Hooked up the HEI, runs like crap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Paul72 · 05-31-2005, 06:38 PM

Took the K5 out for a ride today, and she started bucking and backfiring. I figured it was the points, since I havent looked at them since I installed them back in '94. So instead of running to the parts store and replacing the points, I thought 'Now I can put in the HEI!!'

Here's the problem: I start it up and it runs like crap! I checked the wires about 4 times, making sure they are all in the right order, and pulled the plugs/checked the gap - everything is fine. I'm starting to get a little frustrated.

I crank up the idle so it will run (sort of) and I can check timing at least. I pull the vacuum advance off and she starts running like a champ!! Great throttle response, smooth idle, etc. I look for the timing mark (driver's side)to see where I'm at, and it's no where to be seen. For sh!ts and grins, I check the pass side - lo and behold there it is!

Here's the questions:

Is there any way that the HEI would switch the timing mark to the other side?!! This isn't a real big deal to me, since I can get it close without the light.

Where should I hook up the vac, advance? I've tried both manifold and carburator with the same result (crappy performance).

Probably a simple fix, but I figured it would be faster here than pulling my hair out!!

Thanks,

Paul

smokekiki · 05-31-2005, 06:52 PM

I am thinking You have it in a little off.When You hook the advance up,it is making it worse because it is adding that much more advance.Bring it up to TDC,and check were the rotor is pointed.It should be at the #1 plug tower.

kelsfine69 · 05-31-2005, 06:52 PM

I would start over. pull out the Dist. Put the engine top dead No. one, the timing mark at 0. Then drop your HEI in with the rotor pointing to no. one on the cap, About 5 oclock. Some times you have to put a big flat screwdriver down the dist. hole to turn the oilpump so it all drops in correct.

shifty · 05-31-2005, 06:53 PM

When I swapped to HEI from points, My timing mark was pointed way the hell out of whack from where it should have been. Like, literally, my 0º mark is around 9-o'clock on the harmonic balancer and the timing light at a steady idle was showing the tming mark around 12-o'clock. Not sure how many degrees out of whack that is.

I just basically fired up the truck when it was cold w/vacuum advance off, turned the distributor around until it ran smoothly, then reattached the vacuum line. I know this is far from technical and probably the wrong thing to do, but I honestly have no idea how to set the timing on my truck with the timing mark showing so many degrees out of whack.

smokekiki · 05-31-2005, 06:54 PM

Also,make sure You have full 12v power to the dist.The plugs should be at 045 gap.

smokekiki · 05-31-2005, 07:03 PM

To find TDC,have a helper or use a remote starter,remove the #1 plug(driverside),and bump the engine till the compression blows your finger off the plughole,bump the engine till the mark is on tdc.Now put the distributor in pointed towards the #1 plug.You should be on #1 tdc.

**Palf70Step** · 05-31-2005, 07:16 PM

Quote:

Originally Posted by smokekiki

Also,make sure You have full 12v power to the dist.The plugs should be at 045 gap.

Definitely check this. If you forgot to run a new line and are using the resistor wire, that could very well be the root of the problem.

Russell · 05-31-2005, 07:49 PM

Also make sure you set the base timing with the engine idling around 600 - 700 rpm with the vac advance unhooked and plugged. You wanna set it to about 12 degrees BTDC. Make sure you are not over 700 rpm though, or the internal mechanical advance may already be taking an effect.

After you have set the base timing, then put on the vac advance and set your idle speed.

Longhorn Man · 05-31-2005, 07:59 PM

You may want to double check your ballancer, make sure the rubber isn't rotting away and letting the outer ring slip.

Paul72 · 05-31-2005, 08:52 PM

GOT IT GOING!!!!

I did the old 'put the new dist pointing the same way the old one was' shortcut, and it bit me! Pulled everything out, put it on #1, and put it back together - violla! It still amazes me how far out of tune these can be and still run!

I did run a new wire to the dist, and I do have 12 volts.

Thanks for all the help/suggestions! I now have more confidence making Sioux Falls on Saturday!

This board rules!

Paul

WRMZ71 · 05-31-2005, 08:58 PM

Quote:

Originally Posted by Longhorn Man

You may want to double check your ballancer, make sure the rubber isn't rotting away and letting the outer ring slip.

A lot of people never think about this, but this is a very common problem for old dampeners.

Longhorn Man · 05-31-2005, 09:18 PM

Yup...been there, it'll drive you crazy.

byrd · 05-31-2005, 09:51 PM

My HEI I though was doing the same thing, then my mechanic buddy checked it and the po had the dizzy out 180. then after fixing that and not being able to get in time we realized that the balancer has slipped and was a pita to get it to run decent till I can fix it.

Randy

**VetteVet** · 06-01-2005, 12:01 AM

Glad to hear you got it fixed. Here is a great website for swapping in an HEI distributer.

http://rmcavoy.freeshell.org/HEI.html

GMC AMI · 06-01-2005, 06:00 AM

Quote:

Originally Posted by Paul72

GOT IT GOING!!!!

I did the old 'put the new dist pointing the same way the old one was' shortcut, and it bit me! Pulled everything out, put it on #1, and put it back together - violla! It still amazes me how far out of tune these can be and still run!

I did run a new wire to the dist, and I do have 12 volts.

Thanks for all the help/suggestions! I now have more confidence making Sioux Falls on Saturday!

This board rules!

Paul

Great news, my bet is it was one tooth off when dropped in the first time.

Paul72 · 06-01-2005, 08:58 AM

Quote:

Originally Posted by Mike Files

my bet is it was one tooth off when dropped in the first time

I believe that to be the case. It could have been 2 teeth off as far off as it looked.

