Truck Running problems

**teck** · 07-13-2008, 09:39 PM

Okay did a motor swap in my bud 72 C-10 put an LT81 corvette motor but its still a 350 well we`ve timed it to where it idles right and doesn`t spit back but when we run it it has no power back fires and just dosent respond so any suggestions?

**dr_detail** · 07-13-2008, 10:07 PM

is something wrong with the intake/carb, bad float, stuck choke, low fuel pressure, bad vacuum, etc???

**GearHead_1** · 07-13-2008, 10:19 PM

Firing order would be my first guess on a recently transplanted, known good engine. It`s easy to get a couple of wires crossed. Off one tooth on the distributor would be my second guess. If the distributor hasn`t been out then this obviously isn`t the problem. (18436572) typical 350 firing order.

**bigron62** · 07-14-2008, 07:10 PM

advance the timing till it pings then come back a hair ..counterclockwise ..check valve adjustment ..may have flat cam ..plugs may be gapped wrong .

**teck** · 07-14-2008, 09:08 PM

found the problem we had so many people helping that when the guy who put on the spark plug wires on accidently put #4 to #6 on the distributer problem slove but then we blew a valve cover gasket

**dr_detail** · 07-15-2008, 02:00 AM

Originally Posted by dr_detail

is something wrong with the intake/carb, bad float, stuck choke, low fuel pressure, bad vacuum, etc???

Originally Posted by GearHead_1

Firing order would be my first guess...

another example of why I`ll stick to detailing cars.... lol... I was way off

**GearHead_1** · 07-15-2008, 07:27 AM

Camino, You don`t usually "blow" valve cover gaskets. At least not technically. In virtually all cases they aren`t under pressure like for instance a head gasket. The only way this could happen is if the crank case were not properly vented (perhaps a stuck PCV valve or valve covers with no inlet/outlet). PCV valves do go bad (fairly common) but even when a PCV valve sticks closed it usually just pushes oil out the air inlet in the opposite valve cover. A vented crank case is usually a given unless you are using a set of after market valve covers that require introducing your own PCV valve/down draft system to the engine (punching holes in the valve covers for the valve and inlet screen). Most of the time when a PCV valve sticks it`s in the open position and you end up sucking oil into the intake manifold. Now some of the Japanese engines that by design have negative pressure (vacuum) inside the crank case can in fact suck a valve cover gasket inward and create a vacuum leak. These design of engines seldom if ever have an oil leak. All this said valve cover gaskets go bad (get brittle/deteriorate) and leak all of the time. If you actually blew a valve cover gasket check the venting system.

So I get some good rep points for the crossed wire diagnosis?

I`m kiddin` of course.

**Scott P** · 07-15-2008, 10:32 AM

I think he used the term "blow" to refer to a leak. It`s a verb that has become a little generalized and the definition has gotten a bit broader. At least you were able to help. I got a little confused and found the original post too hard to read.

**teck** · 07-15-2008, 10:43 AM

no it blew.oil air everything comes out now it lifted the valve cover outta place

**GearHead_1** · 07-15-2008, 10:46 AM

Originally Posted by Scott P

I think he used the term "blow" to refer to a leak. It`s a verb that has become a little generalized and the definition has gotten a bit broader. At least you were able to help. I got a little confused and found the original post too hard to read.

Yeah, in rereading my post I`m sure that the information I provided was way more than most wanted to read. I just can`t pull the reigns on myself when engines are the topic. Sorry bout` that.

**GearHead_1** · 07-15-2008, 10:51 AM

Originally Posted by El Camino Kid

no it blew.oil air everything comes out now it lifted the valve cover outta place

Wow!!! How do you lift a valve cover that is bolted down? I`ve seen a push rod and rocker go ballistic and take a valve cover out. I`m thinking out loud here. Gas in the oil, resulting in an internal explosion, backfire through the crankcase ventilation system? Never seen anything that would remotely resemble that. Smell the oil, see if it smells like fuel.

**Scott P** · 07-15-2008, 11:13 AM

Maybe there is some wicked blow-by occurring. Maybe the rings are worn?

**GearHead_1** · 07-15-2008, 11:55 AM

Originally Posted by Scott P

Maybe there is some wicked blow-by occurring. Maybe the rings are worn?

Don`t know but I would have thought a condition such as this would have been evident before it traded homes. Then again I have no idea what the condition of the engine was.