Adjusting valve clearance on a 454 V8.
 

Good morning to you all.

I have a 1979 Chevrolet suburban and would like to check or properly adjust the valve clearance.
I hope I am expressing myself correctly. Please excuse my bad English.
The problem is that I hear a slight clacking sound on the left bench and I know it is coming from the valves.

Can you please tell me what steps I need to take to get the valve clearance right?

I only have found this

https://brianbradburn.tripod.com/chevy454.htm

I assume I have mechanic valve lifters.

I read, that I need to turn the engine while adjusting. If I had a manual transmission, I would just put it in gear, lift the car to one side, and then turn the other wheel. But how do I do that with an automatic?

Thanks in advance and have a nice Sunday

Re: Adjusting valve clearance on a 454 V8.
 

These are the tec specs of my car

Suburban 1979, 7.4 Ltr VIN: TCS269F528860 T - GMC C - Serie S - 7,4 Liter - 4BBL Carburator - 2 - 3/4 ton 6 - Suburban 9 - last digit of model year (1979) F - PlantCode (Chevrolet Flint) 528860 - Production Sequence Number CARBURATOR: 17059520 / 1449 CCP





And maybe it is better to use this link

https://youtu.be/5EGlb_VpTAw?si=fuzntC7Wnu-v9Z2-

Re: Adjusting valve clearance on a 454 V8.
 

I always adjust them with the engine warmed up and running. Back off till clacking then slowly tighten until the noise goes away then another 1/2 turn. It can be messy but it works for me

Re: Adjusting valve clearance on a 454 V8.
 

You don’t need to adjust all the valves, just find the one that’s making the noise and fix it.
Pull the valve cover off and check all the rockers are moving the same amount. If you find one, let us know and we’ll help diagnose it.

Ignore that YouTube vid. Lots of bad info there.

Re: Adjusting valve clearance on a 454 V8.
 

Dont be surprised if you find a lifter and cam lobe has failed, especially if you use Synthetic oil in the engine.

Flat tappet cams and lifters need an oil that has ZDDP additive in the oil...(zinc) to protect the flat running surfaces.

You can use an additive or buy an oil with zinc included in the mix. You need between 1200 to 2400 ppm of zinc to protect fully.

:chevy::chevy::chevy:

Re: Adjusting valve clearance on a 454 V8.
 

It is highly unlikely you have mechanical (solid) lifters unless the engine is a high performance race engine.. Adjust the valve lash with the engine idling, transmission in park, and follow the directions given by kwmech..

Re: Adjusting valve clearance on a 454 V8.
 

That video is of no use to anyone but the mechanic in a shop with the motor on a stand and the intake out of the way. Your 7.4L (454) is a Hydraulic Flat Tappet motor unless someone has stuck a roller cam and lifters in it. I have to agree with Rusty and KWmech and Geezer too. Pull that valve cover and find the noise maker. Use KWmech's method and be spared all the confusing details of finding TDC and using the EOIC method. One last thing, I cant count the number of times, myself included, that an exhaust leak is mistaken for a noisy lifter or loose rocker. Check those manifolds for leaks...

Re: Adjusting valve clearance on a 454 V8.
 

Both at the flange (the block side) and the donut (where it connects to the exhaust tubing).

Here's a trick that might help. Use a piece of tubing - it doesn't really matter too much what type or size) and hold it up to one ear. Move the other end of the tubing around the noisy side of the engine until you zero in on the noise.

If it's a mechanical noise inside the engine, you can use a screwdriver with a long handle. Press it against your ear and touch it to the surfaces of the engine. As the noise grows louder, you're getting closer to the source.