1978 chevy 350 issue

[1982K20]

I have a 1978 c10 350 on the stand to put into my 82 k20. Motor had not ran in a few years. Got it cleaned up and spun it over the other day. Oil pressure gauge read about 35psi with a remote starter button. While it was spinning I noticed #6 intake and exhaust valves were not opening very much and the oil flow to each was not consistent. I kept tightening the nuts a 1/4 turn at a time but the rocker arms continued to loosen again after spinning it over a bit longer. What are the odds that I have two collapsed lifters on the same cylinder, or as I fear, two worn out cam lobes?

 

[NickTransmissions]

I have a 1978 c10 350 on the stand to put into my 82 k20. Motor had not ran in a few years. Got it cleaned up and spun it over the other day. Oil pressure gauge read about 35psi with a remote starter button. While it was spinning I noticed #6 intake and exhaust valves were not opening very much and the oil flow to each was not consistent. I kept tightening the nuts a 1/4 turn at a time but the rocker arms continued to loosen again after spinning it over a bit longer. What are the odds that I have two collapsed lifters on the same cylinder, or as I fear, two worn out cam lobes?

Take the rocker arms, push rods and lifters out and inspect the cam lobes to see if they're wiped. You can also inspect the lifters, push rods and rockers at this time as well. Do it now while it's still on the stand and easy to work on...Let us know what you find.

 

[fast 99]

above or lifters that have bleed off or worn out internally. Sometimes takes while to get all the air out of lifters even with engine at idle. Not just cranking.

 

[75gmck25]

If it has not run in years the lifters may have lost fluid, and are too stuck to refill and pump up. As already mentioned, they may recover if you run it for a while, but YMMV.

I would just plan for a cam and lifters change, and for a DD I would stick with one in the range of about 210-214 @ .050 if you are not going to do anything else to improve the heads and get more compression. Something like the Summit 1102 would be about right. I would also change valve stem seals while it’s easy.

Also pull the timing cover and inspect the timing gear and chain. Replace if it’s loose.

 

[Ricko1966]

Set the valves just like it was a fresh build. Run it on the floor. Leave the valve covers loose. Wait a couple of minutes and run the valves again,running,back off till they clatter,in till the clatter stops+ 1/4 turn. Watch your pushrods. Are they spinning? Yes? You're good,install it. No? Post back.

 

[1982K20]

Update: I pulled the intake manifold off and spun the motor, noticing that the lifters on cylinder 6 were not coming up in the lifter valley as much as the others. Pulled the rocker arms and pushrods and pulled the two lifters to find deep dishes worn into them.

 

[fast 99]

Cam and lifters is in your future. When fixed, use oil for flat tappet cams.

 

[74Blaze]

My '80 Camaro had that issue. Turned out to be worn Cam Lobes on 7 & 8 Exhaust. Someone back in the day told me that GM was using cheaper steel for Cam Shafts in those years. Don't know if that's true or not. But a new Cam, Lifters and Timing Set and that Camaro was back up and running.

 

[ChuckN]

My '80 Camaro had that issue. Turned out to be worn Cam Lobes on 7 & 8 Exhaust. Someone back in the day told me that GM was using cheaper steel for Cam Shafts in those years. Don't know if that's true or not. But a new Cam, Lifters and Timing Set and that Camaro was back up and running.

Yep, apparently it was a common issue- my ‘76 Nova when was given to me to work on while in high school had flat cam lobes.

 

[Shorty81]

My '80 Camaro had that issue. Turned out to be worn Cam Lobes on 7 & 8 Exhaust. Someone back in the day told me that GM was using cheaper steel for Cam Shafts in those years. Don't know if that's true or not. But a new Cam, Lifters and Timing Set and that Camaro was back up and running.

Also my 78 Camaro had a soft cam, wiped out at low miles stock engine.

 

[JD Miller]

Update: I pulled the intake manifold off and spun the motor, noticing that the lifters on cylinder 6 were not coming up in the lifter valley as much as the others. Pulled the rocker arms and pushrods and pulled the two lifters to find deep dishes worn into them.

Tell us what kind of new cam and lifters you're gonna put in it