Evaluating 305E engine noise

[62Burb]

I'll try posting a Google Drive link to a short video I made of my '63 Suburban 305E and its noisy running; just received it this week. Seller said it ran weakly; shipper said it had almost no power. Seller replaced many parts, rebuilt carb, new plugs and wires and fuel pump. Plugs look to be correct and not fouled, firing order seems correct.

https://drive.google.com/file/d/1YhC...ew?usp=sharing

Brad

[BillT]

It's hard to tell really, but after all the simple stuff (Plugs, Points, Timing, etc), I believe I would be checking on the Valve Adjustment. These engines have Solid Lifters and need to be set with a Feeler Gauge.

[George Bongert]

Greetings!

I agree with Bill. It is most likely valve train noise. I heard nothing to suggest that there is anything wrong with the lower end of the engine. The engine itself appears to be idling roughly, and I would definitely check valve adjustment, and timing among other things, including the idle speed mixture adjustment. When I owned my truck, I had my 305 idling so smooth that you could place an orange juice glass half full of water on top of the air cleaner, and barely see a ripple in the water. Yours should be idling just as smoothly. The engine appears to be extremely clean, suggesting that the previous owner may have replaced the valve cover gaskets, and may have made an attempt at adjusting the valves. The lack of power that you describe can come from valve adjustments being too tight, thereby holding valves, especially the exhaust valves, partially open when they should not be, which could very well contribute to loss of power, and to the rough idling of the engine that I observed in your video. Hope this helps, and good luck! Sometimes it takes a little time to chase down those mechanical Gremlins, especially when you don't know what the mechanical aptitude of the previous owner(s) was!

[massey478]

Also, a compression test will tell you where the problem is. Cylinders should be fairly equal in compression. If they are, then you have other problems. At least you will be narrowing it down. Remember to use compressed air to blow out the dirt around plugs before loosening them and after just loosening them to prevent it getting into cylinders. Critical! Also a timing check will tell you if possibly the timing chain has worn so much it has skipped a tooth. Bill T and George have excellent advice also.

[massey478]

You may find bent push rods also. What bothers me is tight valves, tight enough to cause a miss, do not make noise. No lash, no noise! You may have both tight and loose. I really hope it is something like this to make repair easy for you.

[FetchMeAPepsi]

Originally Posted by George Bongert

Greetings!

When I owned my truck, I had my 305 idling so smooth that you could place an orange juice glass half full of water on top of the air cleaner, and barely see a ripple in the water.

Off topic, but George, I sure would like to see you doing a writeup on how to tune one of these engines like that.

[AZKen]

This is what the President of the "United V6's of America" advises. https://www.youtube.com/watch?v=dyoTQ0xaLBo
We all need to save this link for our children and their children.

I don't know what noise you are referring to in your video. First thing is to get a stethoscope and listen to every inch of the motor, pumps, exhaust and hear all the different noises. You may have some normal noises and some not normal. They may be melding together. It does not matter what the seller or the shipper said. What matters is how it's running for you. Noises and how it runs may be unconnected. Report an actual issue and we can help. The motor does not sound abnormal after you view the video I linked.
If it has lack of power, there is a list of checks and causes we can go over after you describe in detail what you experience. In other words, what is the question? What is the problem?

[62Burb]

I like this - the "Zen of V6 Maintenance"! I am eager to dig into this; I haven't attempted an old school tune up for 30 years! Back in the saddle again). My FIL is my Obi Wan Kenobi; he passed away 25 years ago, but was a maintenance maniac with his 1962 GMC Custom Suburban (which I drove afterwords for several years). That V6 reached nearly 500k miles w/o a rebuild. "Feel the Force!

Brad

[FetchMeAPepsi]

We should just transcribe it and add it to our libraries here, bein honest. At least that way we always have it even if YT deletes his stuff. Never know what'll set people off anymore.

[62Burb]

So I made some progress today; confirmed spark to all six cylinders, then pulled the valve covers. lo and behold, cylinders #1, #3 and #6 all had bent intake valve pushrods! The seller said the vehicle had sat for years, and I presume this is the result of stuck lifters? I turned the engine by hand and could see all three push rods move up and down; am I correct this means the lifters are unstuck now? Plan is to replace with a new set of push rods, then do a valve adjustment. Feels nice to move forward!

Brad