Distributor drop in, Top Dead Center? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sactoC10 · 02-11-2005, 01:22 AM

OK, need to drop in HEI this weekend and I'm not sure about the TOP DEAD CENTER part of the install. What's the deal?

Then also, anyone have the firing order in case I screw up the order when taking out the old plug wires?
Thank you very much.

70c10swb · 02-11-2005, 01:29 AM

the #1 piston has to be at the top of the stroke on the compression stroke i belive

i dont have the fireing order on me right now

HTH

sdkid · 02-11-2005, 01:30 AM

18436572

bigjimzlll · 02-11-2005, 01:34 AM

pull # 1 plug...stick a piece of dampened paper towel in the plug hole. turn crank slowly until the paper towel "pops" out. then turn the crank until the damper points to 10 degrees BTDC. Install dizzy so the rotor points to the number 1 spark plug wire terminal.

sactoC10 · 02-11-2005, 01:45 AM

Ya'all make it sound so simple...but you have no idea how clueless I am. And yes, I do feel like a fool admitting it! Still don't "see" exactly what to do in my mind. I do understand bigjimz wet paper towel procedure, but is that firing order starting at the front passenger side, that plug #1?

Sorry, but GREEN I am. Dad sold cars, hated them and never wanted to touch them when home. No shop classes, just sort of learning as I go!

70c10swb · 02-11-2005, 01:51 AM

1. No you are NOT a fool, we all had to learn and we learn by asking questions and doing

2. the #1 cylinder is front driverside

sactoC10 · 02-11-2005, 02:01 AM

Thanks, that's encouraging... By the way 70c10swb, I was born on the cape... Hyannis, MA. Still wondering why it doesn't seem to be a consistent concern, the TDC thing. Some instructions mention it, other don't!

bigjimzlll · 02-11-2005, 02:05 AM

it goes 1357 drivers side and 2468 passenger side. so you would start with the number one plug then the next hole clockwise goes to the #8 plug..then the next hole goes to #4 and so on
18436572

70c10swb · 02-11-2005, 02:17 AM

Quote:

Originally Posted by sactoC10

Thanks, that's encouraging... By the way 70c10swb, I was born on the cape... Hyannis, MA. Still wondering why it doesn't seem to be a consistent concern, the TDC thing. Some instructions mention it, other don't!

cool im from bourne

the TDC is just the easyist way i guess, its the only way i know

Johnny05 · 02-11-2005, 02:37 AM

If you still have the stock intake the firing order and cylinder location(18436572) information is cast into it. Look at the end of each of the intake runners and you'll notice the numbers. The firing order is cast into the intake as well just in front of the carb. If your standing in front of the truck #1 is at the right front. The right side is the odd bank 1357 the left side is the even bank 2468.
If you haven't changed/pulled anything yet you should be able to drop the HEI directly into the same location as the original setup.

Tynee · 02-11-2005, 09:02 AM

Ask me how I know that you should be very choosy in your choice of helpers if you decide to use the "bump the starter method" to get to TDC. Some help will not know when the key is on or off, getting you shocked. Other help will think its amusing that you are now skittish under the hood, and will honk the horn while you're under there just for fun.

Also, if you're using this method, make sure the fuel line is attached to the carb or otherwise blocked. Again, ask me how I know.

sactoC10 · 02-11-2005, 10:54 AM

Gee Tynee, how do you know? Part of me thinks I ought to just pull the old one, put in the new one and just see if it works out OK... If I can get the plug wires this afternoon, probably be doing this tonight. Again, thanks.

junkyardjohn · 02-11-2005, 12:19 PM

Quote:

Originally Posted by sactoC10

Gee Tynee, how do you know? Part of me thinks I ought to just pull the old one, put in the new one and just see if it works out OK... If I can get the plug wires this afternoon, probably be doing this tonight. Again, thanks.

