Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > Porsche 911 Technical Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Dept store Quartermaster
 
lendaddy's Avatar
 
Join Date: Jul 2001
Location: I'm right here Tati
Posts: 19,858
Why two gauges on a leak down tester?

Why cant you set the pressure to 100 psi and hook her up? The reading you get is the inverse of the leakdown, no? What am I missing here?

__________________
Cornpoppin' Pony Soldier
Old 07-09-2003, 07:46 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered
 
skinnerd's Avatar
 
Join Date: Aug 2001
Location: Hayden, ID
Posts: 3,656
Garage
I believe your two gauges are for the following:
gauge 1 - to measure supply pressure
gauge 2 - to measure leakdown pressure

Leakdown is calculated as such:

leakdown% = 100% - [(measured/supplied)*100%]

5% = 100% - [(95/100)*100%]

I think this is how is goes, but others may know better.
__________________
"Are you out of your Vulcan mind?"

Doug
2022 Carrera 4S, 1989 Delta Integrale, 1973 911T CIS

Last edited by skinnerd; 07-09-2003 at 08:00 AM..
Old 07-09-2003, 07:55 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Dept store Quartermaster
 
lendaddy's Avatar
 
Join Date: Jul 2001
Location: I'm right here Tati
Posts: 19,858
Why not install a valve after the guage and simply close to check supply pressure and open to check leakdown?
__________________
Cornpoppin' Pony Soldier
Old 07-09-2003, 08:20 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered
 
skinnerd's Avatar
 
Join Date: Aug 2001
Location: Hayden, ID
Posts: 3,656
Garage
At first glance, you'd think that would work.
I believe the dual gauge leakdown setup has an orifice such that the supply air is restricted from entering the cylinder (i.e. the supply air is carefully metered into the cylinder). Without this, you'd have to have huge problems to see any leakdown. When the air flow into the cylinder is metered by the small orifice, it is more sensitive (i.e. sees easier) issues such as worn rings or valve seats.

So in a nutshell, you have the supply air that is directly measured with a gauge. The second gauge that measures the "leakdown" is isolated from the supply by a metering orifice. If the air leaks away from the cylinder faster than the metering orifice can keep it at the supply pressure, then you have leakdown to some extent.

Make any sense? This is my understanding of why you need the two gauges and how they work. Again, maybe someone out there knows better.
__________________
"Are you out of your Vulcan mind?"

Doug
2022 Carrera 4S, 1989 Delta Integrale, 1973 911T CIS
Old 07-09-2003, 08:35 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Platinum Member
 
dad911's Avatar
 
Join Date: Jul 2001
Location: Leave the gun. Take the cannoli.
Posts: 20,977
leak down test

__________________
The truth is that while those on the left - particularly the far left - claim to be tolerant and welcoming of diversity, in reality many are quite intolerant of anyone not embracing their radical views. - Charlie Kirk
Old 07-09-2003, 08:38 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Reply


 


All times are GMT -8. The time now is 11:24 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.