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B.Ikard

Briggs Engine-Internal Clearances/Tolerances

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B.Ikard
Gents, Putting a 16hp together this week that has been bored and find the Briggs manual is a little short on specs. Been thru both old and new manual several times looking for the following: -Piston to bore running clearance --New piston specs and reject dimensions?? -Crankshaft to rod running clearance --Rod big end specs and reject dimensions?? IMHO Kohler does a lot better job in writing a manual...:O Any experience or numbers would be appreciated: Brent

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B.Ikard
Thanks for the replies: Below is the info I am searching for: Connecting Rod Running Clearance Rod to Crankpin (New) .001/.0025 Rod to Crankpin Wear Limit .003 Rod to Piston Pin (New) .0007/.0008 Small End I.D. (New) .5630/.5633 Crankpin Max. Out of Round .0005 Max. Taper .001 Piston Thrust Face O.D. New 2.371/2.369 Max. Wear Limits 2.366 Thrust Face to Bore Clearance (New) .0035/.006 I edited the info out that Briggs does provide-This is from Kohler for their K91 engine-does Briggs have any of these specs available? There is a reason for the digging. I recently bought this 16hp with a stripped headbolt....opened it up and found a freshly assembeled rebuild... .020 over piston, etc-best luck I have had in a while. Estimate 15min run time till the headgasket blew due to stripped bolt and lack of clamping. Bore is mildly scuffed by the piston skirt, so I ran a bore gauge thru the bore and it is in perfect spec. I want to check a little deeper but have no numbers... Brent

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B.Ikard
I don't think Briggs publishes/releases these tolerances......all other engine manufacturers do-namely Kohler and Onan.. Was not comfortable with the manuals instructions to "Bore cylinder exactly .010-.020-.030 and close your eyes, put it back together and all will be ok":O I have allways used piston dimensions when reboring..what if you got a piston that was barely out of spec and blindly installed it ? It happens daily- Sometimes piston construction and materials put these tolerances all over the place- I did get some measurements from 1 new .020 piston and one near new .020 piston and came up with some numbers. With the info I have it looks like these are designed to run around .007-.008 cylinder running clearance (measured 1/2 below oil ring) and taper out to .003 (CL of pin bore to end of skirt). This falls in right where Kohler specs their K series (.007/.010) I will try to verify a number to look for on Plastigauge for the rod bearing/crankpin, Kohler spec's .0015-.0025 which is probably what I will find on this one.. Hope I did not get too deep in the weeds Brent

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