Something seems wrong... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ryans69chevy · 10-30-2010, 10:28 PM

I got a 69 chevy c10 and I use it to drive 25 miles one way to college everyday. I installed a tach that I bought from harbor freight for $20. When I drive I go about 63 mph because the tach reads just under 5000 rpms! The engine is pretty noisy going that fast. I'm just wondering if there is anything wrong with my truck or if it's just a cheap tach. I couldn't imagine a tach being that far off. It seems like everyone else that has something around my set up revs around 2200-2500 rpms... The truck has got a 307 muncie 4 speed and 3:08 gears in the rear end. I know it has 3:08's because I took the cover off and counted the ring and pinion myself and divided. Any ideas what's going on?

Hubscrub · 10-30-2010, 10:35 PM

does the tach have the switch on it were you switch for 4 cyl. 6cyl or 8cyl? and its in the wrong position? just a thought.............

LandonL · 10-30-2010, 10:37 PM

On the back of the tach I bought, there were settings for 4 cylinder, 6 cylinder and 8 cylinder. See if the one you bought has one, it should be on the back. The other problem may be it came from Harbor Freight. Thats the best I can do, if this doesn't solve it I hope someone else can! Good luck!

EDIT: Hubscrub beat me too it! Haha.

cheepin · 10-30-2010, 10:40 PM

Think your tach is a piece or the setting is wrong on the back.Assuming and 29" tire your should be running just over 2200 rpm.

71swb4x4 · 10-30-2010, 10:41 PM

Just because something is new, doesn't mean it works correctly. Check out what the first two people suggest, if that doesn't work return it for a new one.

ryans69chevy · 10-30-2010, 10:44 PM

haha ya you guys are both right. I actually just checked before I reposted and the switch was and is on the v8 position. I thought it was just because it's harbor freight S#@T, but I just can't imagine a product being THAT far off. The engine is VERY noisy going that fast too.

ryans69chevy · 10-30-2010, 10:47 PM

I bought it awhile ago...like last spring probably. I'm actually bringing my truck down to brookings to visit my friend at college!

**LockDoc** · 10-30-2010, 11:25 PM

-
I have one of those in my Green '67 and even though the needle is not real steady it seems to be pretty accurate. I can't see how you could be turning that many rpm with the setup you have. Yes, the engine might be noisy at 63 mph but I can't believe 5000 rpm worth....

LockDoc

oldblue1968chevy · 10-30-2010, 11:59 PM

dang does it sound like 5k lol!! 5k i couldnt drive @ that much rpm for long!!! LOL

raycow · 10-31-2010, 07:10 AM

Since nobody else asked, what kind of ignition setup do you have? Some tachs made for points do not work right with HEI, and sometimes the reverse is true also.

Ray

ryans69chevy · 10-31-2010, 09:42 PM

I guess I'm not really sure what ignition system I have...I haven't changed anything on it. So I'm assuming it's stock. Whatever type of system that is. What's the difference in types?

oldblue1968chevy · 10-31-2010, 10:23 PM

if its unchanged from the factory its the old points style

newer is HEI

raycow · 10-31-2010, 10:30 PM

Quote:

Originally Posted by ryans69chevy

I guess I'm not really sure what ignition system I have...I haven't changed anything on it. So I'm assuming it's stock. Whatever type of system that is. What's the difference in types?

The original ignition system in 1969 used a set of contact points that are opened and closed by a cam on the distributor shaft. If you take off the cap and rotor you will be able to see if you still have them.

HEI and other types of electronic ignition replace the points with a magnetic sensor. The problem is that the two types of systems generate a signal that the tach "sees" differently. Most modern tachs will work on either type of system without a problem, but a few of them won't.

Ray

ryans69chevy · 10-31-2010, 10:35 PM

Quote:

Originally Posted by raycow

The original ignition system in 1969 used a set of contact points that are opened and closed by a cam on the distributor shaft. If you take off the cap and rotor you will be able to see if you still have them.

HEI and other types of electronic ignition replace the points with a magnetic sensor. The problem is that the two types of systems generate a signal that the tach "sees" differently. Most modern tachs will work on either type of system without a problem, but a few of them won't.

