aluminum bore briggs-expected life

[morrison250r]

From what I have read from various repair manuals is that the cylinder is aluminum. Not plated aluminum, not "heat treated" and not made of a special alloy. Just plain aluminum. The piston is treated with a friction/wear reducing plating. Also this ifno was read from several aftermarket repair manuals not a B&S manual. On a side note I have noticed a slight knock has devolped. It only happens only under a very, very light load at full speed. It is not loud but I notice it. Piston slap? Internal self-distruction?
So far 18 hours on the engine.

 

[XS650]

Originally Posted By: addyguy
How long does an aluminum-bore engine last?

Ask a former Chevrolet Vega owner. He'll tell ya!!!




The same basic aluminum alloy that Vega used was used by competent car manufacturers with good, long life results.

 

[boraticus]

Originally Posted By: morrison250r
From what I have read from various repair manuals is that the cylinder is aluminum. Not plated aluminum, not "heat treated" and not made of a special alloy. Just plain aluminum. The piston is treated with a friction/wear reducing plating. Also this ifno was read from several aftermarket repair manuals not a B&S manual. On a side note I have noticed a slight knock has devolped. It only happens only under a very, very light load at full speed. It is not loud but I notice it. Piston slap? Internal self-distruction?
So far 18 hours on the engine.


Not sure if I agree with your "plain aluminum" statement. I'm certain that most of us know that aluminum is manufactured in various grades of tensile strength and hardness. There are vast differences in characteristics of aluminum alloys. I've seen dimensionally similar pieces of aluminum that were very much different in their composition. Some are very malleable and bend easily with little resistance while others are very hard, rigid and resistant to bending. Some cut like butter while others are very difficult to cut.

So, saying it's "plain aluminum" is open for a great deal of speculation.

At the very least, I'd assume that the aluminum used for an internal combustion engine cylinder bore must be scuff resistant, heat resistant and deformation resistant. That would hardly fall under the classification of "plain aluminum". I'd be willing to bet that the aluminum used for the purpose of cylinder bore applications is probably a specifically designed and developed alloy that's been tested and proven suitable for the job.

 

[Oldmoparguy1]

Earlier, when I said a special alloy, I meant that it had to be compatible with the bore treatment process. Now the info that I have comes from my memory of reading about the subject back in the late 70's, early 80's. What is being done by B&S now could very well be something quite different. If someone has up to date info about it now, I would be very interested in learning about it. Anyway, the bottom line is this, aluminum bores are cheaper to make then CI liner bores. If the engine lasts as long as the product it's mounted on, then it doesn't really matter.

I have a junk pile of old B&S push mower engines that
the mower bodies had failed and the wheels have fallen off of.
Most have broken rewinds or missing parts of one kind or another. Even so, every last one of them will run with just a minimum of repair. One of these days I'm going to melt them down for the aluminum and do some hobby casting.

 

[Cmarti]

Cheap Poulan saws are chrome plated, Dolmar saws use Nikasil. I am not so sure how "expensive" it is at a mass scale B & S makes engines. The question is would it be needed in lower RPM oil cooled applications?

 

[morrison250r]

What I meant by "plain aluminum" was aluminum or an aluminum alloy that had the same composition throughout the thickness of the material. In other words un-plated.

 

[Nick R]

Originally Posted By: morrison250r
What I meant by "plain aluminum" was aluminum or an aluminum alloy that had the same composition throughout the thickness of the material. In other words un-plated.


I don't think even the cheapest of engines use those.

 

[boraticus]

Here's an interesting albeit very short read on Development of Hiper Eutectic Al-Si Alloy Liner-less HPDC Cylinder Block. This article is dated back to 2001. There's a chance that this technology has trickled down from auto manufacturing to OPE engines.


http://sciencelinks.jp/j-east/article/200204/000020020402A0054381.php

 

[kbowley]

In doing some research rather than winging it. i believe I have the answer to the name of the proprietary coating used in the Briggs Aluminum engines. I believe it is called stelite

Stellite® cobalt base alloys consist of complex carbides in an alloy matrix.They are resistant to wear, galling and corrosion and retain these properties at high temperatures. Their exceptional wear resistance is due mainly to the unique inherent characteristics of the hard carbide phase dispersed in a CoCr alloy matrix.Stellite® 6 is the most widely used of the wear resistant cobalt based alloy sand exhibits good all-round perfor-mance. It is regarded as the industry standard for general-purpose wear resistance applications, has excellent resistance to many forms of mechanical and chemical degradation over a wide temperature range, and retains a reasonable level of hardness up to 500°C(930°F). It also has good resistance to impact and cavitation erosion. Stellite® 6 is ideally suited to a variety of hard facing processes and can be turned with carbide tooling. Examples include valve seats and gates;pump shafts and bearings, erosion shields and rolling couples. It is often used self-mated lining of soft metals such as aluminum that require resistance to high heat, fiction and wear.

