Help With Motor Issue... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

HotRod73 · 12-13-2006, 11:29 PM

just bought a 78' bonanza (what is a bonanza?) and it has a 350/350..
Engine starts up but seems to idle rough, when you put it into gear it kinda shakes the whole truck when you give it gas taking off, it seems slugish too, doesnt seem to have much power... what could be the problem???

HotRod73 · 12-14-2006, 12:39 AM

compression on 4 and 6 are lower than the others

JrRacer · 12-14-2006, 12:51 AM

Blown head gasket and fire slotted between 4 and 6

HotRod73 · 12-14-2006, 01:01 AM

but the oil doesnt look milky or anything and the antifreeze doesn't look like it has oil in it...it does however smoke a little when i step on the gas... i cant tell if its white or blue.... could it still be a blown head gasket???

JrRacer · 12-14-2006, 01:19 AM

yes head gasket may be blown between the cylinders and not into the coolant passage

Russell · 12-14-2006, 01:22 AM

Also check your timing, and make sure your valves are adjusted correctly

HotRod73 · 12-15-2006, 11:29 AM

idles rough and when put into gear shakes the truck and acts like doesnt wanna go, i changed plugs that is all... so it COULD be a bad head gasket even tho oil and coolant are clean? its 4 and 6 that has the low compression.. would it most likely be this or timing issue?

piecesparts · 12-15-2006, 11:31 AM

Possible cam problem, lobes wore down. Or carbon on the valves.

motopatzo · 12-15-2006, 01:09 PM

If compression is down on 4 and 6 the head gasket would be the first place where I would look also. That is causing the shaking and no power. Because the compression is down on cylinders beside each other, that is why I would tend to beleive it is the head gasket also.

HotRod73 · 12-15-2006, 07:51 PM

i checked the passenger side valves and they were all moving fine and pumping oil... didnt get driver side valve cover off which is where the low compression is to see if all the rocker arms on moving on that side... i was told it was most likely the head gasket blown.... and im starting to think that..

HotRod73 · 12-15-2006, 07:52 PM

bad cam wouldn't cause 4 and 6 to be low and have no power and shaking would it?

powerdriver 1958 · 12-15-2006, 09:17 PM

Quote:

Originally Posted by HotRod73

bad cam wouldn't cause 4 and 6 to be low and have no power and shaking would it?

you bet.ive stuck a lot camshafts in old 350 and 305 motors

HotRod73 · 12-15-2006, 10:38 PM

how do i tell if the cam is bad and how would i tell if its the head gasket? is there a way to test before i rip into it and spend money????

HotRod73 · 12-15-2006, 10:44 PM

when i take my air cleaner off, and nail the gas and let off it makes a little pop doesnt that mean bad cam??

HotRod73 · 12-15-2006, 10:45 PM

throught the carb it makes a pop or could it be somethin else

hiway · 12-16-2006, 08:37 AM

Bad exhaust lobe will backfire thru the carb. What's your compression readings?

HotRod73 · 12-16-2006, 10:21 AM

i dont know but it was checked and 4 and 6 are low and also my complete exhaust is rusted out, this matter?

it makes a little pop in the carb when i gun it and let off

HotRod73 · 12-22-2006, 11:22 PM

i did compression check today, all my clinders are hitting 90-120 except two that are right next to each other the two middle cylinders on the passenger side they go to like 5 thats all..... so does this sound like head gasket? i pulled the valve cover and my rockers are moving so i know the cam is working, what else could be the problem? a cracked head???

HotRod73 · 12-22-2006, 11:24 PM

im guessing the low ones are 4 and 6 i dont know how to tell the cylinder number but the two next to each other in the middle on passenger side thats low ones 90-120 for the rest, is that good???

sick69 · 12-22-2006, 11:28 PM

cracked head is possible but I would believe the head gasket is toast. either way the head has to come off to find out

sick69 · 12-22-2006, 11:30 PM

from front to back.....
passenger side= 2 4 6 8
driver side = 1 3 5 7

HotRod73 · 12-22-2006, 11:30 PM

doesnt my motor have to overheat in order to blow my head gasket? it doesnt over heat and there is no water/coolant in my oil... just thought if gasket was bad it would over heat or would have to overheat to blow it in first place but it doesnt over heat...

HotRod73 · 12-22-2006, 11:31 PM

so yes 4 and 6 are the ones with bad compression is 90-120 on the rest good or is that low???

7387chevys · 12-22-2006, 11:33 PM

drivers side radiator to firewall 1-3-5-7 pass side radiator to firewall 2-4-6-8

Shane

http://boxwrench.net/specs/chevy_sb.htm

HotRod73 · 12-22-2006, 11:33 PM

my plugs looked black smelled like gas but looked kinda like oil... i just changed them about 5 miles ago... does that mean anything? really only on the side with low compression

12-13-2006, 11:29 PM	#1
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Help With Motor Issue... just bought a 78' bonanza (what is a bonanza?) and it has a 350/350.. Engine starts up but seems to idle rough, when you put it into gear it kinda shakes the whole truck when you give it gas taking off, it seems slugish too, doesnt seem to have much power... what could be the problem???

