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Briggs 3 HP - Want to swap crankshaft

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Re: Briggs 3 HP - Want to swap crankshaft

Postby creia » Wed Sep 12, 2018 8:10 pm

Thank you Brian! :D
If I understand correctly (using our trusty Briggs repair manual guidelines):
080202 = 3 HP, horizontal crankshaft with a "plain bearing" (bored sidecover bushing) on the PTO end- The engine model #'s in the list YOU provided.
080232 - 3 HP, horizontal crankshaft with a "flange mount ball bearing" on the PTO end) - Which is OUR engine.
Is there any reason why we could not just remove the bearing on our engine crank and press it unto the NOS # 492880 crank and install THAT in our engine? This OEM NOS crank selling for $ 40.00 has a 2.25" long straight shaft with keyway, is 3/4" in diameter, and is even drilled and tapped on the end for use with a clutch bolt which is perfect for our application.
Michael
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Re: Briggs 3 HP - Want to swap crankshaft

Postby bgsengine » Wed Sep 12, 2018 9:02 pm

creia wrote:Is there any reason why we could not just remove the bearing on our engine crank and press it unto the NOS # 492880 crank and install THAT in our engine? This OEM NOS crank selling for $ 40.00 has a 2.25" long straight shaft with keyway, is 3/4" in diameter, and is even drilled and tapped on the end for use with a clutch bolt which is perfect for our application.
Michael


None that I can think of.. unless it's an oddball somewhere, usually the crank will have the same bearing journal dimensions , whether it is plain DU bearing or ball bearing , so should fit either case.

As a *general* rule of thumb for something like a crankshaft you can usually do just fine picking a random spec number (first one that comes to mind is -0036-xx which we seem to use a lot of in utility applications) , or if you can find a known good spec number for a similar model series, that can work too - other than crank, majority of internal engine parts will be the same for all the spec numbers in a given model build
How poor are they who have not patience. What wound did ever heal, but by degrees? - Iago (Othello Act II, Scene 3)
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Re: Briggs 3 HP - Want to swap crankshaft

Postby creia » Wed Sep 12, 2018 9:51 pm

bgsengine wrote:
creia wrote:Is there any reason why we could not just remove the bearing on our engine crank and press it unto the NOS # 492880 crank and install THAT in our engine? This OEM NOS crank selling for $ 40.00 has a 2.25" long straight shaft with keyway, is 3/4" in diameter, and is even drilled and tapped on the end for use with a clutch bolt which is perfect for our application.
Michael


None that I can think of.. unless it's an oddball somewhere, usually the crank will have the same bearing journal dimensions , whether it is plain DU bearing or ball bearing , so should fit either case.

As a *general* rule of thumb for something like a crankshaft you can usually do just fine picking a random spec number (first one that comes to mind is -0036-xx which we seem to use a lot of in utility applications) , or if you can find a known good spec number for a similar model series, that can work too - other than crank, majority of internal engine parts will be the same for all the spec numbers in a given model build


With the information you have provided it is now time for my son and I to pull the crank out of our engine and compare a few critical measurements with the
$ 40.00 crank the seller has for sale. (He has been very good at providing information and photos to me already). He even has the original Briggs box with the part # displayed)- it is the old/vintage orange and blue Briggs logo/colors). If everything checks out I'm going to pull the trigger on this crank. If this works out I believe that it is a very good deal at $ 40.00.
Michael :)
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Re: Briggs 3 HP - Want to swap crankshaft

Postby Dale_W » Thu Sep 13, 2018 8:25 am

This has been a good topic to follow. Thank you all.
Michael, please post your results when you are done.

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Re: Briggs 3 HP - Want to swap crankshaft

Postby creia » Fri Sep 14, 2018 12:03 pm

Dale_W wrote:This has been a good topic to follow. Thank you all.
Michael, please post your results when you are done.

Dale


Will do Dale!
Michael :)
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Re: Briggs 3 HP - Want to swap crankshaft

Postby creia » Sun Sep 16, 2018 4:01 pm

UPDATE #2;
I have taken apart our engine so I can now take specific measurements from the crank that came with it and compare it with measurements that I have received from a couple of sellers. Long story short- Briggs crank # 492880 is NOT going to work for a couple of reasons: 1) It is about 3/8" too long overall, and 2)The PTO end of the crank where the ball bearing would slide ("press fit"?) on is too large of a diameter to accept a bearing. :cry: I believe that # 492880 is for a "plain bearing" engine and side cover. The search continues...
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Re: Briggs 3 HP - Want to swap crankshaft

Postby bgsengine » Sun Sep 16, 2018 5:19 pm

creia wrote:UPDATE #2;
I have taken apart our engine so I can now take specific measurements from the crank that came with it and compare it with measurements that I have received from a couple of sellers. Long story short- Briggs crank # 492880 is NOT going to work for a couple of reasons: 1) It is about 3/8" too long overall,
Why? too long where?
and 2)The PTO end of the crank where the ball bearing would slide ("press fit"?) on is too large of a diameter to accept a bearing. :cry: I believe that # 492880 is for a "plain bearing" engine and side cover. The search continues...
Michael