I cant seem to find a direct link to briggs, they are very tight lipped regarding the lining of the cylinders in aluminum bore engines. I could have sworn it was a nikasil lining but i just kind find ANY information regarding what they use as a lining. what ever it may be, i have personally had extreme durability with the aluminum bores. An 40+ year old lawn mower with a three HP thats been handed on down the family chain and I now use it for mowing the sides of my 800ft driveway, banging many a rocks and stumps along the way. A Bolens ST1100 with 1400 hrs on the clock of an aluminum bore 11 hp, still runs as new and burns no oil between 15-20 hr change outs. I do use wally-world 5w-30 synthetic in it however. A late 60's Simplicity walk behind snow blower with an 8 hp briggs. what a tank that thing is. For instance, my Dad bought a husqvarna with a 11 hp that cost him 1200.00 and that 'ol simplicity will put it to shame. It also runs as new, starting in the second pull every time, winter, summer, fall...full choke and second pull it fires off, I would place a monitary bet on it even if it had been sitting all summer. it,too, burns now oil and is very strong. I also have a Toro Personal Pace lawnmower with a Quantum aluminum bore side valve that cost me 699.00 at the dealer with 12 v electric start and a small battery that i charge once per year. i have had it for three seasons and it runs as perfectly and quietly as one could hope for on a push mower. it is a 6.5 HP.

So I dont know if we will ever get to the bottom of it. However, the original poster need not be concerned as I personally believe they are perfectly reliable engines with a 45+ year track record. I also feel the side valve flathead's are far superior to the newer OHV engines. My 212-H Toro rider has a 12 I/C and is at the 1800 hr mark, the highest of any power toys I own. It smokes just a tad at start up and if you go from slow idle to full throttle you can see a very faint blue hue to the exhaust. I have not had to add any between changes yet but is does drop from full to the lower end between add and full on the stick at 25-30 hours. i also use the wally-world 5w-30 synthetic in that machine. Chassis has held up amazingly well...very tough for what wheelhorse designated as a lawn tractor! I wouldn't hesitate to do anything with it that i would do with my 72 Raider.

 

[boraticus]

kbowley:

Are you certain that all of those engines you mentioned all have aluminum bores? Many older B&S and Tecumseh engines had cast iron/steel liners in them.

As far as I know, I have only one piece of four stroke engine OPE that has an aluminum bore. That's my Simplicity snow thrower. I Have tons of OPE but haven't had the need to open any of them up to see what they have for bores. I know some of my smaller Echo two stroke machines have either nikasil or chrome bores in them. My 20 year old Echo two stroke lawn more has a cast iron bore in it.

All of my old two stroke motorcycles have cast iron bores as well.

 

[kbowley]

I only mentioned the aluminum bore Briggs and Stratton engines. If it is a cast lining it will say on the shroud or it will be an I/C. Im talking the L-Head engines, not the newer vanguards, ELS or Intec series nor the OHV engines. Just the older L-Heads and the newer Quantum which is an L-Head with aluminum bore.

 

[morrison250r]

Most of the infomation I have read said that the piston was different between the C.I. bore engines and the aluminum bore engines. There is also a myth that B&S aluminum cylinder engines can not be bored oversize because the "plating" can not be redone. This is not true. B&S makes oversized pistons specifically for that type of cylinder. The cylinders have no special plating. This dose not mean that the cylinder liner is not made of an advanced aluminum alloy. It just means that it is unplated. The piston for the aluminum cylinder is made of an aluminum alloy with a chrome-type plating.
In the post I wrote on the top of this page when I said "special alloy" I meant to say "unusual alloy"

 

[eyolf]

I know, old thread, and noob poster. Apologies, but I ran onto this thread and had to register.

Back in the 1970's I was a young parts and service guy for a regional warehouse distributor that sold a lot of OPE with both Briggs and Techumseh engines. The little 3 hp briggs aluminum engines then were expected to last 40 hrs for warranty purposes.

The blocks were an aluminum alloy with fairly high phosphorus and silicon content which basically made them free-machining and less subject to galling: useful in manufacturing as well as slightly reduced chances of aluminum galling in the upper cylinder. They burned oil from new on purpose: low tension in the piston rings reduced scraping aluminum and left more oil.

Yes, they could be rebuilt, but almost never were. A few special-purpose engines that were very expensive to replace were rebuilt, but most of these started out as better cast-iron lines motors anyway. Applications like mortar mixers and spray rigs.

I have an MTD mower bought new in 1978, still has the original 3 1/2 hp Briggs, and still runs. Probably has about 120-150 hrs, and even with excellent care, its tired. Have a 4hp gear reduction on a rototiller, and a 3-1/2 hp gear red on a cement mixer that still run, sort of, but are similarly tired. None would have more than maybe 150 hrs, and both will burn up a crankcase of oil before using up a two-quart tank of gas. Have a mid-1980's Gilson snowthrower with a Briggs 8hp; that one is pretty fresh yet, but has very low hrs...not more than 25-30, judging by the belts and drive wheel.

I would say that 150 about the limit for an aluminum Briggs. But that's a lot of use for many consumers. WE've all seen manmy many mowers and snowthrowers that were literally rusting away, but had only a few hours of run time.

 

[boraticus]

I put an average of twenty to thirty hours/yr on my B&S equipped Simplicity snow thrower. I'd be sorely disappointed if the engine was shot in six or seven years. My old 10 h.p. Tecumseh L head engines each were running strong with over ten years of hard service on each of them. The Craftsman snow throwers were falling apart but the engines were still very healthy. Could be that the old Tecumseh's were better built. However, the B&S aluminum bore snow engine I have seems like an excellent engine other than a bit of oil consumption.

Your explanation of the low tension piston rings makes pretty good sense and explains why the engine would possibly consume oil. As previously mentioned, it doesn't consume a great deal of oil, but enough to make sure I check it before every use.