Briggs 3.5 HP valve noise

[Kira]

Hello, I'm using a Sensation lawn mower which is nearing 30 years old. It runs well, always did.

It exhibits a clicking which is either normal valve noise or (perhaps a noise relevant to the "valve rotators".

I'm using Valvoline HD-30W. Is that correct oil? Is there something known to be quieter?

Thanks, Kira

 

[AandPDan]

A 30w is what most Briggs models spec.

What model engine is it? It probably does NOT have valve rotators.

Have you ever adjusted the valve clearances?

 

[jeepman3071]

I notice my old Briggs engines run a bit quieter on 15w40 or 5w40. I run Rotella T 15w40 in my 1966 Jacobsen reel mower with a 2 hp Briggs on it. It also consumes hardly any oil with the 15w40 where it burned a noticeable amount with SAE 30.

 

[PhilsSmallEngine]

The model you have can greatly help determine what common problem with something that sounds like a valve tap. I have a 4hp Briggs on my Ariens tiller and it had what sounded like a valve tap. At the end of the day, it was the lack of lubrication on the bearings of the recoil assembly. I finally figured it out when it started making grinding sounds and throwing the starter cord out. I felt like a total moron for missing something so obvious for almost a year.

The old Briggs call for an SAE30 but with their age, I tend to go with a 15w-40 T5 Rotella diesel oil or a 10w-40 Amsoil 4-stroke synthetic.

 

[Joe_Power]

Ummmm, it's a 3.5 Briggs........Seriously?

 

[jhellwig]

How in the world are you hearing any noise other than the exhaust?

There are no valve rotators on that engine.

 

[Kira]

Hello, Thanks for the responses.
I will double check the mower tomorrow and update.
I'm dead certain there's a notification of valve rotators on the side of the engine.
I will clear this up tomorrow.
Thanks, Kira

 

[Dean85]

Sounds to me like there is a little to much clearence between the valve stem and the valve lifter. I have never seen a valve rotator on a sm engine.

 

[ironman_gq]

Those are old flat head style engines, nothing to adjust in the valvetrain at all. There is a tappet that runs on the cam and works the valve. Should be an inspection cover on the side of the block (same side as the spark plug) that will let you take a look at the valve springs/stems and measure lash. After 30 years it could be a broken spring, or just worn out tappets and the lash has grown to the point where you are starting to hear it. Could be a compression leak, could be piston slap, could be a loose rod. Lots of things that it could be. It's a 30yr old Briggs 3.5. If it runs good you could take the time to tear it down and rebuild it but it's probably not worth it.

If it were me, I'd run it till it blows up and pick up a new mower.

 

[old1]

You are probably right that the engine has an exhaust valve rotator. Briggs did use them, and Sensation mowers did use engines that had them. I know, as I used to be a Sensation dealer. ( and am still a Briggs dealer) My guess is probably piston slap on that old of an engine. Probably just ignore the noise, or possibly go with a slightly heavier oil. Might make it a bit quieter, but probably won't make it last any longer. Personally myself I would try some 15/40 or even 20/50 , but that is just me.
P.S. I know that you could buy another mower, but I also know Sensation mowers, and know that there is nothing on the market today that has the quality of an old Sensation.

 

[jhellwig]

I have worked on a few of those old Briggs and haven't seen a valve rotator yet. Not that that means they never were. As simple as those engines are I would never think they would have had them.

Most of those old flat heads would turn the valves though from the lifter spinning on the cam.

 

[old1]

Yep, they did have them, check a b&s parts manual for the proper model and spec number, and it will show up. BUT, I don't remember seeing them used by anybody but Sensation. But also I seriously doubt if they are the only ones.

 

[FastGame]

They used them on some engines to help the exhaust valve from burning.

http://gardentractorpullingtips.com/valvecam.htm

http://www.ebay.com/itm/Briggs-494191-Ex...S-/141170908975

 

[old1]

Exactly, and it seemed to help too.

 

[jhellwig]

Hrm. You learn something new everyday.

Now that I am done talking out of my butt I will restate my original question.

Short of a knock I have never been around and small engine that you could hear anything other than the exhaust or a rattle when the shroud came lose.

Can you really hear valve noise on these?

 

[jeepman3071]

Originally Posted By: jhellwig
Hrm. You learn something new everyday.

Now that I am done talking out of my butt I will restate my original question.

Short of a knock I have never been around and small engine that you could hear anything other than the exhaust or a rattle when the shroud came lose.

Can you really hear valve noise on these?


I haven't been around many Briggs where I can even hear the exhaust.

Most of the noise these things make comes from the engine internals. There are a few people on Youtube who tried to add giant car mufflers to their generator engines. After their hard work, the machine is just as loud as before since the noise comes from the internals.

When working on small engines I often wear noise reducing head phones. The head phones help dampen the "white noise" from the engine and I can hear the valves ticking or any faint knocks that might not be audible without them.

 

[steve20]

i would do whatever you can to help it last longer-whether that be the inspection which reveals a problem, or just thicker oil--i do not know what a sensation looks like but I'm sure it is better than any crud on the market today

 

[old1]

By the way, as an old sensation dealer, I am curious what model it is. Is it white, green, or orange in color? Also is it a push or self propelled?