SX/SXi/SXi Pro compression numbers/break in

[astandupguy]

got about half a tank through my new motor, mostly stock. I just i did a comp check and got 110 psi, how much will this increase when the rings seat? 30-40 psi im assuming

 

[LeftysRule22]

30-40 psi sounds like a large jump. When i rebuilt my 701, the compression changed less than 5% through break in. Maybe a more experienced builder can chime in, but something sounds amiss to me.

 

[Matt_E]

I've never seen more than 10

 

[Nuklear6]

If the compression is even at 110. i would def try another gauge. you def shouldnt need the rings to seat to get more then 110 on a fresh engine even with stock head and parts.

If its 110 on one cylinder and something different on the other, YOU HAVE A PROBLEM ......

 

[astandupguy]

both are 110 psi,Cylinders prof. bored by my local machine shop, matched to my pistons, but when i checked ring end gap, it was around .0018 , its supposed to be around .0010 i believe. i have heard that you dont need to set end gap on wiseco top ends, because they do it from the factory. also, motor was cold, i may start her up for a bit then check again.

 

[Matt_E]

i have heard that you dont need to set end gap on wiseco top ends, because they do it from the factory.

I don't know about that. Those pistons need a specific bore to cylinder clearance. From the sounds of it, that clearance is way too big.
I've had this happen in the past when some d-bag sold me a complete topend with pistons that were damn near two sizes too small.
You need to check what the piston clearance is. Anything over 7 thousandths is too big.
Maybe ask the Machine Shop what they did.

 

[astandupguy]

machine shop says, they used the 4 and a half thousandths gap on the wiseco box, and i believe them, so either they overbored or my rings arent siZed correctly. only way to know is to rip her apart and measure. so do i ride it one more time? or just rip her apart, either way im waiting on a gasket kit

 

[Jordanhiggins2002]

what is stock compress suppose to be. and yes that sounds like you have too much space. I would run her, its not hurting anything and you can tear it apart when you get hm

 

[astandupguy]

where do you ride at jordan? i ride el capitan

 

[engineman44]

same headache here

 

[easyrhino]

check squish to see if pistons are ok. If it's more than .100" maybe rist pin to crown is wrong.

 

[Aquaholic]

where do you ride at jordan? i ride el capitan

..............

 

[astandupguy]

sure take a picture after i fall...