Oh well, it's all good now. Thanks again for all the help!

Paul

iluvmy72 · 06-01-2005, 09:33 AM

also make sure you lean out your mixture a bit. The HEI doesn't need to be as rich in some of the cases that I've found.

05-31-2005, 06:52 PM	#2
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	I am thinking You have it in a little off.When You hook the advance up,it is making it worse because it is adding that much more advance.Bring it up to TDC,and check were the rotor is pointed.It should be at the #1 plug tower. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

05-31-2005, 06:53 PM	#4
shifty Questionable Join Date: Mar 2005 Location: Atlanta Posts: 13,376	When I swapped to HEI from points, My timing mark was pointed way the hell out of whack from where it should have been. Like, literally, my 0º mark is around 9-o'clock on the harmonic balancer and the timing light at a steady idle was showing the tming mark around 12-o'clock. Not sure how many degrees out of whack that is. I just basically fired up the truck when it was cold w/vacuum advance off, turned the distributor around until it ran smoothly, then reattached the vacuum line. I know this is far from technical and probably the wrong thing to do, but I honestly have no idea how to set the timing on my truck with the timing mark showing so many degrees out of whack. __________________ If I've got anything up for grabs, it'll be here: 7-hole gauge cluster for a 67-72 p/u FREE (link) I can't check the forum daily. If I don't reply to you within 24 hours, drop me a PM! I'm (hopefully) still alive and will reply faster to a PM.

05-31-2005, 06:54 PM	#5
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	Also,make sure You have full 12v power to the dist.The plugs should be at 045 gap. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

05-31-2005, 07:03 PM	#6
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	To find TDC,have a helper or use a remote starter,remove the #1 plug(driverside),and bump the engine till the compression blows your finger off the plughole,bump the engine till the mark is on tdc.Now put the distributor in pointed towards the #1 plug.You should be on #1 tdc. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

05-31-2005, 07:49 PM	#8
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Also make sure you set the base timing with the engine idling around 600 - 700 rpm with the vac advance unhooked and plugged. You wanna set it to about 12 degrees BTDC. Make sure you are not over 700 rpm though, or the internal mechanical advance may already be taking an effect. After you have set the base timing, then put on the vac advance and set your idle speed. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

05-31-2005, 06:38 PM	#1
Paul72 Registered User Join Date: Sep 2003 Location: Waterloo, IA Posts: 1,147	Hooked up the HEI, runs like crap - Help please! Took the K5 out for a ride today, and she started bucking and backfiring. I figured it was the points, since I havent looked at them since I installed them back in '94. So instead of running to the parts store and replacing the points, I thought 'Now I can put in the HEI!!' Here's the problem: I start it up and it runs like crap! I checked the wires about 4 times, making sure they are all in the right order, and pulled the plugs/checked the gap - everything is fine. I'm starting to get a little frustrated. I crank up the idle so it will run (sort of) and I can check timing at least. I pull the vacuum advance off and she starts running like a champ!! Great throttle response, smooth idle, etc. I look for the timing mark (driver's side)to see where I'm at, and it's no where to be seen. For sh!ts and grins, I check the pass side - lo and behold there it is! Here's the questions: Is there any way that the HEI would switch the timing mark to the other side?!! This isn't a real big deal to me, since I can get it close without the light. Where should I hook up the vac, advance? I've tried both manifold and carburator with the same result (crappy performance). Probably a simple fix, but I figured it would be faster here than pulling my hair out!! Thanks, Paul __________________ '72 Chevy K20 - 383/4sp/205 - SOLD after 41 years in the family Next project - K/5 Tahoe (71 Blazer on 99 Tahoe chassis) Build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=789958 Last edited by Paul72; 05-31-2005 at 06:48 PM.

05-31-2005, 06:52 PM	#3
kelsfine69 18 Till I Die Join Date: Mar 2005 Location: Alberta, Canada Posts: 1,522	I would start over. pull out the Dist. Put the engine top dead No. one, the timing mark at 0. Then drop your HEI in with the rotor pointing to no. one on the cap, About 5 oclock. Some times you have to put a big flat screwdriver down the dist. hole to turn the oilpump so it all drops in correct.

05-31-2005, 07:59 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	You may want to double check your ballancer, make sure the rubber isn't rotting away and letting the outer ring slip.

05-31-2005, 08:52 PM	#10
Paul72 Registered User Join Date: Sep 2003 Location: Waterloo, IA Posts: 1,147	GOT IT GOING!!!! I did the old 'put the new dist pointing the same way the old one was' shortcut, and it bit me! Pulled everything out, put it on #1, and put it back together - violla! It still amazes me how far out of tune these can be and still run! I did run a new wire to the dist, and I do have 12 volts. Thanks for all the help/suggestions! I now have more confidence making Sioux Falls on Saturday! This board rules! Paul __________________ '72 Chevy K20 - 383/4sp/205 - SOLD after 41 years in the family Next project - K/5 Tahoe (71 Blazer on 99 Tahoe chassis) Build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=789958

05-31-2005, 09:18 PM	#12
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Yup...been there, it'll drive you crazy.

06-01-2005, 12:01 AM	#14
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,703	HeI fixed Glad to hear you got it fixed. Here is a great website for swapping in an HEI distributer. http://rmcavoy.freeshell.org/HEI.html __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

06-01-2005, 09:33 AM	#17
iluvmy72 Registered User Join Date: Jan 2002 Location: Springville, UT, USA Posts: 1,010	also make sure you lean out your mixture a bit. The HEI doesn't need to be as rich in some of the cases that I've found.



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