1977 chev 400 small block

hello
I have just recently purchased a 1977 chev shortbox
with a 400 small block chev in it

upon acceleration or when I rev it up it has a nocking in the motor
can anyone help me out


thank you

[sweet49chevy]

Could be a lifter,push rod,maybe a valve hitting the piston.You could also have a bearing that is bad on the connecting rod to the crank. Sounds like you may have a rebuild on your hand. Try using a extra long socket ext. and listen for the nock with the engine running.This should tell you witch cylinder is the problem. Remove the valve cover and check the push rod for being bend. Check the rockers and make sure they are adjusted correctly Hope this is some help..

also when i took the valve cover off the motor a couple of rockers
were really loose so i torqued them to the proper torque could
a lifter have fallen out while it was loose




thanks jess

[sweet49chevy]

Yes that is a possiblity.You could have them to tight also.You should be able to turn the push rod with your fingers, not to loose just enough to fell the tenson on them.

[KA9MOT]

Is your engine actually knocking or is it pinging?

[towtrucks]

Originally posted by jesse
also when i took the valve cover off the motor a couple of rockers
were really loose so i torqued them to the proper torque could
a lifter have fallen out while it was loose




thanks jess

What do you mean when you say you torqued a rocker??????

You don't torque a rocker arm or lifter in a Chevy V-8

[KA9MOT]

Originally posted by towtrucks
What do you mean when you say you torqued a rocker??????

You don't torque a rocker arm or lifter in a Chevy V-8

I must be slipping. I should have caught that one. Must have been preoccupied with the Knock thing.

[danny]

lifters don't fall out unless you have a serious problem-they have to get by the cam shaft first.

[Wheel]

I stuck a pushrod into the rocker arm once on my moms 71 chevelle with a 350 in it when I was a youngster. Wish I would have kept those parts.

[1fatcat]

Originally posted by jesse
also when i took the valve cover off the motor a couple of rockers
were really loose so i torqued them to the proper torque could
a lifter have fallen out while it was loose




thanks jess

Man, if you don't know how to adjust rockers, then you shouldn't even try it! You may have bent a pushrod and/or valve.

As for the knocking noise, check the flexplate (flywheel) for cracks (I'm assuming it is an auto tranny). Just unbolt the torque converter and push the converter back toward the tranny a little. Then start the engine and see if the noise is gone.

[Gearhead52]

Lots a help you guys........


The 400 engine was prone to hammer out number 7 or 8 rod bearing. Pull both spark plug wires for these two cylinders and see if it stops or changes the pitch of the knocking sound. If it does then the bearing is shot. Don't run the engine anymore if it does indicate the rod bearing. It will spin the bearings in the big end of the rods and the piston will slap the head.

I've owned a couple of 400's and this happened to both. One while many miles from home and the other at the end of the street I lived on.

And for those of you that don't realize this...Chiltons recommended that rockers to be tourqued to 20 fpt on many small block Chevy's when in fact it was NOT the correct proceedure in some cases.

No body ever asked if the engine dveloped a miss either .......

Well guys the motor is shot so I have decided to make
a 383 strocker to blow the ford boys off the road thanks for all the help


jess

[KA9MOT]

Originally posted by jesse
Well guys the motor is shot so I have decided to make
a 383 strocker to blow the ford boys
jess

Rut Roh LOL

Whats a "strocker"?

[towtrucks]

Originally posted by Beefy's Bronco
Rut Roh LOL

Whats a "strocker"?

Strocker Ace, a Burt Reynolds movie........

[KA9MOT]

Originally posted by towtrucks
Strocker Ace, a Burt Reynolds movie........

Oh He must have meant "Stroker" LOL