Vacuum Gage

[ziggurat]

OK so my dad had this idea of putting a vacum gage where the disfunctional clock is in our GTs. Has any one tryed this or know where i could aquire a vacum gage that would fit in the spot? just wondering thought it would be a good idea.

[ddoyle]

You can find VDO guages at many auto stores, or online. They have many styles and sizes. They were also the OEM supplier for opel guages(at least on the Manta).

DAN

[kwilford]

Personally, I like the GT clock. And they almost always can be repaired. Use the search function, and especially look at

http://opelgt.com/forums/showthread.php?s=&threadid=123

More repair tips are on the classicopels site at (look for two files there):

http://autos.groups.yahoo.com/group/...20Information/

(Gary, any chance that you could put these two files in the "Download" section?)

And if you still don't want a clock, I personally think a voltmeter is much more useful than a vacuum gauge

[opeldean]

whatever you put in the space..be sure it is lighted..I put in a cheap smith(MG style) replica clock..looks ok..but no light..this is bad at night

I just bought a
used opel clock off of ebay that I will try to go back to original opel..so I am going to study the prior post on how to fix one...

I hope there is a way to take a short cut and jus t put in new
battery powered works..if I can't fix the 33 year old one...
the original is hard to beat for good looking and lighted

[davegt27]

i had a Vacuum gage in my GT where the clock goes

worked great. i got it from JC Whitney

ran it for a few years and i learned a whole lot

I say go for it you will love it


good luck

Davegt27

[opeldean]

I guess this is a dumb question.but why would you want a vacuum gauge...what does it tell you that is useful?

I assume at idle your vacuum is high ...."floor it "and vacuum is low.

I find myself watching oil pressure,ammeter,temp and fuel...but why watch vacuum?

was the vacuum gauge the same diameter as the clock? was it lighted?
thanks.

[davegt27]

yes the gage was lighted most gages come with a light you just have to hook it up to your lighting system

here are a few questions

what is the stock vacuum?
what happens when you put on a 32/36

if you switch to a 1.5 head what happens

how about FI what happens when you switch to FI

what about single side draft 40 weber
its an interesting tool

to some its no big deal

like indexing spark plugs some people just put the plugs in and go others index there plugs

good luck

Davegt27

[oldopelguy]

Bucky, vacuum is most closely related to engine loading. Low vacuum indicates that the throttle plates are open further than necssary, or that you are accelerating, and high vacuum indicated slowing.

The real benefit of a vacuum guage is in training yourself to get the most mileage out of your car. If you're the type that floors it then lets up, your vacuum guage will be all over the place. If you are a "smooth" driver, and you're not pushing your motor, you can keep the vacuum guage relativly steady, and high. That type of driving, while not nearly as fun, can give you 30% or better gas mileage if you're the hard start/ stop kind of guy. For example, my wife got 14mpg in her Jeep every tank, but when I drove it I always got closer to 19mpg. Same places to drive, same traffic and such, just different driver.

Some vacuum guages were even labeled with low vac labeled "power" and high vacuum labeled "economy". Personally, I'll be installing one shortly as well, except mine will be a combination vacuum/ boost guage.

[ziggurat]

don't suppose you could break down what the boost gage does for me I have no idea. cause if I like it I might go that way.

[opeldean]

I think I am going to buy a vacuum gauge...what do you guys think of this? I like #1..but I don't see a light on it...is the blue plug a space for a bulb....also the size is better for the clock hole.

#2 is a little too high tech ..but well lighted


is there a good place to put a vacuum gauge besides the clock hole? deve27..you got me interested

PS:zigurate..I see you have no heater..have you removed the heater valve,lubed it,and then then flush your heater core...
you need heat in wichita

[ddoyle]

I have had a vac guage in my car for many years. You can find charts that will tell you what troubles different guage readings mean, like ign timing, restricted exhaust, and valve trouble. Heres why I installed the guage(long story). Many years my engine developed a miss at freeway speeds. Did a tune up, no help, replaced distributor,no help, rebuilt carb, no help. Compression was low, but very high miles on motor. Miss was driving me nuts. Installed a Vac. guage, bingo, a steady tick(drop) in the guage. This indicated a leaking valve. Pulled head, burned intake valve on number one, off to machine shop, valve job done. After installation ran 300 miles, miss back, and tick in vac guage back. Burned valve Number one. head off back to machine shop regrind valves and seats. Reinstalled parts, 150 miles, miss back, tick back. Head off Different machine shop, been running ever since! I keep an eye on my Vac guage!!!

DAN

[oldopelguy]

Ziggurat-
You only need to be able to measure boost if you're planning on some sort of forced induction, ie. turbocharging or supercharging the motor. My current winter project is a turbo EFI 1900+ (size yet to be determined) so I plan on adding a guage that measures vac and boost depending on actual conditions in the manifold.

And Bucky, that sure looks like a plug for a light. I don't know if the light you have will fit, but if not I'm sure we can get something to work.

[ziggurat]

Ok so I don't need a boost gage yet.

deffinantly gona go with the vacuum gage though.

and no I haven't messed with my heater yet . its stuck on defrost and gives out a small amount of heat ... /sigh

[opeldean]

i finally put in my vacuum gauge. i tried it out last night and i like it so far. since i fixed my clock, i put it on the rear view mirror,instead of in the dash.
1- where is the best place to tap in avacuum line with side draft. my ports are all t-ed together...yellow line or red line? last night it was pretty jitterey on the end.. readings as the vacuum must be not be of stable pressure

3- is there supposed to be a one way valve here from the master cylinder?


vacuum is interesting..mine drops to zero if a barely floor it. oldopelguy says you can diagnose a sticky valve via vacuum

[MikeyOne]

I was on the freeway in So Cal one day and a little 1970s Toyota truck went by and had at least a dozen guages mounted on top of the dash. I couldnt believe it and slowed down to be certain. Sure enough the driver (a kinda crusty looking character) was constantly scanning the guages while he drove.

I suspect he knew the temp of every fluid in the drive train as well as vacuum in the carb and manifold, pressures in the exhaust , pressures in the brake system and probably under hood temp, interior temp and ambient temp. Battery voltage, charging amperage, and ground resistance and field strength. Probably even engine RPM and drive shaft rpm, possibly true airspeed and ground speed and magnetic heading. Time in several time zones.... barometric pressure.... fuel density ....fuel pressure ... fuel temp ... intake flow volume ...

As you might guess I was quite jealous and immediately went out and started hunting up my own "wall of guages". Now, where to put them on my bicycle...hmmmm.....

[David McCollam]

What a crack up! That conjures up quite the mental picture.

About the vacuum gauge, the guage should have a reading from the balanced line between the carbs. There should be a balanced ported vacuum for your intakes for the brake line. The check valve should fit between the tee for the balanced brake vacuum line and the booster.

Good luck.

[opeldean]

1-what is a source for a check valve?
2- what does it do? hold &vmaintain the vacuum on the booster?
3- I dont have a check valve

[nobody]

They are an odd little item to get. I'll have a look.

[RallyBob]

You could give McMaster-Carr a shot.
http://www.mcmaster.com/
Page 384 for starters....

Scratch that...just type in 'check valves' and a lot of options open up.

Bob