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#1751 |
78K & 79C Jimmys
Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
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Re: Restoring Rusty
yup i used an extender too
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John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350 |
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#1752 | |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
Quote:
problem = solved thank you so much |
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#1753 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
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#1754 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
time to compare the 1974 Mechanical Oil Gauge to the Electronic Oil Gauge circa 1978
note no wired plug into the mechanical one, just one hollow metal tube, on the other hand the electric one has three wires going to it the take away here is that the electronic gauge is only half the battle, it's useless by itself, you cant just wire it up and get results, it is the sending unit behind the scenes feeding it all the pertinent information, ie doing all the heavy lifting |
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#1755 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty - Oil Gauge Test
next it was time to test the Electric Oil Pressure gauge
here's how I do it I set it on the battery and connect the negative stud (bottom most) to the negative battery terminal directly with a black wire with aligator clips on either end I connect the positive stud to the positive battery terminal directly with a red wire with aligator clips on either end Then I connect the third stud to the oil pressure sending unit directly I make these direct connections on purpose, this is to eliminate any wire harness problems such as shorts or broken connections, as well as any bad fuses, keep in mind this is a gauge test and a gauge test only, we are not testing the entire circuit here the goal is to keep it simple |
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#1756 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty - Tachometer Test
I test the Tachometer in the same / similar way
put the Tach on the battery the Tach's blade terminals on the back are labeled, thank god, we have a positive, negative, and coil so we aligator clip positive to battery positive aligator clip negative to battery negative and [wait for it] connect the coil terminal to the left terminal on the HEI distributor I think it says Tach on it, the other one is Ignition or power something like that But I think we might could have a problem, I used my trusty (I love the darn thing) digital timing light to stare and compare the Tachometer reading to its reading, and I think we is a bit off, LOL |
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#1757 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
A Take Away Lesson Learned so far people, and we all may appreciate this, it appears that it don't matter where the needle rests on the gauge when it is unplugged, like for example on them eBay pictures you are staring at going is that Tach jacked why is the needle resting on 15, or why is that oil pressure gauge needle in the middle of that gauge on this guys table at the swap meet, what I noticed is as soon as I send juice to it, by connecting the gauge to the battery, both positive and negative, the gauges 0 zero themselves out
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#1758 |
Registered User
Join Date: Jan 2009
Location: Calgary, AB
Posts: 1,181
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Re: Restoring Rusty
Does that gun do 8 cylinders? I only see 2 and 4 on the panel? Could be why its reading weird?
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#1759 |
Post Whore
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Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
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#1760 |
Registered User
Join Date: Jan 2009
Location: Calgary, AB
Posts: 1,181
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Re: Restoring Rusty
I thought 2 cycle and 2 stroke were the same thing.
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#1761 |
Post Whore
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Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
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#1762 |
Registered User
Join Date: Oct 2014
Location: TN
Posts: 294
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Re: Restoring Rusty
Working on an 80 K5 back around 1998, I discovered the need for the offset extension to get the oil pressure sending unit to fit into the tight space.
Someone else must have become frustrated and installed the idiot light sending unit. I simply wanted the gauge to work so I bought what the local auto parts store said I needed...the big sending unit. After I could not get it to fit under the distributor I came up with the idea of using the elbow extension. It worked. I had no idea that's what was required. Again, I just wanted it to work. I had forgotten about that until now. I'll have use that info once I start but this old 79 back together. I too will be going from idiot lights to gauges. |
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#1763 | |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,957
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Re: Restoring Rusty
Quote:
Tan should be the fuel sender. GM wired the harness for both large and small fuel gauge. You'll have to change terminal positions for the 78 cluster.
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#1764 |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,957
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Re: Restoring Rusty
1974 used a sheet metal ground for the main cluster ground wire. Sounds like the cluster Ground splice gave up the ghost.
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#1765 |
Registered User
Join Date: Sep 2012
Location: Midway, NC
Posts: 3,275
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Re: Restoring Rusty
Good lord you been busy.....good grief.
