Jump to content
SAU Community

Compression Test

morto86

By morto86,
in General Maintenance

 Share

Recommended Posts

Missileman Veteran

Missileman

Posted
Posted (edited)

On a warmed engine with all sparkplugs removed, with accelerator fully depressed and a charge on the battery capable of cranking the motor at 300rpm.

RB20DE/T/26DETT

New = 170psi

Low Limit = 128psi

Max cylinder difference 14psi

...from engine workshop manual.

Edited by Missileman
Ben C34 Grand Master

Ben C34

Posted
Posted

I just got the reply 210. Cold. Does this mean the head has been shaved previously

No as the comp ratio doesnt effect the compression test. it just ensures the rings and valves are sealing as they should.
Ben C34 Grand Master

Ben C34

Posted
Posted

Def 200 all round with snap on gauge and warmed engine. With researsh this proves the comp ratio therefor is 10:1. As for the knob who said the comp is not relayed to the ratio. Actually write out the equation.

Settle down. explain to me how an engine when built has a certain compression test result, then when worn had a lesser compression test result? Did it's comp ratio drop? can you run more boost cos it has less comp ratio? NO. explain how comp ratio effects the comp test results please :)
KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Settle down. explain to me how an engine when built has a certain compression test result, then when worn had a lesser compression test result? Did it's comp ratio drop? can you run more boost cos it has less comp ratio? NO. explain how comp ratio effects the comp test results please :)

Well personally I would have though it was obvious that the higher the compression ratio the higher the expected compression test result . The value of the compression test for measuring wear depends on knowing the original compression so as above if the stock factory figure was 170 psi then yes 130 psi indicates a lot of wear which can be confirmed with a leakdown test. My engine had 130 psi compression when built because of the choice of pistons (CR about 8:1) and leakdown test is within limits at 5%

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
      Ethanol Content Sensor - Always at 11%?

      By joshuaho96 · Posted

      The incentives are mostly the same, yes. Ethanol is cheap compared to the cost of doing 98-100 RON with crude oil alone. 87 to 93-94 AKI all with E10. In 2020 Canada mandated E10 as a part of their "renewable fuel standard" and is supposedly going to go to E15 in 2030. In California where there are only 8 refineries with two threatening to shut down next year it's been over 20 years now of E10 and 91 AKI maximum because there's just not enough refinery capacity or crude oil supply relative to the demand for premium unleaded fuel. And CARB's low carbon fuel standard means functionally none of the diesel available at the pump is made from crude oil anymore. It's almost all entirely 20% biodiesel blended with 80% renewable diesel (hydrotreated vegetable oil) now. The number of gasoline vehicles that support E15 or higher ethanol concentrations is surprisingly low, I can't imagine it being wise to play tricks like this without flex fuel sensors in most of the fleet.
    • GTSBoy
      R34 Skyline climate control unit transistor

      By GTSBoy · Posted

      It's almost certainly the same as the one next to it. Have a fish around amongst these hits https://www.google.com/search?q=surface+mount+transistor+m33&sca_esv=9cb49794e0b2005d&source=hp&ei=2vJ5aNjTB7Kw0PEPldnS8QM&iflsig=AOw8s4IAAAAAaHoA6qkfmF6XcygtrZ4Vu9f92NXF_RFd&ved=0ahUKEwjYqIPP7MWOAxUyGDQIHZWsND4Q4dUDCA8&uact=5&oq=surface+mount+transistor+m33&gs_lp=Egdnd3Mtd2l6IhxzdXJmYWNlIG1vdW50IHRyYW5zaXN0b3IgbTMzMgUQIRigATIFECEYoAEyBRAhGKABMgUQIRigAUjKCFAAWABwAHgAkAEAmAHfAaAB3wGqAQMyLTG4AQPIAQD4AQL4AQGYAgGgAuYBmAMAkgcDMi0xoAfMBLIHAzItMbgH5gHCBwMyLTHIBwU&sclient=gws-wiz
    • GTSBoy
      Blue slip

      By GTSBoy · Posted

      South Australia, which is hardly as far behind as the rest pf Oz makes out, and who is also not a paragon of progressiveness (read that as over-legislation) in the area of vehicle standards, has this to say on the subject: Adjustable coil-over suspension Aftermarket adjustable coil-over suspension components are suspension units that incorporate an external thread on the main body and corresponding threaded spring saddle that allows the vehicle's suspension height to be varied. If fitting aftermarket or coil-over suspension components you must submit an Application to modify a light motor vehicle form and a report from a light vehicle engineering signatory (LVES).
    • bilbo117
      R34 GTR Seats / No longer reclining

      By bilbo117 · Posted

      Hi all, Long time since I've posted here. Looking for some advice on what I can remove to further identify the cause of my issues.  I can move the passenger seat forward and back but the knob used to adjust the seat angle is pretty much free spinning, there's very little resistance.  Removing the side cover I can see that the chain is intact but the shaft for the adjustment spins without the gear attached to it moving.  What's my next step for disassembly here? Is this a common fault? Just being a little cautious as I didn't want to start removing bolts for a spring to fly out or something equally as stupid.  Cheers
    • Dose Pipe Sutututu
      Ethanol Content Sensor - Always at 11%?

      By Dose Pipe Sutututu · Posted

      Those above shitboxes, mediocre and above usually have a turbo strapped to them, hence the slightly higher octane is required.  
×
×
  • Create New...