I have had a 350 motor in my truck for about 1 year now and i bought it used then i put it in and now it is making a loud noise louder then a blown engine noise and all of the pistons have around 150 pounds of presure in them but 2 #3,5 they both have about 40 to 50 pounds in them and nobody know what i should do
2007-01-27 01:51:43 · 8 answers · asked by nick 1 in Cars & Transportation ➔ Car Makes ➔ Chevrolet
Sounds like a blown head gasket, but that wouldn't make a loud noise. # 3 & 5 might have a bent valve and/or bent push rods. Also the rocker arms might have loosened up. The valves might be burnt. Take the left (Drivers side) valve cover off and turn the motor over and watch the rocker arm movement. Don't start the motor. The valves could be stuck open a litle bit. Did you buy the truck with the motor out and then put it in. How's the oil pressure?
We had the same problem with a 350 Pontiac motor. The person who owned it put new head gaskets on. The motor sstarting make a hell of a noise. Sounded like it had thrown a rod. We put in another motor for the person. We starting tearing the motor down and found on the # 6 clyinder the nut on the rocker arm had worked loose. The push rod was beating the inside of the rocker arm cover. We replaced all the rocker arm nuts and reajusted the valves. Put the motor in a Grand Prix. Started the engine up and readjusted the valve and the motor run perfect.
2007-01-28 04:05:44 · answer #1 · answered by keijo47 2 · 0⤊ 2⤋
Could be your rods and/or crank are failing ... that would make the rods rattle (does it sound like that) and you would not get full compression on those cylinders.
Could be a valve problem too but that is usually a pretty distinctive noise
Either way it sounds like you are looking a a teardown. Drain the oil and look for signs of metal first a good indicator.
1) If you think its the bearings, pull the pan off the bottom and check the crankshaft for signs of wear (if the rods are beating up on the crank that will be easy to spot.)
2) for the valves start with pulling the head and see whats there. IF the valves haven't punched into the pistons you may get away with just new or resurfaced heads and new valves.
either way, sounds like you are in for some work.
You may want to opt for a rebuilt motor and avoid the problem entirely...
good luck...
.
2007-01-27 03:27:23 · answer #2 · answered by ca_surveyor 7 · 0⤊ 1⤋
Motor blown, to find exactly what is wrong will require a complete tear down to inspect all the damage and if it is worth it to repair this motor or get another rebuilt one, or used although as you can see you never know what you are going to get.
2007-01-27 05:13:14 · answer #3 · answered by Deano 7 · 0⤊ 1⤋
I own a shop, and have many years experience as a mechanic. Check out my answer on the other question you asked. You will find your answer to your problem there.
Good luck!!!
2007-01-27 11:31:07 · answer #4 · answered by Anonymous · 0⤊ 0⤋
bad motor you may have holes on top of the pistons and bad connecting rod bearings,or you lost your oil pump and have no oil pressure eitherv way it is not going to be worth fixing.sorry
2007-01-27 01:57:04 · answer #5 · answered by marfanman00000 5 · 0⤊ 1⤋
You've blown a head gasket. Replace both of them.
2007-01-27 01:56:09 · answer #6 · answered by Anonymous · 0⤊ 2⤋
check the bearings along with the crank to make sure there is no scoring
2007-01-27 01:55:54 · answer #7 · answered by cwb63ss 6 · 0⤊ 1⤋
rebuild it...sounds like bad valves and rings too.
2007-01-27 01:55:12 · answer #8 · answered by Anonymous · 0⤊ 1⤋