JE pistons and CR (bison?)
- Thread starter DCVING 6
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Using the thin gaskets RJC sells and milling the deck and running the piston .010 in the hole will net closer to 8.6:1 if i remember correctly. Milling the heads and deck more than needed to clean them is not advised. You should never remove material from those surfaces unless they are not flat. You will need to go with a different piston for more. If i was ordering id order a compression height that will let the piston be .010 in the hole and adjust the dish from there. Every 6cc you remove from the clearance volume will give you about .4 increase in CR. So if you were currently 8.5:1 and .010 in the hole with a 29cc dish order the same compression height and just a 22-23cc dish to get 9:1. You will have to do a couple mock ups to get your answers. You need to accurately measure your current compression height, depth, combustion chamber and piston dish and base you needs off of them.
Is the extra compression worth it? Looking into options on a build, but should be as follows:
stock crank, stock rods, new forged pistons, hyd roller 210/210ish, ported irons, turbo somewhere in a 60 or 61, E85 and/or alky. PTC 9.5" No track visits with the car, just something fun on the street.
stock crank, stock rods, new forged pistons, hyd roller 210/210ish, ported irons, turbo somewhere in a 60 or 61, E85 and/or alky. PTC 9.5" No track visits with the car, just something fun on the street.
If youre not looking to squeeze as much out of your parts as possible i wouldnt worry about it. 6265 candidate for sure.
Off the shelf cam probably not matter a ton too? I've been told DLS Dan has a 210 he uses that would match the combo good. I guess obviously I would tell him what the rest of the car consists of and he would give me what I need.
The heads arent worth milling. You dont gain crap from milling them. Milling the deck nets about .15 increase in CR for every .010 removed with the above example. Probably .020 off the heads to get the same. You would have to CC the heads to know for sure since the combustion chamber varies the further you go. Ordering the correct pistons is a couple hundred $ more and will eliminate all th material removal and fitment issues. Angle milling removes material exactly where you dont want to remove itDo you know what each .010 off the head or deck averages for a bump in compression Brian?
And now for the dumb question.Has anyone ever angle milled the heads for an increase in compression?
jasjamz
THS Racer
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- Sep 30, 2004
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Look into the Wiseco pistons... smaller dish, may put you right at 9.0:1.
Just about any grind with around the same duration @.050 and 110-112* LS, .310 lobe lift will net similar results. There are some faster ramps available that require a lot more spring and will make more power if you want to milk it but its not worth the added expense for most. Its cheaper to order pistons and have a higher CR than spend a lot of time and $ trying to set up your valvetrain for a little more hp.
