HELP! rebuild timing problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Kman · 07-19-2003, 12:28 PM

I have a 350 I just put together, all stock w/roller lifters electronic ignition. the thing will not stay running under 1500 rpm and about 15-20 degrees advance If I retard spark it pops out the carb. I rechecked valve adjustment and it was ok,rechecked plug wires ok I'm thinking the timing chain might have jumped a tooth

also the carb a rebuilt carter 4 barrel has fuel coming out of only one side,I took the top off and checked for something clogged but every thing is clear

My question is is the carb problem related to a timing problem or am I missing somthing else before I tear timing cover off to check it? sorry to be so long but this is driving me crazy

any help would be great, thanks
Kman

Kman · 07-19-2003, 01:01 PM

anyone?

jef5150 · 07-19-2003, 01:11 PM

fuel on 1 side????with the engine "OFF" pump the carb a couple of times with your hand ,look into the carb while doing this.this is a way to check your accelerator pump in the carb,,,,you should see gas squirting on both sides,,,,,,,try that first,,,,,,,,id concentrate on the carb as being the problem....jeff

jef5150 · 07-19-2003, 01:12 PM

if your timing chain jumped iwould think it would run rough at ANY rpm..

Kman · 07-19-2003, 01:22 PM

accelerator pump is fine the left side of primaries has no fuel at low rpm at about 2500 there is some fuel maybe vac prob?

runs pretty smooth at 2000 but stalls below 1500 and pops through carb

Kman · 07-19-2003, 01:30 PM

it sounds like firing order is wrong but I ran the wires twice they are right

Kman · 07-19-2003, 02:06 PM

is there a way to tell if the timing chain is off with out pulling the cover??

Kman · 07-19-2003, 04:02 PM

ttt

GasHog396 · 07-19-2003, 04:26 PM

Are you running a single or dual plane intake manifold? If it is dual plane, with no fuel coming through one of the primaries, 1/2 of the cylinders won't be getting gas. I believe the carb should be spitting out fuel in both primaries when you pull on the accelerator cable with the engine off, but I'm not real familiar with Carter carbs. Even a single plane intake would probably run rough, as I doubt only one primary could feed enough fuel to run all 8 cylinders. Also look for a vacuum leak, it would have to be a big one. As for checking the timing, you pretty much have to pull the cover, but I would rule everything else out first, as it is almost impossible to get it sealed back up, and not leak. Good Luck

cableguy0 · 07-19-2003, 05:24 PM

are you sure your distributor isnt off a tooth its almost impossible for a brand new chain to jump a tooth unless you installed it wrong. to me it sounds like your a tooth off

bigjimzlll · 07-19-2003, 06:07 PM

VACUUM leak

**68 Stepside** · 07-19-2003, 06:11 PM

I agree with bigjim. The 79 F100 out back is the same EXACT way....because I tried to reuse the base to manifold gasket (yes, I'm that cheap, it's a woods truck). Use an unlit propane torch around the intake, and see if the RPM's increase. If they do....you've found your leak.

Good luck, keep us posted.

jef5150 · 07-20-2003, 09:53 AM

starting fluid will give the same result,the rpm will rise if theres a leak..........

JayDubBlazer · 07-20-2003, 10:08 AM

How do you use the propane torch, I have heard that one yet. But I guess I haven't that much yet. Yesterday I saw the saying since "Christ was a Corporal" and thought that was new. I found out otherwise.

bigjimzlll · 07-20-2003, 11:33 AM

start the engine...turn the gas on, on the propane torch. do not light the tourch...point the nozzle of the flowing torch at the base of the carb..all the way around the bottom...if the engine smooths out..that is where the leak is

Kman · 07-20-2003, 07:30 PM

Thanks for the input guys.

Wouldn't you be able to adjust dist to compensate for one tooth out?

The fuel problem is the amount of fuel flowing through the two venturi of the primarys one side has no fuel at idle and only a little at higher rpm.

The accelorator pump is fine, two streams of fuel

The timing chain being off a tooth would of happened when I assembled the engine lol.

I am going to work on it tommorow and will check out your suggestions.... I'll keep you posted.....

