bmx9854 Posted May 13, 2008 Report Share Posted May 13, 2008 Has anyone tried to bore an 850 turbo block and throw in a set of 83mm N/A pistons? Link to comment Share on other sites More sharing options...
Dmsee Posted May 13, 2008 Report Share Posted May 13, 2008 And why would you want to do that? Link to comment Share on other sites More sharing options...
bmx9854 Posted May 13, 2008 Author Report Share Posted May 13, 2008 And why would you want to do that?Plan on bringing the motor to the machine shop and I betting that 175000 miles have changed the shape of the cylinder liners a bit. So, I'll probably have to go oversized and I might go to the J-yard to get some pistons. Link to comment Share on other sites More sharing options...
lookforjoe Posted May 14, 2008 Report Share Posted May 14, 2008 Plan on bringing the motor to the machine shop and I betting that 175000 miles have changed the shape of the cylinder liners a bit. So, I'll probably have to go oversized and I might go to the J-yard to get some pistons.Pistons should be ok unless the motor has been ridden hard & put away wet.... My T5 motor has 190K, and the oistons are just fine. Link to comment Share on other sites More sharing options...
prasamin Posted May 14, 2008 Report Share Posted May 14, 2008 83mm is a little overkill.you're better off getting stock Mahle pistons for your turbo in OS1....no need to oversize almost 2mm on the bore.I think your pistons should be fine....you can get the block cleaned up, the specs checked, and put it back together....I think you're better of spending money on a set of forged rods and a doing a good valve job, etc on the head.....throw that stuff in, and you can easily do 350-400hp and not worry about throwing a rod. Link to comment Share on other sites More sharing options...
Kibim Posted May 14, 2008 Report Share Posted May 14, 2008 My car's done 260k, going to every track day possible and putting a BMW in it's place at every oppertunity. When I opened it up, I was expecting a lip and some cylinder wall wear. But once the carbon deposits were cleaned off, it looks like the engine has been test stated, and thats it. I can honestly say it doesn't look like it's seen the road. I was shocked, to the extent i asked my mechanic what he had done with my engine! If you want to change rods, buy a set from R-sport International. $500 for a full set of forged H-beams. www.rsportinternational.com Link to comment Share on other sites More sharing options...
bmx9854 Posted May 14, 2008 Author Report Share Posted May 14, 2008 My only concern with the H beams is that with the thicker rod I feel like it may hit when the piston half way down and up on the bottom of the cylinder liner. I have seen one other person have this issue but I'm not sure if he got the longer rods instead of stock. Anyone know for sure? Link to comment Share on other sites More sharing options...
prasamin Posted May 14, 2008 Report Share Posted May 14, 2008 My only concern with the H beams is that with the thicker rod I feel like it may hit when the piston half way down and up on the bottom of the cylinder liner. I have seen one other person have this issue but I'm not sure if he got the longer rods instead of stock. Anyone know for sure?nope, not an issue as long as you get stock length rods, and make sure you big and small end bearing are good to go.....open up the engine, get everything cleaned up, install h-beams with new bearings if needed, get some headwork done, reinstall everything, and you can have a great engine that can push decent power....and that's with stock pistons.... Link to comment Share on other sites More sharing options...
JHEIII874T5M Posted May 14, 2008 Report Share Posted May 14, 2008 My only concern with the H beams is that with the thicker rod I feel like it may hit when the piston half way down and up on the bottom of the cylinder liner. I have seen one other person have this issue but I'm not sure if he got the longer rods instead of stock. Anyone know for sure?Very valid concern.Rsport used a different supplier for a batch of rods and that batch is "too wide". It requires machining the block for reliefs as you have mentioned. I bought a set from Rsport and they sent me the rods that were "too wide". I contacted them and notified them, then they quickly replaced the "too wide" rods wtih the proper width ones, free of charge. Link to comment Share on other sites More sharing options...
prasamin Posted May 14, 2008 Report Share Posted May 14, 2008 Very valid concern.Rsport used a different supplier for a batch of rods and that batch is "too wide". It requires machining the block for reliefs as you have mentioned. I bought a set from Rsport and they sent me the rods that were "too wide". I contacted them and notified them, then they quickly replaced the "too wide" rods wtih the proper width ones, free of charge.Hmmm, if you got a batch that was too wide, you'd be able to hear the rods hitting the cylinder walls right? Shit, I hope my rods were fine....although they seem to be okay in the car. Link to comment Share on other sites More sharing options...
BlackT5 Posted May 14, 2008 Report Share Posted May 14, 2008 Hmmm, if you got a batch that was too wide, you'd be able to hear the rods hitting the cylinder walls right? Shit, I hope my rods were fine....although they seem to be okay in the car.The machine shop would have checked all the clearances while assembling the motor. Link to comment Share on other sites More sharing options...
prasamin Posted May 14, 2008 Report Share Posted May 14, 2008 The machine shop would have checked all the clearances while assembling the motor.machine shop did all the cleaning and honing/boring and balancing, but assembly was done in a garage using a Haynes manual.would you be able to hear it? engine runs fine, except for the tune issue. Link to comment Share on other sites More sharing options...
JHEIII874T5M Posted May 14, 2008 Report Share Posted May 14, 2008 Hmmm, if you got a batch that was too wide, you'd be able to hear the rods hitting the cylinder walls right? Shit, I hope my rods were fine....although they seem to be okay in the car.Oh yeah, you would definitely hear it.Also it seems like the area by the wristpin bore had different design.Might want to check out the thread I made on the topic: http://volvospeed.com/vs_forum/index.php?showtopic=86886- Both rods next to each other with the too wide on the left and the correct width on the rightHere is a bit of a comparison in beam width to help describe:- Rods that are too wide:- Rods that are the correct width: Link to comment Share on other sites More sharing options...
prasamin Posted May 14, 2008 Report Share Posted May 14, 2008 Oh yeah, you would definitely hear it.Also it seems like the area by the wristpin bore had different design.Might want to check out the thread I made on the topic: http://volvospeed.com/vs_forum/index.php?showtopic=86886yeah, wristpin was checked on my rods....they were fine....I got some from the first batch that R-Sport sold....I don't think they were an issue, but I just wanted to be sure. Link to comment Share on other sites More sharing options...
BlackT5 Posted May 14, 2008 Report Share Posted May 14, 2008 i'd be more concerned with getting that bitch tuned. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.