Did a little research for you - crank drawings show 492095 part number is 5/8-18 threaded end crankshaft , and this crank has a bearing journal of 0.787" diameter so it must have a special bearing for the water pump application, one would think (there's also a crank with .787 journal for generator applications- tapered shaft) - However, part number 261128 (which you took a guess as being for your model) is actually 0.875" diameter , as is the 492880 crankshaft.
I bet all you need is a replacement ball bearing for a standard 80200 series Briggs (which should be the .875" diameter) part number 99158, and oil seal what dimensions are you seeing on your crankshaft?
What I am finding interesting is the 2 different bearing journals, however when I look those part numbers up in the power portal , ALL THREE CRANKS are used in engines that have ball bearing and all the ball bearing part numbers come up as the same part.. It has been over 20 years since I last worked with one of those small water pumps (I still have one) but I seem to recall them being fitted with a different I.D. ball bearing.. but for the life of me I can't seem to come up with the part number for it... Other than those couple limited use cranks, all the other standard briggs cranks for 80200 series horizontal are .875 bearing journals and they should use the same ball bearings and oil seals, so you should be wanting a crank with .875 journal anyhow.
How poor are they who have not patience. What wound did ever heal, but by degrees? - Iago (Othello Act II, Scene 3)
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Re: Briggs 3 HP - Want to swap crankshaft

Postby creia » Sun Sep 16, 2018 7:07 pm

It never ceases to amaze me with not only the knowledge, but also the kindness and caring of the individuals TO HELP OTHERS on this forum! (Brian, you are one of the "poster boys" of that observation) :D
You are exactly correct as to: 1) The bearing journal measurement on MY crank, and 2) The bearing journal measurement on crank # 492880, which I received from the seller. Seems real odd (however I believe you) that Briggs would make an odd ball bearing ID just for water pumps and generators- that seems like something that Tecumseh would do! :lol: I actually have an OEM Briggs ball bearing # 99158 on order being shipped so I will soon see firsthand what the ID will be. As far as the crank being longer, here is another odd ball- it is the "snout" (flywheel) end that the starter clutch slips over and threads unto.It is actually too long on Briggs crank # 492880 for you to install the starter clutch- you would have to cut it down about 3/8"! :o
I wonder if the "special" bearing for the water pump/generator application has a different(smaller)OD as well? :? If so, that means the side cover recess for the bearing to slide into is "special" as well on this engine and will not fit the (possibly larger) OD of Briggs bearing # 99158? :?
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Re: Briggs 3 HP - Want to swap crankshaft

Postby bgsengine » Sun Sep 16, 2018 9:33 pm

creia wrote:As far as the crank being longer, here is another odd ball- it is the "snout" (flywheel) end that the starter clutch slips over and threads unto.It is actually too long on Briggs crank # 492880 for you to install the starter clutch- you would have to cut it down about 3/8"! l
Thought as much.. :) the crank is probably condensed down to one of the more "universal" applications , and a little hint, some engines actually used that extended length of the flywheel end for other applications (flywheel side PTO for one, some used that bit of extended tip as a "hub" for a electric belt-driven starter-generator pulley.. etc) So yes, that bit of 3/8 extra length (or however long it needs to be down to) needs to be trimmed off - hacksaw, cutoff wheel, ,whatever (oxyacetylene torch is NOT recommended however!) .. assuming everything else about the crank will work fine, then just go ahead and trim that bit off...
many more recent models came with that extended crank end on short blocks for example, and to fit to the ewer style cup-and-pawl starters, you;d have to chop off most of that extension.. Likewise many of the briggs replacement engines are equipped with common cranks that the PTO end can be cut down and drilled/tapped as required to modify it for a particular application.. which is fully endorsed and recommended by Briggs, and done by an authorized dealer, carries the same full warranty
How poor are they who have not patience. What wound did ever heal, but by degrees? - Iago (Othello Act II, Scene 3)
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Re: Briggs 3 HP - Want to swap crankshaft

Postby creia » Mon Sep 17, 2018 10:06 pm

UPDATE # 3:
Well, a surprise and another setback...
Today I received the Briggs OEM 99158 ball bearing today. Guess what- it has an ID of 0.782" and will be a perfect (press) fit for my EXISTING crankshaft! :shock: That is to say it DOES NOT have the correct (large enough) ID to fit Briggs Crank # 492880 with the 0.875" journal! This Briggs OEM bearing # 99158 is extremely common and used on many Briggs 3-5 HP horizontal shaft engines that have ball bearing supported PTOs. Apparently, the journal on the # 492880 is the "oddball", or (more likley) is made to be used with a "plain bearing" (bored sidecover bushing). I feel very lucky to have had a seller who was very willing to provide me with accurate measurements. So, the # 492880 crank is a no go, :( however, I have another lead on a good used OEM Briggs # 493633 crank. I am in the process of obtaining measurements from the seller. The search continues and stay tuned for the next update...
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