YOU CAN DO THAT TOO. PULL THE CAP & MARK THE DIRECTION THE ROTOR IS POINTING WITH A MAJIC MARKER, ON THE FIREWALL OR VALVE COVER . PUT IT BACK IN EXACKLY IN THE SAME DIRECTION. JUST REMEMBER THAT THE GEAR ON THE DIST. IS A HELIX GEAR & WILL TURN SLIGHTLY IN THE LAST INCH OR SO OF INSTALLATION.

JOHN

Nima · 02-11-2005, 12:52 PM

I feel stupid to say anything infront of all these experienced people. I had todrop my dist when I changed my intake too. Great people on this board give me different ways of finding TDC. One of them which worked well for me, was using a cloth hanger or something similar. I inserted in #1 and then I rotated the engine manually until the hager stopped coming up (just have to becarefull that hanger doesn't get cut in there). I repeated few times to be differentiate between the compression and exhaust TDC. (other people please correct me if I am confused). Anyways, it worked well. If I could do it, anybodyelse can do it.
Good luck.

avejoe · 02-11-2005, 01:46 PM

Oh come on! Just drop it in and go. You have a 1 in 16 chance of getting it right.

"So, do you feel lucky?"

Perchjerker · 02-11-2005, 01:57 PM

If you haven't turned the motor while the dizzy has been out, you don't need to find aTDC. Just Put it in where you had it.

Zonaman · 02-11-2005, 02:03 PM

[QUOTE=sactoC10]Ya'all make it sound so simple...but you have no idea how clueless I am.

Hey, if you don't do it every day you tend to need to ask. Good on you! Which reminds me, This is a job that can be helped along with one of those remote starter buttons. Which terminal on the starter do you hook those up to?

Thanks.

mrein3 · 02-11-2005, 02:19 PM

Quote:

Originally Posted by junkyardjohn

YOU CAN DO THAT TOO. PULL THE CAP & MARK THE DIRECTION THE ROTOR IS POINTING WITH A MAJIC MARKER, ON THE FIREWALL OR VALVE COVER . PUT IT BACK IN EXACKLY IN THE SAME DIRECTION. JUST REMEMBER THAT THE GEAR ON THE DIST. IS A HELIX GEAR & WILL TURN SLIGHTLY IN THE LAST INCH OR SO OF INSTALLATION.

JOHN

Junkyardjohn beat me to it.

If you are swapping distributors you don't need to know nothing about where the engine is.
Just draw a circle on a piece of paper, take the distributor cap off, mark a pointer on your paper showing where the rotor is pointing, pull the old distributor, and drop in the new one pointing in the same direction.

If there is gonna be a few days inbetween tape your "map" to the firewall so you don't lose it (and you remember which way is "north").

The only time I've had to worry about where TDC is is when I've done a timing chain and/or cam and/or dropped a distributor in a new rebuild. In all of those cases I just make sure I leave it at TDC when I have the timing chain cover off then if I rotate it I just make sure I keep track of whether I'm on #6 at the timing mark or at #1.

sactoC10 · 02-11-2005, 04:39 PM

Like this answer ALOT!

Kid · 02-11-2005, 06:55 PM

another way to find TDC is to remove the spark plug from #1 cylinder and hold your thumb or finger over the hole. Then bump the starter untill compressed air pushes on your finger. That means you are on the compression stroke. Bump starter again until your timing mark on damper is aligned at TDC on pointer, being carefull to not over shoot your mark, If you do no big deal, just do over. Then drop in your distributer.

gmc67swb · 02-11-2005, 10:15 PM

Also once dropped, you may have to keep pressure down on the distributor while turning the motor until the distributor drops into the oil pump.

4x4Poet · 02-12-2005, 01:49 AM

Quote:

Originally Posted by Nima

I feel stupid to say anything infront of all these experienced people....

Quote:

Originally Posted by mrein3

...Just draw a circle on a piece of paper, take the distributor cap off, mark a pointer on your paper showing where the rotor is pointing, pull the old distributor, and drop in the new one pointing in the same direction.

If there is gonna be a few days inbetween tape your "map" to the firewall so you don't lose it (and you remember which way is "north")....

When I pulled the dizzy from my TravelAll's 392 to install a Pertronix Ignitor, I wrote myself a note to record the rotor's position. Lost it because I didn't post it prominently as mrein3 suggests. Had to visit the Binder Bulletin to learn how to find TDC (cyl#8).

