thehillsiderider Posted November 8, 2008 Report Share Posted November 8, 2008 whats up boys. Jus got the engine bored and ordered some wiesco 65.5mm pistons to match the cylinders ,and the shop told me that the pistons wern't the same size that one was bigger than the other. They said not by much but they were definately not even sizes. My questions is even though it is such a small amount can this throw off any balancing or any other issues? Quote Link to comment Share on other sites More sharing options...
THE GRIM RIPPER Posted November 8, 2008 Report Share Posted November 8, 2008 Why the fuck did they machine one cylinder bigger than the other? Tell these douches to machine them to the same size, and return the pistons for your new bore matched ones Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted November 8, 2008 Report Share Posted November 8, 2008 You need to mic those pistons. If you don't have a micrometer, use the machine shops. I'm sure they have a digital one, so it's easy to read. I think your machine shop fucked up. They're probably gonna owe you some jugs. Quote Link to comment Share on other sites More sharing options...
1996dragshee Posted November 8, 2008 Report Share Posted November 8, 2008 i think hes talking about the shop said that the pistons he ordered are different sizes correct? Quote Link to comment Share on other sites More sharing options...
chevrolet banshee Posted November 8, 2008 Report Share Posted November 8, 2008 i think hes talking about the shop said that the pistons he ordered are different sizes correct? souds like he said that the cyis. wear bored too different sizes. i just want to know how hat happens? some one in that shop that did your cylinders is retarded. Chevshee Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted November 8, 2008 Report Share Posted November 8, 2008 i think hes talking about the shop said that the pistons he ordered are different sizes correct? What I was sayin, it sounds to me like the machine shop is tryin to cover up they're fuckup. That's why I said to mic the pistons. To show the shop that they ain't different sizes. What size were the old pistons/bore? Was there a lip on the top of either cylinder wall? Quote Link to comment Share on other sites More sharing options...
chevrolet banshee Posted November 8, 2008 Report Share Posted November 8, 2008 What I was sayin, it sounds to me like the machine shop is tryin to cover up they're fuckup. That's why I said to mic the pistons. To show the shop that they ain't different sizes. What size were the old pistons/bore? Was there a lip on the top of either cylinder wall? Ok ya that makes sense. ya thats what i wood do, that wood fuck them if they wear the same and the bore was different. Chevshee Quote Link to comment Share on other sites More sharing options...
ripper660 Posted November 8, 2008 Report Share Posted November 8, 2008 ordered some wiesco 65.5mm pistons to match the cylinders ,and the shop told me that the pistons wern't the same size that one was bigger than the other he said pistons... so send the odd ball back and have them get the right one. sounds like it may have been mis packaged from the factory. accidents happen. why would you even think about tryin to run it? Quote Link to comment Share on other sites More sharing options...
Onesickcrewcab Posted November 8, 2008 Report Share Posted November 8, 2008 The piston specs should be on the outside of the box. Like said before you need to mic those pistons. Did you buy the pistons and take them to the shop, or did they buy the pistons? Pistons should always be taken to the machine shop before boring is performed so they can match them to the cylinders. Quote Link to comment Share on other sites More sharing options...
alcoholbanshee Posted November 8, 2008 Report Share Posted November 8, 2008 As said each piston should be matched to its own bore. It is very common to have one side be a few thou larger or smaller than the other. Any shop that bores without having the pistons to measure (before boring) is not worth going to. Assuming the one piston is only a few thousandths larger, I would run it. But you must be sure which piston goes in which bore. It will cause no ill effects whatsoever on your engine. Quote Link to comment Share on other sites More sharing options...
thehillsiderider Posted November 8, 2008 Author Report Share Posted November 8, 2008 As said each piston should be matched to its own bore. It is very common to have one side be a few thou larger or smaller than the other. Any shop that bores without having the pistons to measure (before boring) is not worth going to. Assuming the one piston is only a few thousandths larger, I would run it. But you must be sure which piston goes in which bore. It will cause no ill effects whatsoever on your engine. Thats the answer i wanted to hear yeah i bought the pistons from a supplier and they came a few thousandths out but the bores were matched. He marked for me which piston went to the right jug, but i was jus wondering if that gonna be an issue. thanks Quote Link to comment Share on other sites More sharing options...
Mjv420 Posted November 8, 2008 Report Share Posted November 8, 2008 Pistons should always be taken to the machine shop before boring is performed so they can match them to the cylinders. Thats exactly what I was going to say, and any machine shop that has any sense would've told you that before boring. Quote Link to comment Share on other sites More sharing options...
RollinRhino Posted November 8, 2008 Report Share Posted November 8, 2008 I have built hot rod motors, MX motors, Snowmobile motors, and all things un-godly. The procedure for boring and honing is this: You Determine if the bore is out of round and cone shaped from wear and by how much. Typically you have to bore it out. Now usually not by more than one over-size. You first order the pistons you want. Wiseco Pro Lites are what I always shoot for and if not them then Pro X pistons will do on a two stroker. Now you find a reputable shop that specializes in racing engines. Usually they have the equipment to get this right. They will order the correct piston(s) and use them as a prop to determine if they have the bore correct. No two pistons are perfectly alike no matter what the brochure or website tells you. They vary by thousands of an inch and its barely noticeable. Once the correct size is determined they bore to match the exact piston size so that you get a perfect seal with the ring. The ring is built to take the wear, but it only works in conjunction with the correct piston. After the bore is done you should get what is called a "cross-hatch" hone job. If you want to spend some real money get a Carbide Bore job done like what this guy does: Bore-Tech's Carbide Bore process This ensures a perfect seal and you are done. It is inexcusable for any shop to have done this without first having the pistons to match the bore job. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.