Kman

jef5150 · 07-20-2003, 07:40 PM

total rebuild?.......did you put a new timimg chain & gears on?.....did you line up the 2 dots on the timing gears when you put on the new chain on???

jef5150 · 07-20-2003, 07:47 PM

one last thing,,,,,,,,you didnt put the old timing chain and gears on your NEW REBUILD did you??/,,,just asking

Kman · 07-20-2003, 08:43 PM

I double checked the marks on gears but something could have moved and yes I used the old chain and gear..I know I know it should of been changed but it was a very low dollar (make it work ) job for a friend
thanks
kman

jef5150 · 07-20-2003, 08:54 PM

thats probably your problem,,,,,new gears and chain are like what,, $40.00????????

jef5150 · 07-20-2003, 09:02 PM

you could try moving the spark plug wires clockwise 1 position,,,,,see if it helps,,,,then try the other direction,,,,,,,i think even if you pull and move the distributor 1 gear that would be too much,,,,,,butt you can try .....jeff

Kman · 07-20-2003, 09:07 PM

I have a list of things to try first

Thanks for the help
kman

bigjimzlll · 07-20-2003, 09:12 PM

a faulty timing chain..or..mis aligned timing set will effect valve timing. its almost impossable for a timing set to skip a tooth..not enuff room. If the set is worn out,really worn out, you would of noticed when you installed it. Check all of the easy things first. Good luck

07-19-2003, 12:28 PM	#1
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	HELP! rebuild timing problem I have a 350 I just put together, all stock w/roller lifters electronic ignition. the thing will not stay running under 1500 rpm and about 15-20 degrees advance If I retard spark it pops out the carb. I rechecked valve adjustment and it was ok,rechecked plug wires ok I'm thinking the timing chain might have jumped a tooth also the carb a rebuilt carter 4 barrel has fuel coming out of only one side,I took the top off and checked for something clogged but every thing is clear My question is is the carb problem related to a timing problem or am I missing somthing else before I tear timing cover off to check it? sorry to be so long but this is driving me crazy any help would be great, thanks Kman __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-19-2003, 01:01 PM	#2
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	anyone? __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-19-2003, 01:22 PM	#5
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	accelerator pump is fine the left side of primaries has no fuel at low rpm at about 2500 there is some fuel maybe vac prob? runs pretty smooth at 2000 but stalls below 1500 and pops through carb __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-19-2003, 01:30 PM	#6
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	it sounds like firing order is wrong but I ran the wires twice they are right __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-19-2003, 02:06 PM	#7
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	is there a way to tell if the timing chain is off with out pulling the cover?? __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-19-2003, 01:11 PM	#3
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	fuel on 1 side????with the engine "OFF" pump the carb a couple of times with your hand ,look into the carb while doing this.this is a way to check your accelerator pump in the carb,,,,you should see gas squirting on both sides,,,,,,,try that first,,,,,,,,id concentrate on the carb as being the problem....jeff

07-19-2003, 01:12 PM	#4
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	if your timing chain jumped iwould think it would run rough at ANY rpm..

07-19-2003, 04:02 PM	#8
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	ttt __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-19-2003, 04:26 PM	#9
GasHog396 Registered User Join Date: Jun 2003 Location: Ponder, TX Posts: 33	Are you running a single or dual plane intake manifold? If it is dual plane, with no fuel coming through one of the primaries, 1/2 of the cylinders won't be getting gas. I believe the carb should be spitting out fuel in both primaries when you pull on the accelerator cable with the engine off, but I'm not real familiar with Carter carbs. Even a single plane intake would probably run rough, as I doubt only one primary could feed enough fuel to run all 8 cylinders. Also look for a vacuum leak, it would have to be a big one. As for checking the timing, you pretty much have to pull the cover, but I would rule everything else out first, as it is almost impossible to get it sealed back up, and not leak. Good Luck __________________ '67 1/2 Ton Short Bed / 396 cid / AC w-R134a / 5 Lug Leaf spring rear axel / 5 Lug Frt Disk Brake Conversion '97 Trans Am - Black / LT-1 / K&N FIPK Cold Air Kit / Hooker Cat-Back Exhaust / 160 Thermostat '02 Buick Regal GS / Bone Stock

