I have an old Briggs engine with a badly worn crank,the clearance on the rod journal is .020 instead of .002.I am going to attempt to wrap a piece of .008 aluminum around the rod journal on the crank,this will give about .004.This looks like it could work,this engine is going to be used as a display engine and not run that much.I was wondering if anyone has ever tried this and was it sucessful ?.
you could maybe make it work if and i do mean if you took say a racing rod bearing and machined the rod you have to hold that replaceable bearing in place , just shoving in some spacer is pulling like the pin on the grenade , the spacer if not secured will spin and then your oil hole will be blocked and well kaaaaa booooom . as for the rod re bore that 125cc and zook94 are talking about dont do that i read in a old briggs manual never mill the fit on the con rod . messing with the rod like that will cause problems the fit will not be wright and the hole not round . this book had listed all the ways to fix any thing on a block pto mag bearing ,cylinder sleeves, points plunger guides and valve guides. if the repair man wouldn't do it i wouldn't , do as minidragbike said and find a better one . parts maybe spendy but some one hurt is worse. what size motor is it some one may have a rod/crank for it .i dont mean to make any one mad just dont want a nice motor to be wrecked and some one hurt .:surrender:
wayne yes they did use leather also lead sheet, have talked with some of the old boys that did it back then . but the motors they did it to were slow like 2000 rpm was balls out full bore ,also heard of one guy that made a piston out of a oak fence post it ran for years my buddys dad seen it .
wayne yes they did use leather also lead sheet, have talked with some of the old boys that did it back then . but the motors they did it to were slow like 2000 rpm was balls out full bore ,also heard of one guy that made a piston out of a oak fence post it ran for years my buddys dad seen it .
Metalman,'' just out of curiosity but what will be the harm in resizing the rod, it's done on rods in all sorts of engines everyday, thats one of the steps in reconditioning a rod... It would have to be done with machinery and calipers, dial indicators or whatever means they use to check it all once it's done to insure the bore is to spec.....
When we were kids we had a minibike engines (3hp Tec) that had worn rods, Now this wasn't the best solution by no means so we'll leave it at that but we shaved the rod caps down ( on a sand stone) and put the engines back together and rode the daylights out of them... I know that made the bore more egg shaped but being kids with no money to buy new parts that was the only solution....
I personally would replace the parts but was just offering ideas for other avenues..
When we were kids we had a minibike engines (3hp Tec) that had worn rods, Now this wasn't the best solution by no means so we'll leave it at that but we shaved the rod caps down ( on a sand stone) and put the engines back together and rode the daylights out of them... I know that made the bore more egg shaped but being kids with no money to buy new parts that was the only solution....
I personally would replace the parts but was just offering ideas for other avenues..
125ccCrazy i am going off what i have read and was told by people who know more then me . the main thing i understood was that milling the parting line ,caused the half's of the rod to not fit tight causing clamping issues . then there is the egg shape like you said now you round it out you have removed a fair amount of material making it weak.if you dont fix the egg shape it will/can lead to flexing of the rod journal and leading to possible crack.
its like the guy who welds a flywheel he had never had a problem , now the next one kills him , sometimes it is just best to do it wright or not do anything and put it back on a shelf.i know they do it on car engines and such but there you also have a bearing be it a roller or a shell , so that is the wear surface but on a briggs or tec ,ect the rod is the bearing . you will mill away the rod to get a good bearing . think of it as a spun bearing in a car block it dont take much and its toast for its to much to bring things back in to line.
hope i didnt offend you
ill agree we all have done stupid stuff , sometime i have to wonder how im still here and all fingers and toes still on .
its like the guy who welds a flywheel he had never had a problem , now the next one kills him , sometimes it is just best to do it wright or not do anything and put it back on a shelf.i know they do it on car engines and such but there you also have a bearing be it a roller or a shell , so that is the wear surface but on a briggs or tec ,ect the rod is the bearing . you will mill away the rod to get a good bearing . think of it as a spun bearing in a car block it dont take much and its toast for its to much to bring things back in to line.
hope i didnt offend you
ill agree we all have done stupid stuff , sometime i have to wonder how im still here and all fingers and toes still on .