12-14-2006, 12:39 AM	#2
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... compression on 4 and 6 are lower than the others

12-14-2006, 12:51 AM	#3
JrRacer Registered User Join Date: Dec 2006 Location: Oklahoma City, OK Posts: 27	Re: Help With Motor Issue... Blown head gasket and fire slotted between 4 and 6 __________________ 84 GMC LONGBED 84 CHEVY LONGBED 03 CHEVY 1500HD 4X4 CREW CAB

12-14-2006, 01:01 AM	#4
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... but the oil doesnt look milky or anything and the antifreeze doesn't look like it has oil in it...it does however smoke a little when i step on the gas... i cant tell if its white or blue.... could it still be a blown head gasket???

12-14-2006, 01:19 AM	#5
JrRacer Registered User Join Date: Dec 2006 Location: Oklahoma City, OK Posts: 27	Re: Help With Motor Issue... yes head gasket may be blown between the cylinders and not into the coolant passage __________________ 84 GMC LONGBED 84 CHEVY LONGBED 03 CHEVY 1500HD 4X4 CREW CAB

12-14-2006, 01:22 AM	#6
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Re: Help With Motor Issue... Also check your timing, and make sure your valves are adjusted correctly __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

12-15-2006, 11:29 AM	#7
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... idles rough and when put into gear shakes the truck and acts like doesnt wanna go, i changed plugs that is all... so it COULD be a bad head gasket even tho oil and coolant are clean? its 4 and 6 that has the low compression.. would it most likely be this or timing issue?

12-15-2006, 11:31 AM	#8
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: Help With Motor Issue... Possible cam problem, lobes wore down. Or carbon on the valves.

12-15-2006, 01:09 PM	#9
motopatzo Registered User Join Date: Oct 2006 Location: maple ridge, b.c., canada Posts: 190	Re: Help With Motor Issue... If compression is down on 4 and 6 the head gasket would be the first place where I would look also. That is causing the shaking and no power. Because the compression is down on cylinders beside each other, that is why I would tend to beleive it is the head gasket also.

12-15-2006, 07:51 PM	#10
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... i checked the passenger side valves and they were all moving fine and pumping oil... didnt get driver side valve cover off which is where the low compression is to see if all the rocker arms on moving on that side... i was told it was most likely the head gasket blown.... and im starting to think that..

12-15-2006, 07:52 PM	#11
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... bad cam wouldn't cause 4 and 6 to be low and have no power and shaking would it?

12-15-2006, 10:38 PM	#13
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... how do i tell if the cam is bad and how would i tell if its the head gasket? is there a way to test before i rip into it and spend money????

12-15-2006, 10:44 PM	#14
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... when i take my air cleaner off, and nail the gas and let off it makes a little pop doesnt that mean bad cam??

12-15-2006, 10:45 PM	#15
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... throught the carb it makes a pop or could it be somethin else

12-16-2006, 08:37 AM	#16
hiway Mad Scientist Join Date: Jul 2005 Location: Enola Arkansas Posts: 380	Re: Help With Motor Issue... Bad exhaust lobe will backfire thru the carb. What's your compression readings? __________________ Everythang relates to Beer! 86 1/2ton on tons! sbc/465/208/D60/14/35's 81 Postal....with 468 bbc 97 Merc Marq comuter 07 Suburban 02 Danger Ranger



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12-16-2006, 10:21 AM	#17
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... i dont know but it was checked and 4 and 6 are low and also my complete exhaust is rusted out, this matter? it makes a little pop in the carb when i gun it and let off

12-22-2006, 11:22 PM	#18
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... i did compression check today, all my clinders are hitting 90-120 except two that are right next to each other the two middle cylinders on the passenger side they go to like 5 thats all..... so does this sound like head gasket? i pulled the valve cover and my rockers are moving so i know the cam is working, what else could be the problem? a cracked head???

12-22-2006, 11:24 PM	#19
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... im guessing the low ones are 4 and 6 i dont know how to tell the cylinder number but the two next to each other in the middle on passenger side thats low ones 90-120 for the rest, is that good???

12-22-2006, 11:28 PM	#20
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: Help With Motor Issue... cracked head is possible but I would believe the head gasket is toast. either way the head has to come off to find out __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

12-22-2006, 11:30 PM	#21
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: Help With Motor Issue... from front to back..... passenger side= 2 4 6 8 driver side = 1 3 5 7 __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

12-22-2006, 11:30 PM	#22
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... doesnt my motor have to overheat in order to blow my head gasket? it doesnt over heat and there is no water/coolant in my oil... just thought if gasket was bad it would over heat or would have to overheat to blow it in first place but it doesnt over heat...

12-22-2006, 11:31 PM	#23
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... so yes 4 and 6 are the ones with bad compression is 90-120 on the rest good or is that low???

12-22-2006, 11:33 PM	#24
7387chevys Registered User Join Date: Jun 2006 Location: WVa Posts: 758	Re: Help With Motor Issue... drivers side radiator to firewall 1-3-5-7 pass side radiator to firewall 2-4-6-8 Shane http://boxwrench.net/specs/chevy_sb.htm

12-22-2006, 11:33 PM	#25
HotRod73 Registered User Join Date: Mar 2006 Location: Norman, Oklahoma Posts: 553	Re: Help With Motor Issue... my plugs looked black smelled like gas but looked kinda like oil... i just changed them about 5 miles ago... does that mean anything? really only on the side with low compression

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