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KSever

Rebuilding a motor ?'s

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KSever
I'm going to ask some dumb questions. But I guess there is never a dumb question. I've never completely rebuilt an engine before as in having it bored out and the crank reground. Are there steps as to what to do first (A,B,C, etc,etc). Such as should you take the block down to the machinist and say here it is could you bore it out then buy a new piston or do you take the new piston and old block down and say can you bore this out to fit this piston. Then what about the crank? Buy a new rod and have it matched to the crank? In fact, what kind of machinist do I look for to have this kind of work done? The most I've done is hone the cylinder for new rings and resurface for new valves. Just a few questions but it might help other people as well.

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MPH
If your machine shop is close to home, one who does auto engine rebuilds may do it, you could have it checked first to see what size you need to bore it too. In the case of these old briggs, I think its a good plan to make sure you can the new sizes before you have it bored. If you can't find an auto shop to do the work, maybe a friendly local small engine shop can direct you. Ones up here are glad to direct me somewhere cuz they really don't want to deal with my old junk. Many can't belive I know where to find parts for 63 tractors...Thanks too all here...MPH

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ReedS
The first step in an engine rebuild is cleaning. Remove all parts that can be removed clean bock,check for cracks etc. Next measure cylinder bore. How do you know if it needs to be bored (unless it is scored)without measuring? The con rod should be matched to the crank;crank should be polished or ground then measured rod should measured and sized appropriatly for proper clearance on crank. Of course my expirence comes from automotive repair and is not nessceraly entirely correct for small engines however methods are similar. I myself have not yet found a shop around here that does this type of machining on small engines. Usually most auto machine shop should be able to do this kind of work. I've got a 19d that needs resurection but haven't tackled it just yet although I can see that part of the list on the horizon. Just my 2c.

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mowerman1193
I would'nt buy any parts until the machine work is done.Even if they say it will clean up at .010 they can have a problem and possibly have to go to .020.I was rebuilding a motor for a car once and they told me it would clean up at .030 then I got a call saying they ran into a air bubble in the casting and had to bore another .030.I learned then to wait until all machining is final before ordering parts. My .02 worth

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HubbardRA
I had one bored last summer. I took it to a very good small engine shop. They were set up with a guy to do the boring for them. They did the boring and then matched a piston to the final bore. They only had to take out .020 to remove the scoring. They were also set up with another place to turn the crank if needed. This shop didn't mind working on the old engines. It was a Kohler and the parts weren't cheap.

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MDB
I've had good luck with a local machine shop that has worked on briggs engines for years, they are a autherized briggs and stratton service center. They do all of the machine work, supply the parts and reasemble the engine. This comes with a one year garanty. My $.02 worth :)

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charby5
Hi Kris. Every time Ive rebuilt a engine Ive always took the (bare) block with valves,crank and head.I never buy the parts before the machine work is finished.when disassembling you engine be sure to mark you gears (cam to crank and internal balance gears if its a kohler and has them) for reassembly. Also when taking out your cam shaft, there might be shims on either end of it to set the end play ..putting the shims back in differently than the way you took them out can effect you valve timing. And I mark the lifter also.(so I get them right back in the same holes)To mark with I use a paint marker i get at the local auto parts store. Hope this helps... Marc... Oh I almost forgot,I always have new valve guides put in too weather they need them or not ..I figure we've done this much (why not?)

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PatRarick
If you can't find the undersize rod that is needed, or if your crankshaft is worn too bad to turn, welding the journal up and having it turned down is an option. Many will not agree with this method. I didn't either, until I was forced by necessity. I have now had this done on four different engines from Briggs to an Oldsmobile 455 V-8 (one rod journal). I have had excellent results. If one chooses to do so, I would recommend a welder who knows their stuff, so they don't alter the properties of the metal. Pat

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powerking_one
I just got a quote from a reputable machine shop that specializes in crank journal welding & grinding. It was for a now obsolete Tecumseh OH-180 crank someone had really screwed up the undersize grind dimensions. They quoted about $100 to weld/grind it back to original STD size. This is definately an option for not having U.S. rods available. Tom(PK)

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mr.jeffro
KSever, I guess I'll throw my two cents in too. I just rebiult ny 16hp briggs. Took the block/crank assem to my local NAPA machine shop. The machinist measured the bore and figured that it would take a .030 over sized piston. As far as the crank... It had to be ground .020 undersized. He ws able to do everything there and get this.. I was able to buy the piston/ring set for $40.00. The new rod was $20.00. I even bought the gasket set through NAPA instead of a briggs dealer. The entire bill which included boring out the block, grinding the crank and a valve job, piston and rod was $275.00! That's an inexpensive rebiuld. Engine runs extremely strong. Have everything done at one time. Hope this helps. P.S. Get yourself a good engine manual.

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arnoldir
Another thought on having cranks built up rather than cut undersize. Place called Swain Tech Coatings www.swaintech.com does flame spray hard coatings and ceramics. They supposedly can build up a shaft with materials that are much more wear resistant than just welding, and should not affect the strength of the crank. I've been considering sending some snowmobile parts in for the thermal barrier coat and moly coat on the skirts. it supposedly makes them very resistant to typical 2 stroke seizures.

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