What numbers should I get when compression testing an rb20det???

[mgp87zxt]

I am sure its on this site but it wont let me search right now.

Thanks

[boost_boy]

Anything less than 140psi per cylinder, I would become suspect of a not so healthy engine.

Dee

[Nameless EJ6]

It doesn't matter what the number is.. as long as it's consistent. If it's incredibly low on all cylinders, likely your gauge is screwed up..

[PROJECTRB240SX]

I PULLED 145 - 160 ON ALL CYLINDERS

[boost_boy]

Quote »It doesn't matter what the number is[/quote] Unfortunately, this is just not true and any engine builder will say the same. So I guess it's cool to be running around with 50psi for all 6 cylinders! Even from factpry, they have their limitations on what's acceptable and what's not acceptable. Just because they're consistent, doesn't mean it's acceptable. If any of these twin cam motors especially the RB and CA series fall below 140psi, you had best believe that you will be having unusually high crankcase pressure and a lot of oil building up in your catch can.

Dee

[crxcess]

it also depends on the variables too could be a hot test, cold , wet, dry...etc.

[Nameless EJ6]

Unfortunately, this is just not true and any engine builder will say the same. So I guess it's cool to be running around with 50psi for all 6 cylinders! Even from factpry, they have their limitations on what's acceptable and what's not acceptable. Just because they're consistent, doesn't mean it's acceptable. If any of these twin cam motors especially the RB and CA series fall below 140psi, you had best believe that you will be having unusually high crankcase pressure and a lot of oil building up in your catch can.

Dee

Don't overlook my post on this or anything. If you have 60psi on all cylinders.. your gauge is 99% likely to be screwed up. I said that. ANY real technician, not engine builder, could tell you this. I keep more than one set of compression kits in my toolbox for verification purposes. Why? Because too many people these days rely on compression numbers to diagnose their engine troubles. Leak down testers is where you make the diagnosis.

btw, I'm telling you this from experience, not books.