Ray

Ya I'm sure it has the points then, because I haven't touched the ignition system. So is there another way to hook up a tach if it has those contact points to make it work? Or is the tach just not able to work period in my system?

**LockDoc** · 10-31-2010, 10:56 PM

Quote:

Originally Posted by ryans69chevy

Ya I'm sure it has the points then, because I haven't touched the ignition system. So is there another way to hook up a tach if it has those contact points to make it work? Or is the tach just not able to work period in my system?

Mine has the stock points dist. with no problem...

LockDoc

**Stocker** · 11-01-2010, 12:01 AM

My Sun tach worked with the OEM points ignition, and it works with HEI. It's starting to sound like your HF tach may be defective. However, with 3.08 gears, your engine should not be that 'noisy'. I wonder what noise you are hearing, though. Does it have a fixed fan? Those pull a lot of air and make a noticeable roar at anything much over idle speed.

raycow · 11-01-2010, 12:30 AM

Since someone must have done a transmission swap in order for you to have that Muncie, could it possibly have the wrong speedo drive gears in it?

Ray

**El Jay** · 11-01-2010, 02:04 AM

Are you sure you have 3.08:1 rear gears? It's the noise thing that makes me ask.
Both my 1/2 T. Chevy & 3/4 T GMC have 4:10:1 gears and they only turn about 3000 RPM at 65 MPH.
Also, FWIW, they both have aftermarket tachs; the Chevy has electronic ignition & the GMC still has points & condenser (but not for much longer!).

ryans69chevy · 11-01-2010, 01:19 PM

Quote:

Originally Posted by raycow

Since someone must have done a transmission swap in order for you to have that Muncie, could it possibly have the wrong speedo drive gears in it?

Ray

Well I'm fairly certain it has a Muncie. What did they come with? Or how would I tell if I have anything different than a Muncie? If there was a wrong speedo gear in it wouldn't that make the speedometer way off? I'm pretty sure my speedometer is very close to accurate...

ryans69chevy · 11-01-2010, 01:22 PM

Quote:

Originally Posted by El Jay

Are you sure you have 3.08:1 rear gears? It's the noise thing that makes me ask.
Both my 1/2 T. Chevy & 3/4 T GMC have 4:10:1 gears and they only turn about 3000 RPM at 65 MPH.
Also, FWIW, they both have aftermarket tachs; the Chevy has electronic ignition & the GMC still has points & condenser (but not for much longer!).

I'm positive I have 3:08's because after I did the equation I ended up with 3.07 and some more numbers. And I also picked one wheel up and after 2 spins the driveshaft made just over 3 turns. Maybe it has to do with my transmission. I start out in 2nd gear and switch to 3rd by 10mph and then end up in 4th at 25mph.

Papaloo · 11-01-2010, 01:41 PM

I know you said you have a C10, but is the truck 4wd? That's about where mine would shift if I had transfer case in 4Lo.

raycow · 11-01-2010, 02:50 PM

Quote:

Originally Posted by ryans69chevy

Well I'm fairly certain it has a Muncie. What did they come with? Or how would I tell if I have anything different than a Muncie?

After reading your later post where you talk about starting in 2nd gear, I am pretty sure you have an SM465 which would have come stock in the truck. When most people talk about a "Muncie 4 speed" they mean a car type transmission. So this means your speedo gearing probably isn't at fault. At first, I was thinking you might have been going a lot faster than your speedo was showing, but not now.

Ray

**slomotion** · 11-01-2010, 05:41 PM

I probably missed it somewhere.....is this an eight or six cylinder engine?

Never mind, I see it.....307.

Sorry

292farmer · 11-01-2010, 06:36 PM

theirs no exhaust leak is their?

**Stocker** · 11-01-2010, 06:37 PM

Have you verified your actual speed with a GPS or by time between mile posts? Maybe you're running along at 95 or so, which would explain the truck being so noisy.

