posted by sjarrett71

What's the benefit of using a vacuum gauge?

You can educate your foot for better gas mileage for one!

bryanw1968 · 04-09-2007, 10:50 PM

Quote:

Originally Posted by Palf70Step

You can educate your foot for better gas mileage for one!

HA!

You're right!!! It's fun to watch the gauge change!

Seriously it helped me tune when I was having air/fuel problems.
It's nice to have the gauge inside to see where your vacuum is when the weather changes and affects your idle.

And, yes it does fill that empty gauge hole

centsless · 04-09-2007, 11:10 PM

Quote:

Originally Posted by sjarrett71

What's the benefit of using a vacuum gauge?

Cuz it's COOL!!!!!!!!!!!!!!!!!!!!!!
and it fills the empty hole...

76bonanza · 04-09-2007, 11:26 PM

And if you have a vacuum leak it makes it easier to spot (plus the needle dances when the motor goes vrooom)

**VetteVet** · 04-10-2007, 12:36 AM

Here's a good read on vacuum if you're interested.
http://www.lbfun.com/Corvette/Tech/v..._explained.pdf

WinDancer · 04-10-2007, 01:15 AM

I doubt anyone but another owner will ever notice that the one gauge hole doesn't have anything behind it- but I am doing mine, too, to fill the hole I know is there

**Bob B.** · 04-10-2007, 01:45 AM

The vacuum gauge was only 'stock' on the larger (C-50 and 60) trucks with vacuum brakes. The gauge read vacuum in the vacuum tank under the cab. I think the best place to hook it to is manifold vacuum.

WinDancer · 06-12-2007, 09:51 PM

So what else did you have to do to get the vaccum gauge installed and working?

Bob Moore · 06-12-2007, 11:26 PM

I believe the "stock" hook-up was made to the fitting in the intake manifold behind the carb. Not to the carb at all but to the manifold. The fitting also serves the brake booster and transmission(IIRC)

**'68OrangeSunshine** · 06-13-2007, 08:01 AM

My vacuum gauge is run to a small tap in the intake manifold with 1/8" copper line. Cleaner signal and you don't have to disconnect it every time you pull the carb.

**kwmech** · 06-13-2007, 09:10 AM

Last year I found a dash with a pressure guage in the hole. I still have it packed in a box somewhere.

04-09-2007, 01:08 PM	#1
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	vacuum guage install I am installing a vacuum guage and have to splice into one of my vacuum hoses, was thinking of putting a tee conector in the hose that goes to the tranny? I think it would be the best place. __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

04-09-2007, 01:17 PM	#2
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,083	Re: vacuum guage install Mine have always been teed off the distributor connection, but not sure what the difference is. I have not used one in a long time except for tuneups. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

04-09-2007, 01:17 PM	#3
ktlx1 Registered User Join Date: Sep 2002 Location: Clover, SC Posts: 15	Re: vacuum guage install I recently did this as well, I connected a t-fitting into the vacuum line that runs from the distributor to the carburator. Works great in my application, using an auto meter vacuum gauge

04-09-2007, 01:20 PM	#4
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,171	Re: vacuum guage install Anyone know where the factory gauge was hooked up to? __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

04-09-2007, 01:59 PM	#5
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	Re: vacuum guage install I assume you guys are running your advance on the full vacuum port on carb and not the ported one otherwise you would get no reading at idle. __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

04-09-2007, 05:23 PM	#6
ktlx1 Registered User Join Date: Sep 2002 Location: Clover, SC Posts: 15	Re: vacuum guage install Yes, you will know you have the correct vacuum by pulling off the hose to the distributor leading to the carb, motor will run sluggish.

04-09-2007, 06:55 PM	#9
Billla Account Suspended Join Date: Sep 2005 Location: Monroe, WA Posts: 3,815	Re: vacuum guage install Generally, a completely stock engine is fine with ported vacuum. If it's been warmed over at all, the slight vacuum advance at idle from the non-ported (manifold) vacuum will improve the idle quality and off-idle response.

04-09-2007, 06:56 PM	#10
bryanw1968 Senior Member Join Date: Jul 2006 Location: Leander, Texas Posts: 850	Re: vacuum guage install But typically you don't want vacuum at idle pulling advance into your initial right? Once you crack the primaries you expose the other vacuum port and that is the one that's supposed to go to the dist.

04-09-2007, 07:50 PM	#12
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: vacuum guage install What's the benefit of using a vacuum gauge? __________________ -Scott-

04-09-2007, 11:26 PM	#17
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	Re: vacuum guage install And if you have a vacuum leak it makes it easier to spot (plus the needle dances when the motor goes vrooom) __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

04-10-2007, 12:36 AM	#18
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,717	Re: vacuum guage install Here's a good read on vacuum if you're interested. http://www.lbfun.com/Corvette/Tech/v..._explained.pdf __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

04-10-2007, 01:15 AM	#19
WinDancer The Original HotRod KnifeMaker Join Date: Jan 2007 Location: Tenino, Washington Posts: 811	Re: vacuum guage install I doubt anyone but another owner will ever notice that the one gauge hole doesn't have anything behind it- but I am doing mine, too, to fill the hole I know is there __________________ Dave 69 GMC SWB 2WD 454 Turbo 400

04-10-2007, 01:45 AM	#20
Bob B. Senior Member Join Date: Aug 2005 Location: Los Angeles Posts: 1,349	Re: vacuum guage install The vacuum gauge was only 'stock' on the larger (C-50 and 60) trucks with vacuum brakes. The gauge read vacuum in the vacuum tank under the cab. I think the best place to hook it to is manifold vacuum. __________________ 1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90.

06-12-2007, 09:51 PM	#21
WinDancer The Original HotRod KnifeMaker Join Date: Jan 2007 Location: Tenino, Washington Posts: 811	Re: vacuum guage install So what else did you have to do to get the vaccum gauge installed and working? __________________ Dave 69 GMC SWB 2WD 454 Turbo 400

06-12-2007, 11:26 PM	#22
Bob Moore Registered User Join Date: Feb 2004 Location: Tacoma WA Posts: 1,365	Re: vacuum guage install I believe the "stock" hook-up was made to the fitting in the intake manifold behind the carb. Not to the carb at all but to the manifold. The fitting also serves the brake booster and transmission(IIRC) __________________ 67 C-20 LWB, tilt, speed alert, vac, 454, T400 67 C-10 SWB, factory air with more to follow



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06-13-2007, 08:01 AM	#23
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,441	Re: vacuum guage install My vacuum gauge is run to a small tap in the intake manifold with 1/8" copper line. Cleaner signal and you don't have to disconnect it every time you pull the carb. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 06-13-2007 at 08:02 AM.

06-13-2007, 09:10 AM	#24
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,599	Re: vacuum guage install Last year I found a dash with a pressure guage in the hole. I still have it packed in a box somewhere.

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