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Briggs L-head; what an engine!

#1

J

JBtoro

Family member brought me his Briggs 7.25 on a 5 year old Troybilt walk behind. I hadn't seen it nor serviced in a year. Turned it on it's side to drain the old oil; nothing came out. Dipstick showed nothing either. He had somehow failed to check the oil during the last year and also let the air filter get completely clogged. I feel certain that he mowed with it many times in this condition or when the level was quite low. So I put oil in it & it started right up. I ran it for at least 30-40 minutes & it ran & sounded great with no smoking whatsoever. So here's a post of praise for B&S and this engine. But, it appears the co. has gone to OHV's on all its newer offerings. Too bad.


#2

Russ2251

Russ2251

"But, it appears the co. has gone to OHV's on all its newer offerings. Too bad."
Small flat head engines (for our usage) have not been manufactured for many years now due
to emissions issues/concerns.
Too bad? More horsepower per lb. is a good thing in my book.


#3

tom3

tom3

The newer motors, even with the plastic camshafts, seem to be pretty decent engines with routine maintenance. Usually outlast a steel deck mower.


#4

T

Tinkerer200

Russ2251 said:
"But, it appears the co. has gone to OHV's on all its newer offerings. Too bad."
Small flat head engines (for our usage) have not been manufactured for many years now due
to emissions issues/concerns.
Too bad? More horsepower per lb. is a good thing in my book.
Click to expand...

The OHV engines are having a much higher failure rate I think is what he is referencing.

Walt Conner


#5

J

JBtoro

Tinkerer200 said:
The OHV engines are having a much higher failure rate I think is what he is referencing.

Walt Conner
Click to expand...
Folks, I guess I left the impression that I thought OHV's are inferior. Not at all. I was merely trying to point out that the tried-&-true B&S l-heads are really sturdy engines if, as I reported, they can run with low or no oil for ... what?... several weeks , months maybe. And then start on 1st pull with no smoke? Pretty impressive.


#6

B

bertsmobile1

The L heads date back to the slide rule days so are substantially over engineered, which in a product like a lawnmower is not such a bad idea.
The OHV engines have been designed with the aid of computers to be made with a little metal as possible and to a finite service life.


#7

Bob E

Bob E

They'll never make 'um like that again.


#8

tom3

tom3

I used to work in the slide rule days. And logarithms. Then got a Remington (?) calculator @ $169, a full week's take home pay. Worked that thing to death. We were some behind here in Appalach I guess.


#9

J

jp1961

Hello,
I remember old timers back when I was a kid, saying they don't make things like they used to. Now that I'm an old fart, I'm saying the same thing,,,lol.

The engine would be even better if it was one of the old cast iron type, not the "Kool Bore" with aluminum cylinder with no steel liner.

Time to change my Depends and take my meds,,,ROFL.

Regards

Jeff


#10

B

bertsmobile1

jp1961 said:
Hello,
I remember old timers back when I was a kid, saying they don't make things like they used to. Now that I'm an old fart, I'm saying the same thing,,,lol.

The engine would be even better if it was one of the old cast iron type, not the "Kool Bore" with aluminum cylinder with no steel liner.

Time to change my Depends and take my meds,,,ROFL.

Regards

Jeff
Click to expand...

And that is true.
Almost everything you buy from candy bars to lawnmowers get cheaper and nastier every year as the factories chase more profit .
And the days of the profession screen jockie investors have made it worse as they have only one objective, maximum possible dividend and if that kills the business then who cares they just pull their funds the instant the business they have destroyed starts to look shakey and go destroy some one elses company .
As computer modeling got better you get things that were considered impossible decades earlier like aluminium bores on engines with a non replaceable barrel .

As the customer got further & further divorced from manufacturing industry the lost the ability to properly to properly evaluate what they bought so they started relying on other peoples "expert" opinions and price.
We are now at the stage when what we buy has become so complicated we really have no idea so price becomes even more important in our purchasing decisions.
Thus the number 1 rule required to make the demand economy work has not been meet and the system is now spiraling out of control to the point where a technical no body on face book with absolutely no idea about the subject they are posting on can control the destiny of a company .