10-30-2010, 10:28 PM	#1
ryans69chevy Registered User Join Date: Sep 2010 Location: Casselton, North Dakota 58012 Posts: 1,082	Something seems wrong... I got a 69 chevy c10 and I use it to drive 25 miles one way to college everyday. I installed a tach that I bought from harbor freight for $20. When I drive I go about 63 mph because the tach reads just under 5000 rpms! The engine is pretty noisy going that fast. I'm just wondering if there is anything wrong with my truck or if it's just a cheap tach. I couldn't imagine a tach being that far off. It seems like everyone else that has something around my set up revs around 2200-2500 rpms... The truck has got a 307 muncie 4 speed and 3:08 gears in the rear end. I know it has 3:08's because I took the cover off and counted the ring and pinion myself and divided. Any ideas what's going on?

10-30-2010, 10:35 PM	#2
Hubscrub Cruzin Join Date: Dec 2009 Location: on the road Posts: 2,835	Re: Something seems wrong... does the tach have the switch on it were you switch for 4 cyl. 6cyl or 8cyl? and its in the wrong position? just a thought............. __________________ Lime Wife's 67https://www.google.com/url?sa=t&rct=...wZEMODaS2d94u8 Back to the Fifties 59 https://www.google.com/url?sa=t&rct=...NAeStpydfrcj_U Proverbs 3:5,6 "Thanks to the Interstate Highway System, it is now possible to travel across the country from coast to coast without seeing anything."Charles Kuralt In memory of our first baby daughter, daddy and mommy love you. Danica Grace 6/26/14 Last edited by Hubscrub; 10-30-2010 at 10:35 PM.

10-30-2010, 10:37 PM	#3
LandonL Registered User Join Date: Nov 2009 Location: Georgia Posts: 440	Re: Something seems wrong... On the back of the tach I bought, there were settings for 4 cylinder, 6 cylinder and 8 cylinder. See if the one you bought has one, it should be on the back. The other problem may be it came from Harbor Freight. Thats the best I can do, if this doesn't solve it I hope someone else can! Good luck! EDIT: Hubscrub beat me too it! Haha. __________________ ---\| 1967 GMC Stepside \|-- 250 L6 .030 over ---\| 1985 Porsche 944/1 \|--- Build Thread: '67 GMC http://67-72chevytrucks.com/vboard/s...d.php?t=378640 Last edited by LandonL; 10-30-2010 at 10:37 PM.

10-30-2010, 10:40 PM	#4
cheepin Registered User Join Date: Nov 2009 Location: Parachute, CO Posts: 183	Re: Something seems wrong... Think your tach is a piece or the setting is wrong on the back.Assuming and 29" tire your should be running just over 2200 rpm. __________________ 1984 1ton 4x4 crew cab dually 6.2 diesel,465,205,D60,D70,1987 3/4ton 4x4 suburban 5.7 FI350,TH400,208,1985 CJ-7 FI406,465,205,D60,FF14, 1970 Jeepster 350,465,205,D44,FF14,

10-30-2010, 10:41 PM	#5
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: Something seems wrong... Just because something is new, doesn't mean it works correctly. Check out what the first two people suggest, if that doesn't work return it for a new one. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

10-30-2010, 10:44 PM	#6
ryans69chevy Registered User Join Date: Sep 2010 Location: Casselton, North Dakota 58012 Posts: 1,082	Re: Something seems wrong... haha ya you guys are both right. I actually just checked before I reposted and the switch was and is on the v8 position. I thought it was just because it's harbor freight S#@T, but I just can't imagine a product being THAT far off. The engine is VERY noisy going that fast too.

10-30-2010, 10:47 PM	#7
ryans69chevy Registered User Join Date: Sep 2010 Location: Casselton, North Dakota 58012 Posts: 1,082	Re: Something seems wrong... I bought it awhile ago...like last spring probably. I'm actually bringing my truck down to brookings to visit my friend at college!

10-30-2010, 11:25 PM	#8
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,771	Re: Something seems wrong... - I have one of those in my Green '67 and even though the needle is not real steady it seems to be pretty accurate. I can't see how you could be turning that many rpm with the setup you have. Yes, the engine might be noisy at 63 mph but I can't believe 5000 rpm worth.... LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

10-30-2010, 11:59 PM	#9
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	Re: Something seems wrong... dang does it sound like 5k lol!! 5k i couldnt drive @ that much rpm for long!!! LOL __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

10-31-2010, 07:10 AM	#10
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: Something seems wrong... Since nobody else asked, what kind of ignition setup do you have? Some tachs made for points do not work right with HEI, and sometimes the reverse is true also. Ray __________________ Live more responsibly. Eat lower on the food chain. Eat vegetarians.

