Home | Register | Login | Contact Us

 
Auto Math
Classifieds
Forum
Gallery
Games
Garage
Tech Articles
Utilites
 
FAQFAQ    SearchSearch    RegisterRegister    Log inLog in    Log in to check your private messagesLog in to check your private messages    Forum Subscriptions1/4 Mile Table 

air leaking past rings

 
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Chevy - Small Block Gen 2 LT1
View previous topic :: View next topic  
Author Message
10sec.et
Member


Joined: 29 Mar 2006
Posts: 3455
Location: Houston,Texas
346018.46 points


1969 Oldsmobile Cutlass

PostPosted: Sat Jan 02, 2016 4:31 pm    Post subject: air leaking past rings Reply with quote

is it normal to have a lot of air leak past the rings on a new engine that's never been fired?
here's what is going on....
i had to pull a valve spring off and one of the locks broke (some cheap crap that came on the assembled heads). i bought a new set of locks and replaced them. when i put air in the cylinders, 5 of them leak a LOT of air past the rings. i filed the rings myself so i know the gap is right. should i be concerned about this since the engine has never been fired? a couple of the sealing cylinders started out leaking then sealed up. will the rest do that once it runs?

_________________
af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

Back to top
View user's profile Send private message
Big Dave
Moderator


Joined: 04 Dec 2005
Posts: 2638
Location: Tampa Florida
119662.86 points



PostPosted: Sat Jan 02, 2016 9:18 pm    Post subject: Reply with quote

In a cold engine I would expect a loose fit especially with low tension rings. Are you sure the rings are leaking and not the valves?

If using a forged piston without gas ports with a ball de-glazer hone job I wouldn't worry over much until after it is broken in.

If you have a finished honed block honed with head plate torqued in place and the hone was set to piston size and you have gas ported pistons; then yes I would be concerned about a broken ring.

Big Dave
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Mon Jan 04, 2016 1:20 am    Post subject: Reply with quote

Whats alot of air,how you measuring this? By sound?
Big .032 + gaps?

_________________
Back to top
View user's profile Send private message
Paul P
Member


Joined: 15 Aug 2002
Posts: 2379
Location: Townsend, Mass.
80707.22 points


1971 Chevrolet Chevelle

PostPosted: Mon Jan 04, 2016 12:22 pm    Post subject: Reply with quote

No. The motor has not been fired and the rings are not where near seated. If you do a leak test it should be while it is hot so that the end gap has closed up a bit from the normal heat of running the engine. Run it then give it a check.
_________________
2001 Focus 2.0 Zetec
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N.A.
6.95@98.6 MPH 1/8mi
10.97@121 MPH 1/4mi
Back to top
View user's profile Send private message
10sec.et
Member


Joined: 29 Mar 2006
Posts: 3455
Location: Houston,Texas
346018.46 points


1969 Oldsmobile Cutlass

PostPosted: Mon Jan 04, 2016 3:09 pm    Post subject: Reply with quote

this is the first time ive put air in the cylinder of a new engine. it doesnt even have the oil pan on it. i was shocked at how much air was escaping. i had to move really fast changing out those locks because my little "pancake" compressor couldnt keep up.

it does have forged pistons with small skirts. the engine is on the stand and every time i put air to the cylinder, it would rotate to the bottom.

thanks guys.

_________________
af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5557
Location: grassvalley, ca
71189.50 points


1933 Willys Coupe

PostPosted: Tue Jan 05, 2016 8:47 pm    Post subject: Reply with quote

As paul said it needs to be done warm... Then you have to move back then forth to get a good read.
I see 40% on the blown Willys then go back and forth and get 5% almost evey time.

Run the thing down the 1/4 first before you check.
Back to top
View user's profile Send private message
Knarley Darley
Member


Joined: 22 Apr 2004
Posts: 1241

540038.90 points



PostPosted: Mon Mar 07, 2016 1:54 am    Post subject: Reply with quote

Rotate the engine back and forth a bit while the air is going and it will sometimes shift the rings a bit and seal up better.
Back to top
View user's profile Send private message
Big Dave
Moderator


Joined: 04 Dec 2005
Posts: 2638
Location: Tampa Florida
119662.86 points



PostPosted: Tue Mar 08, 2016 9:11 pm    Post subject: Reply with quote

Knarley Darley wrote:
Rotate the engine back and forth a bit while the air is going and it will sometimes shift the rings a bit and seal up better.


Just be sure the piston is at BDC not TDC when you fill it and attempt to rock the piston. 90 psi on the top of the piston will rip your arm off if you are at TDC and the motor decides it wants to push the piston down while you have a hold of a wrench attached to the crank.

Big Dave
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Chevy - Small Block Gen 2 LT1 All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
Home | Contact Us | Automath | Cam Files | Dyno Search | Forum | Garage | Picture Gallery | Reaction Timer

Copyright 1997-2016 SMOKEmUP.com All rights reserved.
Advertising Info     Disclaimer     Privacy Policy