Notices
General Tech Good at troubleshooting? Have a non-specific issue? Discuss general tech topics here. IF YOUR QUESTION IS SPECIFIC TO A CERTAIN MODEL, IT DOES NOT GO IN THIS SECTION.

new pistons breathing too much

Thread Tools
 
Search this Thread
 
Old September 17th, 2010, 1:26 AM
  #1  
CF Beginner
Thread Starter
 
fitzsi's Avatar
 
Join Date: Sep 2010
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Default new pistons breathing too much

Help Needed
Hope you guys can shed some light on this.
Installed new HP pistons /rings/new cam & a set of AFR aluminium heads.
Car runs ok have only done a couple of Km's but it breaths from the 2,4,5 & 8 bank only.The right side is fine.Does anyone have any info as to why this is doing this.
Have done compression test and all cylinders are 185 psi + or minus 3.
Looks like it';s breathing from both sides but the left side rocker cover has the baffle plate below the breather so it is probably taking the easiest route
Old September 18th, 2010, 1:03 AM
  #2  
CF Pro Member
 
2wd-K5's Avatar
 
Join Date: Jul 2010
Location: salmon arm BC
Posts: 845
Likes: 0
Received 1 Like on 1 Post
Default

how do you know it breaths from only 1 bank? it probly wouldnt run if only firing on 4 cyls
Old September 18th, 2010, 3:37 AM
  #3  
CF Beginner
Thread Starter
 
fitzsi's Avatar
 
Join Date: Sep 2010
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by 2wd-K5
how do you know it breaths from only 1 bank? it probably wouldnt run if only firing on 4 cyls
Not sure if you have the right problem.The engine has some pressure or oil leaking past the rings ( Blow by ).All cylinders have about 185 psi give or take 1 psi.
You can see it breathing through one side of the engine ( 2,4,6,8,)this is coming out of the oil cap come breather cap.There is another one ( cap )on the other side of the engine but there is nothing coming out of it.That is probably because there is a baffle located within the rocker cover below the cap.
Old September 18th, 2010, 11:01 AM
  #4  
CF Pro Member
 
2wd-K5's Avatar
 
Join Date: Jul 2010
Location: salmon arm BC
Posts: 845
Likes: 0
Received 1 Like on 1 Post
Default

do u have a pcv valve?
Old September 19th, 2010, 5:11 AM
  #5  
CF Beginner
Thread Starter
 
fitzsi's Avatar
 
Join Date: Sep 2010
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Default cylinder blow by after installing new pistons

Did have pcv valve but took it out to see what blow by I had as it was still coming out of the drivers side rocker cover cap come oil filler.
Have decided to rip the engine out again and check whats going on , neally out now
Old September 19th, 2010, 11:44 AM
  #6  
CF Pro Member
 
2wd-K5's Avatar
 
Join Date: Jul 2010
Location: salmon arm BC
Posts: 845
Likes: 0
Received 1 Like on 1 Post
Default

well, what was your vaccum at? if u have a huge cam, then there is no vacum at idle, and u may need a crankcase evacuation system, this system uses the headers to take the pressure off, but if u have a small cam, then there may be a bigger problem, did you clean all the crankcase venting passages?
Old September 20th, 2010, 7:32 AM
  #7  
CF Beginner
Thread Starter
 
fitzsi's Avatar
 
Join Date: Sep 2010
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by 2wd-K5
well, what was your vaccum at? if u have a huge cam, then there is no vacum at idle, and u may need a crankcase evacuation system, this system uses the headers to take the pressure off, but if u have a small cam, then there may be a bigger problem, did you clean all the crankcase venting passages?
The engine had only done about 300 kms since brand new and as everything was as clean as.Have just found out that when using moly rings the stones used for honing need to 280+ otherwise the rings won't bedd.
I unfortunately used stones that were 220 or lower.These are fine with cast rings but no good with moly rings.So the engines now ready for lifting back out

Last edited by MDTAHOE; September 20th, 2010 at 8:14 PM. Reason: Inappropriate words
Old October 1st, 2010, 3:16 PM
  #8  
CF Pro Member
 
2wd-K5's Avatar
 
Join Date: Jul 2010
Location: salmon arm BC
Posts: 845
Likes: 0
Received 1 Like on 1 Post
Default

ahh yes i see now, good luck
Old October 3rd, 2010, 1:29 AM
  #9  
CF Beginner
Thread Starter
 
fitzsi's Avatar
 
Join Date: Sep 2010
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Default chev breathing too much

It's ok I pulled the engine out again,stripped it and re-honed the bores to the correct grade stones.
Engine all back together now so cross your fingers and I'll install it back into the rod in the next fortnight
Old October 3rd, 2010, 2:15 AM
  #10  
CF Pro Member
 
2wd-K5's Avatar
 
Join Date: Jul 2010
Location: salmon arm BC
Posts: 845
Likes: 0
Received 1 Like on 1 Post
Default

good luck man hope this solves your problem
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
BrandanDeMamp
Silverado, Sierra & Fullsize Pick-ups
1
April 8th, 2014 7:22 PM
grndslm
Tahoe & Suburban
7
April 24th, 2013 11:21 AM
94burbin
Tahoe & Suburban
4
December 18th, 2011 12:29 PM
pamelacay
Tracker
0
August 21st, 2007 12:29 PM
EPJ
Tahoe & Suburban
9
November 13th, 2006 2:44 PM



Quick Reply: new pistons breathing too much



All times are GMT -5. The time now is 6:12 AM.