Good advice, here.

Solver · 02-12-2005, 02:14 AM

I always seem to have to take a long screwdriver and set the oil pump shaft so that distributor will drop down where I want it to.

Tx Firefighter · 02-12-2005, 09:14 AM

I don't bump the starter, I just stick my finger in the hole and turn the engine over by turning the fan with my other hand. Wear a glove.

modifiedGMC · 02-12-2005, 09:42 AM

The first time I ever had to deal with firing order/ timing was when I was sixteen. I had a 69 chevelle with an aluminum intake that had no firing order cast to it. There was a stock one in the shed and me and a buddy went to the shed and looked at the intake. I remembered 1843 and he remembered 6572 and noticed the number 1 on the intake runner. Then went back to the chevelle and put our plug wires on. I always get number one up on top of the compression stroke, line up the crank timing marks on the damper and position the distributor in the intake where it sets, then turn the rotor so it will point straight at or slightly past the carb and drop it in. If it doesn't line up with oil pump and go all way down, then I just simply hold down on the distributor and bump the starter over till it does. then I double check myself and get number one back up and check position of the rotor. dist installed! then wire up the plug wires 18436572 starting with driver side front cylinder (even number side) and proceeding clock wise on the distributor starting the terminal Imarked as number one.

P.S. Tx fire fighter, that only works if you DON"T have a clutch type fan like I do.

02-11-2005, 01:29 AM	#2
70c10swb no brain no headache Join Date: Jan 2005 Location: Cape Cod MA Posts: 567	the #1 piston has to be at the top of the stroke on the compression stroke i belive i dont have the fireing order on me right now HTH __________________ 1996 GMC Sierra z71 1970 SWB 2wd (project)

02-11-2005, 01:45 AM	#5
sactoC10 71 DELUX Join Date: Sep 2003 Location: Northern CA / Sac Posts: 1,055	Ya'all make it sound so simple...but you have no idea how clueless I am. And yes, I do feel like a fool admitting it! Still don't "see" exactly what to do in my mind. I do understand bigjimz wet paper towel procedure, but is that firing order starting at the front passenger side, that plug #1? Sorry, but GREEN I am. Dad sold cars, hated them and never wanted to touch them when home. No shop classes, just sort of learning as I go! __________________ 5/4 drop LWB wood bed - 15x8 front 235/60 - 15x10 rear 295/50 2003 FORD Escape 1998 Honda VTR1000

02-11-2005, 02:01 AM	#7
sactoC10 71 DELUX Join Date: Sep 2003 Location: Northern CA / Sac Posts: 1,055	Thanks, that's encouraging... By the way 70c10swb, I was born on the cape... Hyannis, MA. Still wondering why it doesn't seem to be a consistent concern, the TDC thing. Some instructions mention it, other don't! __________________ 5/4 drop LWB wood bed - 15x8 front 235/60 - 15x10 rear 295/50 2003 FORD Escape 1998 Honda VTR1000

02-11-2005, 09:02 AM	#11
Tynee I miss this truck. Join Date: Dec 2001 Location: Lexington, KY U.S.A. Posts: 2,863	Ask me how I know that you should be very choosy in your choice of helpers if you decide to use the "bump the starter method" to get to TDC. Some help will not know when the key is on or off, getting you shocked. Other help will think its amusing that you are now skittish under the hood, and will honk the horn while you're under there just for fun. Also, if you're using this method, make sure the fuel line is attached to the carb or otherwise blocked. Again, ask me how I know. __________________ '07 GMC Acadia SLT. Sweet ride. '08 Crew Cab Z-71 short bed. Really like this truck A LOT.

