Jump to content
SAU Community

Leak Down Test

black sky

By black sky,
in Engines & Forced Induction

 Share

Recommended Posts

nfi Community Regular

nfi

Posted
Posted

Leak down test involves blowing a lot of air through the spark plug hole and measuring the pressure the cylinder can hold.

This is fiddly as you have to hook the compressor up to a cylinder and then turn the crank until both valves are closed to get a reading.

It is more accurate than a compression test gauge as oil can cover up worn rings where as this doesn't let anything hide.

If the rings are worn badly you will get air up through the dipstick and if the valve stems are worn then you will hear air out the intake or exhaust.

<20% leakdown is considered ok while you really want under 10%.

New engines generally have about 3%.

Link to comment
https://www.sau.com.au/forums/topic/154264-leak-down-test/#findComment-2869187
Share on other sites
black sky Rising Star

black sky

Posted
  • Author
Posted
Leak down test involves blowing a lot of air through the spark plug hole and measuring the pressure the cylinder can hold.

This is fiddly as you have to hook the compressor up to a cylinder and then turn the crank until both valves are closed to get a reading.

It is more accurate than a compression test gauge as oil can cover up worn rings where as this doesn't let anything hide.

If the rings are worn badly you will get air up through the dipstick and if the valve stems are worn then you will hear air out the intake or exhaust.

<20% leakdown is considered ok while you really want under 10%.

New engines generally have about 3%.

and how much does this process cost???

Link to comment
https://www.sau.com.au/forums/topic/154264-leak-down-test/#findComment-2869279
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • joshuaho96
      Tomei gasket

      By joshuaho96 · Posted

      I've heard the Tomei USA head gaskets are decent if you want to o-ring the heads but otherwise not recommended.
    • GTSBoy
      What brakes on R34 GTT(Europe)

      By GTSBoy · Posted

      The 296mm rotors are the R33 turbo brakes. The 310mm rotors are the R34 turbo brakes. The calipers are nearly the same, but not. They're the same caliper but the R34 caliper has longer legs so that it sits out far enough to go over the rotor. The pads are the same for both. When you say, "I bough tsome EBC"....did you just mean pads? Or rotors? 310mm rotors fit under 17" wheels. There may be some wheels without enough clearance though. I can't fit my fingers between the barrel of my wheel and the "corners" of my R34 calipers, but there is plenty of room behind the spokes. This is on Enkei RPF1. You can fit 324mm rotors inside a 17" wheel, but I'd be willing to bet that it would be close to impossible with the Nissan/Sumitomo caliper (using an adapter, of course), because the Sumitomo caliper is fatter than the Brembo caliper that is supposed to go on the 324mm rotors.
    • Kapr
      What brakes on R34 GTT(Europe)

      By Kapr · Posted

      Hi. Can someone tell me what brakes(and mainly WHERE) can i buy brakes on R34 GTT? I bought some EBC which SHOULD go on my car(i have GT but it has GTT brakes) but it does not fit, Brakes are "too" small(296mm) Are 310mm be good or? I have 17 inch wheel so no "big boys" but for me driving i just need one that fits and i can get here in EU/Czech.
    • Marek
      Hi everyone.

      By Marek · Posted

      Since winter isn't that harsh anymore in Poland, i will definetely drive it 365 days a year 😉. But if the snow hits i will try it for sure and let U know. Only swap i am planning to do is of course R34 GTR front 😍.
    • Marek
      WGNC34 - floor mats

      By Marek · Posted

      Hey. Very valuable information about pitwork, I will pay attention when buying any consumable parts 🙏 As for the carpets - I got a handful of information from nengun, from which it appears that indeed the carpets for the driver's side are OEM. They are not able to show me any pictures due to the long chain of different sales entities but after I place the order, as soon as the goods arrive at the nengun warehouse from which they will send the shipment to me they can send me photos and if my purchase differs from OEM I can immediately return it / cancel the purchase. I think I will give it a try 😉. Of course i'll let you know what's what as soon as i get them P.s. I know the topic is not relevant to the thread, but both nengun and amayama have these SICK 😍 trunk room lamps available. Do you know anyone who ordered them? I need to have one in my car
×
×
  • Create New...