Jump to content
SAU Community

Recommended Posts

ey guys,

did a compression test today, however, i disconnnected every hose when i removed the intake manifold and removed all the spark plugs, then i performed the compression test.

Cylinder:

1. 146 PSI

2. 145 PSI

3. 147 PSI

4. 145 PSI

5. 146 PSI

6. 145 PSI

i dunno wat the go is.. And is this the way u do a compression test or not? by removing all park plugs and then cranking it?

Link to comment
https://www.sau.com.au/forums/topic/146595-compression-test-for-rb20det/
Share on other sites

ok....so keep all plugs in, take one out, test it, then put it back it, then take the next one out and test it yer? do i loost compression when all spark plugs r out? coz i just cranked it till it popped...

Depends on how your gauge reads dude. A lot of low qual gauges about that read way off.

Also rb20 donk is fairly low comp I'd expect 130 - 150.

You look more for variation. The readings on your engine are awesome !!

around 150psi is normal for the age the engine,manual specifies 170psi with the limit value (lowest) 128psi, the variance limit shouldnt be more than 14psi beween cylinders

u should have the engine close to operating temp at least, remove ALL plugs, attach gauge to cylinder (screw fitting is the better ones), depress pedal FULLY u must have WOT, crank till needle stops moving which should be about 7 engine revolutions, then record ur readings,

urs seem good not much variation which is good

im not sure if the readings will be lower or higher when stone cold as i have only done it when at operating temp.

maybe someone can verify that as my engine is not finished yet to be running

cheers,

brad

Edited by RB20/30Det_VL

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


  • Similar Content

  • Latest Posts

    • Here's the chart for fuel pressure vs. current draw, assuming your base fuel pressure is 3 bar and you run like 0.5bar boost on WOT, you should only momentarily hit 9amps here and there. (Ignore my prev post, I cannot read a chart these days it seems)
    • Those comp test results are not hideous. Whether they are accurate or not (ie, when that comp tester says 140 psi, is the real pressure120, 140 or 160?) is unknown to us. The state of the battery used to crank it over is unknown, etc etc. Many people around here would say that the absolute values and the spread are perfectly fine to just add boost and keep going. I personally would be happier with a narrower spread than that, but even the diff between 125 and 145 is not terrible. That one cylinder at 125 though, has probably copped some damage relative to the others. You should inspect the valves seeing as you've got it open. Do you know how to measure installed ring gaps? That, and an inspection of the rings themselves, is how you will determine whether they need to be replaced. If you're not good to do these things, take the block and the pistons and rings to a shop that is, and ask them for the go/no-go on them. Do the bores need a hone at all? If so, you might well be justified in getting some different pistons in order to get away from the ring supply problem. Whether you're happy to spend a lot more money right now, on more gear, rather than less money, but an amount that looks stupid given that you will only get a handful of rings in exchange for that money, is for you to decide.
    • also possibly backed up to my filler and shat down it! 🤣
    • Ok so i would love some advice here please, i purchased an R33 a few months back and its had a few mods done to the engine, its an RB25det running a Master ECU, 1200cc injectors, bigger turbo, oil cooler, oil filter relocation kit, Spool H-beam rods, acl/ross pistons. When i removed the motor from the vehicle (as its getting a respray) i thought i would compression test it and these are the following results. Cylinder 1-145psi, Cylinder 2-143psi, Cylinder 3-125psi, Cylinder 4-145psi, Cylinder 5-140psi, Cylinder 6-135psi this test was done with the motor on the ground and powering up the starter motor. I dropped the sump and found broken oil squirters on cylinder 3,5 and 6. I was told my rings are probably worn so i stripped the motor completely to get a new set of rings for it. The trouble is no one has these rings anywhere and they have to be custom made by Ross over in the states and will cost about $600+$200 delivery. My question is how can i tell if my rings are at fault and if they are still ok and is this price ok for a set of rings?
    • What sold me on Trailer Park Boys is this scene: Great stuff, just stay clear from the new Netflix production.
×
×
  • Create New...