02-11-2005, 10:54 AM	#12
sactoC10 71 DELUX Join Date: Sep 2003 Location: Northern CA / Sac Posts: 1,055	Gee Tynee, how do you know? Part of me thinks I ought to just pull the old one, put in the new one and just see if it works out OK... If I can get the plug wires this afternoon, probably be doing this tonight. Again, thanks. __________________ 5/4 drop LWB wood bed - 15x8 front 235/60 - 15x10 rear 295/50 2003 FORD Escape 1998 Honda VTR1000

02-11-2005, 01:22 AM	#1
sactoC10 71 DELUX Join Date: Sep 2003 Location: Northern CA / Sac Posts: 1,055	Distributor drop in, Top Dead Center? OK, need to drop in HEI this weekend and I'm not sure about the TOP DEAD CENTER part of the install. What's the deal? Then also, anyone have the firing order in case I screw up the order when taking out the old plug wires? Thank you very much. __________________ 5/4 drop LWB wood bed - 15x8 front 235/60 - 15x10 rear 295/50 2003 FORD Escape 1998 Honda VTR1000

02-11-2005, 01:30 AM	#3
sdkid Registered User Join Date: Sep 2004 Location: Pierre SD Posts: 1,533	18436572

02-11-2005, 01:34 AM	#4
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	pull # 1 plug...stick a piece of dampened paper towel in the plug hole. turn crank slowly until the paper towel "pops" out. then turn the crank until the damper points to 10 degrees BTDC. Install dizzy so the rotor points to the number 1 spark plug wire terminal. __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

02-11-2005, 01:51 AM	#6
70c10swb no brain no headache Join Date: Jan 2005 Location: Cape Cod MA Posts: 567	1. No you are NOT a fool, we all had to learn and we learn by asking questions and doing 2. the #1 cylinder is front driverside __________________ 1996 GMC Sierra z71 1970 SWB 2wd (project)

02-11-2005, 02:05 AM	#8
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	it goes 1357 drivers side and 2468 passenger side. so you would start with the number one plug then the next hole clockwise goes to the #8 plug..then the next hole goes to #4 and so on 18436572 __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

02-11-2005, 02:37 AM	#10
Johnny05 Registered User Join Date: Oct 2004 Location: Austin, Texas Posts: 73	If you still have the stock intake the firing order and cylinder location(18436572) information is cast into it. Look at the end of each of the intake runners and you'll notice the numbers. The firing order is cast into the intake as well just in front of the carb. If your standing in front of the truck #1 is at the right front. The right side is the odd bank 1357 the left side is the even bank 2468. If you haven't changed/pulled anything yet you should be able to drop the HEI directly into the same location as the original setup.

02-11-2005, 12:52 PM	#14
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	I feel stupid to say anything infront of all these experienced people. I had todrop my dist when I changed my intake too. Great people on this board give me different ways of finding TDC. One of them which worked well for me, was using a cloth hanger or something similar. I inserted in #1 and then I rotated the engine manually until the hager stopped coming up (just have to becarefull that hanger doesn't get cut in there). I repeated few times to be differentiate between the compression and exhaust TDC. (other people please correct me if I am confused). Anyways, it worked well. If I could do it, anybodyelse can do it. Good luck.

02-11-2005, 01:46 PM	#15
avejoe Custer had a plan too. Join Date: Dec 2003 Location: No. California Posts: 344	Oh come on! Just drop it in and go. You have a 1 in 16 chance of getting it right. "So, do you feel lucky?" __________________ 72 K15 GMC (aka Big White) Performance Rockers, Cab Corners, and Floors Fossil Fuel Glutton Neighborhood Nuisance 98 BMW 540i for Speed (Sold ) 05 Subaru Outback for mileage

02-11-2005, 01:57 PM	#16
Perchjerker Beer Power!!!!!!!!!! Join Date: Nov 2003 Location: Nacogdoches, TX Posts: 280	If you haven't turned the motor while the dizzy has been out, you don't need to find aTDC. Just Put it in where you had it. __________________ Rather be fishin'

02-11-2005, 02:03 PM	#17
Zonaman Registered User Join Date: May 2004 Location: Chandler, AZ Posts: 519	[QUOTE=sactoC10]Ya'all make it sound so simple...but you have no idea how clueless I am. Hey, if you don't do it every day you tend to need to ask. Good on you! Which reminds me, This is a job that can be helped along with one of those remote starter buttons. Which terminal on the starter do you hook those up to? Thanks. __________________ 69 C-10 LWB, 350, 700r4, 3.73 posi-traction, front disc brakes. Built for the desert- She can take the heat! Vivat Rex Chevus!