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http://67-72chevytrucks.com/vboard/s...d.php?t=581873 The low buck build threads. Check'em out! http://67-72chevytrucks.com/vboard/s...d.php?t=666022 My build thread Crossmembers CC |
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#1766 |
Registered User
Join Date: Dec 2013
Location: Citrus Heights, CA
Posts: 10
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Re: Restoring Rusty
Are you sure that's a v8 tach and not for a 6?
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#1767 |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,957
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Re: Restoring Rusty
If it were a 6cylinder tach it would read too high.
Freq_Hz=(RPM/60)*(CYL*0.5) An 8cylilnder at 1500 RPM is generating a 100HZ signal A 6cylinder at 2000 RPM is generating a 100HZ signal A 4cylinder at 3000 RPM is generating a 100HZ signal
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#1768 |
Registered User
Join Date: Dec 2007
Location: Kimberley, BC, Canada
Posts: 799
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Re: Restoring Rusty
If the tach gets pulses inductively from the #1 cylinder, then it doesn't matter how many cylinders the engine has. #1 only fires once for every two revs.
If you can drive at a known speed (like using a GPS), and we know your tire size and rear gears, we can figure out what RPM the engine is actually turning.
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Greg 64 GMC Suburban - 283, NV3500, 14 bolt 77 C10 swb - 292, SM465, 12 bolt |
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#1769 | |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,957
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Re: Restoring Rusty
Quote:
What I was explaining was why I know the GM tach is not a 6 cylinder unit... The needle would point to @2000 RPM on a 6cyl tach. @500 RPM too high at @1500 (1490) RPM on the inductive tach. ![]() It's a calibration problem with the analog GM tach drive circuit and it can be repaired.
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#1770 | |
Registered User
Join Date: Dec 2007
Location: Kimberley, BC, Canada
Posts: 799
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Re: Restoring Rusty
Quote:
Another reason you're right that it's not a six cylinder tach is that, all the six cyl trucks I've seen, including mine, are pretty basic, and are unlikely to have the full gauge package.
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Greg 64 GMC Suburban - 283, NV3500, 14 bolt 77 C10 swb - 292, SM465, 12 bolt |
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#1771 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty - Oil Pressure Sending Unit Wire
OK fellas I was able to make it to the junk yards this morning to take advantage of the 50% off sale, although I did not find a radiator core support I did score some little things that I needed, some that are hard to find, so allow me to share
first off of a 1979 I pulled the Oil Pressure Sender Unit wire, that's right I could have made my own, but by pulling an original I get the right plug, the right color, and I get to see where it plugs into the bulk head connector if you just take your time with some needle nose pliars you can actually push out one of them GM connectors, like so... |
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#1772 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
still staying with the '79 I decided to see if I can find a similar black ground wire like the loose one in my truck and see where it bolts up to
I found a similar wire so I unscrewed the loop end and cut the other end where it splices into the wiring harness so I can graft it in properly to my own, score |
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#1773 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty
then I moved on to a 76 manual 4 speed like mine, the first manual I ever saw
this is where I found the Holly Grail... a part I have been looking for, for almost a year and knew the aftermarket one I bought wasn't even close to the original, I also got an answer to where these little two hole round brackets go and en explanation how this super tough spring can span such a huge distance I give you the clutch pedal spring at last... |
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#1774 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty - Clutch Pedal Spring
here is my old broken spring with one mystery bracket, the used replacement one with both brackets which I paid $2.50 for, and the silly thing I bought somewhere online claiming to be the proper new replacement, shame on them
Last edited by Gregski; 05-23-2015 at 05:02 PM. |
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#1775 |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,836
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Re: Restoring Rusty - Headlight Switch Knob
also from the '76 picked up the Headlight Switch knob and rod for $1.50, LMC Truck wants $14.00 bucks for it and I doubt it would match my black knobs, score
my old one gave up the ghost, the insides crumble and it just slides right off I like these small victories! How about you? Last edited by Gregski; 05-07-2020 at 07:12 AM. |
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