#11

J

JBtoro

JBtoro said:
Family member brought me his Briggs 7.25 on a 5 year old Troybilt walk behind. I hadn't seen it nor serviced in a year. Turned it on it's side to drain the old oil; nothing came out. Dipstick showed nothing either. He had somehow failed to check the oil during the last year and also let the air filter get completely clogged. I feel certain that he mowed with it many times in this condition or when the level was quite low. So I put oil in it & it started right up. I ran it for at least 30-40 minutes & it ran & sounded great with no smoking whatsoever.
Click to expand...


#12

J

JBtoro

Follow up on my original post. What specifically would cause an engine with a clogged air filter to go from full oil in the sump to no oil? The owner told me that the engine was not smoking. It surely didn't evaporate:p. I mean I can see where a clogged filter would cause overheating and eventual ring problems thus causing the oil to dissipate from burning. However, to not smoke but otherwise go from full sump to no (or minuscule) oil in the sump?? That's what I'm trying to understand.


#13

StarTech

StarTech

Not all oil problems will cause an engine to smoke; just how it is. I have Briggs OHV engines with a blown gasket to consumer lots of oil and not even smoke as most modern oil are now semi smokeless. Also the oil used matters. A year or two ago heard about the poor quality oil the Dollar General Stores was selling that getting consumed by engines at a high rate.

You mention a clogged air filter. The engine was problem darwing extra in through the crankcase vent valve assembly which would draw in some oil.

You also mention been about a year since you have seen the mower. I have a similar thing last fall with a Swisher walk behind trimmer where the operator never bother to check the oil. What was left in the engine was like molasses especially during the 40F temps that I was working on it in.


#14

cpurvis

cpurvis

JBtoro said:
Follow up on my original post. What specifically would cause an engine with a clogged air filter to go from full oil in the sump to no oil? The owner told me that the engine was not smoking. It surely didn't evaporate:p. I mean I can see where a clogged filter would cause overheating and eventual ring problems thus causing the oil to dissipate from burning. However, to not smoke but otherwise go from full sump to no (or minuscule) oil in the sump?? That's what I'm trying to understand.
Click to expand...
A clogged air filter causes a rich mixture. Rich mixtures run cooler than a normal or lean mixture and will blacken spark plug electrodes. Oil consumption will also leave black residue on spark plugs but it will have a wetter appearance than the carbon deposits left by a rich mixture.

Only three ways for oil to disappear from an engine. 1. It gets drained or suctioned out; 2. It gets burned and goes out the exhaust; and 3. It leaks out, leaving a trail.


#15

tom3

tom3

Oil smoke is basically unburned oil. If the motor is actually burning the oil it might not be visible, might smell a bit though. A whole season around here would sure make it possible to burn most of 18 or 20oz of modern oil, especially this year.


#16

S

seattlepioneer

tom3 said:
I used to work in the slide rule days. And logarithms.
Click to expand...

I remember learning to interpolate tables of mathematical functions using a slide rule to do the calculations. That was circa 1965 or so.

In 1990 I went back to learn the math I'd never learned very well, and completed two quarters of regular college calculus before bailing out of the third quarter of calculus ----twice.

Computers and calculators were readily available at that time, and I remember how much easier things were when you could easily graph equations to better understand what was going on. And of course it was far easier to get much more accurate functions than with a table of values and interpolation.

So my experience was that computers made it much easier for marginal math students like myself to learn a lot more math. I wouldn't be surprised if that was true for talented math students as well, or most of 'em.

I had a friend born about 1937 in Germany to a highly talented mathematician. He was able to visualize the graphs of complicated functions without doing the math to calculate them. He wound up working at Penemunda on the V2 rocket with Werner Von Brown, and he and his family, including my friend, entered the United States through the Mexican border with "Operation Paperclip" after end end of the war.

He closed out his career as a Professor of Physics at the University of Washington.


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