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02-11-2005, 04:39 PM	#19
sactoC10 71 DELUX Join Date: Sep 2003 Location: Northern CA / Sac Posts: 1,055	Like this answer ALOT! __________________ 5/4 drop LWB wood bed - 15x8 front 235/60 - 15x10 rear 295/50 2003 FORD Escape 1998 Honda VTR1000

02-11-2005, 06:55 PM	#20
Kid Senior Member Join Date: Jun 2002 Location: Kansas Posts: 702	another way to find TDC is to remove the spark plug from #1 cylinder and hold your thumb or finger over the hole. Then bump the starter untill compressed air pushes on your finger. That means you are on the compression stroke. Bump starter again until your timing mark on damper is aligned at TDC on pointer, being carefull to not over shoot your mark, If you do no big deal, just do over. Then drop in your distributer. __________________ The kid Build threads: 51 Jimmy http://67-72chevytrucks.com/vboard/s...d.php?t=154951 http://67-72chevytrucks.com/vboard/s...d.php?t=219902 http://www.classictrucks.com/feature...uck/index.html 68 C10 http://67-72chevytrucks.com/vboard/s...ad.php?t=50348

02-11-2005, 10:15 PM	#21
gmc67swb Registered User Join Date: Feb 2003 Location: Mesquite, Tx Posts: 396	Also once dropped, you may have to keep pressure down on the distributor while turning the motor until the distributor drops into the oil pump. __________________ GM 330HP/350, Magnuson 122HH, Tremec TKO 5spd

02-12-2005, 02:14 AM	#23
Solver Registered User Join Date: May 2000 Location: Storm Lake, Ia Posts: 1,449	I always seem to have to take a long screwdriver and set the oil pump shaft so that distributor will drop down where I want it to. __________________ 1972 Cheyenne Super 20 LWB-Blue 1972 Cheyenne Super 10 LWB-Black 1972 Cheyenne Super 10 LWB-Red 1972 Cheyenne Super 10 LWB-green 1972 GMC 4x4 LWB-White 1971 Cheyenne 10 LWB-Ochre 1971 Cheyenne 20 Longhorn-Copper 1971 Cheyenne 20 Longhorn-Black 1969 Custom 10 LWB-lt blue 1968 GMC 3/4 ton-green 1968 1/2 ton swb stepside-silver 1967 Chevrolet CST 10 LWB-green 1967 Chevrolet custom 20 LWB-Maroon

02-12-2005, 09:14 AM	#24
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	I don't bump the starter, I just stick my finger in the hole and turn the engine over by turning the fan with my other hand. Wear a glove. __________________ I'm on the Instagram- @Gearhead_Kevin

02-12-2005, 09:42 AM	#25
modifiedGMC Registered User Join Date: Oct 2004 Location: Walker Co. Alabama Posts: 474	The first time I ever had to deal with firing order/ timing was when I was sixteen. I had a 69 chevelle with an aluminum intake that had no firing order cast to it. There was a stock one in the shed and me and a buddy went to the shed and looked at the intake. I remembered 1843 and he remembered 6572 and noticed the number 1 on the intake runner. Then went back to the chevelle and put our plug wires on. I always get number one up on top of the compression stroke, line up the crank timing marks on the damper and position the distributor in the intake where it sets, then turn the rotor so it will point straight at or slightly past the carb and drop it in. If it doesn't line up with oil pump and go all way down, then I just simply hold down on the distributor and bump the starter over till it does. then I double check myself and get number one back up and check position of the rotor. dist installed! then wire up the plug wires 18436572 starting with driver side front cylinder (even number side) and proceeding clock wise on the distributor starting the terminal Imarked as number one. P.S. Tx fire fighter, that only works if you DON"T have a clutch type fan like I do. Last edited by modifiedGMC; 02-12-2005 at 09:44 AM.

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