robert.b.west Posted June 20, 2008 Report Share Posted June 20, 2008 I just had my pistons ported and bored and my question is the place that I had them done said that they bored the cylinders to the individual pistons. I thought a .020 over piston was a .020 piston. The only reason I ask is because they were going to charge me $250 for wiseco pistons and gaskets and rocky mountain has the same thing for $180 shipped to me. I already ordered the pistons from RM and I don't want to buy another set. Let me know what you think. Quote Link to comment Share on other sites More sharing options...
wesw Posted June 20, 2008 Report Share Posted June 20, 2008 you dont want one cylinder bored at a different spec than the other. if so get them bored the same size. then get the pistons you want. Quote Link to comment Share on other sites More sharing options...
robert.b.west Posted June 20, 2008 Author Report Share Posted June 20, 2008 you dont want one cylinder bored at a different spec than the other. if so get them bored the same size. then get the pistons you want. They are both bored to .020 over. They just said that they match the cylinder to the piston. BS? Quote Link to comment Share on other sites More sharing options...
robert.b.west Posted June 20, 2008 Author Report Share Posted June 20, 2008 Sorry one other thing, what is the break in process? I had a blaster a long time ago and I do not remember what had to be done. Quote Link to comment Share on other sites More sharing options...
sheerider1026 Posted June 21, 2008 Report Share Posted June 21, 2008 i have always heard that a lot of guys bore the cylinders to each piston, but i recenrtly had passion racing bore my cylinders and he said it did not matter which piston went where.. so its going to be your decision.. i would say that when they bore each piston to each cylinder that the clearances are a little tighter . which is a good thing if you take the time to break it in right.. i had a topend done the same way, broke it in right nad it ran for over 6 years.. thats no bull.. its up to you though.. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted June 21, 2008 Report Share Posted June 21, 2008 Both pistons will measure out the same give or take .0005", but your bore needs to be matched to the brand of pistons being installed. One manufacturer to another will have different tollerances. Wiseco recommends .003" of clearance on the piston skirt to bore (that's about the thickness of a hair) If they just bore the cylinders out .020" your bore will likely be sloppy so they need the pistons to match that. Agreed, if you run them tighter (.002") then they need to be individually matched and broken in more carefully. I would just have them wait to do the bore till you get the pistons, then take the pistons in to them. I've never had a machine shop say a word about me not buying my parts through them. Quote Link to comment Share on other sites More sharing options...
robert.b.west Posted June 21, 2008 Author Report Share Posted June 21, 2008 They are already bored and the pistons will be here monday. I can take them in to work and have them measured, so I should shoot for between .002 and .003 clearance on the skirt? Quote Link to comment Share on other sites More sharing options...
sheerider1026 Posted June 21, 2008 Report Share Posted June 21, 2008 we have a shop here that does the same thing.. if you buy the pistons somewhere else he will not bore your cylinders.. you have to buy them from him, he charges waaaay too much for the pistons.. he is pretty much a crooked kinda guy.. it really su ks that people are like that.. it pretty much puts you in a bind.. so i just find a good builder that will treat me right and ship them out to them.. even if (after shipping) it cost the same as getting it done locally, i feel better about not letting someone take advantage of me even if i do not save money.. just my .02 Quote Link to comment Share on other sites More sharing options...
deckheight Posted June 21, 2008 Report Share Posted June 21, 2008 The machinist needs both pistons to bore the cylinders and fit them properly. Wiseco's, since they are "machined finished", are usually within .0005" between the pair and quite often dead nuts between the pair, in which case it wouldn't matter which slug went in which hole... But every once in a while, especially with cast pistons and sometimes even with Wiseco's, there will be .001" or more, then things get a little more critical. If the engine is stock compression, follow the piston manufacturers recomendations for clearance. If higher compression, consider opening it up a little accordingly due to greater piston expansion from higher combustion chamber temps. Ask your machinist to visually inspect both pistons, especially around the ring lands and check both for taper. No comment on the rotten pricks who won't bore cylinders unless the parts are purchased from them... Quote Link to comment Share on other sites More sharing options...
bansheejoel Posted June 22, 2008 Report Share Posted June 22, 2008 Both pistons will measure out the same give or take .0005", but your bore needs to be matched to the brand of pistons being installed. One manufacturer to another will have different tollerances. Wiseco recommends .003" of clearance on the piston skirt to bore (that's about the thickness of a hair) If they just bore the cylinders out .020" your bore will likely be sloppy so they need the pistons to match that. Agreed, if you run them tighter (.002") then they need to be individually matched and broken in more carefully. I would just have them wait to do the bore till you get the pistons, then take the pistons in to them. I've never had a machine shop say a word about me not buying my parts through them. ^^^word Quote Link to comment Share on other sites More sharing options...
tgbanshee Posted June 22, 2008 Report Share Posted June 22, 2008 Sorry but I feel the need to chime in here... I also ABSOLUTELY HATE shops that won't do work unless the parts are purchased through them, and if I ever get that I never go back. I've had that experience more so with a 91 Mustang GT that I own. You ever get the bullshit line, "It's like going to restaurant and bringing your own steak." Sometimes I feel like saying, "If I can buy a prime cut of beef cheap and have a professional cook make the thing perfect then what the hell is wrong with that?" I know the reason they say it is because they make money off parts but regardless it's poor business practice. Luckily I found a machine shop near me, USA Cycle Inc, that works mainly on Harley motors but has an awesome machinist who was very knowledgeable and fairly priced, along with being a damn nice guy to boot. He machined my cylinders to the specs that Wiseco laid out for the .020" over pistons I gave him, wrote down the clearances for reference for me, and even went over a particular cleaning method I should do to ensure any remaining hone grit that might still be in them after I got em back was cleaned out. Turn around time was excellent too, dropped em off on a Wednesday evening, had them back Friday afternoon. I wish places like that were easier to come by. Sorry to hijack the thread but I had to vent and this seemed like the spot after what was said. Quote Link to comment Share on other sites More sharing options...
ThrowinRoost89 Posted June 22, 2008 Report Share Posted June 22, 2008 i had my lt500 cylinder resleeved by northwest sleeve, i didnt know it but i was supposed to send the new piston with it so they could match the bore to the piston. they do 4 thousandths clearance. on the zilla atleast. Quote Link to comment Share on other sites More sharing options...
robert.b.west Posted June 23, 2008 Author Report Share Posted June 23, 2008 Thanks guys I plan on just getting everything measured just to check it myself I just could not see paying $80 more for the same exact thing. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted June 23, 2008 Report Share Posted June 23, 2008 I always try to encourage my customers to price shop on parts, there are a lot of guy who sell parts cheaper than I can buy them. If one of my customers can get thier stuff cheaper elsewhere it's a good thing. I don't understand some of these shops who bitch if you want to provide your own piston ect. Quote Link to comment Share on other sites More sharing options...
'04limited Posted June 23, 2008 Report Share Posted June 23, 2008 well i dont mean to hijack the thread but how do you guys feel abouth the standard bore wiesco's? i had my cylinders dune ported by herr jugs and ordered a set of standard bore wiesco's. will they be ok to run? i realize that i need to take measurements but herr jugs said that the bore and taper in the cylinders was good. oh and he also threw a fresh hone on the cylinders for me. 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.