07-19-2003, 05:24 PM	#10
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	are you sure your distributor isnt off a tooth its almost impossible for a brand new chain to jump a tooth unless you installed it wrong. to me it sounds like your a tooth off __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

07-19-2003, 06:07 PM	#11
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	VACUUM leak __________________ 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

07-19-2003, 06:11 PM	#12
68 Stepside huh? Join Date: May 2000 Location: Washington, Illinois Posts: 5,692	I agree with bigjim. The 79 F100 out back is the same EXACT way....because I tried to reuse the base to manifold gasket (yes, I'm that cheap, it's a woods truck). Use an unlit propane torch around the intake, and see if the RPM's increase. If they do....you've found your leak. Good luck, keep us posted. __________________ Someday when I'm lonely, Wishing you weren't so far away, Then I will remember Things we said today. RIP El Jay

07-20-2003, 09:53 AM	#13
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	OOPS/EDITED starting fluid will give the same result,the rpm will rise if theres a leak.......... Last edited by jef5150; 07-20-2003 at 12:13 PM.

07-20-2003, 10:08 AM	#14
JayDubBlazer go cyclones Join Date: Jun 2003 Location: Ames, IA Posts: 1,885	How do you use the propane torch, I have heard that one yet. But I guess I haven't that much yet. Yesterday I saw the saying since "Christ was a Corporal" and thought that was new. I found out otherwise. __________________ Wes PROJECT OLE GREEN 1972 Blazer 4X4 350/700R4 2017 Silverado LT

07-20-2003, 11:33 AM	#15
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	start the engine...turn the gas on, on the propane torch. do not light the tourch...point the nozzle of the flowing torch at the base of the carb..all the way around the bottom...if the engine smooths out..that is where the leak is __________________ 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



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07-20-2003, 07:30 PM	#16
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	Thanks for the input guys. Wouldn't you be able to adjust dist to compensate for one tooth out? The fuel problem is the amount of fuel flowing through the two venturi of the primarys one side has no fuel at idle and only a little at higher rpm. The accelorator pump is fine, two streams of fuel The timing chain being off a tooth would of happened when I assembled the engine lol. I am going to work on it tommorow and will check out your suggestions.... I'll keep you posted..... Kman __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-20-2003, 07:40 PM	#17
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	total rebuild?.......did you put a new timimg chain & gears on?.....did you line up the 2 dots on the timing gears when you put on the new chain on???

07-20-2003, 07:47 PM	#18
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	one last thing,,,,,,,,you didnt put the old timing chain and gears on your NEW REBUILD did you??/,,,just asking

07-20-2003, 08:43 PM	#19
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	I double checked the marks on gears but something could have moved and yes I used the old chain and gear..I know I know it should of been changed but it was a very low dollar (make it work ) job for a friend thanks kman __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-20-2003, 08:54 PM	#20
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	old gears???????????????????????????????? thats probably your problem,,,,,new gears and chain are like what,, $40.00???????? Last edited by jef5150; 07-20-2003 at 08:56 PM.

07-20-2003, 09:02 PM	#21
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	you could try moving the spark plug wires clockwise 1 position,,,,,see if it helps,,,,then try the other direction,,,,,,,i think even if you pull and move the distributor 1 gear that would be too much,,,,,,butt you can try .....jeff

07-20-2003, 09:07 PM	#22
Kman Registered User Join Date: Sep 2002 Location: Melbourne,Florida Posts: 174	I have a list of things to try first Thanks for the help kman __________________ New 89 chevy 1500 driver 72K20 rust bucket project stripped down to the frame engine rebuild started 71 Blazer - another procect

07-20-2003, 09:12 PM	#23
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	a faulty timing chain..or..mis aligned timing set will effect valve timing. its almost impossable for a timing set to skip a tooth..not enuff room. If the set is worn out,really worn out, you would of noticed when you installed it. Check all of the easy things first. Good luck __________________ 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

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