Wossner piston question
#1
I'm assembling my spare engine bottom end.
Installed are :
Wossner 84.5mm 12:1
Scat rods
I've never dealt with these pistons before and they breach the deck.
The pistons breach the block deck by 0.013, my head gasket is 0.040 thick leaving 0.027 clearance.
Can any one give me info on whether or not this will cause P2V interference when using a factory head?
I've got a few solutions that would reduce compression but I was hoping some one might've been through this.
Thank you
Installed are :
Wossner 84.5mm 12:1
Scat rods
I've never dealt with these pistons before and they breach the deck.
The pistons breach the block deck by 0.013, my head gasket is 0.040 thick leaving 0.027 clearance.
Can any one give me info on whether or not this will cause P2V interference when using a factory head?
I've got a few solutions that would reduce compression but I was hoping some one might've been through this.
Thank you
#2
Which head?
I'm pretty sure there will be interference on any BP head, but most so on a vvt.
Interesting choice in pistons and comp ratio. Will this use pump gas or e85? Turbo or n/a?
I've just built a EJ255 subaru engine using these and overall they are not bad, though a bit more noisy than we hoped for (despite opting for 4032 alloy for this reason)
I'm pretty sure there will be interference on any BP head, but most so on a vvt.
Interesting choice in pistons and comp ratio. Will this use pump gas or e85? Turbo or n/a?
I've just built a EJ255 subaru engine using these and overall they are not bad, though a bit more noisy than we hoped for (despite opting for 4032 alloy for this reason)
#3
Which head?
I'm pretty sure there will be interference on any BP head, but most so on a vvt.
Interesting choice in pistons and comp ratio. Will this use pump gas or e85? Turbo or n/a?
I've just built a EJ255 subaru engine using these and overall they are not bad, though a bit more noisy than we hoped for (despite opting for 4032 alloy for this reason)
I'm pretty sure there will be interference on any BP head, but most so on a vvt.
Interesting choice in pistons and comp ratio. Will this use pump gas or e85? Turbo or n/a?
I've just built a EJ255 subaru engine using these and overall they are not bad, though a bit more noisy than we hoped for (despite opting for 4032 alloy for this reason)
The head is a 96 bp and it is N\A. I'll be using 100 sunoco.
The head has
Fidanza adj gears
super tech valve train
Web camshafts .352 lift, 225° duration, 205° @ .050.
I need to be able to move my power to mid range using cam gears
Should I get a cometic .051 head gasket to make up for the piston height?
I also have a stock head as an option
#5
Outside of that method my only other option, I believe, is to remove lifter and keeper on one intake and one exhaust valve and manually measure clearance with a dial indicator.
#8
I also wonder if they are truly 12:1, since they list stock CR as 11:1 IIRC.
A dome volume of 7cc would not give 12:1 without decking some (or no valve reliefs).
With spending time and effort, custom pistons are probably the best way to get high CRs, not that expensive either.
#13
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I'll give you a hint: '99s with I/H/E don't produce 136wtq during the break-in period. OP is on the right track for a very competitive PT car.
Last edited by Savington; 08-04-2014 at 07:49 PM.
#14
My AFR is going to be around 11.5 to 12 which will kill a little HP but make motor last longer. My old build with 11 to 1 wiseco pistons at 13.8 afr produced 158hp 132tq, but reclass made my weight 2585lbs. And that weight, sir, is unacceptable. So i dropped weight and hp.
my main reason for this choice in engine components is to gain as much TQ as possible. Naturally aspirated reclass doesn't regulate TQ only HP.
my main reason for this choice in engine components is to gain as much TQ as possible. Naturally aspirated reclass doesn't regulate TQ only HP.
#16
Since I'm more likely see to pigs fly than find a Jackson supercharger, I made a choice. Go full N/A, detune and have a gnarly engine with a long life ahead of it... Assuming of course the tuner doesn't lean out the Afr and melt down the forged aluminum pistons. It took 4 seasons but that's how it happened.
#17
We run our NA grand-am motors at 13.5:1 on stock cast pistons and have never melted a piston. Are you sure it was fueling that was your issue? Obviously I'm comparing apples to oranges a bit but 11.5 afr on an N/A motor seems overly rich. I'm no expert in PTE motors though.
I do remember a certain yellow Miata running in PTD(?) with a low boost supercharger and doing pretty well.
Aren't you worried about EGT's tuning a 160hp back to 135?
I do remember a certain yellow Miata running in PTD(?) with a low boost supercharger and doing pretty well.
Aren't you worried about EGT's tuning a 160hp back to 135?
Last edited by Efini~FC3S; 08-04-2014 at 11:03 PM. Reason: Punctuation son
#19
If I run anything higher than 13afr my coolant temps avg 210°. 11 to 13 afr it's at a nice 170° on a hot day. I like to leave at least 20° for a few laps with dirty air.
Egt do get out of control. I've broken 2 headers at the collector since this engine went in. But that's 2 in 4 seasons. I don't fret it because exhaust valves are unharmed.
PTE cars/motors in my opinion are fickle bitches. The point indexing path or reclass path allow so many different ways of producing a competitive car without having to spend 50k. Not to say I wouldn't if I could.
In my eyes, PTE cars are not the slowest nor the fastest.. They're just right for having fun while still getting the thrill
Egt do get out of control. I've broken 2 headers at the collector since this engine went in. But that's 2 in 4 seasons. I don't fret it because exhaust valves are unharmed.
PTE cars/motors in my opinion are fickle bitches. The point indexing path or reclass path allow so many different ways of producing a competitive car without having to spend 50k. Not to say I wouldn't if I could.
In my eyes, PTE cars are not the slowest nor the fastest.. They're just right for having fun while still getting the thrill