Agreed that reboring the rod will take away some meat and strength but since he stated it will be mostly a display engine that will only get fired up here and there, as a cheap fix if it's an engine that is hard to find parts for that reconditioning the rod would be one way of getting it back together, but like I said I'd personally try to find good parts and go from there.... Briggs have been around a long time so someone somewhere has parts, it's just a matter of looking...
you have a good point it would work but as we all know people forget things , i have trashed a few things forgetting that some thing was wrong with it .
your wright that is the beauty of Briggs and stratton , so many parts inter change its kinda easy to fix most stuff . i guess the question to ask is oldfatguy what it this motor you have ????? good chance someone on here has parts sitting around that would work .
your wright that is the beauty of Briggs and stratton , so many parts inter change its kinda easy to fix most stuff . i guess the question to ask is oldfatguy what it this motor you have ????? good chance someone on here has parts sitting around that would work .
thanks guys for your suggestions,this engine is an old Briggs 8b made from 1955 to 1958.it is badly worn out,the cylinder is shot too so it will be an oil burner. I did see a .020 rod available on parts tree for a later style engine 2 to 3 hp engine. pn. 296 079 .it might fit the older engine. My best bet is to find a used crankshaft because the bearing ends are badly worn too.A poster on the smokstak forum told me that the thin aluminum strip will probably bunch up and seize the engine.It isn't worth the cost to re bore it and fix it right .I should be able to find a crank shaft to fit it .Would anyone know what color that engine would have been originally ? it is an aqua green/blue now but I don't think it's the original paint.
8b hey, buddy, cool motor , i have a 6b made in 1955 . yours is a 1.73hp to 2.75 hp briggs manual specs . the crank in a push mower will fit and the rod will to ,make sure its a points type crank tho .only bad thing is the crank is not stepped down and its a longer shaft .
the side plate will fit off models 6B, 6BH, 8B, 8BH, 6000, 8000 series, 140000, 170400, 170700, 190400, 190700, 191700, 192700, 195400 series same gasket same part ,if you need to replace that .
most of the ones i have seen were a black or white i think that may have been the original colors.
the side plate will fit off models 6B, 6BH, 8B, 8BH, 6000, 8000 series, 140000, 170400, 170700, 190400, 190700, 191700, 192700, 195400 series same gasket same part ,if you need to replace that .
most of the ones i have seen were a black or white i think that may have been the original colors.
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metal man,is your 6b an aluminum block ? The 8b was was the first year that they changed from the 8 cast iron block to the 8b aluminum block in that size engine.did they do that with the 6 ? Years ago I had a cast iron 6 on a mini bike,it ran great but it was slow.Back then,I was a tecumseh guy and never liked briggs engines today none of my old tecumsehs seem to want to run right,but all the old briggs engines start and run beautifully and these are 40 to 50 year old engines
yes my 6b is a aluminum block from what i found the cam has the year of manufacture cast on it. 1955 was the first year of the aluminum block .i cant remember where i read it . i have a few of the old briggs , it seems like you can really beat the snot out of them .best thing tho they made the same block for something like 50 years . there is only like 11 blocks that they cast for years . minor changes between them . i had 2 blocks 15 years apart in age and they both had the same everything . including a mark on the casting from the mold .
The Olllllld ass motors some had leather rod bearings in like Model A's and stuff.. They actually would have lead poured into the rod as a bearing when it was new. But they DID get replaced when the lead was gone by guys in the know.. I guess if you are just building an antique motor to put put idle on display you could fix it. I don't think I would try using a thin layer of aluminum though. Normally stuff like that wears on top and bottom more than sides, or something to that effect. I would hone it out to the next newer size then use like a brass or copper type semi mailable material and make rob bearings like a car motor or something would have.. You also will want to make sure it can oil correctly. If you have a rod knocker, not running them is always the best bet. Although I had a briggs 3 horse one time that I could shake the fly wheel up and down probably 3/16 of an inch, and I ran the piss out of that poor thing because I was curious JUST WHAT they WILL handle.... and from as far as I can tell to date, a briggs 3 horse will handle about anything.
OH also your color may very well be the original. Briggs to just go buy a motor from the shelf is usually black, white, gold, red... BUT they were put ONTO a crap load of different units and they were often painted mo match the unit is was driving. I've seen blue, aqua, orange, ... lots of goofy colors..
I saw that duplicolor makes a Pontiac blue engine paint that looks close to the original color.I'm going to try using a piece of leather or even lead under the rod cap so I can get it running.I will eventually find a crank for it at a reasonable price [50 to 80 bucks on e-bay is way too much].Thanks for all you help and advice guys,I will let you know how the home made bearing works out.