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2018/01/16 13:29:51

kibberk

Briggs Aluminum Bore 12 HP Engine

My engine is a Briggs 281707, type 0195-01 12HP from a riding mower. It is aluminum bore engine. I have had excellent service out of it but it was starting to burn oil. The bore is in ideal condition; no measurable wear, no scores, etc. The piston is in excellent shape too. So are all the bearings. I plan on putting a new set of Briggs standard rings which are the iron type. The Briggs manual on page 3 of section 9 says to not hone the walls when putting in new rings in an aluminum block engine. I have read a lot of conversations on many other forums and find that the question of whether or not to hone an aluminum bore engine is controversial with people claiming success either way. The manual says not to hone. I have read the new standard rings have a surface that will quickly wear down to conform to the cylinder even if it is not honed.

I would appreciate any advice or feedback from someone with some experience re-ringing these aluminum bore engines.

Thanks in advance

8 comments Leave a comment

AVB

What manual are you referring to as the Single L-Head Service manual PN 270962 does have what you said would be on page 3 of section 9.

As wear you must measure 3 levels and at least twice at each level with one reading 90 degrees of the first reading. I would not be surprise that have either an ovaled and/or taper cylinder. Also check the valve guides especially the exhaust guide as these can cause excessive oil usage even the cylinder and rings are fine. Also if any of the new rings end gaps exceed the maximum allowed in the service then cylinder must be oversized.

An oval cylinder will show when you install one of the compress rings and shine a light from behind.

If ovaled or tapered then you need to hone the cylinder to .020 over using a rigid hone with stones for aluminum. A flex hone will only make any problems related to taper or oval worse. This honing must also produce a 90 degree cross hatch.

2018/01/16 15:05:50

AVB

AVB
What manual are you referring to as the Single L-Head Service manual PN 270962 does have what you said would be on page 3 of section 9.

As wear you must measure 3 levels and at least twice at each level with one reading 90 degrees of the first reading. I would not be surprise that have either an ovaled and/or taper cylinder. Also check the valve guides especially the exhaust guide as these can cause excessive oil usage even the cylinder and rings are fine. Also if any of the new rings end gaps exceed the maximum allowed in the service then cylinder must be oversized.

An oval cylinder will show when you install one of the compress rings and shine a light from behind.

If ovaled or tapered then you need to hone the cylinder to .020 over using a rigid hone with stones for aluminum. A flex hone will only make any problems related to taper or oval worse. This honing must also produce a 90 degree cross hatch.

CORRECTION. The L-Head Manual 270962 DOESN'T have what you mention. In my previous that was a typo. That is what I get for not wearing my readers. And this site doesn't allows for editing later if needed. Sorry for the typo.

Also even if just installing new rings you should deglaze the cylinder and produce the 45-90 degree crosshatching for the the new rings to seat properly.

2018/01/16 19:52:53

kibberk

Page 3 of section 9 of the Briggs and Stratton Single Cylinder 4-Cycle Repair Manual says near the bottom of the first column, right under Fig. 6: "NOTE: Do not use a hone to deglaze cylinder walls when installing piston rings in aluminum cylinder engines." I have been working with engines of all sizes for over 60 years now and I do find this statement counter-intuitive but I am inclined to follow their recommendation. I have communicated with many small engine rebuilders who tell me they never hone an aluminum cylinder engine. The reason is purported to be that the new standard rings (cast iron) have a special top surface (on the part of the ring that contacts the cylinder wall) that is design to initially wear down quickly thus seating the rings to the cylinder. It is also purported that using a hone on the aluminum bore will embed particulate into the aluminum that is considered undesirable. However, I am interested in other interpretations on this Briggs manual statement, especially if solid technical reasoning is presented.

2018/01/17 10:34:33

AVB

I will need the Briggs PN for that manual to see if I can download a PDF copy thru the Briggs Power Portal or thru TradeBit as I not aware of that particular manual listed on the Power Portal. I will to read though that manual to see what is going on here.

2018/01/17 10:57:04

kibberk

The part number listed on the back cover of the manual is 270962-12/97

2018/01/17 11:53:59

AVB

Then I can't why the printed version is different than what Briggs is providing us techs via the Power Portal site. They should be the same manual.

Below is a link to the current PDF copy that Briggs providing.
https://drive.google.com/open?id=0B-g4TpKUJnh7ZzF0MEpoakFzQlU

2018/01/17 12:05:47

kibberk

Hmmm. I concur the online PDF version does not have the admonition in it. I wonder what the revision date is for that version.

Mine is dated 12/97; I have had my mower since 1990 and I bought the manual sometime, I suspect in 1998 or 1999.

I scanned the page 3 of section 9 in my manual and attached it as a pdf file so you can see the admonition for yourself.

2018/01/18 12:58:24

AVB

I believe that is primarily when you are using the chrome rings. Anyway I haven't seen a totally clean cylinder that didn't need a slight honing except a new cylinder or one that still have the cross hatching visible.

As for the online manual date the following is the PDF created and update dates. Ignore the file location info as that is where I have it stored locally on my internal network.

2018/01/18 16:03:28

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Briggs Aluminum Bore 12 HP Engine

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