10-31-2010, 09:42 PM	#11
ryans69chevy Registered User Join Date: Sep 2010 Location: Casselton, North Dakota 58012 Posts: 1,082	Re: Something seems wrong... I guess I'm not really sure what ignition system I have...I haven't changed anything on it. So I'm assuming it's stock. Whatever type of system that is. What's the difference in types?

10-31-2010, 10:23 PM	#12
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	Re: Something seems wrong... if its unchanged from the factory its the old points style newer is HEI __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

11-01-2010, 12:01 AM	#16
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,722	Re: Something seems wrong... My Sun tach worked with the OEM points ignition, and it works with HEI. It's starting to sound like your HF tach may be defective. However, with 3.08 gears, your engine should not be that 'noisy'. I wonder what noise you are hearing, though. Does it have a fixed fan? Those pull a lot of air and make a noticeable roar at anything much over idle speed. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay Last edited by Stocker; 11-01-2010 at 12:01 AM.

11-01-2010, 12:30 AM	#17
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: Something seems wrong... Since someone must have done a transmission swap in order for you to have that Muncie, could it possibly have the wrong speedo drive gears in it? Ray __________________ Live more responsibly. Eat lower on the food chain. Eat vegetarians.

11-01-2010, 02:04 AM	#18
El Jay Gone to greener pastures Join Date: May 2007 Location: Gateway to the Delta Posts: 7,354	Re: Something seems wrong... Are you sure you have 3.08:1 rear gears? It's the noise thing that makes me ask. Both my 1/2 T. Chevy & 3/4 T GMC have 4:10:1 gears and they only turn about 3000 RPM at 65 MPH. Also, FWIW, they both have aftermarket tachs; the Chevy has electronic ignition & the GMC still has points & condenser (but not for much longer!). __________________ '69 Chevy 1/2 T LWB Stepper: Daily Beater '72 GMC 3/4 T Fleet: Another Daily Beater '72 Plymouth Gran Coupe: ? "Ah women. They make the highs higher and the lows more frequent." Friedrich Nietzsche "Never kick a fresh turd on a hot day." Harry S. Truman GUN CONTROL: Never having to say, "I missed you." Always fire two warning shots into your attacker's chest area before putting a bullet between his eyes. Paraphrased from Louis Awerbuck Last edited by El Jay; 11-01-2010 at 02:05 AM.



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11-01-2010, 01:41 PM	#21
Papaloo Registered User Join Date: Oct 2009 Location: Southeast PA Posts: 57	Re: Something seems wrong... I know you said you have a C10, but is the truck 4wd? That's about where mine would shift if I had transfer case in 4Lo. __________________ Dave 1971 Chevy K10 1972 Chevy C10

11-01-2010, 05:41 PM	#23
slomotion Old Duffer Join Date: Mar 2003 Location: Maine Posts: 1,822	Re: Something seems wrong... I probably missed it somewhere.....is this an eight or six cylinder engine? Never mind, I see it.....307. Sorry __________________ '68 Short C20 Flatbed Dually w/ 292 4bbl, Langdon cast headers, and WC T5 trans. '81 G10 Shorty Van "Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers "Under promise, then over achieve." Last edited by slomotion; 11-01-2010 at 05:56 PM. Reason: numb

11-01-2010, 06:36 PM	#24
292farmer Registered User Join Date: Nov 2009 Location: stoddard nh Posts: 693	Re: Something seems wrong... theirs no exhaust leak is their? __________________ 1972 gmc c25 292/sm465 dana 60 w/5.13s 1973 vw super beetle 1600cc/4spd(baja bug) 1974 chevy c60 351v6/np-540+2 speed eaton rear 2005 chevy cobalt 2.2l

11-01-2010, 06:37 PM	#25
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,722	Re: Something seems wrong... Have you verified your actual speed with a GPS or by time between mile posts? Maybe you're running along at 95 or so, which would explain the truck being so noisy. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

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