VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Funny noise

Hello
I have a '37 1/2 ton p.u with a 1954-55 235 engine in it. The engine has been totally rebuilt this year and installed this year. When it was started, it sounded good and ran great. The valves were adjusted and it sounded good. About 2 weeks ago, I noticed a funny noise coming from what sounded like a noisy lifter. At idle, no noise, but give it a little gas, and the noise returned. I rechecked the lifters and they were fine. I put a piece of pipe to my ear and the noise sounded like it is coming from the # 1 intake and exhaust rockers. Any ideas about what is going on? Maybe weak valve springs? Any help will be greatly appreciated.
Thank you
honk1e

Broken valve spring or valve sticking in guide. Try pouring some ATF or MMo trough the carb. with engine at fast idle - or squirting through the valve spring with some light oil to lube the valve stem/guide.

Thanks Gene, but the head has been totally rebuilt with new seats, valves were ground and guides were checked. There are no broken springs. I located where I was sure the noise was coming from with the cover off. I did reuse the existing rocker arm set up. The noise is for sure coming from #1 & 2 rocker arm area. Could the rocker arm set up be causing the noise? I am at a loss of what to do or what to check.

Thanks Gene
honk1e

Maybe check for a bent push rod hitting the side cover.

Thanks. I will pull the side cover and check it out.
honk1e

Not necessary to remove cover. You can fell it by touching the cover.

Often the expert rebuilders make the valve guides too tight and the valves stick.

I agree with Gene that you need to check if those valves are sticking. Many re-builders like to make the valve stem to guide clearance very small to control oil going into the cylinder. You need some oil to lubricate the valve stem.

Did you have the rocker arm tips ground? If not, I expect that they have a worn area where they hit the top of the valve stem. A feeler gauge is wider than that worn area so the operating clearance is larger than the feeler gauge thickness.

One trick is to grind the tip of the feeler gauge so it is not quite as wide as the diameter of the valve stem/worn spot on the rocker are. Then set your clearances.

Or take the rocker arms to your re-builder and have him grind the tips. Many valve grinding machines have an attachment to do that.

agree with rusty and gene. when i had the 216 in our 39 woodie rebuilt, it started up and no noises. i put it away for its winter hibernation and when it started it in the spring, it sounded like a pair of skeletons fornicating on a tin roof. marvel mystery oil and light tapping of the vale stem with a plastic faced hammer resolved the problem . mike

Thanks for the information. I will talk to the re-builder tomorrow.
honk1e

I chased a rattle in my 216 for years which didn’t go away even after a rebuild. It turned out to be caused by a worn pushrod. The top of the pushrod wore so deeply that the pushrod was actually captive on the rocker adjuster ball. In addition it was so deep that the rod didn’t have a full range of motion. I finally figured it out after the valve clearance kept increasing in large amounts for know obvious reason:

Just an update on the noise I was hearing in my '55 235. It turned out to be the cam gear. When I pressed it on, I did something wrong, The gear was .025 off from being pressed on squarely. Had a shop install a new gear and no more noise
honk1e